DRC, Digital Room Correction- is it the poor relation to Room treatments?

MikeJazz · February 19, 2015

Again, one of several assumptions being made is that the direct response from the speaker and that from the room will sum algebraically as a unit, rather than be heard as two distinct sounds. I'm sure some listeners are not sensitive to this but I'm equally sure other listeners, myself included, are.

Indeed, and that is the reason, I suppose, the same loudspeaker can sound vastly different in different rooms. Room and loudspeaker, they add up differently and they will excite different ranges of frequencies with different intensities, therefore causing also some "tone" deviations.

In my room, (which I of course know very well) the DSP effect of Lyngdorf was good but with a drawback.

When optimizing for the listening position "the FOCUS" position, bass is remarkable better (better following, very intelligible, more focus more intense, timing much improved); but usually harmonics (in voice, piano) are a bit less rich...

Until now, I was not able to have my cake and eat it too...

flak · February 20, 2015

In the past, I've mentioned a number of systems I've heard. I even wrote the user manual for one that is widely used. At this point, I don't like to mention any particular brand names for gear I don't like.

.........

Lastly, I don't debate. I report what I hear. I understand other folks hear things differently and will have their own preferences. I never argue with whatever brings anyone their listening pleasure.

Understood... but I'm under the impression that you have tried several DRCs but none of the mixed-phase solutions like Dirac Live, or Acourate or Audiolense... you don't mention the brands but if you have not carefully tested and listened any of these may be you could suspend your judgement (you have probably noticed that most listeners have found significant improvements)

If I'm wrong and you have tried Dirac Live I'd be interested in looking at your project.

While the latter can be dealt with using DSP (although not as well as if the speaker/crossover designer did their job correctly), the former (i.e., decay time in the room) is outside of the realm of current technology as far as I know, unless time travel is somehow built into the algorithm. ;-}

Interesting that you mentioned that time travel has to be somehow built into the algorithm...

it is true that you need ”time travelling”, but this can be achieved using delays of the primary signal rather than travelling forward in time.

Non-causal filters are routinely used in digital signal processing by buffering the output... that way we know in advance what the signal will be at a later time.

To use an active treatment, you need to delay the speaker’s signal of course.

The decay time is a crude measure of the properties of the impulse response of the room + speaker.

A waterfall plot can also show the decay times as a function of frequency... how much the decay time of the room can be controlled using DSP depends on a number of factors, but from a measurement of the impulse responses throughout the room it is possible to find certain time-domain problems due to the room (not just the speaker) that are identical in the measured positions, and thereby controllable, and some that are too position-dependent to be possible to correct without adding speakers at other positions that act as active treatments... that's what Dirac Unison does and it is a radical departure from conventional DRCs that has been demoed at the CES.

Ciao Flavio

bdiament · February 20, 2015

...Interesting that you mentioned that time travel has to be somehow built into the algorithm...
it is true that you need ”time travelling”, but this can be achieved using delays of the primary signal rather than travelling forward in time.

Non-causal filters are routinely used in digital signal processing by buffering the output... that way we know in advance what the signal will be at a later time.

To use an active treatment, you need to delay the speaker’s signal of course.

The decay time is a crude measure of the properties of the impulse response of the room + speaker.

A waterfall plot can also show the decay times as a function of frequency... how much the decay time of the room can be controlled using DSP depends on a number of factors, but from a measurement of the impulse responses throughout the room it is possible to find certain time-domain problems due to the room (not just the speaker) that are identical in the measured positions, and thereby controllable, and some that are too position-dependent to be possible to correct without adding speakers at other positions that act as active treatments... that's what Dirac Unison does and it is a radical departure from conventional DRCs that has been demoed at the CES.

Ciao Flavio

Hi Flavio,

Again, utilization of the delay allows you to adjust the *attack* time. This is not at all the time travel I'm referring to because there is no control of the *decay* time, which is where room issues reside. You can change the onset of a sound but what is needed to to make certain sounds, held onto by the room, *decay* faster.

Yes of course, if the room is ringing at 200 Hz and you prevent the speakers from reproducing anything near 200 Hz, the room will no longer ring. If you "compromise" and merely diminish the speakers' response in the 200 Hz range, the decay time will *appear* to have been diminished but that is only because the resonance hasn't been excited to the same degree. The resonances of the room remain though.

On top of this, the direct response from the speaker--the thing that will determine the overall color of what we hear--has, in my opinion, been ruined. To me, one might as well just disconnect the woofers -- all room issues in the bass will vanish!

