# System Delay measurement question



## Rudy81 (Aug 5, 2009)

I need some clarification on how REW is reporting system delay in my setup. My mains are actively crossed 3 way speakers that are set up as follows. A Klipsch RSW-15 (internal amp disconnected and powered separately), a 15" woofer bass bin, and an Oris 150 horn. I took individual delay measurements for each driver and find that the subwoofer measures 50ms, the bass bin 13ms, and the Oris 11.5ms. The bass bin and Oris are physically 12 feet from the measurement (listening) position. The subwoofer is just beihind the bass bin close to the room corner approximately 17' from the listening position.

Why does the subwoofer measure so much farther? Is the correct alignment procedure to delay the bass bin and Oris to match 50ms?


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## Rudy81 (Aug 5, 2009)

To start answering my own question, after reviewing other comments on the subject I ran REW again, this time giving each driver the max possible frequency sweep. That reduced the system time for the RSW-15 subs to 34ms. The subs are about 17' from the mic. The increased signal duration obviously make a difference in the system delay time. Note that the RSW 15 has been set up as a passive sub, so no internal amp or crossover. 

The question is, what is the proper 'time' to set the entire speaker to? The LF and HF drivers report about 12ms, which correlates with the phisical distance.


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## jtalden (Mar 12, 2009)

There is no simple answer for this. 

How did you determine the delays? I suggest the delay is best considered to be the delay that results in the driver bandpass phase being as flat as possible. The higher order the LP filter used in the XO the greater the delay for that driver will be. Knowing the driver "delay" does not provide the best delay setting to achieve optimal phase and GD at the XO freq.

There is no single absolute "correct" time/delay alignment for the XO handoff. There are however several good options and several "okay" options in addition to the really bad ones. There are tradeoffs of filter orders, XO freq, and delays that do impact the sound. [I find it difficult in my setup to decide which of the good ones I prefer.]

I can help you find the "conventional" alignment as well as provide good (possibly better) options if you like. This requires significant measuring and time however. 

See  *here* for an idea of what is involved.

If you want me to comment specifically or help you work through all this, I suggest we start with the MW-H XO. Just attach an REW measurement file (with loopback timing activated) including; a MW, a H, and MW+H taken on listening axis at about 2 m distant, also let me know what XO filter setting you have selected. 

If you just want answers to more specific questions I can probably help in that regard also.


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## Rudy81 (Aug 5, 2009)

Thank you for your assistance. I got the delay times using REW 5 by measuring each driver individually, no crossover, just passing through my active crossover with all settings at 0. The time delay numbers I quoted are from REW listed as system delay. 

My goal is to properly integrate the sub, LF box and HF drivers into a single speaker using an active equalizer.


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## Rudy81 (Aug 5, 2009)

To start out, I will upload the files from my driver tests. I basically did what you noted in your linked page. I use an Ashly crossover for my mains and a DCX2496 for the center channel, which is also a DIY unit with its own subwoofer as well. 

The crossover was disabled for each reading and the response tested for what the driver could do.

...looks like the system is not allowing me to upload my files....


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## Rudy81 (Aug 5, 2009)

Trying upload again


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## jtalden (Mar 12, 2009)

The general process I would recommend is to first select a reasonable XO frequency and filter types for both XOs. The "without XO" measurements you attached will help in doing that. If you would like suggestions for that, let me know. 

These can be changed again later if you decide to, but we must start somewhere. Then, measure the MW and H drivers with the upper (or both) these XOs in place. The delay needed to align these 2 drivers can then be determined by evaluating the phase response. [The delay cannot be determined without the upper XOs in place because the filter choice impacts the delay needed.]

Once the upper XO/delay is determined then the mic is moved back to the LP to determine the delay needed between the SW and the Mains.


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## Rudy81 (Aug 5, 2009)

So far, this is the process I have followed. I selected a crossover point at 80Hz from the sub to the LF bass bin, and 180 from the LF bin to the Oris horn based on the raw results for the individual drivers. I am using the L-R 48dB slope, the steepest I can use on the crossover. The idea being to reduce the frequencies in the crossover area.

I would appreciate your suggestions of crossover points etc. The plot for the entire system is also included in those results with those crossover points using the L-R steepest slope.

----This is in fact not true and at this point my procedure goes way wrong because I did not follow the instructions correctly. I started out with plots that were ALL taken at the LP, and not nearfield for the Oris and LF bin as per jtalden's instructions in his "aligning driver phase" post. If you are reading this for the first time to gain insight into the procedure, jump to post 32 so you don't get confused by my mistakes.---------


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## jtalden (Mar 12, 2009)

Rudy81 said:


> So far, this is the process I have followed. I selected a crossover point at 80Hz from the sub to the LF bass bin, and 180 from the LF bin to the Oris horn based on the raw results for the individual drivers. I am using the L-R 48dB slope, the steepest I can use on the crossover. The idea being to reduce the frequencies in the crossover area.
> 
> I would appreciate your suggestions of crossover points etc.


LR-48 is as good a place as any to start if you like. It has the advantage you mentioned. Many people insist that they don't sound as good as lower order filters. I use steep filters like this for SW-MW and a little milder filters for my MW-TW. The nice part is that it is relatively easy to try different setup once you know how. 

The 190 XO point for the MW-H does seem to be pushing the horn to its lower limit. It's acoustic HP Filter would likely be an effective 60 dB/Oct. I thought horns start to unload at their natural roll-off point (190 Hz in this case). I am not an expert, but would have chosen something a little higher (maybe a minimum of 300) to be sure the horn is comfortably operating in its working range. With such a large center to center dimension I can see that it is good to keep the XO as low as possible however. Again, once you know the setup process you can evaluate it at different setting to see which you like best. 



> The plot for the entire system is also included in those results with those crossover points using the L-R steepest slope.


Yes, but the phase shows the alignment to deviate greatly from conventional recommendations that the phase track closely through the XO range. That said, it does appear to be approaching a minimum group delay setting that I often use with high slope filter settings. It's hard to be sure how much the delays should be adjusted without the needed individual driver measurements however.


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## Rudy81 (Aug 5, 2009)

I picked the horn XO after discussions with the designer as well as observation of plots taken outdoors. The horn/driver combination seems to work just fine down to about 130Hz. Actually, the designer suggested that the horn will do just fine at 150Hz. I moved it up a bit to 190Hz for the reason you suggested.

Now, when it comes to the phase issues you mentioned, could you be a little more detailed in your comment? We are now entering my weak area in knowledge and I am not sure what I need to do to achieve a more 'conventional' phase setup. 

The Ashly Protea SP4.8 XO does not allow me to adjust the phase. I can just invert the polarity....if I understand the controls correctly.

Am I trying to align the phase between drivers? I did that in a very basic way by noting the effect of reversing the polarity on response at the XO point. But, that was the extent of my efforts on phase.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> I picked the horn XO after discussions with the designer as well as observation of plots taken outdoors. The horn/driver combination seems to work just fine down to about 130Hz. Actually, the designer suggested that the horn will do just fine at 150Hz. I moved it up a bit to 190Hz for the reason you suggested.


So the measurement you provided of the horn included the 190 XO after all? That's okay then.



> Now, when it comes to the phase issues you mentioned, could you be a little more detailed in your comment? We are now entering my weak area in knowledge and I am not sure what I need to do to achieve a more 'conventional' phase setup.


I am calling the objective to align the phase as closely as possible throughout XO range a "conventional" alignment. The Link provided is reasonably detailed and a good insight into how to do that. There are other alignments that can also be used when using high order XOs.



> The Ashly Protea SP4.8 XO does not allow me to adjust the phase. I can just invert the polarity....if I understand the controls correctly.


A "phase" control is not needed for this effort. The phase alignment is adjusted using the output delay feature and by inverting the polarity if necessary. A "phase" control is very unlikely to provide any additional value.



> Am I trying to align the phase between drivers? I did that in a very basic way by noting the effect of reversing the polarity on response at the XO point. But, that was the extent of my efforts on phase.


Oops - my bad. :R Please just disregard all the confusing info above.
I understood your initial post as a concern about setting proper delays between drivers within a channel. To me this is the same as being concerned as to the phase relationship between the drivers. 

