Let's discuss room correction

[Kal Rubinson]

I don't think it's a controversial observation. Floyd Toole himself says:
We carry on conversations in a vast range of acoustical environments—from cavelike to the near-anechoic—and although we are certainly aware of the changes in acoustical ambience, the intrinsic timbral signatures of our voices remain amazingly stable.

I think the word "stable" would be more properly replaced with recognizable.

The excellence of tone in a fine musical instrument is recognizable in many different, including unfamiliar, environments.

Comme ça.

 

[Nightlord]

Was at a convention last weekend. The guy from Trinnov said as one of his opening statements - if you do decide to do an advanced setup, put 25% of the budget on the room first, and you'll get an extra 100% out of it. And that's coming from someone with a quite capable DSP for room processing. ( Gave him a complement afterwards for having said so. )

 

[Fitzcaraldo215]

Was at a convention last weekend. The guy from Trinnov said as one of his opening statements - if you do decide to do an advanced setup, put 25% of the budget on the room first, and you'll get an extra 100% out of it. And that's coming from someone with a quite capable DSP for room processing. ( Gave him a complement afterwards for having said so. )

If you start with a blank sheet of paper or are building a room, that may be so. And, while there are some well established and widely accepted ideas that seem to make sense for the room, dimensions and surface materials for example, there would also be considerable differences among knowledgable experts about exactly how one should acoustically treat the room. Some "experts" would have you absorb most side reflections, for example. Amir would say that is not really a good approach.

Even then, ideally, careful measurements need to be made, with possible adjustments to treatment regimens. I am not saying the attempt to configure and treat the room is a bad idea. It just ain't simple or easy, though some suppliers of off-the-shelf passive treatments might suggest it is: "just send us your room dimensions, and we will configure a bunch of our treatments in a custom bundle for you to install".

As with equipment comparisons, just listening by ear to a treated room may also be influenced by expectation bias or an assumption that "everything sounded better" after treatment, since that is what it is supposed to do. That is particularly true since it is difficult with passive treatments to hear before and after compared in rapid succession.

With that blank sheet of paper and a decent budget, I would definitely seek expertise in carefully designing and treating my own dream room, not expecting it to be cheap or easy. I would almost certainly also use DSP EQ in conjunction with that.

For most audiophiles, the room, WAF considerations, etc. are fact of life givens. For many of them, though results are not perfect, DSP EQ has provided a major measurable and subjectively audible improvement, even without any passive treatments or room configuration and design expertise. Possibly, the room could sound better still with more investment in design, configuration and treatment of the room. But, many in my circle of friends still find EQ an obvious improvement that has become essential. Switch it on, then off, then on. The difference and the magnitude of improvement are quite clear. We can save the acoustically perfect room fantasy for our pleasant dreams.

 

[amirm]

Only empty rooms/dedicated listening rooms require investments in acoustic products. A room with fair amount of furnishings is not in need of such. Here for example is an exercise Dr. Toole went through documenting each step:

 

[RayDunzl]

The guy from Trinnov said as one of his opening statements - if you do decide to do an advanced setup, put 25% of the budget on the room first, and you'll get an extra 100% out of it.

You know what, I almost did that.

$100 for eight 7 x 24 x 48 Roxul batts...

Then $400 for the DSP and software.

But I'm 5% shy on my room, $100/$500 = 20%

My arithmetic is rusted out.

How much more do I need to spend on room so the new total:

room/(dsp+room) = 25%

 

[Nightlord]

I think he meant on the total system budget. I doubt your Benchmark, Krells and reQuests came free of charge.

My room is in the $15000 range... and there's no DSP running...

 

[RayDunzl]

Oh well, I will just continue to think I'm satisfied with what I have going...

Let's bump the old poll since there are some new folks around:

Are you satisfied with your home Audio System?

 

[oivavoi]

Link to poll seems broken?

 

[RayDunzl]

Link to poll seems broken?

fixed

 

[Fitzcaraldo215]

fixed

Thanks, Ray. Since I already voted, I do not want to be accused by Trump of casting a fraudulent vote.