I keep saying that the assumption made when attempting to alter room response by changing the performance of the loudspeakers is that the direct sound and the room sound will sum algebraically rather than be heard as two distinct entities.

Using dsp to change a speaker's response is one thing and I can see this being successful if done properly and the original speaker design is lacking. I do not agree however, with altering the speakers' response in an attempt to remedy the room, simply because, as I have said before, to my ears, the result is taking one problem and creating two.

This is just my perspective of course. I understand many folks feel differently and have some acquaintances that use dsp in their systems.

Best regards,

Barry

EuroDriver · February 20, 2015

I am a pretty impressed user of Dirac in the standlaone DSP unit from miniDSP. You can see my system in the second half of my sig. I have cutoff frquencies of 2 k for one speaker and 4 k for the other speaker, and with this setup, I seem to get a lot of improvements with no perceptible downside. The listening room acoustics are about as challenging as it gets.

The improvemnts are imaging, improved timbre through less smearing, better bass. The miniDSP also does sample rate conversion which improves the digital output of my Sonos connect very nicely. From the miniDSP, I use Toslink out which the NAD D 3020 seems to sound the best with of all its digital inputs.

Room treatments can not fix unequal speaker to listener distances ;-)

Guidof · February 21, 2015

I'm very much a pragmatist in this, as in other audio matters, and would never argue theoretical issues with the experts.

But in my experience and in my difficult room (small, with a structural protrusion jutting out between speakers) both DRC via a DSPeaker Antimode Dual Core and room treatment have been very effective. They made it possible to achieve excellent timbral accuracy, tonal balance, and three dimensional soundstage, all of which were huge challenges in this room.

Regards,

Guido F.

flak · February 22, 2015

...as I have said before, to my ears, the result is taking one problem and creating two.

This is just my perspective of course. I understand many folks feel differently and have some acquaintances that use dsp in their systems.

Best regards,

Barry

In my previous post #29 I told you that I was under the impression that you had not listened to any of the mixed-phase DRC solutions that I mentioned... even more so Dirac Live (so I told you that if I was wrong I was interested in looking at your project).

I think that if on the contrary you had tested them you would have answered so... but you didn't, so in my opinion any comments about how mixed-phase DRCs sound to your ears are compromised by the likelihood that you never listened to them.

In a few words I'm afraid you are somehow biased :-(

(within this subject only of course)

Flavio

P.S. DSP treatments and analog/passive treatments are both done to affect the signal in a desirable way, and they can both be misused or used to great advantage.

Just because you can’t cure all problems with DSP, doesn’t mean you shouldn’t use it... the same goes for passive treatments.

There are a lot of bad approaches to room correction, but there are a few good ones, and even with single-channel room ”correction” (Dirac Live) as shown in the MIMO paper, you can reduce decay times of the room, although multiple speakers used together can do even more (Dirac Unison).

bdiament · February 22, 2015

In my previous post #29 I told you that I was under the impression that you had not listened to any of the mixed-phase DRC solutions that I mentioned... even more so Dirac Live (so I told you that if I was wrong I was interested in looking at your project).

I think that if on the contrary you had tested them you would have answered so... but you didn't, so in my opinion any comments about how mixed-phase DRCs sound to your ears are compromised by the likelihood that you never listened to them.

In a few words I'm afraid you are somehow biased :-(

(within this subject only of course)

Flavio

P.S. DSP treatments and analog/passive treatments are both done to affect the signal in a desirable way, and they can both be misused or used to great advantage.

Just because you can’t cure all problems with DSP, doesn’t mean you shouldn’t use it... the same goes for passive treatments.

There are a lot of bad approaches to room correction, but there are a few good ones, and even with single-channel room ”correction” (Dirac Live) as shown in the MIMO paper, you can reduce decay times of the room, although multiple speakers used together can do even more (Dirac Unison).

Hi Flavio,

If I'm "biased" it is based on direct experience.

I have said before that I do not mention names of products I do not have a positive experience with.

When addressing the acoustics of a listening room or studio, I'm not interested in, nor do I recommend, processing that adjusts the attack time of the speakers at various frequencies or that alters the direct response from the speakers. With this in mind, for my purposes, the type of filter is of absolutely zero consequence--unless you've invented a filter that can alter the "Q" of the room's response while leaving the speakers' response untouched.

As I've said many times in previous posts, I understand others, including yourself have a different perspective on this. Let us agree then, to disagree.

