# Subwoofer Setup Made Simple?



## Lumen (May 17, 2014)

Some of you have given me pointers on setting up a sub, and I'm very appreciative. Thanks for putting up with my antics. :R Positioning and orientation with respect to nearby surfaces is key. *Also key is getting the sub and mains to politely hand off bass duties at the traditional 80Hz crossover frequency. It's that last part I still need help with. * 

I've tried to find out more on the topic, but the more I read the more confused I get. Here a but a few examples of suggestions that have crossed my wandering path:
 Play a tone at the crossover frequency, and measure its SPL. While you're playing the tone, adjust the sub's phase control and watch the level. Set the control for maximum output. Essentially, the phase shift creates a peak which serves to raise the valley at the crossover frequency. Paraphrased from this thread.
The best approach is to seal the ports, operate the 5 channels as "small", crossover at 80 (or even a bit higher, but NEVER lower) and correct the timing issues inherent in all modern subs by setting ALL the distances THE SAME, and to a small number such as 7 feet; then set the sub to 12 feet MORE and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point. Paraphrased from this white paper.
If you have 2 LF sources of differing phase relationships and/or timing relationships they will cancel. Period. And if they are "in phase", but 1, 2, 3 or more wavelengths shifted (that means 360 or 720 degrees out of phase), then the overall frequency response will not seem bad but the impulse response and clarity and focus will be smeared, and localization and imaging will be lost. _This is the main reason measuring in the frequency domain especially in a home-sized room is such an incredible waste of time._ Your measurements "seem" pretty flat and yet you don't like the end result - isn't as "clear" as you think it should be, and it isn't as focused as you think it should be. The issue is ONLY timing! Paraphrased from this white paper.

*Item-1 begs the questions:
(a) Do you play the tone through the sub+mains? 
(b) Should crossover frequency be trimmed as well? 
(c) I think the adjustments should be made after any auto-EQ/correction but I would like your feedback to be sure.*

Item-2 is only useful if your room correction software allows distances to be changed. I have Dirac, which handles those chores by itself (a disadvantage in this case).

Item-3 paints a bleak picture of climbing impulse-response learning curves and imposes worries of time-smeared bass! Oh my.


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## Savjac (Apr 17, 2008)

No one has really asked my opinion but as always I have one.
Dont Overthink This.

Run your front speakers full range and let them melt away as the normally do. The THX recommendations seem to cover smaller speakers and sub-woofer, not to mention a day when large amplifiers were hard to come by....this is my belief, not industries. 

Then grab several of your favorite tunes, not too many, and play them. Go through a couple to get good and familiar then make a change in crossover and volume until you feel that the sound melds as best as possible. You will have to go past the sound of great to the sound of icky and then back again slowing closing in on Great again. 

Find the sound of great on the most recordings and sit back and relax. One of our problems is that we are phobes, and many things cannot be right and just as we get to a place of goodness, we feel something is wrong because we cannot measure it or define it. 

I found a decent balance in your room by means of trying things over time and while you may forget but you were all jiggly when things sounded pretty good. Minor changes were all that was needed, and you can do it. If not I WILL.
Take that.


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## willis7469 (Jan 31, 2014)

Hey Lou. Got 2 sec. 
A) yes
B) see what rew sez. Adjust to taste. 80 is mostly good but I've run at 40 and 50 also. 
C) yes. 
Good luck buddy.


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## Savjac (Apr 17, 2008)

...or you could take advantage of the modern day tools and do what Willis says 

I am such an old dork


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## Lumen (May 17, 2014)

Savjac said:


> ...Dont Overthink This.
> 
> Find the sound of great on the most recordings and sit back and relax. One of our problems is that we are phobes, and many things cannot be right and just as we get to a place of goodness, we feel something is wrong because we cannot measure it or define it.
> 
> ...


If only I could, Jack. If only I could. But I can't leave it alone. As long as I keep learning about new issues and techniques, the system will have room for improvement. It is the nature of my beast. I am sorry. Take comfort in the knowledge that your advice falleth not on deaf ears. Some fine tuning needs a heavy objective hand, while some more favorably lends itself to a subjective touch. 

A paraphrased passage from the aforementioned white paper seems appropriate here:
_Notice that some humans actually LIKE the fattening up of the bass loudness envelope in time. Therefore even IF your sub is 12 msec late, and you are one wavelength off, as long as you get that delayed wavelength to line up with the bass coming out of your mains, your frequency response will be pretty good and you won't have any awful objections, again, assuming you get as much else right as possible._


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## Lumen (May 17, 2014)

willis7469 said:


> Hey Lou. Got 2 sec.
> A) yes
> B) see what rew sez. Adjust to taste. 80 is mostly good but I've run at 40 and 50 also.
> C) yes.
> Good luck buddy.


Thanks, and that was 2.5 sec (I'm a little out of phase today) :gulp:


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## Lumen (May 17, 2014)

Savjac said:


> ...or you could take advantage of the modern day tools and do what Willis says


My dear Jack. I should have better explained myself. Even though the latest application of room correction yielded a subjectively pleasing result, there is something still significantly wrong with the presentation.
A very short but audible delay exists between the sub and mains. Not enough to generate a distinct echo, but enough to be disturbing. It took a while to lay a finger on what sounded wrong. This is a delay/timing issue which can be remedied either by adjusting physical distance (Dirac has no adjustments for that), or by adjusting the sub's Delay Control.

Certain bass lines drop out and certain low frequencies wander or grow larger/smaller. According to my REW measurements, the frequency range of concern is between about 55 and 75 Hz as shown below by the brown line. The sharp dip at around 96 Hz is indicative of a room mode, so won't respond to EQ (I shall double-check that). Apologies for the similar colors; I know not what came over me!

*FR Sub+Mains: Purple = Before Dirac ; Brown = After Dirac*


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## Savjac (Apr 17, 2008)

I understand now Lou, thank you for taking the time to spell it out.

I am not sure how to read the graph as yet, but that dip after the application of Dirac seems kind of hearty. As far as time delays, that seems to be very interesting. I guess I would have assumed that there would be some delay or difference as the sub and mains are in two different plains. Hey I made a rhyme. I look forward to your further findings on this issue.


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## Lumen (May 17, 2014)

Savjac said:


> I understand now Lou, thank you for taking the time to spell it out.
> 
> I am not sure how to read the graph as yet, but that dip after the application of Dirac seems kind of hearty. As far as time delays, that seems to be very interesting. I guess I would have assumed that there would be some delay or difference as the sub and mains are in two different plains. Hey I made a rhyme. I look forward to your further findings on this issue.


I would rather not appear to have a working knowledge of subwoofer integration in its entirety, so please take what I say with a grain of salt. I am not alone in thinking that the topic of subwoofer time alignment (or any speaker/driver alignment for that matter), is one shrouded in mystery and technobabble. It almost makes me want to write a simple guide; we could call it _The Hitchhiker's Guide to the Sub-Inverse_! During the short opportunity I've had to thus far research the topic, I've encounter many members of our own forum who have struggled as I did to even define the issue. As the saying goes: "I believe I know enough to be dangerous!" I'm counting on at least one of our more experienced members to chime in if I post anything misleading. 

It's my understanding that yes, the real-world physical separation between sub and mains results in a measurable delay in arrival time of the sound at the LP. If the delay is severe enough it can skew the presentation as lower frequencies from the sub (and its port if any) combine with others from the mains (and their ports if any). Add to this reflections from room boundaries, and the result becomes even more distorted. While auto-EQ can correct for many frequency response and distance anomalies, it only applies to a single sweet spot and usually doesn't account for time-domain behavior. Hence the need for post-processing measurement. Some time domain characteristics can be analyzed using frequency domain data. Group delay derived from the measured FR is one example. But most time-domain work is accomplished by interpreting and manipulating IR or Impulse Response. The solution to full time-domain integration (as I understand it) involves adding a post-processor such as a miniDSP 2x4 or Behringer Feedback Destroyer to handle the proper delays and tweak EQ. 

EDIT: 
Compared to using the bass management built into your AVR, the advantages of (some) miniDSP products for bass management and/or post-processing are:
Precise control over the slopes and frequencies of the low pass and high pass filters
Steeper filter slopes (up to 48 dB/octave)
Ability to fine-tune every single channel independently
More accurate subwoofer-speaker integration by using nanoAVR features like time delay
Combined with measurement and equalization, a much more accurate system!