There is no major issue in just setting the driver delays within the channels by first by aligning the driver IRs and then fine tuning by maximizing the SPL in the XO range. Inverting one driver and looking to maximize the null at the XO point can usually provide a similar result. So what you did for the driver alignment is okay. 

Now I see that actual question was in post 2 where you asked what total delays to set for the different channels. I completely misread that. The answer is that it doesn't matter unless it gets so great as to provide too much delay for good video sync. I just set minimum delays (as most AVR do). I set zero delay for the closest channel and then set the delays for other channels by aligning the other channel IRs with its IR. As long as the IRs are aligned between channels at the LP the sound will be the same no matter what total delay values are used.

Sorry I led you off into the weeds!


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## Rudy81 (Aug 5, 2009)

No, you didn't lead me astray. I really enjoy learning the nuances of this hobby. 

Yes, my initial question had to do with how to set the time delays for each driver based on the fact that the subwoofer gives me a delay that does not correspond with the physical location of the subwoofer. The subwoofer presents the longest delay and the LF bin and Oris are very close since they sit on top of one another. 

The plots I posted were taken as follows. The individual drivers were run with no crossover, no eq, from the limits of the driver capability. The full system measurement was taken after I set the polarity at the crossover points and set the time of all the drivers to match a 17ms. delay. I arbitrarily picked that since the sub gave me 32ms. (located 17' away) and the LF and Oris both about 12ms. My curiosity is what to use as a delay for the LF bin and Oris since the sub number does not match the physical location.

I hope I am making sense. I will review your other post to get a better handle on the phase issue.


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## Rudy81 (Aug 5, 2009)

I was looking at the plots I sent you and note that the sub measurement shows an IR of roughly 17ms. Coincidentally, it is the number I pulled out of a hat and set the sub to 0 delay (since it is the farthest) and then delayed the LF and Oris to match the 17ms. I then checked the SPL at the XO point to check the polarity. As it turned out, I needed to invert the LF and that gave me max SPL at both the low and high XO points.

I think I did this correctly and that was the gist of my question. I originally had not checked the IR time, just the system time reported by the info button. That time, for the sub was very high....which led to my question.

Should I do anything else to set the drivers up?


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## Rudy81 (Aug 5, 2009)

I noticed in your linked thread that your mic points at the speaker vs. pointing at the ceiling. I have read several articles that speak of pointing the mic at the ceiling for measurements. Which is correct?


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## jtalden (Mar 12, 2009)

> The value of total delay of the drivers/speakers does not matter to a setup. It is only the relative delay measured between the drivers/speakers that is important. Delays added by any digital electronics settings as the Ashley, DCX, Pre/Pro, SW amp all add additional delay. Any distance settings in those units is impacting the total delay setting. It's just 2 ways of looking at the same thing.

> The XO filter setting adds significant delay and impacts the phase. To adjust the driver delays/phase it is necessary to have measurements with the XOs turned on. If delay settings have already been set and we want to see if they are correct it is no problem to analyze those initial settings.

> The current measurement file does not include the XOs so the relative delays cannot be accurately determined.

> If you want me to review your current timing or suggest new timing I need to see driver measurements with the XOs turned on.

> The best direction of the mic is determined by purpose of the test and the mic calibration files available for it. For this purpose (determining the driver delays/timing) neither the direction of mic, nor the calibration file used will effect the result.


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## Rudy81 (Aug 5, 2009)

OK, let's see if these help. These are individual and system readings, with the XO, no time delay, no EQ, just direct readings from individual drivers.


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## Rudy81 (Aug 5, 2009)

Here is a comparison of a full system sweep with XO. One with no time delays. One with Time delay and LF bin polarity inverted.


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## Rudy81 (Aug 5, 2009)

And finally, the individual drivers and full system as I currently have it set for listening.


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## Rudy81 (Aug 5, 2009)

Here are the impulse responses I get as the system sits right now, with XO and delays. If I understand your other thread correctly, I need to delay the Oris and LF bin to match the subwoofer reading of about 44.2m....Is that correct?

The green line is the subwoofer, the blue is the LF bin and the red is the Oris horn.


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## Rudy81 (Aug 5, 2009)

Now that you have all the readings for various measurements, perhaps we should approach this from a different direction. 

Assuming I have three drivers, sub, LF bin and Oris horn driver, what is the best way to set these up to achieve a coherent sounding speaker?

After researching this issue I believe my problem is the belief that if I time align all three drivers so the system response of each individual driver is the same then that is the proper setting. I am learning that the correct setting is a time delay that will align the driver phase at the crossover point....I think?

I really appreciate your help! Thank you for taking the time to school me on the issue.


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## jtalden (Mar 12, 2009)

I'm still working on it. It takes several hours work for me. 

As I have gotten older I discovered my mind really is like a steel trap after all... There is stuff in there, but it is very difficult to figure out how to get it out.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> And finally, the individual drivers and full system as I currently have it set for listening.


I used the "OrisPhaseTimeChange.mdat" measurement data for this analysis.

Was the mic positioned at the LP for all these measurements? If not, let me know as it will impact this analysis. 

The delay settings you provided reinforced the SPL in the XO range very well. The phase and IR analysis supports that you found an alignment that comes very close to the "Conventional" target alignment. The DBB-Oris is almost right on the proper timing. A very small delay change will line it up perfectly. The Sub-DBB XO is timed very well also. I think it would phase align just slightly better is the Sub polarity was reversed and the sub channel delay reduce about 1/2 wavelength (6.25 ms). Neither is perfect, but it is better to miss on the side of reduced Sub delay as it reduces the total phase rotation by 180° and reduces the GD as well. I didn't fully understand your quick description of the process you used, but it worked very well.

Still, I will detail an alternate alignment I found and you can try it out if you like. There are always several alignment options using high order filters like this, but I prefer the one detailed below. 

The Oris retains its current polarity and both the DBB and SW polarity need to be reversed for this setup.

Below is the overview of the SPL that will result. There is a little more SPL reinforcement in the XO range than the setup timing you provided, but not very much. It is just due to the slightly better timing alignment.








Below is the relative IR timing needed for this setup.








To set this up with the mic still set at the same LP. Add 17.22 ms delay to the Oris channel and then measure the Oris. If the mic position was not changed the Oris IR peak should be at 32.75 ms. Then add 3.07 ms to the DBB delay channel. The Sub delay stays the same value as it is currently. If the mic has changed position x.xx ms the absolute numbers will be shifted accordingly.

Below are measurements of the DBB and Sub IR offsets from the Oris IR peak. They can also be used to setup the delays if you prefer.

To locate the DBB IR relative to the Oris IR peak I chose a zero crossing point on the DBB IR as shown below. The offset to that zero crossing point is about 5.09 ms.








To locate the Sub IR relative to the Oris IR peak I chose a zero crossing point on the Sub IR as shown below. The offset to that zero crossing point is about 6.33 ms.








In summary your current setup is very good and closely approaches the "conventional" alignment. Also provided is a compromise alignment that contains some tradeoffs that you may want to try. 

It is not clear if you will hear a difference or which you will prefer. 

Someday you may also want to try out a higher XO for the DBB-Oris; at least 300 Hz (or maybe 350 Hz). The XO orders can then be reduced to LR-24s for both XOs. These changes will reduce the total phase rotation and lower GD further. Of course the IR alignment will then need to be reevaluated to find either the new conventional setup or the new compromise setup. I think the tradeoffs may be favorable with that type of setup.

You have a very nice system an lots of flexibility for XO and EQ experimentation. Good Listening. :sn:


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## Rudy81 (Aug 5, 2009)

jtalden said:


> I'm still working on it. It takes several hours work for me.
> 
> As I have gotten older I discovered my mind really is like a steel trap after all... There is stuff in there, but it is very difficult to figure out how to get it out.


I know all to well what you mean. My problem is I don't have any more room for new information in there.


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## Rudy81 (Aug 5, 2009)

I'm glad to hear that I am in the ballpark on this issue. Although I'm sure I did not use your technique to get there, and I would like to truly understand what you are doing so I can duplicate the effort. So, some comments and more questions.

-Yes, the mic was at the listening position, so we are good there.

? In your second graph (IR), how did you offset the data? By using the offset feature in the tools box?

