The Official Dirac Live Thread: Start w/1,2,3 🙋‍♂️

[ttocs]

FW-2.2
Dirac 3.0.11
Center Sub channel is only Subwoofer channel used.

Confirming that Bass below 70Hz is bumped up 6dB !!! Then it gets worse . . .

Left setup as Large vs Small, the difference in bass when using the subwoofer for bass is 10dB. Not a typo, 10dB. Setup as Large, REW measures the Left channel below 100Hz as 67dB, but when setup as Small it jumps to 77dB below 70Hz with the Subwoofer channel supplying the bass below 80Hz. But, the jump up in bass level below 70Hz happens when measuring only the Subwoofer channel, so there's something really wrong here.

This bass problem is only for the Subwoofer channel, in my case the Center Sub, and doesn't matter if setup as LFE or Mono, same result.

I had a Movie Night! this week and watched Batman Begins and The Dark Knight, both are bass intensive mixes, and just before my guests arrived was the first time I had run Dirac since FW-2.2. I had to chase the Subwoofer channel trim down as we went by watching a SPL meter at scenes with extra effects. Quiet speaking was below 70dB, normal speaking was 76ish-dB. Before running the first movie I already set the subwoofer down a little, but after hitting 112dB I cranked it down to -6dB trim, then two more, then two more for a total of -10dB trim. This was simply my ears saying it's too loud while checking the meter, and after trimming down the Subwoofer I also lowered the volume and also raised the Center channel +4dB to be able to hear the quiet dialogue.

Today I ran REW and was surprised that my 10dB of too much bass for those movies matched what REW found. I was expecting REW to measure that as a little bit lower, but I guess my ears are calibrated correctly.

Before updating to FW-2.2 I had been using Dirac 3.0.11 without these anomalies.

edit: It turns out that the Left Large vs Small mentioned above now with strike through was due to the processor needing a Mode Change after changing settings. After doing the measurements I wanted to make sure of some things so I did a LPS reboot and that was the only thing not repeatable, but I later discovered that it was due to changing the XO setting and the volume level was wacky and can be put back to normal by a simple Audio Mode change and back. Subwoofer is still boosted even though the Sub Channel is adjusted in Levels same as before. It seems to be about 5-6dB higher than previous firmware.

edit2: 
This is what was measured with previous firmware. The Center Small is at the same level below 100Hz as the Left Large, as are all the other Small channels. The Subwoofer level is about 7dB higher.


This is with FW2.2. The Subwoofer is now 12dB higher level than the Left Large, but now the Small channels are at a higher level than the Left Large by a few dB as is the case with Left Small and Center Small in this plot and all other Smalls. So it would appear that the Subwoofer is around 5dB more than previous firmware and brings the Small channels with it, but leaving the Large channels where they were before.

[leonski]

At some point with all that boost, aren't you going to run out of amplifier power? 10cb is 10x the power while 6db is 4x the power. At higher levels that could be an issue.

[richb]

Possible Bug: ATV4K 2.0 upmixer is not user the center subwoofer output

I run my 5.1 system with FR/FL Large, center small, rears Large, and center subwoofer.
With ATV4K 2.0 content the upmixer is not sending anything to the subwoofer.

It may be that the upmixer is not sending any low frequencies to the center so it may not be a bug.
I'll have to try setting my mains to small to see if the subs are engaged.

- Rich

[vmbray]

Feb 26, 2021 16:32:30 GMT -5 ttocs said:

Subwoofer is still boosted even though the Sub Channel is adjusted in Levels same as before. It seems to be about 5-6dB higher than previous firmware.

Interesting, I re-ran Dirac on 2.2 today and did not see that, not saying it didn’t happen of course just saying didnt happen here. I did still have bright somewhat fatiguing midrange and wanted to do a better comparison to no eq. Used the db meter in rew and the white noise levels to try to set both presets to the same levels, of course that’s not going to be perfect due to spectral balance but it helped. Wanted to make sure the overall level wasn’t the reason it sounded bright, and it wasn’t. The Dirac result is more dialog intelligibility but at the expense of a slightly harsh edge to the sound, enough to notice. The Dirac sounded better in ways but for loud listening it’s not as smooth here and makes you reach to turn it down not up. Just my .02 and not completely scientific but I tried. This is just sub channel because I was mainly trying to figure out why the bass on the non-dirac sounded better but sub trim was not changed, only the other channels to balance fwiw. Brown is dirac, blue is no eq. 