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## Lumen (May 17, 2014)

At this time, I'd like to credit the others who have helped thus far in clearing the, ahem... Muddy Waters of subwoofer integration. The following list is NOT all-inclusive so feel free to add on. Here in no particular order, are my current resources and references:
AudiocRaver
jtalden
JohnM
HTS Thread: Time-Alignment
HTS Thread: Aligning Driver Phase
HTS Thread: A Few Time Alignment Questions
HTS Thread: Audyssey vs Dirac Single Mic Test
miniDSP Article: Subwoofer integration with miniDSP (condensed version)
miniDSP Article: Subwoofer Equalization and Integration with the miniDSP 2x4 (detailed version)


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## Savjac (Apr 17, 2008)

I see this time alignment and filtering stuff requires math usage and I am mathematically dyslexic to be sure. I have printed out the REW manual and will head to the jackcave to see what I can cipher

BTW: I would buy your book.


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## AudiocRaver (Jun 6, 2012)

Not right on topic but related:

Here is a very slow continuous (no frequency jumps) sweep with precise frequency readout that can help one hear localization issues, mainly useful at sub/bass frequencies - judging anything with sine waves by ear above 120 or so is folly, and below that should be taken with a grain of salt. My sub is to the side with crossover at 60, I can hear its direction with this sweep, not with music. It might be a useful crosscheck.


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## Lumen (May 17, 2014)

AudiocRaver said:


> ....Here is a very slow continuous (no frequency jumps) sweep with precise frequency readout that can help one hear localization issues, mainly useful at sub/bass frequencies...


Now that is so  (especially the readout)!
I have a test CD with 1Hz increments from 10 to 400 Hz, but it's unwieldy because you have to decipher the time-stamp to identify the currently playing tone.


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## willis7469 (Jan 31, 2014)

Audio Function Generator PRO by Thomas Gruber
https://appsto.re/us/pgCw1.i

Hey Lou. Check this app out. 
I'll check in later.


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## AudiocRaver (Jun 6, 2012)

willis7469 said:


> Audio Function Generator PRO by Thomas Gruber
> https://appsto.re/us/pgCw1.i
> 
> Hey Lou. Check this app out.
> I'll check in later.


Nice. The price is right. Except it requires an i-thingy.:rolleyesno:


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## Lumen (May 17, 2014)

AudiocRaver said:


> Nice. The price is right. Except it requires an i-thingy.:rolleyesno:


With sincere respect Mr. Wayne, sir, 
.
.
.


Sent from my iPad using HTShack


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## Lumen (May 17, 2014)

AudiocRaver said:


> .... judging anything with sine waves by ear above 120 or so is folly, and below that should be taken with a grain of salt. My sub is to the side with crossover at 60, I can hear its direction with this sweep, not with music. It might be a useful crosscheck.


I'm having trouble here; please help me understand. The sweep makes a useful cross check against ____________________? I mean, if you notice the sub's direction only with test signals, then why would a cross-check matter? Not trying to start an S vs. O debate, just trying to learn!

Sent from my iPad using HTShack


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## willis7469 (Jan 31, 2014)

AudiocRaver said:


> Nice. The price is right. Except it requires an i-thingy.:rolleyesno:


 lol! That's true but Lou has one. I use AirPlay with it. WAY easier than disks/YouTube etc.


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## willis7469 (Jan 31, 2014)

BlueRockinLou said:


> With sincere respect Mr. Wayne, sir, . . .  Sent from my iPad using HTShack


 lol!


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## Lumen (May 17, 2014)

AudiocRaver said:


> Nice. The price is right. Except it requires an i-thingy.:rolleyesno:


Your our daily-double winner! You're exclamation has been quoted over 1,000 times. You win 2,000 gallons of snake-oil :bigsmile:

Seriously, some people have an aversion to all things "Apple"
Not that there's anything wrong with that :rofl:


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## Lumen (May 17, 2014)

Hope I didn't go overboard with that.


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## willis7469 (Jan 31, 2014)

BlueRockinLou said:


> Hope I didn't go overboard with that.


 lol. I want some snake oil!!!
Fwiw, I enjoy my apple devices Lou.


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## Chromejob (Feb 19, 2015)

I have iOS and Android devices. They each have strengths and weaknesses. Frankly, the iOS devices are better for recreation, the androids for work.


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## Lumen (May 17, 2014)

Chromejob said:


> Frankly, the iOS devices are better for recreation, the androids for work.


Perfect, I'm lazy at heart! :whistling:


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## vidiot33 (Dec 12, 2013)

BlueRockinLou said:


> Some of you have given me pointers on setting up a sub, and I'm very appreciative. Thanks for putting up with my antics. :R Positioning and orientation with respect to nearby surfaces is key. Also key is getting the sub and mains to politely hand off bass duties at the traditional 80Hz crossover frequency. It's that last part I still need help with. I've tried to find out more on the topic, but the more I read the more confused I get. Here a but a few examples of suggestions that have crossed my wandering path: [*] Play a tone at the crossover frequency, and measure its SPL. While you're playing the tone, adjust the sub's phase control and watch the level. Set the control for maximum output. Essentially, the phase shift creates a peak which serves to raise the valley at the crossover frequency. Paraphrased from this thread. [*]The best approach is to seal the ports, operate the 5 channels as "small", crossover at 80 (or even a bit higher, but NEVER lower) and correct the timing issues inherent in all modern subs by setting ALL the distances THE SAME, and to a small number such as 7 feet; then set the sub to 12 feet MORE and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point. Paraphrased from this white paper. [*]If you have 2 LF sources of differing phase relationships and/or timing relationships they will cancel. Period. And if they are "in phase", but 1, 2, 3 or more wavelengths shifted (that means 360 or 720 degrees out of phase), then the overall frequency response will not seem bad but the impulse response and clarity and focus will be smeared, and localization and imaging will be lost. This is the main reason measuring in the frequency domain especially in a home-sized room is such an incredible waste of time. Your measurements "seem" pretty flat and yet you don't like the end result - isn't as "clear" as you think it should be, and it isn't as focused as you think it should be. The issue is ONLY timing! Paraphrased from this white paper. Item-1 begs the questions: (a) Do you play the tone through the sub+mains? (b) Should crossover frequency be trimmed as well? (c) I think the adjustments should be made after any auto-EQ/correction but I would like your feedback to be sure. Item-2 is only useful if your room correction software allows distances to be changed. I have Dirac, which handles those chores by itself (a disadvantage in this case). Item-3 paints a bleak picture of climbing impulse-response learning curves and imposes worries of time-smeared bass! Oh my.


Since I've been spending a lot of time studying and working on this very issue, I will weigh in.
1. Regardless of the capabilities of your speakers, do not set a lower crossover than 80 Hz.
2. Specify an equal distance for all your speakers , except subwoofer.
3. Unless your sub is very close to your speakers, set its distance as between 18-20 ft ( this is to begin to approximate proper phase).
4. Find an 80 hz test tone ( calibration CD or even YouTube)
5. Set your mains, one at a time, to reproduce the 80 Hertz tone at 75 db ( need a sound pressure level meter to do this)
6. Play the tone using only your subwoofer and set it to reproduce the same 80 hertz tone at 75 db.
7. Sit at your listening position, set up your SPL meter, and play the tone again through the subwoofer. Have an assistant slowly adjust the sub's phase control until it reproduces the 80 hz tone the loudest.

Sent from my iPhone using HTShack


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## vidiot33 (Dec 12, 2013)

vidiot33 said:


> Since I've been spending a lot of time studying and working on this very issue, I will weigh in. 1. Regardless of the capabilities of your speakers, do not set a lower crossover than 80 Hz. 2. Specify an equal distance for all your speakers , except subwoofer. 3. Unless your sub is very close to your speakers, set its distance as between 18-20 ft ( this is to begin to approximate proper phase). 4. Find an 80 hz test tone ( calibration CD or even YouTube) 5. Set your mains, one at a time, to reproduce the 80 Hertz tone at 75 db ( need a sound pressure level meter to do this) 6. Play the tone using only your subwoofer and set it to reproduce the same 80 hertz tone at 75 db. 7. Sit at your listening position, set up your SPL meter, and play the tone again through the subwoofer. Have an assistant slowly adjust the sub's phase control until it reproduces the 80 hz tone the loudest. Sent from my iPhone using HTShack


On point 2, 7 feet is a good distance to set all your speakers except subwoofer. The reason for doing this is to get them in phase with each other and later, with the subwoofer.
Don't see a way to make it any simpler than this. Properly done, this will make everything sound better, not just the bass. As a bonus, it reduces or eliminates subwoofer localization issues. Best of luck!

Sent from my iPhone using HTShack


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## AudiocRaver (Jun 6, 2012)

BlueRockinLou said:


> I'm having trouble here; please help me understand. The sweep makes a useful cross check against ____________________? I mean, if you notice the sub's direction only with test signals, then why would a cross-check matter? Not trying to start an S vs. O debate, just trying to learn!
> 
> Sent from my iPad using HTShack


What I meant to say was that the sine wave sweep can help point to potential localization issues, but to take it with a grain of salt, and to use music or movie content to determined if there are real problems or not. A music track with a "walking bass" line is a good real world test to verify with. The complex tones and sound effects of typical program material will be somewhat more forgiving than the sine sweep.

