# REW Newbie- First Measurements revised



## Dwight Angus

Had a few problems posting graphs. Hope this works.
















As mentioned using audyssey xt32 consumer version 8 measurements positions.
HT seems bass dominate and does cloud midrange frequencies. Would I benefit from additional eq to reduce bass
levels?

I hope to post more graphs in the next few days of main speakers as well to show cross over integration and upper frequencies.


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## Dwight Angus

Referring to waterfall graph. Looks like I have problems at 40 hz and below These frequencies are hard to fix. Not sure if tuned traps can help.


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## AudiocRaver

Just for clarity: Guessing that you ran Audyssey MultEQ with all speakers active, then this is your measurement of the sub only.

What was the LFE crossover frequency? 60 Hz?

Quite smooth and well controlled above 40 Hz, except for that mode at 70 Hz. Below 40 will definitely need some attention. As you suggested, taming below 40 Hz would take some BIG traps. All that LF resonance is really going to muddy the rest of the sound. Others have found the need for "pre-eq" in the LFE range to tame the worst nodes before applying Audyssey MultEQ. That means a BFD or MiniDSP processor in the LFE chain working on modes below 40 and maybe at 70, too.

It would be interesting to see REW plots of your subs raw, MultEQ off, see what those room modes look like.

Then you might post in the Home Audio Acoustics area for room treatment suggestions. Or just cut off your audio below 40 Hz - sorry, bad joke.:R


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## phazewolf

Tuned traps can help with your issue below 40hz however your looking at needing several of them to be able to effect the room. 

Gik makes one that is tuned to 40hz and would most likely work I would email them your room info and rew info and see what they say about it.


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## Wayne A. Pflughaupt

Dwight Angus said:


> HT seems bass dominate and does cloud midrange frequencies. Would I benefit from additional eq to reduce bass
> levels?


Likely. I’d say the area below ~30 Hz is elevated too much in relation to the rest of the curve. Above 30 Hz a flatter slope, rather than rounded like you have, could “tighten up” the sound and make it sound less bloated.

Regards, 
Wayne


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## Dwight Angus

AudiocRaver said:


> Just for clarity: Guessing that you ran Audyssey MultEQ with all speakers active, then this is your measurement of the sub only.
> 
> What was the LFE crossover frequency? 60 Hz?
> 
> Quite smooth and well controlled above 40 Hz, except for that mode at 70 Hz. Below 40 will definitely need some attention. As you suggested, taming below 40 Hz would take some BIG traps. All that LF resonance is really going to muddy the rest of the sound. Others have found the need for "pre-eq" in the LFE range to tame the worst nodes before applying Audyssey MultEQ. That means a BFD or MiniDSP processor in the LFE chain working on modes below 40 and maybe at 70, too.
> 
> It would be interesting to see REW plots of your subs raw, MultEQ off, see what those room modes look like.
> 
> Then you might post in the Home Audio Acoustics area for room treatment suggestions. Or just cut off your audio below 40 Hz - sorry, bad joke.:R


That is correct. REW measurements reflect subs only after running audyssey xt32 for all channels.
LFE crossover is 70hz.

The rew graph is from the mlp. I want to take some more measurements across the 1st row of 3 seats and then average the 3 as for pre eq purposes. However given that sub frequencies are omni directional I suspect I won't see any material differences comparing measurements. The 2nd row of seats are not used all that much so I will not take any measurements there.

I contacted GIK regarding tuned traps and Brian suggested Scopus traps would help and estimated I would probably need about 10 traps to do the job. These traps tuned to 40 hz are 2 ft by 2 ft and 10 inches thick. Placement would be difficult as the room is already treated & not allot of available real estate for placement although they are stackable.

I hope to run more rew graphs today so I will post later.


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## Dwight Angus

phazewolf said:


> Tuned traps can help with your issue below 40hz however your looking at needing several of them to be able to effect the room.
> 
> Gik makes one that is tuned to 40hz and would most likely work I would email them your room info and rew info and see what they say about it.


I am looking at the GIK Scopus tuned traps but lack any available space. Hoping Pre Eq will help resolve the issues below 40 HZ.


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## Dwight Angus

Wayne A. Pflughaupt said:


> Likely. I’d say the area below ~30 Hz is elevated too much in relation to the rest of the curve. Above 30 Hz a flatter slope, rather than rounded like you have, could “tighten up” the sound and make it sound less bloated.
> 
> Regards,
> Wayne


Yes the resonances 30 hz and below are dominating the room. I'm hoping that by applying some additional eq I am able to forgo additional room treatments. So it looks like I would apply EQ filters in the sub 30 hz range and at the above 30 hz range. I better start reading up on stand alone EQ boxes. I know there are not many out there but I want to chose one that does not introduce allot of noise into signal path.


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## AudiocRaver

Dwight Angus said:


> I better start reading up on stand alone EQ boxes. I know there are not many out there but I want to chose one that does not introduce allot of noise into signal path.


Of course you want to make a quality choice. About adding noise to the signal path: Natural electronic noise is white noise, with its amplitude increasing with frequency. If the device ends up between the AVR and your subwoofer, any noise above your sub's low-pass filter frequency will get filtered out, and the amount of noise below that will be _extremely_ low - not a big deal, just so you know not to fuss too much over noise specs.

Sounds like you have a plan.:T


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## Dwight Angus

Good to know. So noise produced from low cost eq devices are not audible at low frequencies. How about mid/high frequencies? I plan to measure my mains with rew &may decide to eq them as well depending on the results of the measurement. If I eq 4 channels (2 subs /mains)can I still pursue a low cost eq or an eq with more horsepower?


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## Barleywater

Long sweep from 2Hz would be nice.

also full range with mains.


And Fletcher-Munson curves speak volumes. Few dB rise in bottom octave is trivial.

Please post .mdat of measurement set that shows some better resolution at bottom end.

In previous post:











What appear to be mains noise around 120Hz make quality of result questionable. Whatever it is, it is only about 25dB below most of signal. Yuck.