As I also said, I would not take dsp away from anyone who likes the results, as I never argue with whatever brings anyone their listening pleasure. I've also said I believe DSP *can* have a place in adjusting speaker response in certain instances. At the same time, like addressing a broken arm by changing hats, the idea of addressing the room's issues anywhere but where they originate just isn't for me.

Happy listening!

Best regards,

Barry

dallasjustice · February 22, 2015

Your policy of not mentioning unfavorable experiences seems to be designed to protect those softwares from your would be negative comments. You assume your negative comments would have a negative impact on their bottom line? However, it seems at least DIRAC is asking you to waive that policy and support your claimed negative experience with a specific example related to DIRAC.

It's free to try, easy to use and only requires a PC or Mac and a USB or FireWire DAC/ADC and a calibrated mic. I assume you have this gear already. Although you have never said you tried DIRAC, Acourate or Audiolense, I personally assume you have not based on your comments.

Michael.

Hi Flavio,

If I'm "biased" it is based on direct experience.

I have said before that I do not mention names of products I do not have a positive experience with.

When addressing the acoustics of a listening room or studio, I'm not interested in, nor do I recommend, processing that adjusts the attack time of the speakers at various frequencies or that alters the direct response from the speakers. With this in mind, for my purposes, the type of filter is of absolutely zero consequence--unless you've invented a filter that can alter the "Q" of the room's response while leaving the speakers' response untouched.

As I've said many times in previous posts, I understand others, including yourself have a different perspective on this. Let us agree then, to disagree.

As I also said, I would not take dsp away from anyone who likes the results, as I never argue with whatever brings anyone their listening pleasure. I've also said I believe DSP *can* have a place in adjusting speaker response in certain instances. At the same time, like addressing a broken arm by changing hats, the idea of addressing the room's issues anywhere but where they originate just isn't for me.

Happy listening!

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

bdiament · February 22, 2015

Your policy of not mentioning unfavorable experiences seems to be designed to protect those softwares from your would be negative comments. I guess you assume your negative comments would have a negative impact on their bottom line? However, it seems at least DIRAC is asking you to waive that policy and support your claimed negative experience with a specific example related to DIRAC.

It's free to try, easy to use and only requires a PC or Mac and a USB or FireWire DAC/ADC and a calibrated mic. I assume you have this gear already. Although you have never said you tried DIRAC, Acourate or Audiolense, I personally assume you have not based on your comments.

Michael.

Hi Michael,

I don't name names in a negative light because that is how I choose to behave in a public arena like an Internet audio forum.

It is out of respect for the people who create hardware and software, and for their efforts, regardless of what I think of the results.

I call this civility and as such, do not respond to such "challenges".

I have been very specific about what I would consider a successful DSP approach to room issues and I'll repeat it one more time here:

Unless there is a filter that can alter the "Q" of the room's response while leaving the speakers' response untouched, my personal take is that it is making a grave sonic--and logical--mistake to assume the direct sound from the speakers and the subsequent sound of the room's response will sum algebraically rather than be heard as two distinct entities. These things remain separate and are heard (by some folks) as separate. Some folks may not be sensitive to it but others are, and that would include me.

I continue to read posts about types of filters but no mention of altering the "Q" of the room's response while leaving the speaker's response untouched. (Note: alteration of the attack time has nothing whatsoever to do with what I'm talking about.)

As I've said before many, many times, I understand some folks, including yourself, like the results. I have no argument with what anyone likes or with whatever brings them joy in their listening. I would hope those who are confident in what they like will have no concern about whether I feel the same or feel differently and will be able to accept those instances where I hear it differently than they do and thus reach different conclusions.

Best regards,

Barry

Audiophile Neuroscience · February 23, 2015

Barry,

your view could not be more fairly, more reasonably, or more plainly stated. The logic supporting your views is hard to flaw but really that is, as you say, not really the point. If anyone feels something improves the sound, go for it. Your respect for others opinions, products, and listening experience is without equal. Bravo.

Cheers

David

Liam · February 23, 2015

Barry's reticence to make adverse comments about products or service in forums such as this is laudable, and I have, no doubt like many others, been horrified by comments frequently made on the Internet that can have disproportionate affects on Companies.

Nevertheless, in this case, Flavio is offering to present his Companies' software for Barry to specifically try, if not already evaluated, and comment on. He would also like to have the filter's for analysis, believing that Dirac can allay Barry's concerns.

Barry has an adverse conviction regarding digital room correction. Having stated that, however, he is in effect, passing a negative comment about the efficacy of Dirac, and given his standing in the recording industry this will have impact.