And my sincerest apologies to all for the Apple comment. I truly have no malice toward their wares whatsoever, I am simply not a user. Hopefully the comment was taken as the lighthearted jest I intended it to be.


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## Lumen (May 17, 2014)

AudiocRaver said:


> And my sincerest apologies to all for the Apple comment. I truly have no malice toward their wares whatsoever, I am simply not a user. Hopefully the comment was taken as the lighthearted jest I intended it to be.


Never doubted your high integrity, Wayne!


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## chashint (Jan 12, 2011)

I thought accurately setting the speaker distance to the MLP was to phase align the speakers.
How does setting all the speakers distance to '7ft' create phase alignment at the LP?


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## Lumen (May 17, 2014)

chashint said:


> I thought accurately setting the speaker distance to the MLP was to phase align the speakers. How does setting all the speakers distance to '7ft' create phase alignment at the LP?


I honestly don't know, Charlie. A 7ft wavelength corresponds to 161 Hz - not much help, I know. Here's a thread that tries to explain the difference between phase and distance. http://www.avsforum.com/forum/113-subwoofers-bass-transducers/1480094-phase-vs-distance.html. My take on all this is that the intention is to treat all speakers the same to eliminate variability while the subs phase is aligned with the rest of the system as a whole. Then you would go back and set distances accurately. Because phase and delay are not the same entity in terms of sub integration, the method works. Just a guess on my part.

Sent from my iPad using HTShack


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## willis7469 (Jan 31, 2014)

Doesn't make sense to me to set them all at 7' feet either. 1) why 7' as opposed to any other arbitrary number? Why not 12'? 2) when audyssey sets distances, even if they differ from the actual physical distances, I think it's common to accept the settings because that's what audyssey sees from the mic. As for phase vs delay, I like to use the phase knob for mains integration, and multiple sub phase matching. I use delay for trying to tidy up impulse response. They may be more closely related than I'd like to admit. Semantics? Works for me.


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## vidiot33 (Dec 12, 2013)

willis7469 said:


> Doesn't make sense to me to set them all at 7' feet either. 1) why 7' as opposed to any other arbitrary number? Why not 12'? 2) when audyssey sets distances, even if they differ from the actual physical distances, I think it's common to accept the settings because that's what audyssey sees from the mic. As for phase vs delay, I like to use the phase knob for mains integration, and multiple sub phase matching. I use delay for trying to tidy up impulse response. They may be more closely related than I'd like to admit. Semantics? Works for me.


 I would refer you to the soundoctor at soundoctor.com. The advice to set all speakers the same distance was also in the manual for the Outlaw ICBM active crossover which I use in my system to manage crossovers for my 7.1 system and 4 Rythmik servo subwoofers (2 for low bass and 2 for mid bass).

Sent from my iPhone using HTShack


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## willis7469 (Jan 31, 2014)

Thanks vidiot33. I am browsing sound doctor.com now. I'm not finding the advice for using the same distance for all speakers. While I dig, could you elaborate on why the recommendations for this, and why 7' was your number. Just looking for insight into a recommendation I haven't seen before. IOW, what's the nuts and volts? (Couldn't help that)


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## vidiot33 (Dec 12, 2013)

willis7469 said:


> Thanks vidiot33. I am browsing sound doctor.com now. I'm not finding the advice for using the same distance for all speakers. While I dig, could you elaborate on why the recommendations for this, and why 7' was your number. Just looking for insight into a recommendation I haven't seen before. IOW, what's the nuts and volts? (Couldn't help that)


 In the soundoctor site under the category "test CD" you'll find his suggestion about the 7 feet, although he stresses it's an arbitrary value, the main point is to set all your speakers to this distance. I bought his test CD and I'm looking forward to using it to help dial in my rather complex setup.

(
"(action=_highlightLongPressRecognized:, target=<UIWebDocumentView 0x17aa4000>)"
)


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## AudiocRaver (Jun 6, 2012)

If I understand it correctly, the distance setting we are talking about is a starting point, and Audyssey/Dirac does "fine tuning" from there. That fine tuning might be tenths of microseconds or it might be many milliseconds (apparently, the limits are not published). So, apparently, the "fine tuning" delta can be from any chosen reference distance setting.

That being the case, I do not see that it matters what the reference distance setting is. Using a number you can easily remember makes it easier to check after a calibration to see if Audyssey has messed with it. My rule of thumb is that if Audyssey has changed it in the process of running a calibration, change it back to your setting and see if the sound with that setting makes sense in SS&I terms. If it does not, you have to re-run the calibration. If in doubt, re-run the calibration (the simplest rule of thumb is: if the distance was changed by Audyssey, re-run the calibration).

It might be that 7 feet is a good midpoint in the range over which Audyssey can vary the distance/delay internally. If so, then 7 feet is a good number to use. I suspect that it is arbitrary and one may pick a number that is easy to remember and/or work from.


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## Lumen (May 17, 2014)

vidiot33 said:


> ...7 feet is a good distance to set all your speakers except subwoofer.





chashint said:


> I thought accurately setting the speaker distance to the MLP was to phase align the speakers.
> How does setting all the speakers distance to '7ft' create phase alignment at the LP?





willis7469 said:


> ...why 7' as opposed to any other arbitrary number? Why not 12'?


Not to discount Wayne--and not to contradict him--the passage in the soundoctor article that references the 7 foot distance is:

_"There is ONLY ONE truly correct way to "add a sub" to a (stereo) system in an controlled listening room situation: you must correctly cross over the 2 sealed cabinets; and their timing must be correct. ANY other method will lessen the focus and clarity you have tried so hard to preserve. A similar situation exists with home theater setups where the customer THINKS that the front speakers are "full range". Even so, the BEST approach is to seal the ports, operate the 5 channels as "small", crossover at 80 (or even a bit higher, but NEVER lower) and correct the timing issues inherent in all modern subs by setting (in the receiver or processor's setup menu) ALL the distances THE SAME, and to a small number such as *7 feet*; then set the sub to 12 feet MORE (i.e. 19 feet) and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point."_

The driving force behind that reasoning is to treat the sub as one "driver" in a 2-way speaker, and all the other channels as the other "driver":

_"The ONLY correct way to add a sub to system is to define everything ABOVE the sub's range as an entity; clearly define the impulse, phase, and lastly frequency response of this entity; and then make a new "2-way" system where the sub is one way and everything above it is the 'other' way. The parts must be combined correctly so that there are no cancellations and no smearing of time-related musical events.

This CANNOT be easily measured in the frequency domain, because you could have (as an example) an 80 Hz signal coming from both the mains and the sub, and if the sub is 12.5 msec late the two sources will "seem" to be in phase but the sub really will be 360 degrees late. It is the impulse smearing that this affects, but people don't measure that because there is no simple "hand held" phase or impulse meter as there is an SPL meter. The REASON this meter does not and essentially can not exist is in order to measure impulse response or phase response you need a starting REFERENCE point..."_


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## AudiocRaver (Jun 6, 2012)

Thanks for the info, just trying to make sense of it all.

If all drivers excluding the subs are equidistant from the LP, and if all distance settings are set to the same number, then all the drivers can be considered "a single driver" in timing terms. If they are different distances from the LP - hopefully mains are the same distance, but surrounds often vary for practical reasons - then their signals will NOT be arriving at the LP at the same time unless (1) the distance settings are used to COMPENSATE for those differences with appropriate precision, and/or (2) the DRC program (Audyssey, Dirac) does that compensation, which they DO with or without the help of item #1.

Setting the distance settings to an equal number does nothing magical unless it represents the actual speaker to LP distances, it is arbitrary and purely for easily remembering what the number should be, or for possible later calculations.

Not saying not to do it, just don't assume it means more than it does.

The ONLY way to have all signals from all drivers arriving at the LP simultaneously is to have drivers equidistant from the LP, or have the timing from varying distances compensated for _with appropriate precision - usually not the case with distance setting alone._


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## vidiot33 (Dec 12, 2013)

Another point in this whole discussion. Audyssey calibration has taken on iconic, nearly epic proportions. However, the main benefit to any auto correction system is in the lower frequencies. Audyssey can't compensate for poor speakers, poor speaker positioning, an acoustically poor room or listening position. In my view, much of what it does in the upper frequencies is largely inaudible, with the exception of some taming of the upper frequencies on some curves.
Try an experiment: set your speaker distances all to 7 ft, listen to some familiar material, then apply the Audyssey distances and see if you can detect a difference with the same material and volume level. More attention needs to be paid to proper room treatments, speaker and listening positions and good source material. Personally, I no longer use Audyssey, but caljbrate my 4 subs with DSpeaker software, with what I believe to be great results. Obviously, YMMV.