But, I will say this. I have tried many things in my system and I have been upgrading it for many decades. I installed Dirac Live Full Mch PC version for about $600 plus another $100 for the calibrated UMIK-1 about 3 years ago. There is absolutely no audio expenditure that can come remotely close to the obvious, slam dunk, bang for the buck sonic improvement this has provided, mixed metaphors and all. My circle of audiophile friends agrees.

Yes, I used Audyssey prior to that, and it made a big difference, too. But, different platform: preamp/processor vs. PC. Dirac is definitely much better than Audyssey, though either is just so much better than no EQ.

I have often said that DSP Room Correction is an "equalizer" in more ways than one. It measures and EQ's measured system response in the room. That also tends to improve the performance of lesser systems so as to make them sound more like the pricier systems. And, if those more expensive systems do not also use EQ, they might even sound worse in many ways.

 

[Blumlein 88]

Thanks, Ray. Since I already voted, I do not want to be accused by Trump of casting a fraudulent vote.

But, I will say this. I have tried many things in my system and I have been upgrading it for many decades. I installed Dirac Live Full Mch PC version for about $600 plus another $100 for the calibrated UMIK-1 about 3 years ago. There is absolutely no audio expenditure that can come remotely close to the obvious, slam dunk, bang for the buck sonic improvement this has provided, mixed metaphors and all. My circle of audiophile friends agrees.

Yes, I used Audyssey prior to that, and it made a big difference, too. But, different platform: preamp/processor vs. PC. Dirac is definitely much better than Audyssey, though either is just so much better than no EQ.

I have often said that DSP Room Correction is an "equalizer" in more ways than one. It measures and EQ's measured system response in the room. That also tends to improve the performance of lesser systems so as to make them sound more like the pricier systems. And, if those more expensive systems do not also use EQ, they might even sound worse in many ways.

I agree completely.

For an extreme example I once used two different brand speakers on each channel and let a Tact RCS correct for it. The result had a nice stereo sound stage that were you blind folded you wouldn't have commented upon as everything sounded alright. I did choose a target curve that was amenable to the speaker with less bass and loudness so it wouldn't be called upon for something it couldn't manage. I always thought the correction companies should have a demo display at audio shows done like that. Very impressive when you see/hear it happen.

 

[RayDunzl]

I have tried many things in my system and I have been upgrading it for many decades.

I haven't tried much at all... I'm pretty patient, easily amused, and don't like spending on sideways changes. Of course I'm deaf and don't hear all the problems others may hear (or imagine). And I'm most excellently amused with what I have going now. I don't have a bunch of audio buddies to come over and tell me how bad it all is and what I should try next. The one that I do have likes it too. Casual visitors, if interested at all, typically emit a "Wow".

I've subscribed to Stereophile since 1996, it rarely moves me to become anxious, but it has provoked some progress.

Tone controls when they were standard equipment - 60's 70's
31 band manual EQ - 80's - "professionally" and then at home, along with the PA amps.
(enter a long period of working and being on the road and not having a system set up or even a place to put one - car radio (I drove around the country) and an FM Walkman sufficed)
4dB pads on the ML woofers - late 90's 00's
Behringer DEQ2496 - intro to digital modification - 10's
MiniDSP OpenDRC-DI - with manual and later automated correction - mid 10's (best solution so far)

What will the 20's bring to my relatively antique system and ways of thinking?

 

[Barry]

I'm curious about the audibility of group delay, specifically as it relates to different frequencies. There are general references to the subject in Toole's, "Sound Reproduction", but they seem inconclusive. Have there been more recent studies?

When I first used REW and my DSPeaker Anti-mode Dual Core 2.0 for room EQ, I focused on getting a flat frequency response, nice waterfall plots, and to a lesser extent on RT-60s and ignored group delay plots because I didn't know what they were at the time.