Flavio is anxious to analyse further, having confidence in Diracs algorithm(s), so perhaps in this instance Barry you might reconsider your overall stance.

For my own part I find Dirac Live improves clarity, precision and dynamics, without diminishing timbre. I feel that timbre is more readily revealed as there is less muddling in the sound.

My room is approx. 13ftx11ft and I listen across the short dimension. The seated position is about 8ft from the speakers, which are 5ft apart centre to centre.

I found the sound to be a bit bass light with the default Dirac filter, so I followed Flavio's advice to another user in a different thread and increased the filter slope to the bottom end and personally added a further boost from 100hz. Below are the results, including the impulse response.

bdiament · February 23, 2015

Barry,
your view could not be more fairly, more reasonably, or more plainly stated. The logic supporting your views is hard to flaw but really that is, as you say, not really the point. If anyone feels something improves the sound, go for it. Your respect for others opinions, products, and listening experience is without equal. Bravo.

Cheers

David

Hi David,

Thank you for your kindness.

Best regards,

Barry

bdiament · February 23, 2015

Barry's reticence to make adverse comments about products or service in forums such as this is laudable, and I have, no doubt like many others, been horrified by comments frequently made on the Internet that can have disproportionate affects on Companies.

Nevertheless, in this case, Flavio is offering to present his Companies' software for Barry to specifically try, if not already evaluated, and comment on. He would also like to have the filter's for analysis, believing that Dirac can allay Barry's concerns.

Barry has an adverse conviction regarding digital room correction. Having stated that, however, he is in effect, passing a negative comment about the efficacy of Dirac, and given his standing in the recording industry this will have impact.

Flavio is anxious to analyse further, having confidence in Diracs algorithm(s), so perhaps in this instance Barry you might reconsider your overall stance.

For my own part I find Dirac Live improves clarity, precision and dynamics, without diminishing timbre. I feel that timbre is more readily revealed as there is less muddling in the sound.

My room is approx. 13ftx11ft and I listen across the short dimension. The seated position is about 8ft from the speakers, which are 5ft apart centre to centre.

I found the sound to be a bit bass light with the default Dirac filter, so I followed Flavio's advice to another user in a different thread and increased the filter slope to the bottom end and personally added a further boost from 100hz. Below are the results, including the impulse response...

Hi Liam,

I'm very glad the DSP you are using is working for you and that you are pleased with the results.

Please accept that I have a different perspective.

Rather than type the same response over and over again, I'm going to quote my previous post:

I have been very specific about what I would consider a successful DSP approach to room issues and I'll repeat it one more time here:

Unless there is a filter that can alter the "Q" of the room's response while leaving the speakers' response untouched, my personal take is that it is making a grave sonic--and logical--mistake to assume the direct sound from the speakers and the subsequent sound of the room's response will sum algebraically rather than be heard as two distinct entities. These things remain separate and are heard (by some folks) as separate. Some folks may not be sensitive to it but others are, and that would include me.

I continue to read posts about types of filters but no mention of altering the "Q" of the room's response while leaving the speaker's response untouched. (Note: alteration of the attack time has nothing whatsoever to do with what I'm talking about.)

As I've said before many, many times, I understand some folks, including yourself, like the results. I have no argument with what anyone likes or with whatever brings them joy in their listening. I would hope those who are confident in what they like will have no concern about whether I feel the same or feel differently and will be able to accept those instances where I hear it differently than they do and thus reach different conclusions.

I consider it important to say that I would not want anyone to simply take my (or anyone else's) word for anything in audio. I always suggest folks listen for themselves and draw their own conclusions. I can only report my own. Some will hear it similarly and others will hear it differently.

Best regards,

Barry

Soundkeeper Recordings

Barry Diament Audio

SteveS1 · February 23, 2015

An interesting discussion. I don't find myself with a different view to Barry on much, if anything and I'm certainly pleased to have many of the recordings he mastered.

I don't have the luxury of a dedicated listening room, to be honest I'm not sure I want one. Listening to music is part of my normal environment and I like it that way. So using furniture, soft furnishings and careful layout with regard to positioning myself and the speakers is as far as I have ever gone. I had no interest in passive treatments that either look pig ugly or dominate the space in some other domestically unacceptable way.

So when easier methods to apply parametric EQ or DSP room correction came along I was curious and have experimented with some. I did manage to improve things but never got the results I was looking for, the changes seemed to come at the expense of some timing or phase aspects.