[ttocs]

Feb 26, 2021 16:32:30 GMT -5 ttocs said:

FW-2.2
Dirac 3.0.11
Center Sub channel is only Subwoofer channel used.

Confirming that Bass below 70Hz is bumped up 6dB !!! Then it gets worse . . .

Left setup as Large vs Small, the difference in bass when using the subwoofer for bass is 10dB. Not a typo, 10dB. Setup as Large, REW measures the Left channel below 100Hz as 67dB, but when setup as Small it jumps to 77dB below 70Hz with the Subwoofer channel supplying the bass below 80Hz. But, the jump up in bass level below 70Hz happens when measuring only the Subwoofer channel, so there's something really wrong here.

This bass problem is only for the Subwoofer channel, in my case the Center Sub, and doesn't matter if setup as LFE or Mono, same result.

I had a Movie Night! this week and watched Batman Begins and The Dark Knight, both are bass intensive mixes, and just before my guests arrived was the first time I had run Dirac since FW-2.2. I had to chase the Subwoofer channel trim down as we went by watching a SPL meter at scenes with extra effects. Quiet speaking was below 70dB, normal speaking was 76ish-dB. Before running the first movie I already set the subwoofer down a little, but after hitting 112dB I cranked it down to -6dB trim, then two more, then two more for a total of -10dB trim. This was simply my ears saying it's too loud while checking the meter, and after trimming down the Subwoofer I also lowered the volume and also raised the Center channel +4dB to be able to hear the quiet dialogue.

Today I ran REW and was surprised that my 10dB of too much bass for those movies matched what REW found. I was expecting REW to measure that as a little bit lower, but I guess my ears are calibrated correctly.

Before updating to FW-2.2 I had been using Dirac 3.0.11 without these anomalies.

edit: It turns out that the Left Large vs Small mentioned above now with strike through was due to the processor needing a Mode Change after changing settings. After doing the measurements I wanted to make sure of some things so I did a LPS reboot and that was the only thing not repeatable, but I later discovered that it was due to changing the XO setting and the volume level was wacky and can be put back to normal by a simple Audio Mode change and back. Subwoofer is still boosted even though the Sub Channel is adjusted in Levels same as before. It seems to be about 5-6dB higher than previous firmware.

edit2: 
This is what was measured with previous firmware. The Center Small is at the same level below 100Hz as the Left Large, as are all the other Small channels. The Subwoofer level is about 7dB higher.
View Attachment

This is with FW2.2. The Subwoofer is now 12dB higher level than the Left Large, but now the Small channels are at a higher level than the Left Large by a few dB as is the case with Left Small and Center Small in this plot and all other Smalls. So it would appear that the Subwoofer is around 5dB more than previous firmware and brings the Small channels with it, but leaving the Large channels where they were before.
View Attachment

Well, the stuff I striked through above is actually corroborated in this plot, so what I thought was an anomaly is for real. With the Fronts setup as Large, the Center Sub as LFE, all the Bass Managed Small speaker bass goes to the Large Fronts. That bass is shown going at a higher peak than even the LFE channel, which carries no bass for Small speakers. Keep that in mind, LFE is only for Low-Frequency Effects, not Bass Management.

Firmware 2.2 is different from the previous firmware. I reverted back to 2.1 today to verify. This REW plot is with FW-2.2 and the system is setup with Large Fronts and Center Sub=LFE. Teal is LFE, Blue&Red are the Large Fronts, the purple dashed line is both Fronts together, and the dotted lines are the Small Center and Surrounds. The Small channels should be no higher than the dashed line.


Also note that all the Small channels meet up with the Large Fronts above 130Hz.

[vmbray]

Did you try setting the mains to small to see if it corrected? As in is it a bug just when mains are large? I was hoping to sweep all the channels on both presets but ran out of time. 

Also noticed that my ears and dirac said the center was about the same level as the mains but rew says it's 1.5 db hot, which makes sense because it's closer to mlp, at least seems to make sense.

[ttocs]

Feb 27, 2021 23:33:18 GMT -5 vmbray said:

Did you try setting the mains to small to see if it corrected? As in is it a bug just when mains are large? I was hoping to sweep all the channels on both presets but ran out of time. 