Later, I noticed that sometimes when I added additional filters based on REW EQ suggestions, it could create millisecond humps below about 400 Hz in the GD plots ( I only use DSP on subs xo'd at 80 Hz and 24dB/octave as the unit isn't transparent enough but there's still usable response 2 octaves up for EQing).

I assumed these bumps would be less audible at the lowest frequencies, but I had no target levels to know what ms level not to exceed. I couldn't hear noticeable differences; but, then again, I didn't know what I should be listening for.

Any thoughts or experiences to share on this?

 

[hvbias]

Some very good discussion here. My own experiences are with older DRC where I felt like correcting over Schroeder did sound a bit "weird" and like others here I wasn't exactly sure how to describe it, these were not my systems so maybe more long term listening was needed. Which is where I became interested in Acourate when it said it could correct for frequency and "time optimization by phase correction".

Interesting, I think my weird sound is different to yours - as that is not what I hear. For me it's more an overall softness in the sound that is not at all unpleasant. It is extremly difficult to describe as sometimes it seems contradictory and it's that contradictory nature that I keep wrestling with.

As this is the audio science review perhaps we need a weirdness graph so we all know where our perception of room correction is on the weirdness scale...

This is the first dissenting opinion I've read on Acourate and I'm definitely interested in hearing more of your thoughts.

 

[Brad]

I found this video pretty useful
https://twit.tv/shows/home-theater-geeks/episodes/345?autostart=false

I took from it that the target curve needs to reflect the directivity of the speakers, and the measurement mic should be above the chairs (covering the chair with a blanket is insufficient)
I made these changes with my acourate processing and got an improvement

 

[Burning Sounds]

Some very good discussion here. My own experiences are with older DRC where I felt like correcting over Schroeder did sound a bit "weird" and like others here I wasn't exactly sure how to describe it, these were not my systems so maybe more long term listening was needed. Which is where I became interested in Acourate when it said it could correct for frequency and "time optimization by phase correction".

This is the first dissenting opinion I've read on Acourate and I'm definitely interested in hearing more of your thoughts.

It's not that I'm dissatisfied with Acourate, far from it. It's very rare that I switch it out of my system these days. I'm really just trying to determine what is causing the differences I am hearing in the bass region. I need to do more investigation, but listening to music is much more fun and that pesky What are you listening to now thread keeps thowing up gems that I've not come across... I will contribute to it once I've ploughed my way to the end...

Anyway, back to Acourate - the big positives I get are beautiful solid vocals, audience sounds and the overall ambience of live recordings seem enhanced and high freqencies sound much improved. Overall it's a real positive. It's only in the bass region where I feel there is something that could potentially be improved, but it doesn't spoil my enjoyment of the music.

Siegfried Linkwitz has an interesting piece on his website about group delay at low frequencies - I'm not saying this is the cause - but it makes interesting reading - http://www.linkwitzlab.com/frontiers.htm#F

I streamed some tracks from Qobuz last night - Thunder by Stanley Clarke, Marcus Miller and Victor Wooten - much more cone movement when Acourate is switched in (the Acourate filter probably eqs down further - I'll need to check), but the growl in (I think) Wooten's bass was better defined with Acourate switched out. But having Acourate switched in didn't stop my enjoyment of being battered by those three bass players And it could have been nothing more than that extra low bass was simply swamping the leading edge of that growl....

 

[Fitzcaraldo215]

There is no arguing with listener perceptions or preferences. If the "growl" upon turning EQ off is preferred, then what can we say? But, in the history of audio, many are the boomy, overhangy, non-linear boxes through many decades that were immensely popular, decidedly preferred and commercially successful in the untreated and unEQed room situation that prevailed.

Yes, by all means, investigate further. But, if you are completely thorough about it, you have to question what is really there on the recording vs. what is in your head in terms of artificial expectations of the sound that are not really there on the recording. Are you hearing something real, or just a reproduced coloration and artifact you like? We have no way of actually knowing.

I am not saying that EQ is automatically correct and therefore to be preferred no matter what. EQ might deliver better measurements with test tones. But, your mind and your imagination may take you elsewhere. That has happened before many times.