? As you play with the IR offset, is the SPL changing as well? 

? In graphs 3 & 4, why are you choosing the 0 crossing point as the second crossing of the 0 line in each wave? 

- The sub currently does not have any added delay at all, so I can't reduce it any more as you recommend. Does that mean you would prefer to add more delay to all channels so that I can then reduce the delay on the sub as you recommend?

? If you were trying to voice this system from scratch, what steps would you take to accomplish this ....done properly and not guessing like I did.

Thank you again......


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## jtalden (Mar 12, 2009)

Rudy81 said:


> ...
> ? In your second graph (IR), how did you offset the data? By using the offset feature in the tools box?


Yes



> ? As you play with the IR offset, is the SPL changing as well?


The driver SPL doesn't change, but the combined response changes as shown.



> ? In graphs 3 & 4, why are you choosing the 0 crossing point as the second crossing of the 0 line in each wave?


The position chosen doesn't matter so long as you can identify it and measure it accurately. The crossing points fit both criteria well.



> - The sub currently does not have any added delay at all, so I can't reduce it any more as you recommend. Does that mean you would prefer to add more delay to all channels so that I can then reduce the delay on the sub as you recommend?


The process says:
"To set this up with the mic still set at the same LP. Add 17.22 ms delay to the Oris channel and then measure the Oris. If the mic position was not changed the Oris IR peak should be at 32.75 ms. Then add 3.07 ms to the DBB delay channel. The Sub delay stays the same value as it is currently. If the mic has changed position x.xx ms the absolute numbers will be shifted accordingly." 

If the Sub delay is 0 ms to start with and you add nothing to it then the final value should be 0 ms. And yes, that is why we are adding delay to the Oris and the DBB rather than reducing the delay in the Sub.

Oh Duh, I get it now. :doh: You are referring to the other minor adjustment to the current "conventional setup". Yes you are correct - just add the 6.25 ms delay to both the Oris and DBB. 



> ? If you were trying to voice this system from scratch, what steps would you take to accomplish this ....done properly and not guessing like I did.


You can find a very good setup easily by aligning the initial IR rise of each driver. Then switch to RTA mode and adjust the delay on the DBB as little as necessary in either direction until to get the maximum SPL reinforcement in the Sub-DBB XO range. Then adjust the Oris delay the minimum needed in either direction to get the maximum fill in the DBB-Oris XO range. The best polarity for each driver is the one that minimizes the offset needed. This method will find the "conventional" alignment in most cases. 

To understand the tradeoffs of phase alignment and GD is more complex and does not guarantee better results. It just lets you find good alternative setups and listen to them. This is fun for me, but...

You can also puruse *This* thread and possibly get some idea of what is involved in digging into Phase and GD. I got involved at Post 129 and tried to summarize the process in Post 193 The thread only deals with SW-Main alignment, but if that is understood then the basic process is similar for the other XOs in a channel. It all looks confusing to me now so I don't know if it will help you much. The other Alignment Thread that was linked above is clearer to me and deals directly with a MW to TW XO alignment. I have no way of summarizing beyond what is found in those links, but will try to answer any more specific questions you may have.


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## Rudy81 (Aug 5, 2009)

Ok, I need to delve into this deeper after reading your references. 

In order to start from common ground, you mention aligning the initial IR rise of each driver. How do I determine the initial IR rise point?


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## jtalden (Mar 12, 2009)

Rudy81 said:


> In order to start from common ground, you mention aligning the initial IR rise of each driver. How do I determine the initial IR rise point?


You are probably going to push my hobbyist knowledge to the edge or beyond, but I will share my understanding, weigh it accordingly.

The initial rise is just that. The point at which the IR starts to rise as a result of the signal being received at the mic, i.e., back into REW. It is good enough to just look a the IR chart and decide the point where you think it starts to rise up/down to the first peak. For a high order XO as an LR-48 this first peak is normally very small as it was in the Sub and DBB and even the Oris (if I remember correctly). For low order XOs the small leading peaks are not there. You can do a loopback measurement on the soundcard and play with various XO filters and see the impact they have on the IR even though there is no speaker involved. It is a normal IIR minmum phase filter characteristic. 

Remember that the XO filter is not the only actor here. The driver’s filter response is acting in addition to the XO (the acoustic response vs. the XO response). Also keep in mind that the initial rise is just a convenient starting point to experimentally find the best timing to achieve the best SPL reinforcement in the XO range and to put us close to the “conventional” alignment. 

---------
Other comments for perspective:
If I set an LR-48 XO and expect to will see a textbook LR-48 acoustic response I will be disappointed. If I want that response I must account for the driver response. If we take the Oris Horn for example your measurement without XO shows the response to fall off rapidly at 190 Hz. A horns lower cutoff (stop-band) normally falls at 12 dB/octave if I remember correctly (it’s very questionable if I do, but you can look it up). So if we wanted an acoustic LR-48 at 190 Hz we would need to set a “But-36” High-pass filter at 190 to go with the But-12 horn at 190 so the acoustic result will be an LR-48 for the acoustic high-pass section. Since the DBB is not rolling off at 190 Hz we would still need to set an LR-48 low-pass at 190 Hz to complete the XO. We could then expect the acoustical XO response to more closely follow a textbook LR-48 XO response for SPL, phase and GD.

[In my mind there is no requirement to follow a particular textbook defined response anyway. I currently use different filters for high-pass and low-pass sections and even use a different freq setting for the 2 sections. I just experiment to find and evaluate settings that achieve my target objectives of SPL, stop-band slope, phase and GD.]


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## Rudy81 (Aug 5, 2009)

Thank you for all the explanations. I am getting a good handle on this issue and will focus on getting some good starting delay times for the DBB and Oris. I realize that using the IR time for the sub and even the DBB is not a good measure due to the limited scope of the LF spectrum put out by the sub and DBB and the accompanying slow peak times. They led me astray to begin with. 

I will now focus on getting some reasonable delay times and then use fine adjustments to maximize the response at the selected XO point. 

I have been trying to reproduce the steps you took in your suggestions on this thread and just can't seem to be able to duplicate what you did. I really want to understand what you did, and why selected the values you picked. Just a matter of gaining knowledge.

Cheers.


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## natehansen66 (Feb 20, 2011)

Rudy81 said:


> Thank you for all the explanations. I am getting a good handle on this issue and will focus on getting some good starting delay times for the DBB and Oris. I realize that using the IR time for the sub and even the DBB is not a good measure due to the limited scope of the LF spectrum put out by the sub and DBB and the accompanying slow peak times. They led me astray to begin with..


I like to use the step response for time alignment, especially for the lf where it's still easily distinguished.


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## Rudy81 (Aug 5, 2009)

natehansen66 said:


> I like to use the step response for time alignment, especially for the lf where it's still easily distinguished.


Can you explain how that process is used? I had not heard of that technique for time alignment.


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## natehansen66 (Feb 20, 2011)

Same method as using the impulse response (the step response is derived from the impulse). I find it easier to see the initial rise of each driver/speaker using the step response. Here's a good article from Stereophile about impulse and step response among other measurements: http://www.stereophile.com/features/100/


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## Rudy81 (Aug 5, 2009)

jtalden said:


> The general process I would recommend is to first select a reasonable XO frequency and filter types for both XOs. The "without XO" measurements you attached will help in doing that. If you would like suggestions for that, let me know.
> 
> These can be changed again later if you decide to, but we must start somewhere. Then, measure the MW and H drivers with the upper (or both) these XOs in place. The delay needed to align these 2 drivers can then be determined by evaluating the phase response. [The delay cannot be determined without the upper XOs in place because the filter choice impacts the delay needed.]
> 
> Once the upper XO/delay is determined then the mic is moved back to the LP to determine the delay needed between the SW and the Mains.


I feel like a real dunce right about now. I had some time to kill and decided to re-read this entire post in order to try and understand not only your recommendations here, but also the example you posted in the "aligning driver phase" post. I noticed that you recommend setting the time and phase alignment for the Oris and LF bin FIRST! Which was all good, except that I have not mastered your example. So, off to carefully read your example. First thing that jumps out is that you used a nearfield reading!!!! I took all my readings from the LP and as such my phase readings are all unusable to try and duplicate your example!