The iRC is a solution that has worked for me without me being aware of a downside. I have improved clarity, tonal balance and detail. The low end is better extended and more even. Whether it's the mixed phase approach that makes the difference, I cannot say.

As somebody who is only interested in listing to my music in the home without distraction, I'm very pleased. So I'm left thinking that either there is no downside, or there is and I mercifully cannot hear it. Or as a final possibility my room aberations were so grim that any downside is disregarded. Although with other solutions that remained illusive.

Anyway, just my experience. I'd be interested to hear from others who have had the time to experiment and the conclusions they have reached.

Steve

flak · February 23, 2015

An interesting discussion. I don't find myself with a different view to Barry on much, if anything and I'm certainly pleased to have many of the recordings he mastered.

I don't have the luxury of a dedicated listening room, to be honest I'm not sure I want one. Listening to music is part of my normal environment and I like it that way. So using furniture, soft furnishings and careful layout with regard to positioning myself and the speakers is as far as I have ever gone. I had no interest in passive treatments that either look pig ugly or dominate the space in some other domestically unacceptable way.

So when easier methods to apply parametric EQ or DSP room correction came along I was curious and have experimented with some. I did manage to improve things but never got the results I was looking for, the changes seemed to come at the expense of some timing or phase aspects.

The iRC is a solution that has worked for me without me being aware of a downside. I have improved clarity, tonal balance and detail. The low end is better extended and more even. Whether it's the mixed phase approach that makes the difference, I cannot say.

As somebody who is only interested in listing to my music in the home without distraction, I'm very pleased. So I'm left thinking that either there is no downside, or there is and I mercifully cannot hear it. Or as a final possibility my room aberations were so grim that any downside is disregarded. Although with other solutions that remained illusive.

Anyway, just my experience. I'd be interested to hear from others who have had the time to experiment and the conclusions they have reached.

Steve

Thanks Steve,

some may not know but iRC is Dirac Live as implemented in the top of the line version of the Amarra player (iRC is an acronym of impulse Response Correction)

Flavio

LBob · February 24, 2015

An interesting discussion. I don't find myself with a different view to Barry on much, if anything and I'm certainly pleased to have many of the recordings he mastered.

I don't have the luxury of a dedicated listening room, to be honest I'm not sure I want one. Listening to music is part of my normal environment and I like it that way. So using furniture, soft furnishings and careful layout with regard to positioning myself and the speakers is as far as I have ever gone. I had no interest in passive treatments that either look pig ugly or dominate the space in some other domestically unacceptable way.

So when easier methods to apply parametric EQ or DSP room correction came along I was curious and have experimented with some. I did manage to improve things but never got the results I was looking for, the changes seemed to come at the expense of some timing or phase aspects.

The iRC is a solution that has worked for me without me being aware of a downside. I have improved clarity, tonal balance and detail. The low end is better extended and more even. Whether it's the mixed phase approach that makes the difference, I cannot say.

As somebody who is only interested in listing to my music in the home without distraction, I'm very pleased. So I'm left thinking that either there is no downside, or there is and I mercifully cannot hear it. Or as a final possibility my room aberations were so grim that any downside is disregarded. Although with other solutions that remained illusive.

Anyway, just my experience. I'd be interested to hear from others who have had the time to experiment and the conclusions they have reached.

Steve

I'm in pretty much the same situation. I have a dedicated (basement) room with judicious acoustic treatments (bass traps and apsorption) and can situate my listening position wherever I like. I got the same improvement with Dirac as you did. I initially thought that I had lost substantial bass response, but after more extended listening I came to realize that I was reacting to the loss of a rather prominent bump in the bass that Dirac had eliminated. About the only down side I've had is that Dirac and Yosemite don't seem to want to play nice so now I get some dropouts and some noise when I change sample rates, but it's minor and easily remedied. Bottom line is that my system has never sounded better.

Fitzcaraldo215 · February 25, 2015

Hi Liam,

I'm very glad the DSP you are using is working for you and that you are pleased with the results.

Please accept that I have a different perspective.

Rather than type the same response over and over again, I'm going to quote my previous post:

I have been very specific about what I would consider a successful DSP approach to room issues and I'll repeat it one more time here:

Unless there is a filter that can alter the "Q" of the room's response while leaving the speakers' response untouched, my personal take is that it is making a grave sonic--and logical--mistake to assume the direct sound from the speakers and the subsequent sound of the room's response will sum algebraically rather than be heard as two distinct entities. These things remain separate and are heard (by some folks) as separate. Some folks may not be sensitive to it but others are, and that would include me.