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## Dwight Angus

I had to redo room measurements. Thanks to JohnM who spotted an error in REW "Soundcard preferences" setup that skewed REW results that I have now corrected.

I have a good idea of what needs to be corrected but wanted to confirm my understanding. The room is bass dominate and clouds mid range frequencies. Need to apply PRE EQ to sub frequencies below 30 hz. I would like to get your feedback as to whether mains would benefit from some additional EQ as well.

Other Information:
HT is dedicated 25ft by 16ft by 8ft
Treatments are DIY plus GIK panels
Subs are co-located mid screen wall


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## Dwight Angus

Thnx Barleywater 

I mentioned in my recent post I submitted more graphs and that noise at 120 hz has disappeared. I used battery power this time and did not plug in my laptop. 

Not familiar with Fletcher-Munson curves. Can you give me more info on this.


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## Dwight Angus

As suggested by Audyssey my crossover is 70 Hz.
Also my dual subs are sealed. Gave me the smoothest response.


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## AudiocRaver

Dwight Angus said:


> Good to know. So noise produced from low cost eq devices are not audible at low frequencies. How about mid/high frequencies? I plan to measure my mains with rew &may decide to eq them as well depending on the results of the measurement. If I eq 4 channels (2 subs /mains)can I still pursue a low cost eq or an eq with more horsepower?


If you purchase an EQ product for full range EQ, then noise is something to consider. Even-low cost products by companies like Behringer are pretty good spec-wise these days. Something to keep an eye on, but you probably will not see much of a difference in specs versus cost. Just a guess.

Not a huge deal, but your latest FR curves show a curious rise of almost 10 dB above 20 kHz. Any idea what that might be from? If it is real, that is a lot of energy working your tweeters for no good reason. I would be trying to figure that one out.

Fletcher Munson curves show hearing sensitivity versus frequency at different levels. There is a newer standard, considered more accurate called equal loudness contours. The equal loudness contours show hearing sensitivity really dropping below 100 Hz, even more so at lower levels.


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## Dwight Angus

AudiocRaver said:


> If you purchase an EQ product for full range EQ, then noise is something to consider. Even-low cost products by companies like Behringer are pretty good spec-wise these days. Something to keep an eye on, but you probably will not see much of a difference in specs versus cost. Just a guess.
> 
> Not a huge deal, but your latest FR curves show a curious rise of almost 10 dB above 20 kHz. Any idea what that might be from? If it is real, that is a lot of energy working your tweeters for no good reason. I would be trying to figure that one out.
> 
> Fletcher Munson curves show hearing sensitivity versus frequency at different levels. There is a newer standard, considered more accurate called equal loudness contours. The equal loudness contours show hearing sensitivity really dropping below 100 Hz, even more so at lower levels.


Thats the part I am wrestling with. If I EQ 30 hz & below and ignore the upper ranges I will be able to forgo noise in upper ranges. I am not sure if I would be able to detect any improvement in the mid to upper frequencies by EQing those upper ranges. To me the biggest payback is to sort out the low frequencies. At least that would remove the cloudiness in the midrange and this would be an audible improvement.
Based on your experience should I just ignore full range EQ or pursue it?

Yeah I noticed that rise above 20 KHz. No idea what that is. It shows up in the left main & right main graphs. Both mains are sitting 4 ft out from screen wall and approx 2 1/2 ft from side parallel walls so there is no boundaries to worry about. I could try moving them & remeasure to see if there is any change. Strange it shows up in both graphs.


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## Wayne A. Pflughaupt

Dwight Angus said:


> I better start reading up on stand alone EQ boxes. I know there are not many out there but I want to chose one that does not introduce allot of noise into signal path.


If you’re only equalizing the subwoofer signal chain, noise isn’t an issue. The cheap BFD will do fine.

If you want to equalize full range (and judging from your Post #12 full range graphs it looks like you’d benefit), you can’t go wrong with a vintage Yamaha YDP2006 parametric EQ. It’s dead silent. Just try to find one that was in a studio or other permanent installation rather than one that was a rental unit or otherwise used for live applications. Here’s some info I posted on it a while back.

Regards, 
Wayne


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## Barleywater

Low frequency measurements are highly suspect; increasing output to below 15Hz is highly unlikely. These results look nothing like results on SVS website. Sealed woofer has got to roll off at some point. If you aren't capturing this, then measurement isn't capturing a real response. 

microphone calibration curve below 20Hz could easily give massive boost that is effectively noise.


What does long sweep from 1Hz-200Hz look like?


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## AudiocRaver

Dwight Angus said:


> should I just ignore full range EQ or pursue it?


XT32 will do a pretty thorough job if the worst LF nodes have been pre-tamed with a few bands of parametric EQ. Sonnie documented that in his Denon AVR review awhile back. That's probably the way I would go.

Barleywater's points are valid, though, might want to make sure your measurements are fully trustworthy before proceeding with any purchases.

A flakey mic calibration curve is a possible cause for the apparent HF rise, too. Might take a close look at that cal file. What is your measurement mic?


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## Dwight Angus

Barleywater said:


> Low frequency measurements are highly suspect; increasing output to below 15Hz is highly unlikely. These results look nothing like results on SVS website. Sealed woofer has got to roll off at some point. If you aren't capturing this, then measurement isn't capturing a real response.
> 
> microphone calibration curve below 20Hz could easily give massive boost that is effectively noise.
> 
> 
> What does long sweep from 1Hz-200Hz look like?


Yeah your right the SVS graph does not line up. I will do a long sweep 1hz - 200 hz and post that.


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## Dwight Angus

AudiocRaver said:


> XT32 will do a pretty thorough job if the worst LF nodes have been pre-tamed with a few bands of parametric EQ. Sonnie documented that in his Denon AVR review awhile back. That's probably the way I would go.
> 
> Barleywater's points are valid, though, might want to make sure your measurements are fully trustworthy before proceeding with any purchases.
> 
> A flakey mic calibration curve is a possible cause for the apparent HF rise, too. Might take a close look at that cal file. What is your measurement mic?