Sent from my iPhone using HTShack


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## Savjac (Apr 17, 2008)

AudiocRaver said:


> Thanks for the info, just trying to make sense of it all.
> 
> If all drivers excluding the subs are equidistant from the LP, and if all distance settings are set to the same number, then all the drivers can be considered "a single driver" in timing terms. If they are different distances from the LP - hopefully mains are the same distance, but surrounds often vary for practical reasons - then their signals will NOT be arriving at the LP at the same time unless (1) the distance settings are used to COMPENSATE for those differences with appropriate precision, and/or (2) the DRC program (Audyssey, Dirac) does that compensation, which they DO with or without the help of item #1.
> 
> ...


I believe this to be true. 7' seems quite arbitrary and not needed in these cases. If one is to use a room correction software then it will handle the differences in distance internally. I find it very difficult to think of placing a sub in a location which will render it the same distance from any speaker in the room, rather place the sub wherein it provides the best sonic responses and they add the audyssey for delay.


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## FargateOne (Mar 3, 2015)

Well, now I am a little bit confused.
I thought that it is better to let the EQ to set the relative distances between fronts and sub. For instance, YPAO set my fronts to 2,75m from MLCP which is right on the spot and 5,40m for the SVS PC 2000. Doing so time delay are correct is'nt it?
This sub has a phase control (0 to 180 degrees). The owner manual indicates:
_Phase Control
This control delays the signal being processed through the amplifier. For
connection to an A/V receiver, it should be set to 0 degrees. For 2-channel
applications, it should be adjusted to obtain the most coherent and stable
soundstage and transition between the loudspeakers and the subwoofer_

Are you suggesting that with HT 5.1 I must adjust also the phase to get good transition ? I set my xover to 110hz by ear and try to find a way to check it if it is the best.


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## kingnoob (Mar 12, 2013)

Yeah my room is tiny, and my sub is stuck in its spot. Thankfully SI HT 15" is so loud placement is not an issue with this sub.
Center of the room almost , works the best lowest distortion.


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## Lumen (May 17, 2014)

kingnoob said:


> Yeah my room is tiny, and my sub is stuck in its spot. Thankfully SI HT 15" is so loud placement is not an issue with this sub.
> Center of the room almost , works the best lowest distortion.


Actually, the center of the room is the WORST spot because it has overlapping nulls. Placing a sub in that position will result in reduced and uneven bass. Almost the same with playing loud; doesn't change nulls or uneven response.

But... if you're happy, then don't worry! :bigsmile:


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## kingnoob (Mar 12, 2013)

Lumen said:


> Actually, the center of the room is the WORST spot because it has overlapping nulls. Placing a sub in that position will result in reduced and uneven bass. Almost the same with playing loud; doesn't change nulls or uneven response.
> 
> But... if you're happy, then don't worry! :bigsmile:


Yeah room is rather small, Only spot I can fit the 15" . Otherwise I gotta get rid of a dresser.


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## Lumen (May 17, 2014)

Or... Sub on top of dresser (lol)! I really do feel your pain. I'm in the Small HT Club myself.

Sent from my iPad using HTShack


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## Lumen (May 17, 2014)

FargateOne said:


> Well, now I am a little bit confused. I thought that it is better to let the EQ to set the relative distances between fronts and sub. For instance, YPAO set my fronts to 2,75m from MLCP which is right on the spot and 5,40m for the SVS PC 2000. Doing so time delay are correct is'nt it? This sub has a phase control (0 to 180 degrees). The owner manual indicates: Phase Control This control delays the signal being processed through the amplifier. For connection to an A/V receiver, it should be set to 0 degrees. For 2-channel applications, it should be adjusted to obtain the most coherent and stable soundstage and transition between the loudspeakers and the subwoofer Are you suggesting that with HT 5.1 I must adjust also the phase to get good transition ? I set my xover to 110hz by ear and try to find a way to check it if it is the best.


 Yes and no. It's best to let whatever flavor of auto-EQ you're running do the job for you if you just want to enjoy your system (Ignorance is bliss!), or if you're not technically inclined. But if you're a glutton for punishment and are willing to tackle the complex steps, then performing pre-EQ makes the job if auto-EQ much easier, IMO. I have no firsthand experience with pre/post EQ, so I'm unable to make a comparison. For a multichannel system, the subs phase control can be used to adjust its distance relative to the mains after auto-EQ is complete, which helps smooth the response through the crossover region. Adjustment needs to be done while playing a test signal and measuring FR (REW can do this). Sound familiar, Willis? Sent from my iPad using HTShack

EDIT: As for correct time delays? They are only as accurate as the AVRs distance resolution allows. Your above measurements indicate a 0.01m resolution at best, which equates to about 0.4ft. Not bad! As far as I know, higher end models get as good as 0.1ft resolution.


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## kingnoob (Mar 12, 2013)

Lumen said:


> Or... Sub on top of dresser (lol)! I really do feel your pain. I'm in the Small HT Club myself.
> 
> Sent from my iPad using HTShack


 Yeah Maybe I should have built a smaller box , I think mine is about the size for a ported SI HT 15, yet its sealed.


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## gdstupak (Jul 13, 2010)

"..._setting ALL the distances THE SAME, and to a small number such as 7 feet; then set the sub to 12 feet MORE (i.e. 19 feet) and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point_.

The important part doesn't seem to be setting the main/surround speakers to specifically 7', it is just supposed to be a small number.
The important part seems to be _setting the sub distance 12' more_. So you can set the main/surround speakers to 4', then the important part is to set the sub to 16'.
Why always 12' more?


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## vidiot33 (Dec 12, 2013)

gdstupak said:


> "...setting ALL the distances THE SAME, and to a small number such as 7 feet; then set the sub to 12 feet MORE (i.e. 19 feet) and THEN use the variable phase control on the sub to fine tune the relationship at the 80 Hz crossover point. The important part doesn't seem to be setting the main/surround speakers to specifically 7', it is just supposed to be a small number. The important part seems to be setting the sub distance 12' more. So you can set the main/surround speakers to 4', then the important part is to set the sub to 16'. Why always 12' more?


 The principal here is that you want all frequencies to arrive at the listening position at the same time. Bass frequencies are much longer and slower than high frequencies, so using the distance settings in your receiver/processor you can optimize their output. The 12" difference is simply a starting point. Once you've done that, play an 80 HZtest tone (the ideal crossover in most cases) through the subwoofer only and adjust the phase switch until the volume at 80HZ is maximized, measuring with an SPL meter at the listening position. This will bring coherence to your setup, virtually eliminate localization issues, and allow your system to sound as though all frequencies are emanating from a single source. Well worth doing, in my opinion. Obviously, you want to make sure your speakers and listening positions are optimized, and room treatments can help enormously. Hope this helps clarify this.

Sent from my iPhone using HTShack


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## Medi0gre (Oct 30, 2012)

Does the speed of sound change in relation to wavelength?


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## vidiot33 (Dec 12, 2013)

Medi0gre said:


> Does the speed of sound change in relation to wavelength?


 It has to do with Hertz, which is how frequency is measured. Hertz can be defined as "cycles per second." The range of human hearing is 20 HZ (the low limit) to 20,000 kilohertz, the upper limit. Bass frequencies have long wavelengths which take a number of milliseconds longer to reach the listener's ears than high range frequencies do.

Sent from my iPhone using HTShack


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## Chromejob (Feb 19, 2015)

"Subwoofer setup made simple"

Boy have we strayed off course....


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## Lumen (May 17, 2014)

Medi0gre said:


> Does the speed of sound change in relation to wavelength?


The speed of sound changes according to its propagating medium (air, water, wood, etc.) among other variables. For home theater purposes, you can generally accept the speed of sound to be 1130 ft/sec. The speed of sound is considered a constant in mathemetical terms and is related to wavelength through the equation: WAVELENGTH = SPEED OF SOUND / FREQUENCY.


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## Lumen (May 17, 2014)

AudiocRaver said:


> ...just trying to make sense of it all.


Me more than you! :dizzy:




AudiocRaver said:


> The ONLY way to have all signals from all drivers arriving at the LP simultaneously is to <snip>, or have the timing from varying distances compensated for _with appropriate precision - usually not the case with distance setting alone._


Kaaaaah=Ching! Take that to the bank! 
AFAIK, entry level receivers resolve to 0.5 ft. The better ones resolve to 0.1 ft. Does that make an audible difference? Maybe when manually setting distances and NOT running auto-EQ. But not when relying on the internal accuracy of the receiver's DSP, which as Wayne mentions, sweeps-up afterward. 




vidiot33 said:


> Another point in this whole discussion. Audyssey calibration has taken on iconic, nearly epic proportions... Personally, I no longer use Audyssey, but caljbrate my 4 subs with DSpeaker software, with what I believe to be great results. Obviously, YMMV.