The interesting philosophical, psychoacoustic and technical question is how do we decide "what is sonically right"? Upon what, exactly, does our internal sonic gyroscope depend? I am not sure it is the right answer, but my answer, as a classical music listener, is to go to a lot of live concerts to inform my inner sense of what I should be expecting from reproduced playback in my room. For those who listen primarily to rock/pop, etc., whose recordings come primarily from a studio mix, I have no idea what to offer in terms of a way to develop more accurate expectations of recorded vs. live, which, to me, is the gold standard.

 

[Brad]

Have you tried adjusting the subsonic filter parameter in macro4?
It's apparently best to set it to match your speaker's (or sub) natural low frequency roll-off

 

[Cosmik]

...if you are completely thorough about it, you have to question what is really there on the recording vs. what is in your head in terms of artificial expectations of the sound that are not really there on the recording...

If we want just what is on the recording, we just need to sit close to some small speakers. Or we can wear headphones for the ultimate stereo crosstalk removal.

Is there still a residual notion of hi-fi being a "lifestyle" product that allows us to walk around a large room, chatting to the many young women who have been attracted there by the idea of meeting a cool cat with a high end stereo, and all the while hearing clinically accurate sound in every location? If so, this is in fundamental contradiction to the idea of room correction via manipulating what comes out of the speakers, which can only be valid in one location. If you're limiting yourself to one location anyway, just sit closer to some smaller speakers.

 

[Burning Sounds]

The interesting philosophical, psychoacoustic and technical question is how do we decide "what is sonically right"? Upon what, exactly, does our internal sonic gyroscope depend? I am not sure it is the right answer, but my answer, as a classical music listener, is to go to a lot of live concerts to inform my inner sense of what I should be expecting from reproduced playback in my room. For those who listen primarily to rock/pop, etc., whose recordings come primarily from a studio mix, I have no idea what to offer in terms of a way to develop more accurate expectations of recorded vs. live, which, to me, is the gold standard.

I understand completely where you are coming from and for classical music it makes sense. In fact, for acoustic (unamplified) music in general it makes sense. But I do think it can be applied to amplified music also. I'm 67, I've been going to concerts in small and large venues for many years. Singers have distinctive voices, and I expect to be able to identify them live and on record. A hammond organ has a distinctive sound and I know how I expect it to sound live and on record. Is it identical live and on record, no, but I know its distinctive tone.

Our local jazz club hosts regular music nights in a church hall. I recently attended an evening of music for violin and piano where most of the music performed was in the style of Django Reinhardt. But they also played Massenet's Meditation which was quite captivating. The tone of the violin was beautiful and I thought that if I could find a recording for violin and piano it would be a good benchmark. Most recordings I could find were for violin and orchestra rather than violin and piano, but I did manage to find a performance by Elmar Oliveira and Robert Koenig. It may not be a great performance or recording and the violin I heard that night and the one on the recording are unlikely to be by the same maker and are being played in different acoustic settings. Yes, I can use that live experience to give me a good approximation of how a solo violin sounds. Interestingly, the tonal quality of the violin I heard that night is most closely matched to Olivera's on the recording when I have Acourate switched in.

I completely understand that rock and pop studio recording is an artificial construct, but that doesn't mean that it's invalid as a means of judging sonics. I recently went to see Bad Company on their farewell tour. Paul Rodgers has a powerful distinctive voice and Paul Rodgers live sounded remarkably like Paul Rodgers on recordings. I heard the Lebanese jazz trumpeter Ibrahim Malouf at the Sage Gateshead, a venue with excellent acoustics - his distinctive four valve trumpet sounded like Ibrahim Maaloof sounds on all the recordings I have of him. Charlie Hunter often uses a 7 string guitar put through a a Leslie rotary speaker simulator - I know how that is supposed to sound.

I'm happy to agree that unamplified music may be the the gold standard, but it doesn't mean you can't judge sonics from a good studio mix.