The mic is Minidsp Umik-1. Calibrated by CSL. Just got it last week. A bad calibration file would account for strange measurements at both ends. Better check calibration file. More to come


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## Dwight Angus

Attached is a trace of the calibration txt file and looks ok as it compares to CSL detail. Later today I will run a long sweep (1hz-200hz)


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## Dwight Angus

Attached is a long sweep dual subs (1hz -200hz) without Audyssey xt32. Both subs were measured together and separately and they showed the identical result.


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## Dwight Angus

Black line is the mic trace


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## Phillips

> The mic is Minidsp Umik-1. Calibrated by CSL.


Should be fine and looks ok.

How have you connected to your computer to the receiver e.g. Headphone, HDMI?

Operating system and age of laptop?


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## Dwight Angus

Phillips said:


> Should be fine and looks ok.
> 
> How have you connected to your computer to the receiver e.g. Headphone, HDMI?
> 
> Operating system and age of laptop?


I connected my Dell Inspiron Laptop by HDMI to Onkyo 5508 Preamp. Cable is 25 ft to get from HT back to Tech room. Could cable length be an issue?

Age of laptop 1 year. 
O/S Windows 7 64 bit architecture


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## Dwight Angus

AudiocRaver said:


> XT32 will do a pretty thorough job if the worst LF nodes have been pre-tamed with a few bands of parametric EQ. Sonnie documented that in his Denon AVR review awhile back. That's probably the way I would go.
> 
> Barleywater's points are valid, though, might want to make sure your measurements are fully trustworthy before proceeding with any purchases.
> 
> A flakey mic calibration curve is a possible cause for the apparent HF rise, too. Might take a close look at that cal file. What is your measurement mic?


Yeah I posted the mic calibration trace and it looks ok. Pls comment if you don't agree. I sent an email to SVS and attached the long sweep rew graph and asked them to comment on the graph specifically the spl below 5 hz. Hope to get their response soon


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## Dwight Angus

Wayne A. Pflughaupt said:


> If you’re only equalizing the subwoofer signal chain, noise isn’t an issue. The cheap BFD will do fine.
> 
> If you want to equalize full range (and judging from your Post #12 full range graphs it looks like you’d benefit), you can’t go wrong with a vintage Yamaha YDP2006 parametric EQ. It’s dead silent. Just try to find one that was in a studio or other permanent installation rather than one that was a rental unit or otherwise used for live applications. Here’s some info I posted on it a while back.
> 
> Regards,
> Wayne


Thanks Wayne
Based on my REW graphs it looks like I would benefit from both sub 40hz eq and full range eq. Looks like the Yamaha YDP2006 takes 2 xlr inputs so I would need 2 boxes to control dual subs and left/right mains. Looks like the Yamaha goes down to 20 hz. Just wondering if this is enough given I have to tame frequencies below 30 hz. For that matter I am not aware of any eq that goes below 20 hz so not an issue.

Just stepping back a bit. If I just pre eq the dual subs and then run Audyssey xt32 setup afterwards perhaps Audyssey will now have enough incremental resources to do a better job of full range eq that were previously used to manage sub frequencies. Not sure if this makes sense.


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## Dwight Angus

I adjusted sub room compensation at 25hz 6db with a low Q and it reduced lower end gain allot. Its not perfect but a big improvement. The adjustment dropped low end gain by 20 db at 25 hz. Have not had chance to test it out to see if the change is audible although I suspect it is.

Attached is the revised rew graph


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## Dwight Angus

This is the response I received from Ed Mullen over at SVS. I had attached an REW graph showing significant low end gain and asked for his help.

Hi Dwight -

It looks like the subs are delivering usable response down to 9 Hz, which is pretty awesome. The response at 9 Hz is the same as the average response from 30-100 Hz. What's skewing your perception of frequency response is some excessive room gain in the 12-25 Hz region, manifesting itself as a peak in the response. Were you able to flatten that peak, the FR curve would look essentially flat to 9 Hz. 

The graph starting at 3 Hz is normal - if you see the woofer moving, it's generating sound pressure and REW is picking that up. But again, the usable response limit is ~9 Hz, where the SPL is about the same as 30-100 Hz. 

So based on Ed's response plus validating the calibration file I believe I can rely on the the REW graph as being accurate. Thanks for your help Ed. Appreciate it.


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## Phillips

A long shot but can you try another laptop, why i ask is that i changed laptops and noticed there was a increase in the bass region, it ended up being the laptops soundcard. Purchased a cheap outboard computer soundcard (USB) and was even with the other laptop.

Windows "Sound" plays games with systems.

Is there any settings in Windows 7 "Sound" that might make a difference?

Again just a thought if still have any doubt.


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## Dwight Angus

Hi Phillips
I believe I can rely on the room measurement as it is. I have validated the calibration file and SVS believe it is a valid rew room response. You can read Ed's note above. Now that I have reduced the low end gain I am going to focus on full range eq for the mains. Perhaps the Yamaha YDP2006 or the Xlicia XP4080. Not sure yet.


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## Wizard

Hi Dwight,

Checked Your measurements. They look quite strange as there's according to curves so much energy in really low frequencies. There may be something wrong in the signal coming out from HDMI of Your laptop. Have You checked that there's no DSP-effects of any kind in laptops audio out settings nor in Your amp except EQ?


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## Dwight Angus

Hi 
I rechecked my laptop settings and there are no DSP effects included in room measurements nor any effects from my pre amp


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## Phillips

If you can, as i said in my previous post eliminate this can you try another laptop?

Just a thought.


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## Dwight Angus

Phillips said:


> If you can, as i said in my previous post eliminate this can you try another laptop?
> 
> Just a thought.


Access to another laptop is not likely. I will have to proceed with what I got.


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## Phillips

Dwight Angus said:


> Access to another laptop is not likely. I will have to proceed with what I got.


Ok entirely up to you.