Also noticed that my ears and dirac said the center was about the same level as the mains but rew says it's 1.5 db hot, which makes sense because it's closer to mlp, at least seems to make sense.

You mean, like this? Here is Fronts Small and Center Sub=Mono.


This shows that the Subwoofer is about 7dB higher than all the speakers.

[vmbray]

Feb 27, 2021 23:56:00 GMT -5 ttocs said:

This shows that the Subwoofer is about 7dB higher than all the speakers.

Your pic isn't working there. I'm wondering if the bright thing I'm experiencing is possibly due to room treatments confusing dirac? I didn't have this result before adding a ceiling cloud (4'x6' 4" thick 703 hung below the ceiling which is a 7.5' attic peak). I might be a little overdamped and have been meaning to add some slats to the surface or rearrange things, but the sloped ceilings and low ceiling and so on causes some serious mayhem when not treated. Anyway dirac doesn't have a setting for room treatments so it may be expecting to be in a less treated room. Their page seems to suggest this in the studio section where it says "Traditionally, acoustic room treatments have been used to address these issues; however, this method takes substantial resources and time, and still fails to resolve some of the key acoustical challenges.". They might say treatments don't matter because you're measuring but it sure seems like once I think about it more it started when I added the cloud.

Interesting testing from Ethan Winer that I hadn't read before that is more centered on bass response but points out that some things are made better and some worse by dirac. I was also frustrated again that dirac doesn't show you what it's done, and there's no way to tweak the adjustments. You are left not knowing how much boost it's added or where, you can't use the distances it sees as a baseline for your own manual eq, and it's a black box once done. If I get time I'll run some sweeps full range to see if it's doing the sub thing you see. I'm not giving up on it but I will work more on my manual setup as far as manual parametric eq, more precise distances, levels, etc. for two reasons. One to have a better A-B comparison to dirac results the overall response and levels need to be as close as possible. Second because the manual setup still sounds better and plays louder comfortably.

[marcl]

Feb 28, 2021 8:40:02 GMT -5 vmbray said:

Feb 27, 2021 23:56:00 GMT -5 ttocs said:

This shows that the Subwoofer is about 7dB higher than all the speakers.

Your pic isn't working there. I'm wondering if the bright thing I'm experiencing is possibly due to room treatments confusing dirac? I didn't have this result before adding a ceiling cloud (4'x6' 4" thick 703 hung below the ceiling which is a 7.5' attic peak). I might be a little overdamped and have been meaning to add some slats to the surface or rearrange things, but the sloped ceilings and low ceiling and so on causes some serious mayhem when not treated. Anyway dirac doesn't have a setting for room treatments so it may be expecting to be in a less treated room. Their page seems to suggest this in the studio section where it says "Traditionally, acoustic room treatments have been used to address these issues; however, this method takes substantial resources and time, and still fails to resolve some of the key acoustical challenges.". They might say treatments don't matter because you're measuring but it sure seems like once I think about it more it started when I added the cloud.

Interesting testing from Ethan Winer that I hadn't read before that is more centered on bass response but points out that some things are made better and some worse by dirac. I was also frustrated again that dirac doesn't show you what it's done, and there's no way to tweak the adjustments. You are left not knowing how much boost it's added or where, you can't use the distances it sees as a baseline for your own manual eq, and it's a black box once done. If I get time I'll run some sweeps full range to see if it's doing the sub thing you see. I'm not giving up on it but I will work more on my manual setup as far as manual parametric eq, more precise distances, levels, etc. for two reasons. One to have a better A-B comparison to dirac results the overall response and levels need to be as close as possible. Second because the manual setup still sounds better and plays louder comfortably.

A few thoughts ....     First to the bright thing, I have recently (and rarely previously) heard an unusual brightness right after calibration that went away after a cold reboot of the processor.  I can't explain it, but it happened three times in the past week.

I have a lot of room treatment (many diffusers and bass traps and a little strategic broadband absorption), and none of that will have any undesirable effect on the Dirac calibration.  It is possible for a very strong and asymmetrical reflection to confuse Dirac's impulse response adjustment which is based on the MLP measurement only.  I have a very unusual situation specific to my setup which caused this and I put up a temporary absorber just for the MLP measurement.  But to your point about seeing what Dirac actually does with distance settings, you can see this if you use REW.  The Overlays screen will show you if all the channels are precisely aligned.  