So, as soon as I get home from a business trip I'll start over with this process. Hopefully, I'll actually be able to make some progress and not confuse you while I'm doing it by not following the process correctly.

My first question is that in your example you start with an arbitrary time delay of 2.91ms. Why any delay at all? Is that necessary? 

I suppose the objective is to first align the LF bin and Oris since they are the easiest to work with. Once we get to the sub, things get more complicated and the physical distance is greater. 

I apologize for having confused the issue so much. I just had not paid enough attention to the points made in the instructions. I had given up trying your technique since I could never get my phase graphs to unwrap as yours did.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> I feel like a real dunce right about now. I had some time to kill and decided to re-read this entire post in order to try and understand not only your recommendations here, but also the example you posted in the "aligning driver phase" post. I noticed that you recommend setting the time and phase alignment for the Oris and LF bin FIRST! Which was all good, except that I have not mastered your example. So, off to carefully read your example. First thing that jumps out is that you used a nearfield reading!!!! I took all my readings from the LP and as such my phase readings are all unusable to try and duplicate your example!
> 
> So, as soon as I get home from a business trip I'll start over with this process. Hopefully, I'll actually be able to make some progress and not confuse you while I'm doing it by not following the process correctly.


The purpose of the near field measurement is just to clean up the Phase and GD charts so they are easier to read. So long as the mic position is on the listening axis the near field setup just make the charts easier to read because there is much less influence of room reflections that play havoc with those charts. 

I had no trouble determining the phase from your measurements at the LP, but I have lots of experience doing it that way. 

The near field setup is not possible with your Sub because the only point on the listening axis is the LP, so the mic must be positioned there.



> My first question is that in your example you start with an arbitrary time delay of 2.91ms. Why any delay at all? Is that necessary?


I picked 1000 mm (2.91 ms) as a convenient round number for that example.
Some initial excess delay is recommended just to provide room to adjust the delays of the Sub and DBB as needed relative to the Oris delay setting. This saves work and confusion during the process. The leftover excess delay is easy to pull back out once all drivers in all channels have been timed properly. The driver with the shortest delay can then be reset 0 ms delay and all the other driver delays can be reduced the same amount. In your case you may want to start with a larger initial delay just to be safe as the SW is behind the Oris and its delay will therefore need to be significantly less than the ORIS. A 20 ms initial delay will work just fine and as is a nice round number.



> I suppose the objective is to first align the LF bin and Oris since they are the easiest to work with. Once we get to the sub, things get more complicated and the physical distance is greater.


Yes...
It's easiest set everything relative to the Oris and thus the DBB must be set before the Sub can be set.

Also:
You found a conventional alignment and I already detail one compromise alignment. I have since played with the options and found the option that minimizes the total phase rotation and the GD. The disadvantage of it is that the phase is steeply crossing at the XO points. Let me know if you want me to detail that one also.


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## Rudy81 (Aug 5, 2009)

In your example, you start out with a 2.91ms delay to allow for positive and negative latitude. Why does REW then report a 67.81 ms delay for the TW? Why did it go from 2.91 or so to 67.81? Not sure I understand why it reports such a large displacement from 0 time for the IR.


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## jtalden (Mar 12, 2009)

Yes, I see that is confusing. Remember the absolute delay value is not important. The objective was to determine the relative delay for the 2 drivers.

I'm sure I left the "long delay" setting in the DCX from my then current setup and just reset the "Short delay" in the DCX to 2.91 ms for that example. 

The total delay in that experiment included; long delay + short delay + mic distance + digital processing time (PC, Audio interface, Pre-pro, DCX). I could have just as easily removed the DCX "long delay" for that example which would removed something between 5 m and 9 m, i.e., between 14.493 ms and 26.087 ms. That is the range of "long delays" I use for my various setups. I don't have any handy record as to what the long delay was actually set at however.


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## Rudy81 (Aug 5, 2009)

Excellent. I figured you had some other influences causing the long delay. I just don't want to 'not' understand something and get stuck again. I believe I have a good feel for what you have done and how the technique works. I can't wait to try this again properly.


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## Rudy81 (Aug 5, 2009)

John, I think I am finally making some progress. I took my time and followed your measurement example to the letter this time. The results look very promising, at least in terms of being able to recreate your technique. 

The first part has been to measure the Oris and DBB (double bass bin) again without any XO, EQ, time delay or other enhancement. I then decided on a 200Hz XO to start. Assumed a 20ms. delay to give myself plenty of adjustment room. The Oris sits on top of the DBB, so I don't expect a huge time difference in the test.

From my interpretation of the results, the crossover (L-R 48dB) set a 204.293 (Ashly restriction) gives me a crossover range of roughly 150-250Hz for the drivers. I originally determined the DBB needed a delay change of 6.524ms to align impulse peaks. 

After setting DBB to 13.746 delay and applying the Oris 24.671 IR delay to BOTH plots, I get a nice Impulse with both driver results superimposed at 0. 

After unwrapping the phase, and evaluating the results, I decided on a 14.0ms delay for the DBB, giving me a good phase line crossing at 200Hz, with relatively equal phase change over the span of the XO region.

How did I do this time? Any suggestions? 

Now I will start working on how to properly work in the passive subwoofer to the newly aligned 'system'. I downloaded HOLMimpulse, but have yet to fire it up....more learning to do there. However, I feel I am getting a good handle on this issue. Thank you so very much for all your help.


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## Rudy81 (Aug 5, 2009)

Here are the files that produced the above results.


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## Rudy81 (Aug 5, 2009)

Also, in running a 200Hz tone through both driver sets I get a +6dB reading vs. running either Oris or DBB alone. I had originally made sure both drivers were evenly matched in SPL at the XO frequency. If I understand the L-R crossover correctly, this is the result I should expect when the crossover frequency is set up correctly. 

I ran this SPL test to confirm that the phase alignment was in fact correct. BTW, this technique rocks!


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## Rudy81 (Aug 5, 2009)

Here are the results of the Oris, DBB and Both for SPL and Phase.


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## Rudy81 (Aug 5, 2009)

Step and GD for the above results.


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## Rudy81 (Aug 5, 2009)

Played around with HOLMimpulse and got the results pictured. According to HOLMimpulse, I needed to slightly reduce the time delay on the top end by approximately 4.5ms. That shows to align the time nicely....if I'm using the program correctly. 

The phase graphs showed a need to invert the polarity of the sub to get close to the top end polarity at 80Hz.

I am not real clear on the proper use of HOLMimpulse to get the sub and main phased correctly, but hope this is right. Again, please correct me or make suggestions as required.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> John, I think I am finally making some progress. I took my time and followed your measurement example to the letter this time. The results look very promising, at least in terms of being able to recreate your technique.
> 
> The first part has been to measure the Oris and DBB (double bass bin) again without any XO, EQ, time delay or other enhancement. I then decided on a 200Hz XO to start. Assumed a 20ms. delay to give myself plenty of adjustment room. The Oris sits on top of the DBB, so I don't expect a huge time difference in the test.
> 
> ...


:clap: This look good. You found one the possible phase alignments and you have it fine tuned to perfection. You understand the process basics very well. You may be missing some of the fine points, but I am impressed at how fast you picked this up.

Comments:
The alignment you found is the “Time Aligned” alignment. This is the alignment at one of the extremes of the tradeoffs. This one provides:
> The 30-200 Hz range of the DBB to will arrive closely in time to the 400-20k Hz range of the Oris. If those ranges are set to arrive at 0 ms GD then:
> A 200 Hz signal from the Oris will arrive 360° later (5 ms) than the same signal from the DBB. 
> The phase at the XO is aligned, but the crossing is at the maximum angle so the phase diverges rapidly as your graph shows. This creates a little chaos in the XO range.

The other extreme alignment would be the “conventional” alignment where the GD is allowed to rotate up gradually to higher values as the freq drops. The phase between the drivers will be closely aligned throughout the XO range that way. 

There’s a “compromise” alignment that falls in the middle of these extremes.


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## Rudy81 (Aug 5, 2009)

After having adjusted the DBB delay for to match the sub phase, I went back to check the top end phase and of course, it was off since I had moved the delay on the DBB. But, now that I new the correct delay for the sub I decided to start again but going the other way. I kept the sub at 0 and adjusted the dBB to match phase. 