Point is you don't want to adjust via EQ etc if the measurement is not correct.
Just trying to help
I know whats its like to EQ when the measuremnt was incorrect, luckily i had another laptop though.

Does the bass sound excessive etc?


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## Dwight Angus

Phillips said:


> Ok entirely up to you.
> 
> Point is you don't want to adjust via EQ etc if the measurement is not correct.
> Just trying to help
> I know whats its like to EQ when the measuremnt was incorrect, luckily i had another laptop though.
> 
> Does the bass sound excessive etc?


I appreciate the "heads up" Phillips. I will see if I can borrow another laptop for a few hours just to confirm measurements. 

I made a small adjustment on the sub PEQ as follows: 25hz 6 db cut low Q and that really cleaned up the low end. Mid range frequencies were clearer and the muddy low end improved. Still needs some fine tuning but certainly an improvement.


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## Dwight Angus

Ok I have fine tuned speaker & front row seat placement based on REW RTA function & I have attached 2 graphs:

The graph on the left is an average of 3 front seats front row with left main plus subs
The graph on the right is an average of 3 front seats front row with right main plus subs
Audyssey xt32 is on in both graphs.
Dynamic EQ of off
I also used subs parametric EQ 25hz 6 db cut. 

Overall these changes did make an audible improvement. Mid range frequencies are more defined with lower sub frequencies less dominant.


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## Phillips

Looks good

How does the Waterfall graphs look

Also combined left and right with subs.


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## Dwight Angus

Finally got a chance to measure both subs and mains with audyssey.


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## Phillips

Dwight Angus said:


> Finally got a chance to measure both subs and mains with audyssey.


What has changed from the last measurements?


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## Dwight Angus

Phillips said:


> What has changed from the last measurements?


This measurement as well as the last 2 reflect result of adjusted speaker placement and moving front row up 6 inches based on RTA function. The last 2 measurements showed 1)left main plus subs 2) right main plus subs. Todays graph is the combined left and right main plus subs.


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## Phillips

Dwight Angus said:


> This measurement as well as the last 2 reflect result of adjusted speaker placement and moving front row up 6 inches based on RTA function. The last 2 measurements showed 1)left main plus subs 2) right main plus subs. Todays graph is the combined left and right main plus subs.


Do you have in your measurement collection (like we do) the last measurements but both mains/subs playing together like this one?

Also post this waterfall graph.


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## Dwight Angus

This is the equivalent subs/mains graphs that was taken initially. I believe this is what your looking for. I also attached a current waterfall graph.

You can see on the subs/mains graph that I managed to reduce the lower sub frequencies by making an adjustment on the subs parametric EQ. This has helped with some of the muddiness clouding mid range frequencies. Other subtle response improvements between 700hz and 2KZ from moving speakers and seats as per RTA funtion.

Looking at the waterfall graph there is low frequency bloat between 17 hz and 38 hz. Not sure what to do with that. Some additional EQ may help.


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## Dwight Angus

The attached comparison graph show changes from initial measurements to current measurements. Audyssey xt32 in ON Dynamic EQ is OFF.

The red line initial measurements
The blue line is current measurements

You can see the improve in the lower sub frequencies that was causing some muddiness in mid range frequencies.
This has improved audio but there is room for improvement. Audyssey was not able to fix the response in the 20hz and below frequencies. The 15db cut at 10hz was achieved by applying a 20 hz cut on both subs parametric eq with a low Q

Referring to the blue line I have some nasty peaks at 100 hz 200 hz & 300hz. Also the dip around the 70 hz crossover needs some work. 

Not sure where to go from here. I am considering some supplementary EQ to fine tune sub and full range frequencies.

Any ideas.


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## Phillips

What was your crossover again?

Did you reduce the subs volume and re-measure.

I have a DSpeaker Antimode Dual Core 2.0 (to EQ my mains, which is full range and has Auto EQ up to 500HZ and 16 manual filters that can be used really anyway, stereo so it only uses i filter slot instead of two. This EQ has alot of other features as well. This is used for my mains only.

Another option is a second hand Velodyne SMS-1 just for the subs, which is basically the same as whats in my Velodyne Digidtal Drives (i think the real only difference is the Servo control which i don't adjust anyway). REW has this EQ in the "EQ tab" as a auto feature, so easy to use, just dial in the exact filters that REW suggests, done. Then see the difference in the vwatrfall grpah. I re - mesured and was very very close to the predicted response. Also the Velodyne has 5 presets for different types, music, movies etc. What i did was have a reference that was music and then tried to better that, personal preference. 

Can you post the .mdat files?


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## Dwight Angus

Phillips said:


> What was your crossover again?
> 
> Did you reduce the subs volume and re-measure.
> 
> I have a DSpeaker Antimode Dual Core 2.0 (to EQ my mains, which is full range and has Auto EQ up to 500HZ and 16 manual filters that can be used really anyway, stereo so it only uses i filter slot instead of two. This EQ has alot of other features as well. This is used for my mains only.
> 
> Another option is a second hand Velodyne SMS-1 just for the subs, which is basically the same as whats in my Velodyne Digidtal Drives (i think the real only difference is the Servo control which i don't adjust anyway). REW has this EQ in the "EQ tab" as a auto feature, so easy to use, just dial in the exact filters that REW suggests, done. Then see the difference in the vwatrfall grpah. I re - mesured and was very very close to the predicted response. Also the Velodyne has 5 presets for different types, music, movies etc. What i did was have a reference that was music and then tried to better that, personal preference.
> 
> Can you post the .mdat files?


Hi Phillips
The crossover is 70hz as set by Audyssey xt32. I measure at 75db consistently or as close as possible. The only volume adjustment is to get me to 75db. I use REW spl meter.

I have been looking at Antimode Dual Core 2.0 seems to do everything I need. Can I use the Dual Core and then use Audyssey xt32 after for the final pass? If so how does Audyssey treat parameters set by Dual Core? I hope Audyssey does not override them. I got a lead on a reconditioned Xilica XP4080 PEQ. Its got 4 XLR inputs and 8 outputs with 16 bands of PEQ per channel. So I could connect both subs and mains and as you suggested "y" connect the sub output at my preamp.