Ethan ... well I have learned a LOT from Ethan on many topics, especially bass traps.  But he has a block about digital room correction.  I've read a couple of his posts about the subject - particularly Dirac - and he clearly did not follow Dirac's instructions on how to calibrate and he complained about the results on a premise that Dirac has never claimed.  He insisted that Dirac could have no affect on the time domain, and when I posted a reply with evidence from my before/after Spectrum plots .... he didn't reply.

[motogp34]

Not sure if i'm reading right ? Are we getting a different Dirac run on FW 2.2 ??

[leonski]

I see some people here who 'recalibrate' on what appears to be a regular basis.

Doesn't ANYONE simply leave it alone after getting a positive result?

This doesn't quite apply to software, but ONE defiinition of insanity is doing the same thing over and over and expecting a different result....

My personal opinion, which I'd love to verify by observation of users is that measurement Technique plays a huge role in Outcome.

The idea of speaker correction to match a room is a good one and should give more consistent results......IF the measurer does his or her part.

[Lsc]

Feb 28, 2021 23:20:11 GMT -5 leonski said:

I see some people here who 'recalibrate' on what appears to be a regular basis.

Doesn't ANYONE simply leave it alone after getting a positive result?

This doesn't quite apply to software, but ONE defiinition of insanity is doing the same thing over and over and expecting a different result....

My personal opinion, which I'd love to verify by observation of users is that measurement Technique plays a huge role in Outcome.

The idea of speaker correction to match a room is a good one and should give more consistent results......IF the measurer does his or her part.

Correct. I run my Dirac when needed - I don’t enjoy running it, dating back to the XMC1. Also at one time I was running 9.1.4, that’s 14 speakers x 13 points and they run that one speaker twice. 195 Dirac tones is not only very annoying, it’s tedious and takes like an hour.

Now I have 7.1 but will have 7.1.4 soon. So one more run then I’ll hopefully be done for a looong time.

I don’t think it’s insanity for others. Many of them are on the beta team so their work is very appreciated especially by folks like me who don’t like to run Dirac.

[KeithL]

Let me start by saying that I personally agree with you.

I find performing measurements and calibrations a nuisance (not a major nuisance - but I certainly don't enjoy doing it for entertainment).

Therefore I tend to do it when necessary... and be satisfied when it's "good enough"...

(And, yes, I would consider for a room and speakers to be flat within 2 dB at my favorite listening chair to be "plenty close enough".)

And, as you do, I tend to calibrate my system and then leave it alone.

(Excluding things I do for "work".)

HOWEVER, room calibration, and room acoustics themselves, are not as cut-and-dried as some people would like to think.

Move your speakers a few inches... or move a chair a few inches... or move the microphones a few inches...and the measurements will change at least a little...

In fact, even things like changes in humidity, and changes in barometric pressure, may make small but measurable differences...

And, of course, if you make measurements using software as different as REW and Dirac Live, the results will of course be rather different...

And you can add to that the fact that software like Dirac Live makes "intelligent choices" about what to correct and what not to correct.
(So, when the software gets updated, the new version of the software just might make slightly different decisions as well.)

Another thing worth remembering is that the number of listeners in a room also has a major effect on the acoustics of the room and system.
Any pro who does EQ on a theater or concert hall KNOWS that the hall will sound very different when crowded than when empty.

The bottom line is that, when it comes to acoustics, measurements are rarely repeatable to within a dB or two.

(This is very different than electronic measurements of the electronic performance of audio gear - which can be quite precise and repeatable.)

The simple fact is that some people actually enjoy endlessly tinkering with and making adjustments on their system looking for perfection...

While others eventually decide it's good enough and sit down to listen to music or watch a movie...

From time to time someone in almost every audiophile forum asks the question:

"Do audiophiles listen to their system or do they listen to music?"

I have to admit that what I find most humorous is this....

I've read endless discussions about how measurements taken with REW aren't exactly the same as those taken with Dirac Live...

Yet I haven't seen a single similar discussion about measurements of COLOR calibration on screens and projectors...

Color calibrations also vary depending on what calibrator you use and the conditions under which you take your measurements.

And, if you have a projector, are you sure that the factory lens is giving you a picture that's quite as good as that aftermarket upgrade?