Certainly! The DSPeaker models and software do help simplify matters. 
*What I'd like to accomplish is not just auto-setup made simple, but pre and post auto-setup setup made simple for subwoofers.* 




Chromejob said:


> "Subwoofer setup made simple"
> Boy have we strayed off course....


Now on with the show? :filmstrip: :bigsmile:


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## Lumen (May 17, 2014)

So far we have the following steps for simple subwoofer setup:
Location, Location, Location of speakers & sub for best LF Response and SS&I
Auto-EQ or Auto-Setup for flat FR and/or Time-Alignment
Manually tune Phase, Xover Freq, and LPF Roll-Off for smooth, non-localized transition to mains.

My current response at the LP is shown below and is the result of REW-assisted speaker placement and Dirac Live LE Full room correction (Emotiva's enhanced versionfor the XMC-1 pre/pro). The approx 6dB rise starting around 200Hz is due to baffle diffraction effect of my speaker's sharp enclosure edges. I now need to adjust phase to smooth response in the crossover region (the big dip around 80Hz).


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## Lumen (May 17, 2014)

Chromejob said:


> "Subwoofer setup made simple"
> Boy have we strayed off course....


Did I say, "Nice haircut" (same barber, you know) :R


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## AudiocRaver (Jun 6, 2012)

vidiot33 said:


> ...Bass frequencies are much longer and slower than high frequencies...


As others have pointed out, the speed of sound in air is constant. However, it is true that human perception of low frequencies is somewhat slower than that of mid and high frequencies. While I have no direct experience with it, one might end up with a more responsive bass sound by using the subwoofer distance setting to give those lowest frequencies a little head start (1 cycle?), then using phase control for integration at crossover. Is that what you mean?

This is not something I have tried or am suggesting, just exploring possibilities.

In measurement terms, it would probably make for a pretty weird-looking step response / impulse response, FWIW.


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## gdstupak (Jul 13, 2010)

vidiot33 said:


> The principal here is that you want all frequencies to arrive at the listening position at the same time.


If you set all main/surround speakers to 7', but if in reality all speakers are different distances, then the signals would not arrive at the same time.
To arrive at the same time, the speaker distances need to be set using the actual distance. If the center speaker is 2' closer than the left speaker, the distance settings need to reflect that. If the left surround back speaker is 2' further than the left speaker, the distance settings need to reflect that.


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## willis7469 (Jan 31, 2014)

gdstupak said:


> If you set all main/surround speakers to 7', but if in reality all speakers are different distances, then the signals would not arrive at the same time. To arrive at the same time, the speaker distances need to be set using the actual distance. If the center speaker is 2' closer than the left speaker, the distance settings need to reflect that. If the left surround back speaker is 2' further than the left speaker, the distance settings need to reflect that.


 exactly. My mains are at 14.5. My surrounds are at 7'. That needs compensation.


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## kingnoob (Mar 12, 2013)

Does Driver direction affect my sound? In my Sealed SI HT 4.5-5 cu foot box.
Any specific direction I should face it?
Like corner loading ? My sub got louder facing it to corner , its on the far right side. Near best spot for bass.


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## chashint (Jan 12, 2011)

After taking in everything in this thread and the one linked to from AVS the 7ft distance setting may have very good validity as a starting point.
The crossover between the sub and the speakers is the most likely spot you will hear differences/issues.
While many people choose a different crossover the most widely recommended starting point is 80Hz.
80Hz is a very good starting point, most tower speakers can easily produce this frequency and it is easily heard so you don't have to stress your sub or speakers by overdriving them with the tone.
The wavelength of 80Hz (in air) is 14ft, which makes 1/2 wavelength 7ft.
Many subwoofers have a either a 180 degree variable phase knob or two position "phase" switch (0/180) which conveniently enough switches the phase of 80Hz the equivalent of 7ft.
This phase on the sub and the distance setting in the processor is all most of us have to work with to adjust phase/time.
So knowing that 80Hz phase changes 180 degrees every 7ft and the subwoofer phase control has 180 degrees of change gives everyone a nice reference to start from.
If you are listening and trying to adjust the phase alignment by ear it doesn't really matter if the listening position is actually 7ft or not, 
You are listening (measuring SPL with a meter) and switching the subwoofer phase switch for max volume.
Then you would adjust the distance setting for each main and for the sub to achieve max volume.
Max volume should equal phase match.
Of course phase matching the sub and the speakers only addresses cancelation caused by the phase match between the sub and the speakers, it does not do anything to address issues in the room itself.


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## vidiot33 (Dec 12, 2013)

chashint said:


> After taking in everything in this thread and the one linked to from AVS the 7ft distance setting may have very good validity as a starting point. The crossover between the sub and the speakers is the most likely spot you will hear differences/issues. While many people choose a different crossover the most widely recommended starting point is 80Hz. 80Hz is a very good starting point, most tower speakers can easily produce this frequency and it is easily heard so you don't have to stress your sub or speakers by overdriving them with the tone. The wavelength of 80Hz (in air) is 14ft, which makes 1/2 wavelength 7ft. Many subwoofers have a either a 180 degree variable phase knob or two position "phase" switch (0/180) which conveniently enough switches the phase of 80Hz the equivalent of 7ft. This phase on the sub and the distance setting in the processor is all most of us have to work with to adjust phase/time. So knowing that 80Hz phase changes 180 degrees every 7ft and the subwoofer phase control has 180 degrees of change gives everyone a nice reference to start from. If you are listening and trying to adjust the phase alignment by ear it doesn't really matter if the listening position is actually 7ft or not, You are listening (measuring SPL with a meter) and switching the subwoofer phase switch for max volume. Then you would adjust the distance setting for each main and for the sub to achieve max volume. Max volume should equal phase match. Of course phase matching the sub and the speakers only addresses cancelation caused by the phase match between the sub and the speakers, it does not do anything to address issues in the room itself.


Excellent summary!

Sent from my iPhone using HTShack


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## gdstupak (Jul 13, 2010)

OK, so you make the adjustments to sound cohesive while all main/surround speakers are set to 7'. But because that's just a starting point don't you finally need to readjust the main/surround speaker distances to reflect actual distances. Wouldn't this mess up the sound?

If you say, "no, readjusting the distances wouldn't change anything," then why not just go ahead and make your initial adjustments while the speaker distances are set according to the actual distances (instead of making adjustments with the false 7' settings).
Or if you say, "you never need to change the initial false 7' settings," then all the speaker sounds will be getting to the listening position at incorrect times and that would sound wrong.

Hopefully that question makes sense.


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## chashint (Jan 12, 2011)

The original intent of the article talking about using 7ft distance setting and 80Hz crossover and tweaking around that 7ft distance was to integrate a sub into a stereo system.
If you get that set correctly the mains and the sub will be working together and should be good without needing to be adjusted to the actual distance to the listening position.
As far as adjusting the distance of the surround speakers, that probably won't matter unless you listen to music using all channels.
If that is a listening mode that you need just go through the phase matching scenario with the surrounds the same as was done with the mains with the difference being you only adjust the surround speaker distance to achieve the SPL peak with the sub.

I don't know that this method would be better than what the auto room correction does.
If you start messing with distance settings after you run the auto EQ that will pretty much invalidate the cal.

I just became interested in the method after seeing it referenced in this thread and decided to figure out if I thought it had merit.
It does, depending on what the user wants to achieve.


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## AudiocRaver (Jun 6, 2012)

gdstupak said:


> OK, so you make the adjustments to sound cohesive while all main/surround speakers are set to 7'. But because that's just a starting point don't you finally need to readjust the main/surround speaker distances to reflect actual distances. Wouldn't this mess up the sound?
> 
> If you say, "no, readjusting the distances wouldn't change anything," then why not just go ahead and make your initial adjustments while the speaker distances are set according to the actual distances (instead of making adjustments with the false 7' settings).


Making distance adjustments for mains and surrounds in the AVR after calibration WILL mess up the sound. Making distance adjustments for subs is a fairly common way to try to improve sub/mains integration.



> Or if you say, "you never need to change the initial false 7' settings," then all the speaker sounds will be getting to the listening position at incorrect times and that would sound wrong.


If the AVR distance adjustments were the only factors affecting timing, your statement would be correct. Audyssey/Dirac make additional adjustments beyond that initial setting, including extremely fine ones, that make up for the differences.

So why have the AVR adjustments at all, if Audyssey/Dirac don't need them?

For those who do not use Audyssey/Dirac.
To get the timing close so Audyssey/Dirac do not have to adjust it as far (not sure what the limits of adjustment are for either one).