Every time I try to post mdat files I screw it up. I'll go back and try to find out how to do it.
I appreciate your assistance Phillips it really has helped me move forward with this process.

Cheers


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## Dwight Angus

Ok I am posting some mdat files


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## Phillips

Could you post the non average files, these don't give enough info?

Have you tried reducing the subs level/volume?


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## Dwight Angus

Phillips said:


> Could you post the non average files, these don't give enough info?
> 
> Have you tried reducing the subs level/volume?


Sub levels volume has already been reduced. Speakers are calibrated to 75 db and subs to 61db. These settings are reflected in REW graphs.

I will send non average files later today.


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## Dwight Angus

Dwight Angus said:


> Sub levels volume has already been reduced. Speakers are calibrated to 75 db and subs to 61db. These settings are reflected in REW graphs.
> 
> I will send non average files later today.


Audyssey xt32 sets sub trim levels to +1 on both subs.


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## Dwight Angus

I need to clarify. REW graphs volume calibrated to 75db for subs.


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## Phillips

Please post measurements with the subs reduced level by 2,4,6,8, db, don't take ant notice of the SPL reading just the flatness of the transition from mains and subs in the frequency response graph.

This is to do with your original graph, mains + subs.


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## Dwight Angus

So I 'm clear. You want to revisit the first graph that showed all that low frequency gain below 20 hz. Since then I have cut that gain by using subs parametric eq. So do you want me to bypass parametric eq to increase low frequency gain or just reduce db with parametric eq engaged?


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## Phillips

Dwight Angus said:


> So I 'm clear. You want to revisit the first graph that showed all that low frequency gain below 20 hz. Since then I have cut that gain by using subs parametric eq. So do you want me to bypass parametric eq to increase low frequency gain or just reduce db with parametric eq engaged?


Yep no PEQ (except for Audyessy) as per post 45.


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## Dwight Angus

Ok. This graph show reductions in sub volume totalling 8 db. The .mdat files would not load. I will try loading them again later


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## Phillips

Also include the just the subs graph with the crossover disengaged.


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## Dwight Angus

I have attached a sub graph and ran crossover out to 200hz. Onkyo 5508 preamp runs down crossover options to full band and then doesn't recognize subwoofer and redirects LFE to main speakers so I ran crossover to its highest level option which is 200hz.

Still having problems with .mdat files and cannot load any.mdat files.


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## Phillips

Dwight Angus said:


> I have attached a sub graph and ran crossover out to 200hz. Onkyo 5508 preamp runs down crossover options to full band and then doesn't recognize subwoofer and redirects LFE to main speakers so I ran crossover to its highest level option which is 200hz.
> 
> Still having problems with .mdat files and cannot load any.mdat files.


My posts won't be prompt like they have been.

Ok looks good except for that peak/mode at about 150hz what does the waterfall look like?

How do you mean you can't post the .mdat files, nothing happens etc.


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## Dwight Angus

Phillips said:


> My posts won't be prompt like they have been.
> 
> Ok looks good except for that peak/mode at about 150hz what does the waterfall look like?
> 
> How do you mean you can't post the .mdat files, nothing happens etc.


Yeah saw that peak at 150 hz. Will eq that out.
I had to reload REW as .mdat and EQ filters tab not responding.


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## Dwight Angus

Here is the .mdat attachment for the sub/room response out to 200hz


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## Dwight Angus

After deinstalling and reinstalling REW I can access EQ filters tab and upload .mdat files. Problem solved.


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## Dwight Angus

Hope to post new graphs shortly after installing PEQ.


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## Dwight Angus

I have attached 3 graphs after applying peq. Still needs some work but already a big audio improvement.
I have reduced the lower sub frequencies that were over whelming mid frequencies. Now I can here those mid frequencies. 
Graph 1- subs
Graph 2- subs plus left main
Graph 3- subs plus right main

Filters have been applied as follows:
subs- 3 filters
left main -2 filters
right main- 3 filters

I avoided applying any filters around Excess Group delay peaks as I understand that no amount of eq can alter those results. 

Can you tell me if I am on the right track or are there areas of concern that I need to focus on?


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## Dwight Angus

In the sub graph. Can someone tell me what is happening between 120hz-180hz? I have a LPF set at 120hz. & any frequencies above 120 hz should roll off. It does seems to be following the lpf downwards trend line from about 100 hz on wards but the tallest peak is approx 62 db at 128 hz and perhaps audible.


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## Wayne A. Pflughaupt

Dwight Angus said:


> In the sub graph. Can someone tell me what is happening between 120hz-180hz?


Assuming you’ve done the SPL calibration, the level is pretty low in that range – it might simply be ambient noise in the room.

Regards, 
Wayne


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## Dwight Angus

Thanks Wayne

REW setup looks ok and as you pointed out the level is low so I will ignore it.


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## Dwight Angus

Referring to the right main plus subs graph it shows a suck out at 68hz. That dip is absent when looking at either the sub graph separately. I tried to adjust sub distance but although the adjustment changed the shape of the dip it remains. When looking at EXCESS GROUP DELAY there is a peak at 70 hz that corresponds closely to the dip at 68hz. 

Some questions
Is the dip audible?
How to fix the dip? (If the dip is audible I suspect my only option is to move MLP or speakers & remeasure
to see if the dip is corrected.


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## Phillips

Looking at your mdat measurements you seem to be only posting Averaging not individuals as averaging restricts data.


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## Dwight Angus

Phillips said:


> Looking at your mdat measurements you seem to be only posting Averaging not individuals as averaging restricts data.


Yeah. I am using averages to measure HT front row. I will show some individual graphs shortly.


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## Dwight Angus

Attached are 3 graphs as follows:

1) subs
2)left plus subs
3)right plus subs

Referring to 2 & 3 this is large dip at 70 hz does not respond to eq I suspect it has something to do with Excess Group Delay as it shows large peak at that frequency. Need help with this one


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## Phillips

Ok what is your crossover?
The subs look pretty good. I presume you are treating the subs as mono?