It turned out that at a nearfield position, the mic does a great job of picking up the subwoofer. Remember, my setup is not a standard subwoofer since each main has it's own passive sub powered by an independent amp. 

After setting the sub to DBB phase, I figured out the time on the Oris to be a delay of 21.5ms....it gives me a very good phase match at the 202Hz XO frequency. 

So, I think I'm there John. These are the new plots from my 'reverse' process.

There is a big suckout at 60Hz from what I assume is a room mode. 

What you do think? Did I get it?


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## Rudy81 (Aug 5, 2009)

Here are my final measurments.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Also, in running a 200Hz tone through both driver sets I get a +6dB reading vs. running either Oris or DBB alone. I had originally made sure both drivers were evenly matched in SPL at the XO frequency. If I understand the L-R crossover correctly, this is the result I should expect when the crossover frequency is set up correctly.
> 
> I ran this SPL test to confirm that the phase alignment was in fact correct. BTW, this technique rocks!


+6 dB at the XO is expected whenever the the 2 signals are in phase. It has nothing to do directly with an L-R filter selection. There are lots of filter choices and alignments that can be chosen to provide good SPL reinforcement in the XO range. The L-R just has the characteristic that it will happen in an electrical XO without needed to adjust the delay in one of the channels.


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## Rudy81 (Aug 5, 2009)

jtalden said:


> :clap: This look good. You found one the possible phase alignments and you have it fine tuned to perfection. You understand the process basics very well. You may be missing some of the fine points, but I am impressed at how fast you picked this up.
> 
> Comments:
> The alignment you found is the “Time Aligned” alignment. This is the alignment at one of the extremes of the tradeoffs. This one provides:
> ...


John, I can't thank you enough for sticking with me during this process. I will study your suggestions. I hope I didn't mess things up by reworking the problem from the other end. But, that last set of graphs and posts give me the following excess GD...which if I understand this correctly, looks ok.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Step and GD for the above results.


Yep, looks good.

Just a note: It better to offset the IR peak to 0 ms for the GD chart just as we do for the Phase chart. It just makes reading the GD of the system a little easier by taking out the overall delay.


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## Rudy81 (Aug 5, 2009)

Will do! Now working on my center channel which is a similar setup but has a 2" compression driver on a P. Audio horn.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Played around with HOLMimpulse and got the results pictured. According to HOLMimpulse, I needed to slightly reduce the time delay on the top end by approximately 4.5ms. That shows to align the time nicely....if I'm using the program correctly.
> 
> The phase graphs showed a need to invert the polarity of the sub to get close to the top end polarity at 80Hz.
> 
> I am not real clear on the proper use of HOLMimpulse to get the sub and main phased correctly, but hope this is right. Again, please correct me or make suggestions as required.


I can't read this chart - it doesn't look right.

> Expand the IR section back to the default size.
> Start by aligning the DBB and Oris IRs (in the "Options" windows)
> With the IR "Offset Increment" set to a resonable value, use the IR "Offset" controls to move the DBB IR and adjust its Phase. [Always leave the Oris IR aligned at its peak so that its phase is aligned across the range.]


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## Rudy81 (Aug 5, 2009)

Decided to play around with HOLMimpulse some other time since I have not time to delve into the nuances.
Center channel was just a little faster to do since I am getting the hang of this.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> After having adjusted the DBB delay for to match the sub phase, I went back to check the top end phase and of course, it was off since I had moved the delay on the DBB. But, now that I new the correct delay for the sub I decided to start again but going the other way. I kept the sub at 0 and adjusted the dBB to match phase.
> 
> It turned out that at a nearfield position, the mic does a great job of picking up the subwoofer. Remember, my setup is not a standard subwoofer since each main has it's own passive sub powered by an independent amp.
> 
> ...


Yes, you got there. :sn:
You found one of the phase aligned timings for both XO's for that channel. It is difficult to see exactly which ones because of the way the IRs are aligned. I would have left a fixed delay in the Oris channel and then adjusted the delay on the DBB to align it and then adjusted the delay on the Sub to align it.

Since your Subs located in the same boxes as the DBB and Oris it’s okay to use the closer mic position. You can set them all alike and then move the mic to the LP just to confirm the channel to channel timing.

With distributed Subs it is be more difficult to align the other channels and create and overall system timing without keeping the first Oris IR as the reference and then adjusting the delays on all the other drivers relative to it. That is why I suggested you set the Oris to high value and a nice even number. 

To see the charts for phase and GD along the way you can just subtract out the Oris IR offset in REW from all the drivers. That way the overall picture can be easily reviewed. 

It’s also easier if all this is from the LP mic location. Done that way then the other channel drivers can be aligned just by adjusting their delays until they overlay the IR of the same driver on the first channel. The excess delay can then be removed at the end. 

If you work through a full setup of different alignments a few times with distributed Subs you would quickly find that that method is much easier.

You don’t have to deal with that with the Subs in with the main speakers.

I haven't reviewed the actual data yet.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Here are my final measurments.


The Sub to DBB is about 180° out of phase in this data yo may want toreview this again and see what went wrong. Maybe you just offset the Sub using the wrong value. 

Also, the mic postion not being at the LP may produce a very different room response. We did not see the large dip at 60 when you measured at the LP (if I remember correctly).

Please confirm your settings and then provide another set of measurements from the LP.
> Sub
> DBB
> Oris
> All 3 together

Just leave the loopback offsets as measured so that I can offset them myself.
Thanks,


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Decided to play around with HOLMimpulse some other time since I have not time to delve into the nuances.
> Center channel was just a little faster to do since I am getting the hang of this.


Looks good.

It will be interesting to see how the phase of the center aligns with the L/R. With different designs they will not match exactly, but it will be good enough to adjust the IRs arrivals so that the LF and MF are aligned at the LP and not worry about the HF.


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## Rudy81 (Aug 5, 2009)

jtalden said:


> The Sub to DBB is about 180° out of phase in this data yo may want toreview this again and see what went wrong. Maybe you just offset the Sub using the wrong value.
> 
> Also, the mic postion not being at the LP may produce a very different room response. We did not see the large dip at 60 when you measured at the LP (if I remember correctly).
> 
> ...


Hmmm. Here is a whole new set of sweeps at the LP with no other settings touched. Please let me know what you find. Obviously the 80Hz region has some issues...although at the LP the room resonances are a big factor....


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## Rudy81 (Aug 5, 2009)

Not sure if there is a problem or not. Just placed the mic back at the nearfield and ran all the tests again. Still looks ok to me.....of course I could be way off.

Here are the untouched results nearfield.


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## Rudy81 (Aug 5, 2009)

John,
I have a new question for you. My Oris and DBB are always very close in time measurement, but the Sub is way longer than either. Part of that is because it sits behind the DBB Oris combo, but a lot has to do with the seemingly long time the subs frequency takes to bounce off the front wall and be measured. The sub is physically just 3' or so behind the Oris, but gives a much longer signal time. 

This issue has been forcing me to delay the DBB and Oris quite a bit. Is it possible to just align in time and phase the Oris DBB combination and just try to phase align them to the sub without the delay? Would that sound ok? Is the time difference going to be a big deal below 80Hz?

I'm just trying to entertain ways to get good phase alignment at the top end without delaying each speaker so much. This is an issue with video lip-syncing.....or at least can cause problems in that area.


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## EarlK (Jan 1, 2010)

Rudy,

John is giving you exemplary help ( so I'm not going to interfere ) .

Most subs ( with heavy cones & relatively weak motors ) suffer from a form of propagation delay ( which is electro-mechanical in origin ). This delay ( typically ) is not predictable and will always place the apparent origin of the soundwave , as emanating from behind the actual physical woofer position . 

Personally, I wouldn't synch ( backwards ) to that point of origin . I would simply ( catch the wave ) & get in-phase with it . 

:sn:


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## Rudy81 (Aug 5, 2009)

EarlK said:


> Rudy,
> 
> John is giving you exemplary help ( so I'm not going to interfere ) .
> 
> ...