Feb 28, 2021 23:20:11 GMT -5 leonski said:

I see some people here who 'recalibrate' on what appears to be a regular basis.

Doesn't ANYONE simply leave it alone after getting a positive result?

This doesn't quite apply to software, but ONE defiinition of insanity is doing the same thing over and over and expecting a different result....

My personal opinion, which I'd love to verify by observation of users is that measurement Technique plays a huge role in Outcome.

The idea of speaker correction to match a room is a good one and should give more consistent results......IF the measurer does his or her part.

[marcl]

Guilty!     Being a musician and engineer my brain works on all the stuff of music at once.   People poke at me saying "Don't you ever listen to music?  All you do is measure!"  I'm very sure I do more of both than most people, especially now being retired.  Because I can.

Adding and agreeing with KeithL on most points (as usual) ...

Moving speakers, changing room treatments, changing listening position, changing furniture ... significant changes, like more than a few inches ... your system may sound just fine, but doing a recalibration could make a difference.  Will you hear it if the change causes a 3db peak at 80Hz?  Maybe.  Will you hear it if the change causes a 3db dip at 200Hz?  Probably not.

One thing I like to do is establish cause and effect.  Make a change, make a measurement, listen.  Make another change, make another measurement, listen.  What if I see something in a measurement that is technically incorrect - like that 200Hz 3db dip?  Maybe I'll make a change, make a measurement, listen ... did it go away, can I hear it, what effect did it have on the sound?  Listen to 3-4 pieces of music ... do they sound different?

And - Dirac gives us the ability to make as many measurements as we want from 1 to 17.  It may complain, but you can do whatever you want.  Dirac suggests three measurement patterns, but it doesn't know the difference if you vary the distance or eliminate a measurement or two.   So .... take a set of 9 measurements and take a set of 17 measurements.  Will it sound different?  Maybe ... maybe a LOT different ... or maybe not so different at the MLP, but VERY different 3ft either side.  Which do you like better?  Maybe you want to have the tight 9 position measurement in one slot for focused 2-channel music listening at the MLP, and the wide 17 point measurement in another slot for family movie night with everyone sprawled all over the couch and floor.

Nice to have choices!

[vmbray]

Feb 28, 2021 9:56:24 GMT -5 marcl said:

First to the bright thing, I have recently (and rarely previously) heard an unusual brightness right after calibration that went away after a cold reboot of the processor.  I can't explain it, but it happened three times in the past week.

I have a lot of room treatment (many diffusers and bass traps and a little strategic broadband absorption), and none of that will have any undesirable effect on the Dirac calibration.  It is possible for a very strong and asymmetrical reflection to confuse Dirac's impulse response adjustment which is based on the MLP measurement only.  I have a very unusual situation specific to my setup which caused this and I put up a temporary absorber just for the MLP measurement.  But to your point about seeing what Dirac actually does with distance settings, you can see this if you use REW.  The Overlays screen will show you if all the channels are precisely aligned.  

Ethan ... well I have learned a LOT from Ethan on many topics, especially bass traps.  But he has a block about digital room correction.  I've read a couple of his posts about the subject - particularly Dirac - and he clearly did not follow Dirac's instructions on how to calibrate and he complained about the results on a premise that Dirac has never claimed.  He insisted that Dirac could have no affect on the time domain, and when I posted a reply with evidence from my before/after Spectrum plots .... he didn't reply.

Thanks Marcl I will reboot and also take some measurements with rew to see if it persists and also if it does, to determine if it’s measurable. I think it’s baked in the calibration because I reboot frequently and the previous bright result was baked in. Appreciate your comments about room treatments, you would think that they would make Dirac’s job easier and a better result starting from a better controlled environment.

I’ve been recalibrating repeatedly because first I ran nine positions to learn and then discovered the supplied mic isn’t as good as umik1 (which I posted all about), and then added room treatments, and then it sounded bright, got a umik2 because I was having 60hz hum spike in rew measurements and low headroom, and so on. So I’ve been changing things and my non-eq sound has gotten better and Dirac result has gotten bright.

I have large sealed subs I built in front and some near field and bottom line is with the bright result it can be punishing at volume where the bass is good. I’m typically listening at -15 up to -10 occasionally and with the subs a little hot OR with bass eq by movie loaded in minidsp. Without Dirac the chair is shaking, everything sounds good, dialog is intelligible, and so on. With Dirac I currently have to back off the volume and chair stops shaking as much which is bad. Two channel or two channel up mixed is another discussion and I’ve tinkered with Dirac vs no with upmixed music but not enough to have a strong opinion so this is all about movie tracks.