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## Lumen (May 17, 2014)

AudiocRaver said:


> Making distance adjustments for mains and surrounds in the AVR after calibration WILL mess up the sound. Making distance adjustments for subs is a fairly common way to try to improve sub/mains integration.


 Thanks to all of your input, here's how I fixed the wide dip in the crossover region that prevailed even after a Dirac calibration:
Ran an REW "Check Levels" on sub+mains
Calibrated the REW SPL meter
Ran a baseline sweep through the crossover region
Incremented subwoofer "Phase" by 45 degrees
Ran a subsequent sweep with same settings
Repeated Steps 4 & 5 until reached 180 degree phase angle.
*So which Phase setting do you like???* 

*Phase=90 through 180 (sub+mains after Dirac)*







*Phase=0 and Phase=45 (sub+mains after Dirac)*


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## chashint (Jan 12, 2011)

Looks like you nailed it.
Do you hear a difference?


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## willis7469 (Jan 31, 2014)

Looks great Lou! The white whale has been landed! Now put down the test equipment and spin some Floyd. Please! Lol


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## kingnoob (Mar 12, 2013)

Are the mics for REW affordable? I still only have Audysee xt32 no mic,


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## FargateOne (Mar 3, 2015)

I have read this winter a lot on internet before to find this forum and I remember that one said that in a room all woofers (sub and speakers) must act in thesame way at the sme time (I am trying to find the web address, if I can I woill give it here) BUT, when I checked the date it was written before all PEQ (YPAO, Audyssey etc) went on the market.
If I understood correctly the theory of sound (maybe it is the problem !) I am a little bit surprise by your result, IMHO.
Lumen, is it audible?


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## Lumen (May 17, 2014)

chashint said:


> Looks like you nailed it. Do you hear a difference?





willis7469 said:


> Looks great Lou! The white whale has been landed! Now put down the test equipment and spin some Floyd. Please! Lol





FargateOne said:


> I am a little bit surprise by your result, IMHO. Lumen, is it audible?


No whales here, just Ents (LOTR). I have Ent in my bloodline. W e a r e v e r r r r y v e r r r y s l l l l o o o o w w w !
Did you know that if you play Pink Floyd backwards at 78 speed, it'll sound bad?

You guys asked the million dollar question, but I have no definitive answer at this point. I watched part of Joe Bonamassa's Muddy Wolf at Red Rocks BD in DTS 5.1 HD-MA because I'd just gotten it in the mail. If it weren't for some residual bass overhang (see the waterfall plot above), I would have thought someone swapped out my ported sub for a sealed one. Bass guitar lines were tight, and stayed on stage ( instead of fading away in the crossover region ). The return of the missing notes wasn't night-and-day, but once they were there, I knew what I'd been missing. OTOH, This was unfamiliar material, so I can't speak in general. More listening and reports on the way! Thanks again for all your help!

Sent from my iPad using HTShack


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## FargateOne (Mar 3, 2015)

Hello,
I would like to know what to think about the transition between my sub and my mains for a crossover set at 110hz. I would appreciate your help to understand my measurements.
Is this graph means something?
I used the mic of Antimode 2.0 and made a 0 to 500hz room response measurement for fronts only and fronts with the sub (volume in the sub minus 10db to match the fronts)








Any comments will be greatly appreciated.


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## kingnoob (Mar 12, 2013)

Lumen said:


> No whales here, just Ents (LOTR). I have Ent in my bloodline. W e a r e v e r r r r y v e r r r y s l l l l o o o o w w w !
> Did you know that if you play Pink Floyd backwards at 78 speed, it'll sound bad?
> 
> You guys asked the million dollar question, but I have no definitive answer at this point. I watched part of Joe Bonamassa's Muddy Wolf at Red Rocks BD in DTS 5.1 HD-MA because I'd just gotten it in the mail. If it weren't for some residual bass overhang (see the waterfall plot above), I would have thought someone swapped out my ported sub for a sealed one. Bass guitar lines were tight, and stayed on stage ( instead of fading away in the crossover region ). The return of the missing notes wasn't night-and-day, but once they were there, I knew what I'd been missing. OTOH, This was unfamiliar material, so I can't speak in general. More listening and reports on the way! Thanks again for all your help!
> ...


Good idea maybe ill watch LORT extended blu ray that is so good! I like dolby True HD.:T
I think I need more then one large sub though, when I get a bigger room.

Should I XO my sub at 100hz , or 80?? my floorstanders can go down to 33/ running them at 40hz.


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## Lumen (May 17, 2014)

FargateOne said:


> Hello,
> I would like to know what to think about the transition between my sub and my mains for a crossover set at 110hz. I would appreciate your help to understand my measurements.
> Is this graph means something?
> I used the mic of Antimode 2.0 and made a 0 to 500hz room response measurement for fronts only and fronts with the sub (volume in the sub minus 10db to match the fronts)
> ...


I'm no expert but I'll try to answer as best I can! I'm sure someone will correct me if I'm wrong. Based on what's shown (more on that in a minute), it looks like there's a dip in the crossover region. That's the same problem I had, and I'm beginning to understand it's a common problem. Willis knows, don't you Willis?! 

To get rid of the dip around 110 Hz, follow the steps described in Item-1 of Post-1, or the steps in Post-65 of this thread. Once you know how to do it, the fix seems easy, but I know it was hard to understand at first; so don't be shy about asking questions.

Before I can comment further, I'd like to see your graph in a different format. Can you please repost the graph with standard settings of 10 to 200 Hz and 45 to 105dB? Click on the icon labeled "LIMITS" to get a pop-up window (the icon is in the upper right corner of the measurements panel). The values should show up with the defaults I mentioned. If not, change them. More help is available here.. Applying variable smoothing after your measurement makes it easier to interpret.

Another Useful Tip I Learned The Hard Way: 
You can change the name of a graph by typing in the area shown on the measurements panel below (second pic).


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## Lumen (May 17, 2014)

kingnoob said:


> Should I XO my sub at 100hz , or 80?? my floorstanders can go down to 33/ running them at 40hz.


If it sounds good to you, cross your mains wherever you like. But you should cross them at 80Hz because that's how movie soundtracks are mixed in the studio (music is a different story). Also, crossing lower than 80 Hz robs the mains amplifier of power it could otherwise use for mids/highs. So headroom goes down and dynamics suffer. Surrounds can be crossed higher (especially if they're bass-limited), but not so high that you can start to localize the sub. What's too high? Generally, stay below 150Hz for surrounds.


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## Lumen (May 17, 2014)

willis7469 said:


> Looks great Lou! The white whale has been landed! Now put down the test equipment and spin some Floyd. Please! Lol


Thanks, and don't mind if I do. :highfive:


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## willis7469 (Jan 31, 2014)

Lumen said:


> Thanks, and don't mind if I do. :highfive:


 :highfive: back!


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## Chromejob (Feb 19, 2015)

kingnoob said:


> ...
> 
> Should I XO my sub at 100hz , or 80?? my floorstanders can go down to 33/ running them at 40hz.


What does that mean? Bass management cross over shouldn't be less than 80hz, and running it sub+main just invites confusion....

80, 100... Such a negligible difference, most likely.


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## vidiot33 (Dec 12, 2013)

Regardless of your main's capabilities, 40Hz is too low. 80hz is the minimum for best results.

<CALayer: 0x16605e80>


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## Savjac (Apr 17, 2008)

vidiot33 said:


> Regardless of your main's capabilities, 40Hz is too low. 80hz is the minimum for best results.
> 
> <CALayer: 0x16605e80>



I will be the "other" vote here so don't hate the Hoosier. 

There are many experts that say we should let out mains run full range and mate the subs accordingly. The mains have a crossover, usually, that will run them down to where the manufacturer feels it best to roll off bass so as to fit the speakers design. What the 80hz generalization is doing is saying that a processor in the system knows more than the designer of the speakers. If all designers thought that 80hz was the way to go then few would waste the money to go lower. Now I do understand that these ratings may be for music mainly, however, if a speaker can do music well it might just be the peach for a system of home theater components. 

As to the amp running out of power i would say that would be an issue so one needs to plan ahead. If someone is running a 5 or 7 channel system then said someone should ensure that their amplifier or AVR has the horsepower to move the air to significant levels. In general the sub will be connected via a single LFE connection and will not drain the main AVR or Amp of any power so that should not be a consideration. Granted if the HT owner upgrades speakers at some time and cannot upgrade the amp to meet or exceed the speakers need for power, the crossover would really be a home run. 

In my limited opinion there is a power zone between say 30hz and 100hz give or take a few and the power zone should be of one voice theoretically. However, it seems very proper to run the speakers as low as they can go and blend the sub and the roll offs with the speaker so when the speaker is trying to catch a breath the sub can take over with the goal being seamless. This is why I think we can really run into major changes in tone and timbre while running between these extremes of the settings are wrong. 