Yes, John has been an outstanding teacher on the subject as you can see by my progress. I am painfully aware that what has been causing major problems in finding a 'cohesive' solution is the inherent problem in getting good readings on a sub woofer. 

I asked this question since last night it occurred to me that I should give up trying to time and phase align the main top end to the sub and just keep the top end time and phase aligned....then, phase align the sub to the top end at the XO point. Thus giving me a good response at 80Hz (my XO for sub and main) and good time and phase with the main components. 

I have been reading various methods of aligning a sub to the main components. They approach the subject differently, using limited bandwidth to get times of the main vs. sub, using GD, and using excess GD to get a timing reference. But, none seem perfect and as such I'm questioning the usefulness of trying to perfectly time and phase align the three drivers.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Hmmm. Here is a whole new set of sweeps at the LP with no other settings touched. Please let me know what you find. Obviously the 80Hz region has some issues...although at the LP the room resonances are a big factor....


*Side Note:*
The Sub and DBB IRs looks like another TW was on that caused a small blip in the IRs of both the Sub and DBB drivers. It was probably on in the Oris also, but it would not be discernable there. The level is very low so the impact did not show up in the SPL and it will not impact the following analysis - just FYI. Possibly the Oris was on at a very low level or the center channel TW was active at a low level?

*Now the analysis:*
The DBB to Oris is set correctly as we previously found. The Sub is timed incorrectly as it is about 110° out of phase. The SPL confirms we get slightly more SPL support with the Sub inverted, being then about 70° out of phase at the XO. See Charts below:
















I suspect what caused the confusion was the room mode that disrupted the direct signal phase of the DBB near the XO. This takes some experience to sort out correctly. We are interested in aligning the direct signal phase and not trying to align the phase as distorted by the room effects. To see the direct phase better we can use the "IR Window" feature of REW. If this is done wrong the phase is even more distorted instead of cleaned up. To do it correctly place the Left Window at just before the initial rise of the DBB IR and adjust the Right window down from 500 ms to a value that just cleans up the late arriving room effects without distorting overall general direction/shape of the phase. The direct phase will be smoothly changing without the sudden changes that reflections/modes cause. Don't over do it.

Please also note that the window type of the right window is usually more effective with a Blackman-Harris 4 Window setting for this particular type of phase cleanup. You can see my final window settings in phase chart above.

Note that a narrow windows causes a significant change in SPL that can be misleading at low frequencies. It is better to leave the windows at the default values for SPL charts as I did above.

It is not necessary to unwrap the phase after you get a feel for what is a normal wrap vs what is caused by a room effect. I just left it wrapped for these charts.

I was going to offer and adjustment to correct the alignment, but decided to leave that as at task for you.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Not sure if there is a problem or not. Just placed the mic back at the nearfield and ran all the tests again. Still looks ok to me.....of course I could be way off.
> 
> Here are the untouched results nearfield.


This timing looks good.

Are you running 2 mono Subs or 2 Stereo Subs?


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## jtalden (Mar 12, 2009)

Rudy81 said:


> John,
> I have a new question for you. My Oris and DBB are always very close in time measurement, but the Sub is way longer than either. Part of that is because it sits behind the DBB Oris combo, but a lot has to do with the seemingly long time the subs frequency takes to bounce off the front wall and be measured. The sub is physically just 3' or so behind the Oris, but gives a much longer signal time.
> 
> This issue has been forcing me to delay the DBB and Oris quite a bit. Is it possible to just align in time and phase the Oris DBB combination and just try to phase align them to the sub without the delay? Would that sound ok? Is the time difference going to be a big deal below 80Hz?
> ...


In an earlier post I mentioned that the excess delay is removed at the end of the process of alignment. In your case with the subs behind the mains. The final sub delay will be 0 ms for one of the 2 subs. The other will be at or near 0 ms also, depending on how symmetrical your setup is. Because you have very steep filters the DBB and Oris will be delayed greater than a physical measurements would suggest. Don't be concerned with that.

In the end we want the direct signal from each driver to arrive at the LP aligned such that the timing and phase is matches the alignment target we selected.


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## Rudy81 (Aug 5, 2009)

John,
Those graphs really help me understand your comments. Very clear to see what you mean and I now understand your comment on the sub phase issue. 

I suspect that the problem driver has been the sub all along due to IR and room modes at the LP. 

I am going to get on this in a few minutes and start over for both practice and to have a known start point vs. trying to manipulate data I worked on yesterday. 

Although a trying experience for you, I have really increased my knowledge on the subject and am very appreciative of your time. I wish I knew a of a lot more on the subject.


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## Rudy81 (Aug 5, 2009)

jtalden said:


> This timing looks good.
> 
> Are you running 2 mono Subs or 2 Stereo Subs?


I have three identical subs for L, R, and Ctr duty. Each sub is independently powered and has a crossover channel assigned to it. The goal has been to make each L, R, and Ctr channel fully full range. I also have two DIY horn subs for the LFE channel. 

In other words, each main channel is composed of three 'drivers' sub, DBB and HF (Oris or compression driver). This is why I have gotten into this phase and timing issue, so that I might properly set up each L, R, and Ctr 'speaker'.


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## Rudy81 (Aug 5, 2009)

Since a picture is worth a thousand words, here is the setup.

Main L Channel composed of independent sub, DBB and Oris horn. (Main R channel is identical)
Center Channel composed of independent sub, DBB and 2" compression driver horn. (DBB has different 15" woofers capable of higher extension)
Last picture is of the three front channels from the LP.

Note: Although the three subs look stock, they are not. The internal amp and crossover has been disconnected. Each sub is individually controlled by a dedicated XO channel and dedicated amp channel.

As you can see the subs are physically close to the other components, particularly the center channel. The sub time readings are a real pain to process properly. That is why much of this did not make much sense from a physical viewpoint.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> John,
> Those graphs really help me understand your comments. Very clear to see what you mean and I now understand your comment on the sub phase issue.
> 
> I suspect that the problem driver has been the sub all along due to IR and room modes at the LP.
> ...


Actually it's the DBB phase that I needed to window to clean up. The Sub Phase was very clean in this XO range.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Since a picture is worth a thousand words, here is the setup.
> 
> Main L Channel composed of independent sub, DBB and Oris horn. (Main R channel is identical)
> Center Channel composed of independent sub, DBB and 2" compression driver horn. (DBB has different 15" woofers capable of higher extension)
> ...


Nice setup!

I don't understand your concern with Sub timing. Can you explain?

It is no doubt the separation between the Sub and DBB that results in the deep cancellation at 60 Hz when using the close mic position. Stick with the mic at the LP for that XO alignment. 

*Side Comment*:
With the 80 Hz XO, 3 equal subs in separate boxes, and delay capabilities on all the subs it would be advantageous to run the subs as mono. Their positions could be distributed more freely (although its probably not necessary) and the resulting EQ would be much easier/smoother and equal for all channels. Go ahead and with the present plan, but keep that in mind for a future evaluation. I am pretty sure you will prefer it. 
If you do it:
> Set the sub delays for equal arrival times. 
> Change positions of the subs if needed to get a reasonably smooth SPL. 
> Set an EQ for the subs. 
> Set your target alignment for one channel. 
> Match the IR arrivals of the drivers on other channels. 
> Final EQ for each channel.
> Pull out any excess delay.


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## Rudy81 (Aug 5, 2009)

jtalden said:


> Nice setup!
> 
> I don't understand your concern with Sub timing. Can you explain?
> 
> It is no doubt the separation between the Sub and DBB that results in the deep cancellation at 60 Hz when using the close mic position. Stick with the mic at the LP for that XO alignment.


My concern is likely due to lack of knowledge. My line of thinking has been to time and phase align the three 'drivers', sub, DBB and Oris. The DBB and Oris are easy as we have seen. However, the subs are difficult for IR estimated time to even closely match the physical reality. As an example, the center sub gives and Estimated IR of near 32ms! The center DBB and HF are about 12 ms at the LP. In my attempt to 'time' align the three, I have to delay the DBB and HF so much that it begins to impact video lipsync, which is a huge deal when watching a movie and causes all sorts of other problems when setting up the 7.1 channels.