A good idea is to measure and post everything full range mains and subs separate and together.
Another thing to is to save any settings or measurements from shifting speakers etc in a book etc.

One easy thing to do is move the mic around while playing the RTA to see any improvements, but could also make others not so good.

Adjust the  sub distance setting to get the flattest response from the lowest to the highest sub frequency
Then adjust the phase on the sub/s

Please post full range measurements form the mains (separately and together) and with the crossover set to max or turned off on the sub.

How many filters have you used from 250hz up on the mains? 
I would only use mono (same for each channel) filters from 0 - 250hz


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## Dwight Angus

Phillips said:


> Ok what is your crossover?
> The subs look pretty good. I presume you are treating the subs as mono?
> 
> A good idea is to measure and post everything full range mains and subs separate and together.
> Another thing to is to save any settings or measurements from shifting speakers etc in a book etc.
> 
> One easy thing to do is move the mic around while playing the RTA to see any improvements, but could also make others not so good.
> 
> Adjust the sub distance setting to get the flattest response from the lowest to the highest sub frequency
> Then adjust the phase on the sub/s
> 
> Please post full range measurements form the mains (separately and together) and with the crossover set to max or turned off on the sub.
> 
> How many filters have you used from 250hz up on the mains?
> I would only use mono (same for each channel) filters from 0 - 250hz


Crossover is set to 80 hz but I will try other settings to bypass the 70 hz dip when combining mains/subs
Yes subs are setup as mono.
I have adjusted the distance setting to minimize the 70 hz dip but has little effect. Also phase adjustments have little effect. Best results are with phase settings at zero as recommended by Audyssey.
The dip does not show up on the subs only graph or mains only graph only when combined. Implies some cancellation or some group delay issue as I have a corresponding peak referring to minimus phase graph.

Don't have allot of room to move speakers but I can make small adjustments to seating front row distances. Subs look good so no need to move them so I am focusing only on mains/front row seats

I will run full range mains/subs with xo turned off and post shortly. Cheers


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## Dwight Angus

Finally got a chance to do more work on subs room response & eq. I managed to remove allot of the low sub frequency muddy response that clouded mid range frequencies. I loaded a low shelf filter at 20 hz and 3 additional filters at 25/35/50. There is a better blend subs/mains without subs dominating the HT. I took the time to listen to music and watch a few movies to detect changes. Music is clearly defined and more enjoyable. Movies don't have as much slam but I need to get more familiar with the new sound to see if its what I want.
I have been reading up on HOUSE CURVES to find out what I need to do if I go down this road.

I have attached my latest rew sub graph. If I decide I want to build a house curve not sure on the approach as my sub response is already fairly flat (30hz to 70hz). 

Your suggestions on my house curve approach are appreciated.


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## Phillips

Your subs crossovers now are set too?

4 x more filters to apply as a play on top off the measurement posted, *make sure you take note of your current filter settings.*

20hz G - 5.0 BW 0.20
29hz G - 3.5 BW 0.32
40hz G - 5.0 BW 0.36
52hz G - 5.5 BW 0.36

Can you send a measurement with your loaded low shelf filter at 20 hz in place and with no crossover set (either turned off or turned up to max) or filters (other than the low shelf).


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## Dwight Angus

Just to clarify. Are the 4 extra filters positive or negative gains? I will just set up a additional profile to house the new filter scenario.

For the 2nd sweep I cannot shut off the xo but I can turn it up to a max of 200hz so that will suffice.


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## Phillips

> Just to clarify. Are the 4 extra filters positive or negative gains?


They are all negative gains.



> I will just set up a additional profile to house the new filter scenario.


Good idea, the above filters are on top of whatever was in the posted file.



> For the 2nd sweep I cannot shut off the xo but I can turn it up to a max of 200hz so that will suffice.


Good


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## Dwight Angus

Ok. I have attached 2 graphs as follows:

1) The first one show the subs response when adding you suggested filters to mine. It certainly looks better. Thanks for your suggestions. I will listen to this setup when I have some time to see if I can detect any audible difference. You will notice there is a slight rise at about 53 hz to 73 hz. I ignored this area as my xo is 70 hz and any filters added in this area probably would be overridden by the mains. 

2) The 2nd graph shows the subs response when using only the low shelf filter at 20hz without any other filters & raising the xo to 200hz. Not sure why this graph appears so flat with only the low shelf filter employed as I bypassed the other filters. Better double check this.


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## Phillips

> 1) The first one show the subs response when adding you suggested filters to mine. It certainly looks better. Thanks for your suggestions. I will listen to this setup when I have some time to see if I can detect any audible difference. You will notice there is a slight rise at about 53 hz to 73 hz. I ignored this area as my xo is 70 hz and any filters added in this area probably would be overridden by the mains.


Attached are added suggested filters.

I have posted them as one file.

View attachment subs.mdat




> 2) The 2nd graph shows the subs response when using only the low shelf filter at 20hz without any other filters & raising the xo to 200hz. Not sure why this graph appears so flat with only the low shelf filter employed as I bypassed the other filters. Better double check this.


Yeah could be a good idea, but again i have given suggested filters as well.

With both measurements there was some decay around the 30hz that i was able to reduce.

Let me know what you think, for music they should be good, movies very dependent on taste / use to.

Hope this helps


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## Dwight Angus

Thanks Phillips
Looking at the Spectrogram after adding your extra filters has removed the majority of the "hot spots" except for that "hot spot" around 70 hz. Remember this was the area I avoided adding a filter due to proximity to the 70hz xo. Spectrogram looks much better. 

Waterfall also has improved except there is some ringing at 20-30hz. I am not going to chase this area as I would probably give up too much in terms of bass response & can add some add'tl bass trapping in future. Although at frequencies this low they will need be tuned traps to be effective. 

I see you have suggested some addt'l filters to further smooth out the response in the auto eq section. One of the filters is 89 hz but my xo is 70 hz. Should I include this one? 