I continue to read posts about types of filters but no mention of altering the "Q" of the room's response while leaving the speaker's response untouched. (Note: alteration of the attack time has nothing whatsoever to do with what I'm talking about.)

As I've said before many, many times, I understand some folks, including yourself, like the results. I have no argument with what anyone likes or with whatever brings them joy in their listening. I would hope those who are confident in what they like will have no concern about whether I feel the same or feel differently and will be able to accept those instances where I hear it differently than they do and thus reach different conclusions.

I consider it important to say that I would not want anyone to simply take my (or anyone else's) word for anything in audio. I always suggest folks listen for themselves and draw their own conclusions. I can only report my own. Some will hear it similarly and others will hear it differently.

Best regards,

Barry

Soundkeeper Recordings

www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

Barry - as they say in Washington, the perfect is often the enemy of the good. Firstly, I do not hear what you are hearing from DSP EQ. I am not saying I am right and you are wrong. Perhaps your ears are better than mine. Perhaps the EQ tools I have heard differ from those you have heard - some are better than others. Who knows?

What I do hear from Dirac Live and my friend's Anthem ARC setups, and what I heard from my previous Audyssey MultEQ/XT32 setup with Audyssey Pro Kit calibration is much better sound. It is not only more pleasing to me, but it has been to many visitors to my listening room. Many became converts to DSP EQ based on that. I am talking about guys with systems in the $50k - $100k range. Most of them are, like me, frequent classical music live concert attendees. We do not have any reservations at all about declaring DSP EQ to be a major, indispensable sonic advance closer to the sound of live music.

No one says it is perfect. But, the sonic improvement is beyond obvious just with a flick of the switch - on or off. That is something you cannot do with passive acoustic treatments. Debatably, treatments might indeed be potentially more nearly perfect in solving a room's acoustic problems. But, as a DIY project, you will have a lot of learning to do about room acoustics, their measurement, the interpretation of those measurements, specific treatments to apply, etc. There will be installation issues. Bass traps or absorbers that go much below 100 Hz have to be mighty big, usually custom built in situ. There is trial and error, remeasurement, etc. Or, you can pay an acoustician to do all that for you for thousands of $$. Either way, it is a really big commitment. Hopefully, when you are done, it sounds terrific, although it will now be impossible to compare it audibly to the room pre-treatment except via measurements.

Speaking of measurements, I just saw a summary of an AES paper showing the frequency response of 372 Genelec speakers done in 164 professional control rooms. Response (Max to Min) varied by > 20 dB at 100 HZ and > 10 dB at 10k Hz, average levels normalized, of course. That, and the curves are quite lumpy and bumpy. It is not the speakers varying by that much, of course. It is the rooms. And, this data tells us how crappy and variable even supposedly professional rooms are. It is only a microcosm of how bad response is in millions of audiophile listening rooms.

I also just looked at Art Dudley's in-room frequency response for several speakers in Stereophile. John Atkinson measures this for speaker reviews. It is clear that Dudley's room measures terribly in a consistent way regardless of the speaker. Looking at that, I have no idea why anyone would want to trust his sonic judgement on anything, colored as it would be by that room. Atkinson's own (treated) room, as measured for many of his own speaker reviews, is superlative, by the way. But, Dudley's is just like several audiophile rooms I have measured myself, but with its own unique and perverse signature.

So, why don't these audio professionals do something to clean up their room acoustics? Ignorance (it's bliss), tradition, laziness, rationizations, fear, uncertainty, doubt, etc., etc. More likely it is the difficulty, time, cost and the knowledge required to acoustically treat the rooms. Besides, many people get used to the sound of their rooms and they even come to prefer that sound, inaccuracies and all.

If people listen to you, they have yet another reason to do nothing, because treatments are too daunting. DSP EQ is relatively easier and cheaper to install and compare than treatments. Even if it is less than perfect - treatments aren't perfect either - millions have found DSP EQ worthwhile. Sure, some have heard it and do not like it, for whatever reason. But, it sure beats doing nothing, in my book. And, I am sure they are a minority, but a number of recording engineers do use and endorse various DSP EQ systems, unlike you.

bdiament · February 25, 2015

Barry - as they say in Washington, the perfect is often the enemy of the good. Firstly, I do not hear what you are hearing from DSP EQ. I am not saying I am right and you are wrong. Perhaps your ears are better than mine. Perhaps the EQ tools I have heard differ from those you have heard - some are better than others. Who knows?