This is why I asked about just time and phase aligning the HF and DBB at near field. Then, move to LP and just phase align, but not time align, the sub to the top end for that channel. I have come to the conclusion that this is the only reasonable way to handle this setup without causing all sorts of other headaches. Does that make sense?

On your side note...interesting idea having the three subs as a mono setup. Do you mean running all three all the time, being fed by each channel as required? I can see where that could make for a smooth LF performance for each channel. They are, in fact, all crossed at 80Hz. 

I have an extra channel in my Ashly that I can use. I might just do that!


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## jtalden (Mar 12, 2009)

Rudy81 said:


> My concern is likely due to lack of knowledge. My line of thinking has been to time and phase align the three 'drivers', sub, DBB and Oris. The DBB and Oris are easy as we have seen. However, the subs are difficult for IR estimated time to even closely match the physical reality. As an example, the center sub gives and Estimated IR of near 32ms! The center DBB and HF are about 12 ms at the LP. In my attempt to 'time' align the three, I have to delay the DBB and HF so much that it begins to impact video lipsync, which is a huge deal when watching a movie and causes all sorts of other problems when setting up the 7.1 channels.


There is a setting wrong somewhere. You said you are using the DCX for the CC duties. It adds only about 1 ms of delay. If the LP physical distance is 10 ft for example then the IR will be at about 11 ms with 0 ms delay settings. Check for the lost DCX delay setting. There are both Long-Delay and Short-Delay settings on both the input and the output channels being used. The digital devices in the setup is the 9.9 Pre/Pro. Are there Distance settings entered there? I set all my 9.8 Pre/Pro distances to the same value otherwise delays are being introduced there. Just set all channels to 10 ft for example. That will remove any delays. You can use a loopback cable to confirm the Pre/Pro delay and then Pre/Pro + DCX. Their impact should be small, maybe 1 or 2 ms each.

Also regarding lipsynch, I am surprised that 32 ms creates a problem. I would even guess the video processing might be greater than that. I have just over 100 ms delay on some of my setups and normally that is not a problem although I have had to adjust a video delay on my 9.8 Pre/Pro for some DLNA streamed music video. My 9.8 has several different settings in that regard. Your 9.9 is no doubt similar. I would fix it there.



> This is why I asked about just time and phase aligning the HF and DBB at near field. Then, move to LP and just phase align, but not time align, the sub to the top end for that channel. I have come to the conclusion that this is the only reasonable way to handle this setup without causing all sorts of other headaches. Does that make sense?


No, you need to locate the problem. A 32 ms difference between channels will sound terrible.



> On your side note...interesting idea having the three subs as a mono setup. Do you mean running all three all the time, being fed by each channel as required? I can see where that could make for a smooth LF performance for each channel. They are, in fact, all crossed at 80Hz.
> 
> I have an extra channel in my Ashly that I can use. I might just do that!


I didn't really think through how this would be implemented. I suppose I would send all 3 input channels to each unit (DCX and Ashly). Use one unit for the upper XOs and the HPF of the lower XOs as well as EQ for the 3 channels. The other unit can provide summed inputs and LPF XO duties and well as EQ for the 3 subs. Two DCX's can do this. I don't know about the Ashly.


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## jtalden (Mar 12, 2009)

RE Mono SWs:

I wrote the last bit above before the rest and didn't change it once I saw that you have the 9.9 Pre/Pro.

It is of course much easier to let the 9.9 manage the sub XO. That way you will only have the single sub output for the input to the DCX. The signal can be sent to 3 outputs for separate delays as needed. A single EQ can just be set on the input channel. 

The 9.9 XO will apply an LR-24 LPF and a B-12 HPF to create the XO. There will be no problem with that, but you can augment it if you like by adding additional LPF and/or HPFs in the DCX/Ashly. 

If you are planning to run Audyssey that will change all the distances/delays in the Pre/Pro and make any initial manual EQ's a waste of time. You can use Audyssey for EQ, but the timing process gets even more confusing.


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## Rudy81 (Aug 5, 2009)

Lots of stuff to consider. I was using direct mode in the 9.9 to avoid any Audyssey issues. I'm not sure if the distances in the 9.9 also play a role in direct mode, but they were set at about 14 feet in any event. 

Yes, something just does not jive with the delay on the RSW-15 subs. 

I decided to implement your mono sub idea...and yes, it turned out great. It certainly sounds good, but I was never able to integrate the center sub properly. The two corner subs were almost perfectly in phase. The center sub located next to the center DBB was another story. I could not get it to match the other two subs. I then decided to just use the two corner subs and save myself more headaches....certainly plenty of output with just the two. 

So, the way it works now is that all three front channels feed the two corner RSW-15 subs. The Folded Horn SPUD subs do LFE duty so I had checked all the subs to ensure they would not cancel each other out. I lucked out and only needed to reverse the polarity in the SPUDS to get decent phase agreement between subs.

From there, setting the main and center DBBs and HF sections was quick. I think in the last few days I have done that 100 times. 

The reason I went to all this trouble is that I needed to align each individual speaker with the three main driver sets. Then, working as one speaker, I can run Audyssey Pro like anyone else does with normal speakers. 

I had assumed that when Audyssey makes changes to the entire system it will of course have an effect on the main three channels if it makes any changes in the XO regions....but then isn't that true of all speakers?


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## Rudy81 (Aug 5, 2009)

BTW, when I was struggling with the reported IR timing on the subs, I checked and re-checked the DCX and Ashly. All 3 subs report very long LP times vs. the DBB and HF. The DBB and HF all come in around 12-14ms. at the LP, although the DCX controlled the CC at the time. The sub on the DCX and the subs on the Ashly were all very long in the 20-30ms. range.

It just seems that the long wavelength and limited FR of the subs leads to inaccurate IR readings. I have read several articles now that discuss this issue and all point to those two items as the source of the difficulty.

The good news is that I just ran a basic sound check on the main channels in stereo to see where I stand and it sounded very good. Now a little more tweaking and hopefully I will be done with this.

I did change the CC XO to LR 24dB in order to get a more gentle transition between the DBB and the HF horn. I quickly tested a movie with good CC dialog and liked what I heard. I got a more 'full' vocal in conversation. The HF driver is the weak point right now, but that upgrade I'll leave for another day.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Lots of stuff to consider. I was using direct mode in the 9.9 to avoid any Audyssey issues. I'm not sure if the distances in the 9.9 also play a role in direct mode, but they were set at about 14 feet in any event.
> 
> Yes, something just does not jive with the delay on the RSW-15 subs.
> 
> ...



Lots to consider – I guess!! I didn‘t realize that the system was so complicated – 7 channels, Audyssey Pro, folded horns for LFE? I may be out of my league in helping you align all of this. It's safe to say that you are not with the minimalistic crowd. I’m sorry I didn’t catch on sooner. I understood we were talking 3 channels and assumed some of the listed equipment must be used in other setups.

It is tough to know where to start. 
I do see you have pro amps and read that some now have delay/XO/EQ capabilities built in. Is the CC sub P-amp the source of the extra delay?

I am only now starting to see why you were focused on a 3-way setup for the fronts as the LFE was to be separate. That does probably make sense considering the combination of LF equipment.

On the negative side (I’m a pessimist) I would expect the phase rotation for the Subs vs the folded horns to be different. If a signal was common to both then there may be a phase problem at some freqs. The LFE is maybe/probably always a unique signal and if so, it is probably no issue. [Just thinking out loud.]

As I said, I probably don’t have enough experience to sort all this out with only peep hole view to the reality of it. You seem to have absorbed most all the concepts and methods I use so maybe you can fit it all together. 

It is getting very confusing for me to understand the exact situation and questions in the proper context. I think most of my comment above were okay, but without proper context it is difficult to be sure. I will still try to answer questions if you like, but please take my comments cautiously.


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## Rudy81 (Aug 5, 2009)

Yes, some pro amps have those capabilities and I checked all that as well.

Yes, it is a complicated system, but I rely on Audyssey Pro to handle the nuances between the 7 channels and the .1 LFE. 

All our discussion is solely directed at getting the L, C, and R channels to each act as one 'speaker'. The various drivers and subs just give me the option of having a truly full range speaker. In a word, I was trying to 'voice' each main speaker.

I think all your comments and ideas have been right on.