I certainly appreciate your help. 
Cheers!


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## Dwight Angus

I see what happened. You added the 89 hz filter to the 10 hz -200hz sweep without xo. Perhaps I should ignore this one. Not sure.


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## Phillips

> Thanks Phillips
> Looking at the Spectrogram after adding your extra filters has removed the majority of the "hot spots" except for that "hot spot" around 70 hz. Remember this was the area I avoided adding a filter due to proximity to the 70hz xo. Spectrogram looks much better.


You are welcome
Add all the filters including the ones above the crossover, measure with the speakers in play and adjust from there, they might still have a effect or they might not.
With my Velodyne Digital Drive 15 and 12 i mostly add the filters that are 1 octave above the crossover, i was advised to do this.



> Waterfall also has improved except there is some ringing at 20-30hz. I am not going to chase this area as I would probably give up too much in terms of bass response & can add some add'tl bass trapping in future. Although at frequencies this low they will need be tuned traps to be effective.


I was able to reduce that 30hz range with fine manual adjustment on both measurements.
Quite right i wouldn't chase that either.



> I see you have suggested some addt'l filters to further smooth out the response in the auto eq section. One of the filters is 89 hz but my xo is 70 hz. Should I include this one?


Yes as above



> I certainly appreciate your help.
> Cheers!


No worries at all, enjoy it.


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## Phillips

Dwight Angus said:


> I see what happened. You added the 89 hz filter to the 10 hz -200hz sweep without xo. Perhaps I should ignore this one. Not sure.


Yes you should but you can adjust when the mains are in play, look at the decay.

With room treatment i think from about 60hz down is very hard to treat with bass traps.

If you look at the Acoustic thread you will most likely find something there.

Good you have profiles, that's what i like about the Velodyne (x 5 spare) and DSpeaker Anti Mode Dual Core 2.0 (x 3 spare). I use certain profiles as a reference and play withe the rest as a challenge to beat the reference.

Looks like you should have headroom with the subs?
With my DD15 it is great with music and for music it runs at 5 out of a 100 and for movies 7 - 9 out of 100.

Post the results if you wouldn't mind.


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## Dwight Angus

Phillips said:


> Yes you should but you can adjust when the mains are in play, look at the decay.
> 
> With room treatment i think from about 60hz down is very hard to treat with bass traps.
> 
> If you look at the Acoustic thread you will most likely find something there.
> 
> Good you have profiles, that's what i like about the Velodyne (x 5 spare) and DSpeaker Anti Mode Dual Core 2.0 (x 3 spare). I use certain profiles as a reference and play withe the rest as a challenge to beat the reference.
> 
> Looks like you should have headroom with the subs?
> With my DD15 it is great with music and for music it runs at 5 out of a 100 and for movies 7 - 9 out of 100.
> 
> Post the results if you wouldn't mind.


The room is acoustically treated & includes bass traps. A while back I contacted the folks at GIK about tuned traps in the 30-40hz range and they suggested the Scopus tuned traps. They measure 2 feet square by 10 inches thick. Based on my room response they suggested 8 tuned traps were required. You can hang them or stack them. 
This maybe an option for me. I just need to find some available space in my dedicated HT. 

Yeah I can set up to 30 profiles on my Xilica 4080 PEQ so lots of flexibility. I organized profiles by audience ie a profile for only mlp and then another for mlp plus one other seat and another profile for front row of 3 seats. The sweeps are of course averages based on the # of seats. I realize this will have to change as I need to create profiles for music vs movies. A very flat sub woofer response will work for music but I need more chest slam for movies so # profiles will expand as I work through my learning curve of the peq and build profiles that my ears appreciate.

Perhaps a silly question. Can you explain " for music it runs at 5 out of a 100 and for movies 7 - 9 out of 100". Not sure what you are referring to here.

Once I get everything dialed in I will post the results.

Cheers


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## Phillips

T


> he room is acoustically treated & includes bass traps. A while back I contacted the folks at GIK about tuned traps in the 30-40hz range and they suggested the Scopus tuned traps. They measure 2 feet square by 10 inches thick. Based on my room response they suggested 8 tuned traps were required. You can hang them or stack them.
> This maybe an option for me. I just need to find some available space in my dedicated HT.


Oh ok wasn't aware of these specially in the 30-40hz range, wonder how effective they are. 



> Perhaps a silly question. Can you explain " for music it runs at 5 out of a 100 and for movies 7 - 9 out of 100". Not sure what you are referring to here.


No such thing as a silly question

Sorry I left out *volume / level* so the DD15 is just idling. 



> Once I get everything dialed in I will post the results.


That would be good

This is what Antimode did for my mains floorstanders only, no sub included in these measurements.


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## Dwight Angus

The Scopus traps are available in different sizes to treat different tuned frequencies ie the 30 to 40hz range are larger dimensions then treatment required at higher frequencies. Not sure about performance. I believe available in various colour schemes.

Your comparison of floorstanders with Antimode vs no EQ is dramatic specifically in the 20 to 250 hz range. The 40 to 80 hz dip is gone. Nice job. Did you load any filters higher then 250 hz? I try to limit them no higher then 250 hz range.


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## Phillips

> The Scopus traps are available in different sizes to treat different tuned frequencies ie the 30 to 40hz range are larger dimensions then treatment required at higher frequencies. Not sure about performance. I believe available in various colour schemes.


Interesting let me know if you get them the results.



> Your comparison of floorstanders with Antimode vs no EQ is dramatic specifically in the 20 to 250 hz range. The 40 to 80 hz dip is gone.


Yeah pretty good all automatic too. Absolutely no bass traps used.

Did you load any filters higher then 250 hz?

Yes i have on the reference profile, think it was three.
These were used in Stereo (exactly the same for both) so EQ the speakers not the room. I did close mic measurements etc.



> I try to limit them no higher then 250 hz range.


Good if you can, i had a couple of issues that needed to be addressed.