What I do hear from Dirac Live and my friend's Anthem ARC setups, and what I heard from my previous Audyssey MultEQ/XT32 setup with Audyssey Pro Kit calibration is much better sound. It is not only more pleasing to me, but it has been to many visitors to my listening room. Many became converts to DSP EQ based on that. I am talking about guys with systems in the $50k - $100k range. Most of them are, like me, frequent classical music live concert attendees. We do not have any reservations at all about declaring DSP EQ to be a major, indispensable sonic advance closer to the sound of live music.

No one says it is perfect. But, the sonic improvement is beyond obvious just with a flick of the switch - on or off. That is something you cannot do with passive acoustic treatments. Debatably, treatments might indeed be potentially more nearly perfect in solving a room's acoustic problems. But, as a DIY project, you will have a lot of learning to do about room acoustics, their measurement, the interpretation of those measurements, specific treatments to apply, etc. There will be installation issues. Bass traps or absorbers that go much below 100 Hz have to be mighty big, usually custom built in situ. There is trial and error, remeasurement, etc. Or, you can pay an acoustician to do all that for you for thousands of $$. Either way, it is a really big commitment. Hopefully, when you are done, it sounds terrific, although it will now be impossible to compare it audibly to the room pre-treatment except via measurements.

Speaking of measurements, I just saw a summary of an AES paper showing the frequency response of 372 Genelec speakers done in 164 professional control rooms. Response (Max to Min) varied by > 20 dB at 100 HZ and > 10 dB at 10k Hz, average levels normalized, of course. That, and the curves are quite lumpy and bumpy. It is not the speakers varying by that much, of course. It is the rooms. And, this data tells us how crappy and variable even supposedly professional rooms are. It is only a microcosm of how bad response is in millions of audiophile listening rooms.

I also just looked at Art Dudley's in-room frequency response for several speakers in Stereophile. John Atkinson measures this for speaker reviews. It is clear that Dudley's room measures terribly in a consistent way regardless of the speaker. Looking at that, I have no idea why anyone would want to trust his sonic judgement on anything, colored as it would be by that room. Atkinson's own (treated) room, as measured for many of his own speaker reviews, is superlative, by the way. But, Dudley's is just like several audiophile rooms I have measured myself, but with its own unique and perverse signature.

So, why don't these audio professionals do something to clean up their room acoustics? Ignorance (it's bliss), tradition, laziness, rationizations, fear, uncertainty, doubt, etc., etc. More likely it is the difficulty, time, cost and the knowledge required to acoustically treat the rooms. Besides, many people get used to the sound of their rooms and they even come to prefer that sound, inaccuracies and all.

If people listen to you, they have yet another reason to do nothing, because treatments are too daunting. DSP EQ is relatively easier and cheaper to install and compare than treatments. Even if it is less than perfect - treatments aren't perfect either - millions have found DSP EQ worthwhile. Sure, some have heard it and do not like it, for whatever reason. But, it sure beats doing nothing, in my book. And, I am sure they are a minority, but a number of recording engineers do use and endorse various DSP EQ systems, unlike you.

Hi Fitzcaraldo215,

I'm glad you like the results you are getting.

As to proper room treatments, yes, they can cost a bit but then again, if one has spent large sums of money on the system, in my experience using up a small percentage of the room's space (assuming one can do this) to get the acoustics right is not at all the daunting prospect you seem to think it is.

Neither in my experience, do these have to be "custom built in situ" (and in fact, I'd be wary of anyone offering such). And for those who don't want to incur the expense of commercial products, there are some pretty good DIY (do it yourself) recipes that can be found on the web.

I've built and installed treatments for a number of clients in addition to those in my own studio/listening room. No acoustician and no acoustic measurements are needed - though I have used such measurements just for the curiosity. What is needed are physical measurements of the room's dimensions and a means of finding the proper fractional lengths along those dimensions. The physics of sound in enclosed spaces will not change from room to room. Pressure zones occur at boundaries and are worse where boundaries meet. Reflection points are simple geometry based on speaker and listening position.

Now this should not be confused with altering the response of the speakers. When treating the room, I want to alter the response of the room, not the speakers. (If I was treating the speakers, I'd want to alter the response of the speakers, not the room.) In my view, those seeking to compensate for some issue of speaker design can certainly benefit from judiciously applied DSP. However, with well designed speakers, my experience has been that treating the room works wonders. And one is not prone to the consequences of the assumptions I've mentioned in previous posts.