Just a thought to drink in this morning.


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## AudiocRaver (Jun 6, 2012)

Savjac said:


> I will be the "other" vote here so don't hate the Hoosier.
> 
> There are many experts that say we should let out mains run full range and mate the subs accordingly. The mains have a crossover, usually, that will run them down to where the manufacturer feels it best to roll off bass so as to fit the speakers design. What the 80hz generalization is doing is saying that a processor in the system knows more than the designer of the speakers. If all designers thought that 80hz was the way to go then few would waste the money to go lower. Now I do understand that these ratings may be for music mainly, however, if a speaker can do music well it might just be the peach for a system of home theater components.
> 
> ...


Was not going to say anything, but Savjac opened the door...

I fully agree that for a fine-tuned system, lower crossover frequencies should be considered, for the very reasons Jack stated. Maybe a good way of looking at it, from my own viewpoint, is:

80 Hz crossover is a very good starting point for the user who is fairly new to this arena and is looking for a safe, uncomplicated approach with assurance of pretty good results.
The more advanced user may find improved results by carefully considering further options as Savjac and others suggest.
There is rarely only one _right_ way to do anything.
My 2¢ worth.:bigsmile:


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## Savjac (Apr 17, 2008)

Agreed Craver, 80hz is a great way to start a system and then once comfortable move from there as needed, up or down.

I was thinking of the Martin Logans among other speakers that are manufactured to work as one unit from top to bottom. Any changes in the allowed frequencies fed to the speaker is a bit of a slap in the face of the designer. I can only imagine the amount of research that went into making that speaker sound as one unit, especially considering we are dealing with a vented box for the woofer and an ESL mid-top end. This speaker is a speaker that should remain un messed around with imo. 

With speakers I am using presently, it would seem a waste to throw away the 32hz low end extension and change that to 80hz. That is a lot of hz in the air no longer being used. No for me I use a crossover for the subs in way of 40hz and the blend is very nice indeed. This is done mainly using my ears but once I get the REW stuff down, I will do some sweeps and graphs a cool things like that. :T


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## willis7469 (Jan 31, 2014)

I was gonna hold back too but the door IS open. Lol
I've had great success employing 40 and 50hz crossovers. As well as 80.


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## Lumen (May 17, 2014)

AudiocRaver said:


> Was not going to say anything, but Savjac opened the door...
> My 2¢ worth.:bigsmile:





willis7469 said:


> I was gonna hold back too but the door IS open. Lol


:TT


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## vidiot33 (Dec 12, 2013)

I respect people's preferences in this discussion, but there are a number of compelling arguments for setting crossovers at 89Hz:
1. First, and I think most compellingly, the fronts are not generally positioned to give the best response for bass. I'm learning this firsthand in my own situation: I have a pair of Rythmik FMB 8's to act as mid bass drivers for my Sierra 2's, and my original position in line with the fronts was terrible for both low bass volume and extension.
2. The mains will optimize the upper and mid registers effortlessly in nearly all cases.
3. The pesky issue of phase integration is greatly simplified.
4. There is little stress on the amps so little risk of clipping.
5. Many authorities who having studied this in detail (including THX), have come to this conclusion.
I recognize that those of us with large mains and/or built in subwoofers are resistant to designating these as "small," but it's at least worth experimenting and discovering firsthand what works the best. If those with larger speakers prefer the sound in this way, then that's what they should do. But I think it's worth a little experimenting to arrive what works the best in your individual setup.

{
kCFHostNames = (
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## vidiot33 (Dec 12, 2013)

Should have been "80hz," not 89 HZ, sorry for the typo

www.hometheatershack.com


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## AudiocRaver (Jun 6, 2012)

vidiot33 said:


> I respect people's preferences in this discussion, but there are a number of compelling arguments for setting crossovers at 89Hz:
> 1. First, and I think most compellingly, the fronts are not generally positioned to give the best response for bass. I'm learning this firsthand in my own situation: I have a pair of Rythmik FMB 8's to act as mid bass drivers for my Sierra 2's, and my original position in line with the fronts was terrible for both low bass volume and extension.
> 2. The mains will optimize the upper and mid registers effortlessly in nearly all cases.
> 3. The pesky issue of phase integration is greatly simplified.
> ...


Well stated points, worthy of re-emphasizing.


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## Savjac (Apr 17, 2008)

Yes Sir Video, points well taken.
Your system is prime to take advantage of the thx standards in that the mains are not the most efficient and rolling them off high may surely help the amp. So yes I agree.

As far as having subs and speakers in the same plain, well that is not often, imo a good game to play. Speakers have their sweet spots as do subs and the two do not often match save for speakers with built in subs like the Def Techs and their kind. Although I am not sure that phase integration is built in to thx as much as some other factors. 

Lastly a big agreement on trying things !! This I have done many times and that is why I have chosen a path not necessarily described by THX as it does not work for me. 
Thank You for taking the time to post.:wave:


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## FargateOne (Mar 3, 2015)

Lumen said:


> I'm no expert but I'll try to answer as best I can! I'm sure someone will correct me if I'm wrong. Based on what's shown (more on that in a minute), it looks like there's a dip in the crossover region. That's the same problem I had, and I'm beginning to understand it's a common problem. Willis knows, don't you Willis?!
> 
> To get rid of the dip around 110 Hz, follow the steps described in Item-1 of Post-1, or the steps in Post-65 of this thread. Once you know how to do it, the fix seems easy, but I know it was hard to understand at first; so don't be shy about asking questions.
> 
> ...



Here the same measurements with horizontal axis 15 to 200hz and vertical scale of 60 dbs from -58 to + 2 db (Antimode put the target to 0 db instead of 75db) . 
And, as you can see, thanks for the tip !


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## FargateOne (Mar 3, 2015)

Lumen said:


> I'm no expert but I'll try to answer as best I can! I'm sure someone will correct me if I'm wrong. Based on what's shown (more on that in a minute), it looks like there's a dip in the crossover region. That's the same problem I had, and I'm beginning to understand it's a common problem. Willis knows, don't you Willis?!
> 
> To get rid of the dip around 110 Hz, follow the steps described in Item-1 of Post-1, or the steps in Post-65 of this thread. (...)
> 
> Before I can comment further, I'd like to see your graph in a different format. Can you please repost the graph with standard settings of 10 to 200 Hz and 45 to 105dB? (...)


OK to complete my homework (!) I ran a measurement with sweep fromm 0 to 200hz (Antimode send it to my receiver) . My graph above was with a sweep from 0 to 500hz.

Here is the black hole at 110hz !!








And for your consideration I add the curve of EQ make with Antimode to my sub only.








Why the sub only is great with EQ by Antimode and, with the fronts why do I get this hole ?
The mic was always at the MLCP for all the measurements and speakers and sub were not moved of course.


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## Chromejob (Feb 19, 2015)

Sure, if someone has mains that really, truly duly go down to 60Hz, why crossover (with bass mgmt) at 80Hz? 

Go ahead.

But there are so many speaker manufacturers who claim their speakers go from 35Hz to 24kHZ, that the consumer may say, "Hey, my speaker manufacturer promised me these speakers will go that low, so I'll cross over my sub at 40Hz." But ... do those speakers go that low without deviation, roll off, etc? 

I have Bose 401s that I've tested will go down to 35 or 40. But when I listen to sweeps from 10 to 200, I can hear lots of unevenness, PARTICularly around 80Hz. Someone remembers reviews showing some inconsistency around 110Hz. So I have my cross over higher. 

it's one thing to say 'my speakers go down to 35Hz, so I don't have to use 80Hz as a default crossover,' it's another to say, 'my speakers are rated down to 35Hz, but really only go down consistently to 60Hz, so I set my cross over at 60Hz.' Make sense?


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## Savjac (Apr 17, 2008)

Chromejob said:


> Sure, if someone has mains that really, truly duly go down to 60Hz, why crossover (with bass mgmt) at 80Hz?
> 
> Go ahead. But there are so many speaker manufacturers who claim their speakers go from 35Hz to 24kHZ, that the consumer may say, "Hey, my speaker manufacturer promised me these speakers will go that low, so I'll cross over my sub at 40Hz." But ... do those speakers go that low without deviation, roll off, etc?
> I have Bose 401s that I've tested will go down to 35 or 40. But when I listen to sweeps from 10 to 200, I can hear lots of unevenness, PARTICularly around 80Hz. Someone remembers reviews showing some inconsistency around 110Hz. So I have my cross over higher.
> it's one thing to say 'my speakers go down to 35Hz, so I don't have to use 80Hz as a default crossover,' it's another to say, 'my speakers are rated down to 35Hz, but really only go down consistently to 60Hz, so I set my cross over at 60Hz.' Make sense?