[tngiloy]

When I check speaker levels:
-If my Dirac solution is loaded into the slot in a speaker preset and chosen, if I check the levels in that preset is it measuring the Dirac levels ??
-If I choose the 'user' slot does that revert to my base speaker settings (distances, levels, etc. I entered before running Dirac).

I'm getting my RMC-1L back from repair today and v2.2 was loaded by Emotiva repair tech before shipping and I'd like to check levels. I did load v2.17 beta version before sending back to see if it might fix my network problem (per Emo tech) and didn't really check levels then, didn't notice any bass boost in minimal listening before boxing and shipping it back to Franklin.

[davidl81]

Feb 28, 2021 23:20:11 GMT -5 leonski said:

I see some people here who 'recalibrate' on what appears to be a regular basis.

Doesn't ANYONE simply leave it alone after getting a positive result?

This doesn't quite apply to software, but ONE defiinition of insanity is doing the same thing over and over and expecting a different result....

My personal opinion, which I'd love to verify by observation of users is that measurement Technique plays a huge role in Outcome.

The idea of speaker correction to match a room is a good one and should give more consistent results......IF the measurer does his or her part.

I think the only reason so many of us (myself included) are recalibrating is because something in FW2.2 has made the subs jump a ton in HT use.  So I also re-ran DIRAC with no success.  Basically DIRAC did not really change my settings form the last time I ran it, yet the subs in HT use are too much.  So it seems like when setting up DIRAC the subs are getting a certain amount of gain and the system sets up on that.  Yet when in actual use that gain is jumped up by 10dB or so.  I do think the best way to address this for the time being will be to just lower the trim level on the subs, since nothing else I have done has made a difference.

[marcl]

Mar 1, 2021 9:46:08 GMT -5 tngiloy said:

When I check speaker levels:
-If my Dirac solution is loaded into the slot in a speaker preset and chosen, if I check the levels in that preset is it measuring the Dirac levels ??
-If I choose the 'user' slot does that revert to my base speaker settings (distances, levels, etc. I entered before running Dirac).

I'm getting my RMC-1L back from repair today and v2.2 was loaded by Emotiva repair tech before shipping and I'd like to check levels. I did load v2.17 beta version before sending back to see if it might fix my network problem (per Emo tech) and didn't really check levels then, didn't notice any bass boost in minimal listening before boxing and shipping it back to Franklin.

What SHOULD happen - and I believe something regarding this was fixed in 2.2 - is that when a Dirac slot is loaded the Dirac levels are set behind the scenes and then the values you may have set in Levels are applied on top of the Dirac levels.   When the User slot is selected, then only the Levels values are applied (along with your Distance values and any filters).  In both cases, the Dirac filters and User filters should be applied to the noise signal played to check the levels.

[vmbray]

Mar 1, 2021 9:51:53 GMT -5 marcl said:

What SHOULD happen - and I believe something regarding this was fixed in 2.2 - is that when a Dirac slot is loaded the Dirac levels are set behind the scenes and then the values you may have set in Levels are applied on top of the Dirac levels.   When the User slot is selected, then only the Levels values are applied (along with your Distance values and any filters).  In both cases, the Dirac filters and User filters should be applied to the noise signal played to check the levels.[/quote]

This is what I think too. I measured within 0.5 db between channels with all trims at zero after running Dirac. Except the center measured +1.5 db both in Dirac and in my “by ear” settings.

[leonski]

My point is simple.
Not ALL measurements or Measurers are equal. One of the guys here takes time to make sure his setup is the same for every measuring session.
And reports good success

There are several sources of variability when making such measurments. Not the LEAST of 'em is the contribution of the person doing the work.

When I did measurment as part of my job and working in an ISO certified facility, we were taught 'Man, Method, Machine'......All must come together for success.

The amount of trouble and detail you go thru Should make it less likely to have to repeat over and over. But the points made by several, above, that room changes make
a big difference must also be factored in.

RECORD Keeping is a must. Knowing what you did and HOW is important as are any measurments of physical location of speakers and furnishings.

I wish I lived near enough to someone doing this to go and have a look for myself.