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## Rudy81 (Aug 5, 2009)

After two days of working on this and implementation of your mono sub idea, I was confident enough to see how Audyssey would 'see' the speakers and handle the EQ. Amazingly, there were no obvious problems with the L, C, and R speakers as they are set up. The two RSW-15s in the corner really put out a lot of LF! Although I reduced the dB input a bit, they still crank LF as you can see in the Audyssey plot. 

I am going to take some time to listen to the system and see how it sounds as it is. Some day when I'm bored I'll hook everything up again and see how the system phase and time has changed at the LP in the current setup.

Great learning lesson. I hope I passed Time and Phase 101....

Thank you for your help, I can't say it enough.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> BTW, when I was struggling with the reported IR timing on the subs, I checked and re-checked the DCX and Ashly. All 3 subs report very long LP times vs. the DBB and HF. The DBB and HF all come in around 12-14ms. at the LP, although the DCX controlled the CC at the time. The sub on the DCX and the subs on the Ashly were all very long in the 20-30ms. range.
> 
> While I still can't relate to a 30 ms delay being an issue for lip synch from my limited experience, I do remember something that might help you with lip synch.
> 
> ...


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## jtalden (Mar 12, 2009)

Rudy81 said:


> After two days of working on this and implementation of your mono sub idea, I was confident enough to see how Audyssey would 'see' the speakers and handle the EQ. Amazingly, there were no obvious problems with the L, C, and R speakers as they are set up. The two RSW-15s in the corner really put out a lot of LF! Although I reduced the dB input a bit, they still crank LF as you can see in the Audyssey plot.
> 
> I am going to take some time to listen to the system and see how it sounds as it is. Some day when I'm bored I'll hook everything up again and see how the system phase and time has changed at the LP in the current setup.
> 
> ...


Glad to help. :sn:


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## Rudy81 (Aug 5, 2009)

This evening got to test various movie material. Music, and mostly dialog as well as action. First impression is that the LFE subs and the RSW-15s are definitely in phase. Huge amounts of very clean and authoritative bass.

The other issue was lipsync was right on the money on all dialog movies. 

So far so good. The real test will be pure 2 channel listening of my favorite songs. I did listen to some multi channel SACD and they sounded very, very good. Again, great bass reinforcement. Hopefully this will work out as I had hoped.

An unexpected, but very worthwhile, change was to go with mono subs. What a great idea John. Now I get really well balanced LF from all three main channels. The omnidirectional nature of LF lends itself well to this setup.

So far I'm very pleased with the results. More tomorrow.


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## Rudy81 (Aug 5, 2009)

jtalden said:


> If you are planning to run Audyssey that will change all the distances/delays in the Pre/Pro and make any initial manual EQ's a waste of time. You can use Audyssey for EQ, but the timing process gets even more confusing.


Your comment on Audyssey has had me wondering if using Audyssey will invalidate all the work on time and phase alignment. I have been researching the issue and feel that changes made by the Integra PRIOR to the XO, should not change or affect the driver phase and timing settings. This, if I understand this correctly, is what is happening when the Audyssey modified signal is sent from the Integra to the Ashly to apply the XO.

The signal outputs from the Ashly to the amps and then the speakers.

This is my understanding based on this article.

On a side note, your idea to run the subs in mono was brilliant. Although I was only able to get the two corner RSW subs in phase and working together, they work great for the L, C and R speakers. The extra RSW is now just a spare.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> Your comment on Audyssey has had me wondering if using Audyssey will invalidate all the work on time and phase alignment. I have been researching the issue and feel that changes made by the Integra PRIOR to the XO, should not change or affect the driver phase and timing settings. This, if I understand this correctly, is what is happening when the Audyssey modified signal is sent from the Integra to the Ashly to apply the XO.
> 
> The signal outputs from the Ashly to the amps and then the speakers.
> 
> ...


Sorry for the confusion: My comments do not conflict with the article (at least from my quick scan of it). I only pointed that any timing/distance for the Sub or Mains pre-outs that is set in the pre-pro before Audyssey is run will be reset once Audyssey is run (or as I worded it above; "Audyssey ... will change all the distances/delays in the Pre/Pro"). It will of course not change settings in the DCX/Ashly that make adjustments within a channel as from the DBB to the Oris or to your "Subs" as they are XO by the Ashly/DCX within the channels. I was thinking of the overall system that includes the Sub pre-out. Sorry this wasn't clear. Part of the confusion is that to me a SW is driven from the sub pre-out on a pre-pro or AVR. Your "Sub" is, to me, a Woofer in a separate box so I confused the discussion.


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## Rudy81 (Aug 5, 2009)

John, ok. I think we are on the same page. You are correct, the RSW-15 subs are acting as true LF woofers for the L, C & R speakers. My dual tapped horn subs are the once connected to the LFE output. 

You are correct that Audyssey will change the delay of the speakers based on its calculations. 

BTW, the article I mentioned in the last post is an excellent review of the same principles you discuss in your post. In my case, it helped to clarify what you discussed. The three part article is very good and has several examples on implementation of the procedure. 

I am currently going through the HOLMimpulse help file to learn how to use it. I want to see how it works on the LP and the sub phase measurements.


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## Rudy81 (Aug 5, 2009)

John, I'm still spending time planning my next journey into measuring everything again. I am not totally clear on the procedure to measure the RSW-15 sub after completing the time and phase alignment of the DBB and Oris. Is the below sequence correct?

Assume I start with a 20ms added delay.
Align the Oris and DBB with REW. Assume DBB is moves back 1ms.
Move the mic to the LP
Switch to HOLMimpulse
Do I start by measuring the Oris again with the 20ms added delay and the DBB with the 19ms delay?
Measure RSW-15 with 20ms added delay?
align phase of RSW-15 to DBB.
Subtract the smallest change from all drivers so that smallest change (Likely the RSW-15) will have 0 delay?

My point is that I'm having trouble planning the exact sequence of events when transitioning the measuring the RSW-15.


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## jtalden (Mar 12, 2009)

Rudy81 said:


> ...
> > Assume I start with a 20ms added delay.


Okay



> > Align the Oris and DBB with REW. Assume DBB is moves back 1ms.


DBB delay reduced to 19 ms - okay



> > Move the mic to the LP


Okay [You could just do the whole process from the LP, i.e., the above steps.]



> > Switch to HOLMimpulse


Just use REW as you have a reasonably clean IR measurement and are experienced with the REW process. [HolmImpulse is recommended more as a learning experience to better understand how phase changes with IR location. If you are familiar with HolmImpulse it is easier and quicker to align the phase of drivers because the controls it provides suit this alignment process better.]



> > Do I start by measuring the Oris again with the 20ms added delay and the DBB with the 19ms delay?


Yes - Leave the delays as set above (Oris 20 ms and DBB 19 ms) you should mute the Oris though and just measure the DBB again at the LP. 



> > Measure RSW-15 with 20ms added delay?


Yes, start there or at 19 ms, but then adjust RSW-15 delay to align its initial IR rise with the initial rise of the DBB IR. 



> > align phase of RSW-15 to DBB.


Yes - fine tune RSW-15 delay for final phase alignment.



> > Subtract the smallest change from all drivers so that smallest change (Likely the RSW-15) will have 0 delay?


Yes, the smallest delay will depend on which alignment you chose for the 2 XOs. You are correct that it is likely that it will be the RSW-15 considering it is placed several feet further away. So if the final RSW-15 delay is found at 12 ms then 12 ms can be removed from all 3 delays. The final delays would be RSW-15 = 0 ms, DBB = 7 ms and Oris = 8 ms.

---------------

[Note: The 20 ms delay was intended to provide a safe cushion for upcoming timing of the other mains and the SW/LFE channel. I now understand that you are going to leave that final channel to channel adjustment for Audyssey to set via the pre-pro distances. That is the correct thing to do when using Audyssey. It just means there will just be more excess delay to remove in that last step.]


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## Rudy81 (Aug 5, 2009)

Thank you sir. In fact I did as you suggested earlier today. Ran everything from the LP and REW worked very well indeed. 

System is up and running and have not noticed any issues in sound, Audyssey measurements or full range sweeps.

Now to enjoy...finally!

:R


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