Interesting point of view, thank you.
Maybe I need to re-do some of my thoughts to be a bit more clear and maybe it will make better sense. As AudioCraver has mentioned, the THX presentation is a good place to start, or end should the user be happy with the results. But as you have clearly mentioned, you may not feel that the speaker manufacturers are always telling the truth in the brochures and of this I have no doubt. Part of the reason one persons results will be different from the manufacturer specs is the rooms. Very few rooms will mimic the test rooms used by the manufacturers and frankly very few rooms of us end users are similar enough to be able to test even your speakers and come up with the same thoughts.

The thx specs also do not take into account how the speakers really work in different rooms so while my room may support your speakers down to 40hz yours does not and as such, the thx spec is general enough to cover many bases. This then is where the responsibility of the enthusiast comes into play in way of knowing what is real and what is hype. I do not like my speakers against the front wall however Bose intimates that the speakers can be as close as 2" from the wall which is where the max bass would be found. If crossing over at 110 hz one must have a sub that is quite able to go that high with great finesse and quality, which imo is rare in most of the moderately priced subs in the stores these days. 


Next we have to judge if in reality having our speakers cross over at the generalized point of 80hz sounds reasonable and many times for many reasons it does. Lets say you do not like the bloat your speakers have in the 40hz to 80hz range and try as you may, you cannot remove it with room treatments or placement. In that case, it would certainly be very beneficial to get rid of that nasty range by crossing same over in hopes that allowing the mains to slope off at 80hz and allowing the sub to take over makes a ton of sense.

For myself and many others, it makes the most sense to allow the speakers to do what they do naturally and then blend the sub from there. We must NEVER be able to know when the sub flows in while we are listening or that would preclude the use of a sub. The system should sing as one, not parts and the only real way to do that is with your ears. Computer programs can get things close, but none of them can tell us what is right for our individual tastes anymore than a stranger can tell us what color of blue is most appealing to our eyes. Never the less, this way of doing things requires some education and long term listening coupled with hours, days, weeks and more of experimentation to get it right. Initially music systems and home theater systems are rarely a set and leave type of evolution. 

However, when everything is finally working together, this includes electronics, interconnects, speaker cable, speakers and room it is almost like pouring liquid happiness right into our ears. Truly.


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## Chromejob (Feb 19, 2015)

Yes, one reason I bought a better sub than I was initially shopping for was to get one with range. The Hsu VTF-2 goes way low, also sounds good to 160Hz (to MY ear). Tests with sweeps and several bass-heavy demo tracks indicated a better handoff and seamless blend around 110, 120.


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## gdstupak (Jul 13, 2010)

vidiot33 said:


> I respect people's preferences in this discussion, but there are a number of compelling arguments for setting crossovers at 89Hz:
> 1. First, and I think most compellingly, the fronts are not generally positioned to give the best response for bass. I'm learning this firsthand in my own situation: I have a pair of Rythmik FMB 8's to act as mid bass drivers for my Sierra 2's, and my original position in line with the fronts was terrible for both low bass volume and extension.
> 2. The mains will optimize the upper and mid registers effortlessly in nearly all cases.
> 3. The pesky issue of phase integration is greatly simplified.
> ...


1. So what if my situation is different than yours and the bass from my front main speakers add proper audio?
2. So my system can not optimize upper and mid registers if I run a xover under 80hz?
3. So what if I take the time and effort (along with having the proper gear) to integrate phase?
4. So what if my quality ATI amp can handle the added work without stressing?
5. Those conclusions are very helpful to the average Joe that may not have the inclination or the gear to do otherwise. 



vidiot33 said:


> I recognize that those of us with large mains and/or built in subwoofers are resistant to designating these as "small," but it's at least worth experimenting and discovering firsthand what works the best. If those with larger speakers prefer the sound in this way, then that's what they should do.


Maybe many of us has spent the last 15yrs or more experimenting with our systems and have found that a lower xover works best. And maybe it's not just that we prefer the sound 'in this way,' but maybe it actually sounds best.



vidiot33 said:


> But I think it's worth a little experimenting to arrive what works the best in your individual setup.


This is not the advice you gave earlier. Maybe if you had started out with this sentiment....


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## Lumen (May 17, 2014)

gdstupak said:


> Maybe many of us has spent the last 15yrs or more experimenting with our systems and have found that a lower xover works best. And maybe it's not just that we prefer the sound 'in this way,' but maybe it actually sounds best.


. Sometimes someone just verbalizes your own feelings better than you thought possible = wish I had said that! 



gdstupak said:


> This is not the advice you gave earlier. Maybe if you had started out with this sentiment....


 Maybe they're working on their first 15! Sent from my iPad using HTShack


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## Lumen (May 17, 2014)

FargateOne said:


> OK to complete my homework (!) I ran a measurement with sweep fromm 0 to 200hz (Antimode send it to my receiver) . My graph above was with a sweep from 0 to 500hz.
> 
> Here is the black hole at 110hz !!
> View attachment 97537
> ...


Yes, that's quite a notch at 110 Hz. To get rid of it you'll need to move the sub, add more of them, and/or fine-tune time delays using DSP. Or you could just live with it, because it should be inaudible. The top graph (sub+mains) looks very good up to about 120Hz where it seems you have some comb filtering. That's some extension you have going there! What sub do you have? Is there any acoustic treatment in the room?



FargateOne said:


> Why the sub only is great with EQ by Antimode and, with the fronts why do I get this hole ?
> The mic was always at the MLCP for all the measurements and speakers and sub were not moved of course.


The hole/dip/notch appears only with the sub+mains (and not with sub only), because it's related to the physical distance between the sub and the mains. The signal from the sub reaches your ears at a different time than the signal from the mains. The only way to fix that is to move them physically next to each other, or to correct the time delay with DSP.


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## FargateOne (Mar 3, 2015)

Lumen said:


> Yes, that's quite a notch at 110 Hz. To get rid of it you'll need to move the sub, add more of them, and/or fine-tune time delays using DSP. Or you could just live with it, because it should be inaudible. The top graph (sub+mains) looks very good up to about 120Hz where it seems you have some comb filtering. That's some extension you have going there! What sub do you have? Is there any acoustic treatment in the room?
> 
> 
> 
> The hole/dip/notch appears only with the sub+mains (and not with sub only), because it's related to the physical distance between the sub and the mains. The signal from the sub reaches your ears at a different time than the signal from the mains. The only way to fix that is to move them physically next to each other, or to correct the time delay with DSP.


Thanks for your much appreciated reply. I think I will live with it (can not move the sub it is the best place taking into count WAF). Since I began to learn about sound and PEQ, specially on this forum, I bought Antimode 2.0 and changed my old sub for a SVS PC 2000. I am not Bank of Canada and if I tell to my wife that I need a second sub in our room (see my system) I am not sure that I will see next winter !

About the room, I do not have any acoustic treatment, maybe I am lucky!

About time delay, YPAO set a different distance from the sub to LCP than the distance from the speakers (2,75m against 5,40m for the sub) to compensate and I thought that must not be changed. If I could, I do not know how to do it right. Any suggestion about that?


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## Lumen (May 17, 2014)

FargateOne said:


> Thanks for your much appreciated reply. I think I will live with it (can not move the sub it is the best place taking into count WAF). Since I began to learn about sound and PEQ, specially on this forum, I bought Antimode 2.0 and changed my old sub for a SVS PC 2000. I am not Bank of Canada and if I tell to my wife that I need a second sub in our room (see my system) I am not sure that I will see next winter ! About the room, I do not have any acoustic treatment, maybe I am lucky! About time delay, YPAO set a different distance from the sub to LCP than the distance from the speakers (2,75m against 5,40m for the sub) to compensate and I thought that must not be changed. If I could, I do not know how to do it right. Any suggestion about that?


You're welcome! Seems like you've already "done it right". You're correct in saying that YPAO compensated between sub and mains. Something's not wrong with a calibration when the software sets distances differently from what they are in the real world. Changing distance equates to manipulating signal delay in the time domain. The same effect results from changing the phase setting on the sub. Most people stop there and that's just fine. Hardcore enthusiasts go one step further with fine tuning delays to be exact. That involves a long learning curve, additional DSP (your DSPeaker Antimode is one of them), and a lot of effort. As AudiocRaver said in another post, the benefit of that kind of fine-tuning follows the law of diminishing returns: SQ improvements become less and less the more effort you expend. 

I'm sure others would disagree, but I suggest leaving things as they are provided that your happy with the sound. Humans are less sensitive to bass anomalies; that's why we need measurements to tell us what's going on. I believe the same holds true for comb filtering.

Sent from my iPad using HTShack


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