Of course, not everyone wants to take the room treatment approach. That is a personal call. I've always found that different folks have different sensitivities to different aspects of sound. For my ears, all of the systems I've heard that I would call great systems have been free of DSP. And the many I've heard that use it just aren't for me. I understand you feel differently. The main thing is that you are enjoying your system and your music library.

Best regards,

Barry

Audiophile Neuroscience · February 26, 2015

If people listen to you, they have yet another reason to do nothing, because treatments are too daunting. DSP EQ is relatively easier and cheaper to install and compare than treatments. Even if it is less than perfect - treatments aren't perfect either - millions have found DSP EQ worthwhile. Sure, some have heard it and do not like it, for whatever reason. But, it sure beats doing nothing, in my book. And, I am sure they are a minority, but a number of recording engineers do use and endorse various DSP EQ systems, unlike you.

Hi Fitzcaraldo215

I think the point here is that if you are hearing subjective improvements in sound quality then use whatever intervention that produces that improvement.This takes into account considerations of cost, practical issues of implementing the intervention, and the pros and cons of alternative approaches.

Now I believe many here on this forum would place me in the subjectivist audio camp, which by the way I do not accept (both camps being subjective in their own ways). I believe in trusting ones ears and brain in circumstances where measurements and science cannot reliably validate the perception of complex music experiences.Now I have NO intention of debating this here as it has been already done ad nauseam in other threads. My point however is that just as many measurements do not exclude hearing audible differences, neither do they necessarilly bear a causal relationship to hearing differences justifying said audible differences. Having said that, and notwithstanding the science based challenges to some of the DSP premises, if it sounds better - use it. Do not let anyone persuade you differently....and in my view Barry is not trying to persuade anyone to stop using DSP/DRC.

Cheers

David

dallasjustice · February 26, 2015

David and/or Barry,

Have either of you ever done any high resolution (at least 1/12 per octave smoothing) logsweep measurements from your seated position using a calibrated microphone and a quality ADC? If so, would you mind posting the SPL response?

Audiophile Neuroscience · February 26, 2015

David and/or Barry,
Have either of you ever done any high resolution (at least 1/12 per octave smoothing) logsweep measurements from your seated position using a calibrated microphone and a quality ADC? If so, would you mind posting the SPL response?

Saw it done at a friends place but do not have the measurements

bdiament · February 26, 2015

David and/or Barry,
Have either of you ever done any high resolution (at least 1/12 per octave smoothing) logsweep measurements from your seated position using a calibrated microphone and a quality ADC? If so, would you mind posting the SPL response?

Hi Michael,

I have done all sorts of measurements on the room. However, what you are asking for is a single dimension. Showing you a beautiful frequency response will tell you absolutely nothing at all about the time response. Again, it is those erroneous assumptions I keep mentioning. For starters, my face is wider than any accurate microphone. I have an ear on either side of my head, not a single one centered on my face. And that's just for starters.

Who cares if the frequency response is dead flat is some frequencies get to your ear a lot later than others --- or if some frequencies "ring" in the room for longer than others?

The response in my room, without DSP but with full acoustic treatment and with well-designed loudspeakers is within a couple of dB, all the way down. While tells you the frequency response is pretty good, it tells you absolutely nothing about the sound. It doesn't tell you if the treble is smeared and engenders headaches, or if it is a smooth as silk all the way up into the stratosphere. It doesn't tell you if the bass lags so much it sounds like the players can't keep tempo, or if the pitch at the bottom is so natural it is just there and does not draw attention to itself. It doesn't tell you if vocalists sound dismembered, outsized heads a la the Great Oz, or if they sound like humans. I could go on and on but I think (I hope) you get the idea.

I hope you are comfortable enough with your own liking of DSP to accept that (why do I have to keep repeating this?) it just isn't for me. No great system I've heard uses it and all the systems I've heard that use it sound like un-natural Hi-Fi to me.

I'll put it another way: When speaking with aspiring engineers, I always talk about what I call "The Questions" - which must be asked, and for which good answers must be found, lest one pile mistake upon mistake when making a recording. I tell them, before you turn that EQ knob, you must ask yourself "What did I do wrong in a previous step that makes me want to turn this knob?" Once they have the answer to that, I ask them to try it both ways - fixing what they did wrong in the previous step, and trying to fix it by turning the knob. Comparing a patch-over "fix" after the fact with a genuine one at the source of a problem can be a valuable experience.

Again, we must agree to disagree.

Best regards,

Barry