I have EQed flatish and it sounds exactly that flat, no life at all, so i went down the other direction, talking 2 channel here.


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## Dwight Angus

So you eq'd in stereo above 250hz. Interesting approach. I will have to remember this if I decide to eq above 250hz.

Your eq results are amazing & with no bass traps. It gives me hope.


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## Phillips

> So you eq'd in stereo above 250hz. Interesting approach. I will have to remember this if I decide to eq above 250hz.


If you look at the trend of left and right main and see if a stereo filter will do the trick.



> Your eq results are amazing & with no bass traps. It gives me hope.


Yeah not bad, but only one done with MLP.

The interesting thing with DSpeaker Anti Mode is that more positions (as many as you like i hear) can be added later and it adds to the existing measurement. 

I think manually play with the filters in REW to fine tune, thats what i did with your measurements.


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## Dwight Angus

I have attached my left/right mains with no eq. Left is red right is blue. Don't see many similar responses that would benefit from stereo filters. When I get a chance I will remeasure just to confirm. The room is assymetrical and there is HVAC running along ceiling above right main so ceiling height is shorter vs left main.

I hope to take more measurements early next week. Hard to find the time.


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## Phillips

Cool see how some of the frequencies cancel each other out.

When you do measurements like this again just add both together as well and you will see what i mean.


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## Dwight Angus

Ok. Will do.


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## Dwight Angus

Finally got some time to eq l/c/r The attached graph shows the average response for 3 seats HT front row with eq applied. 

Ctr channel - green 5 filters
Left Channel - gold 6 filters
Right Channel - Red 6 filters


For the mains/ctr channel I did not apply filters higher then 300 hz. According to REW auto eq function there were approx 15 filters out to 1000 hz suggested per channel but I limited them to only the worst problem frequencies 80 hz to 300 hz.

Just looking for some feedback on the approach
Cheers


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## Phillips

Sorry i meant Left, Right and Both together.


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## Dwight Angus

Ok here is the left & right main plus combined.

Left is red
right is green
combined is blue.

The combined shows a large dip at 700hz to about 1.7khz. Not sure what to make of that. I don't normally measure both mains together. Not sure if mic can accurately measure both speakers simultaneously.


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## Phillips

> The combined shows a large dip at 700hz to about 1.7khz.


Yes also at 400hz though the mentioned is broader, can happen if you averaged over more than one listening position, and used filters around this area.

Take a average of left and right and see how that looks, will look better.



> I don't normally measure both mains together. Not sure if mic can accurately measure both speakers simultaneously.


Yes it should


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## Dwight Angus

Hey Phillips
This measurement was only at mlp with only 1 measurement & does not include averages over several listening position.l


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## Dwight Angus

The profile I used is for mlp so not covering other seats. Also I did not use filters in the 700hz to 1.7khz range. Is the dip a result of cancelled frequencies from both speakers. Does not show up in the left or right speaker measurements (uncombined)


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## knuklhed

*Waterfall Data*

I've seen somewhere people referring to getting these graphs and data analyzed by some one . Who is that and How:scratch: ? I watched the Video On making measurements. Awesome :clap:. Id there one on looking and graphs and Reading the data ? :dontknow:


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## Phillips

> Is the dip a result of cancelled frequencies from both speakers. Does not show up in the left or right speaker measurements (uncombined)


I wondered that too.

Try and move the Mic around a little to see if that makes any difference.


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## Wayne A. Pflughaupt

Dwight Angus said:


> For the mains/ctr channel I did not apply filters higher then 300 hz.
> 
> Just looking for some feedback on the approach.


It’s fine to apply filters above 300 Hz. However, for the left and right channels they probably should be matching. At least that’s what I found with 1/3-octave equalizers: If the filters above ~300 Hz didn’t match, I could tell it was doing weird things to the imaging. Might be a different story with parametric equalization, though, since filters can be precisely matched to the problem. But it’s something to be aware of and listen for.

Regards, 
Wayne


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## Dwight Angus

Wayne A. Pflughaupt said:


> It’s fine to apply filters above 300 Hz. However, for the left and right channels they probably should be matching. At least that’s what I found with 1/3-octave equalizers: If the filters above ~300 Hz didn’t match, I could tell it was doing weird things to the imaging. Might be a different story with parametric equalization, though, since filters can be precisely matched to the problem. But it’s something to be aware of and listen for.
> 
> Regards,
> Wayne


Ok so I will apply stereo filters where appropriate. Looking at the # 96 measurement there are similar peaks & dips in the L&R portions of the measurement and they are above 300 hz. Once completed I will take your advice Wayne and listen for any imaging issues.

For the combined response I will take measurements around the MLP to see if it improves. FYI I am pointing the Umik 1 at the centre channel for combined Left/Right channel measurements or the mid point between both speakers. Will post results later today.


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## Phillips

> It’s fine to apply filters above 300 Hz. However, for the left and right channels they probably should be matching. At least that’s what I found with 1/3-octave equalizers: If the filters above ~300 Hz didn’t match, I could tell it was doing weird things to the imaging. Might be a different story with parametric equalization, though, since filters can be precisely matched to the problem. But it’s something to be aware of and listen for.


Exactly what i have done, less filters (in Antimode Dual Core) and able to retain the imaging.

I tried eq speakers separately and got a flat response but lost imaging. Each speaker where closely matched with peaks and nulls.

Then able to use the tilt controls (tone controls) in the Antimode to adjust to taste.

Funny i thought flat was the ultimate, but this sounds exactly what it is called "flat" sounding. 

Having profiles is a good advantage to switch on the fly.


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## Dwight Angus

Finally had sometime to take some measurements. Attached is the left/right mains & also the combined response.

Red is left main
Purple is right main
Gold is combined.

Not sure what else to do at this stage other then to listen to music/movies to see if I like the result. I could perhaps use GEQ to adjust to personal taste.


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## Phillips

Bit hard to see but yeah i would listen, your ears are the final taste test i wouldn't use a graphic EQ just a Parametric EQ to fine tune.


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