Why Don't You Use Digital Room Correction?

The Computer Audiophile · August 23

Members of the Audiophile Style community know that I use digital room correction and have talked about it many times in these pages. Now, I have an honest question for those who don't use it. Please don't read into this question or assume anything, that doesn't help anyone. There is absolutely zero judgement here. Whatever people prefer is all good with me. If people are happy without DRC, I'm happy for them.

Question: Why don't you use digital room correction?

P.S. There are no wrong answers :~)

JoeWhip · August 23

Well, for me, at least with my two channel set up, I am too, shall we say inexperienced, to use it. With BACCH, it seems a good option. Working on that. As with the HT, Anthem makes it somewhat easier, enough for me to figure out.

treitz3 · August 23

39 minutes ago, The Computer Audiophile said:

Question: Why don't you use digital room correction?

IME, DRC can help in certain situations. No doubt about that. I have heard some superb examples, as well as some very bad implementations.

I would personally rather address the issues and keep the original signal as pure as possible, without any manipulation of the signal at all - other than addressing any noise that rides the line or is created along the way. A KISS approach, if you will.

As strictly a 2 channel guy, my stance would probably change if I were to dabble in a HT setup.

Tom

The Computer Audiophile · August 23

3 minutes ago, treitz3 said:

IME, DRC can help in certain situations. No doubt about that. I have heard some superb examples, as well as some very bad implementations.

I would personally rather address the issues and keep the original signal as pure as possible, without any manipulation of the signal at all - other than addressing any noise that rides the line or is created along the way. A KISS approach, if you will.

As strictly a 2 channel guy, my stance would probably change if I were to dabble in a HT setup.

Tom

Thanks for the reply Tom.

jcbenten · August 23

I do not listen critically. Too much effort. Vast majority of my listening is background music, earbuds while riding my bike (indoors) or cutting grass or whenever. Even listening to vinyl is primarily background.

joelha · August 23

I tried it, with help from the author of the software, and found the sound became less analog.

I wanted the product to work but, for this listener, at that time, it didn't.

I'd prefer not to mention the software as I don't want to take anything away from the author's efforts to develop his product.

I envy those who find digital room correction improves their sound.

Maybe someday . . .

Joel

The Computer Audiophile · August 23

Hi Guys, I’m removing posts from people saying they do use digital room correction. This topic is for those who don’t.

NikosTsaf · August 23

I have not had a chance to tried yet although speakers face big windows doors and I can not install absorbing panels easily

hipstone · August 23

7 hours ago, treitz3 said:

IME, DRC can help in certain situations. No doubt about that. I have heard some superb examples, as well as some very bad implementations.

I would personally rather address the issues and keep the original signal as pure as possible, without any manipulation of the signal at all - other than addressing any noise that rides the line or is created along the way. A KISS approach, if you will.

As strictly a 2 channel guy, my stance would probably change if I were to dabble in a HT setup.

Tom

1 hour ago, joelha said:

I tried it, with help from the author of the software, and found the sound became less analog.

I wanted the product to work but, for this listener, at that time, it didn't.

I'd prefer not to mention the software as I don't want to take anything away from the author's efforts to develop his product.

I envy those who find digital room correction improves their sound.

Maybe someday . . .

Joel

I also sense that it would result in a truncated bit depth to do any digital treatments including simple EQ.

But I do have all-analog receivers and can and often will do some tone adjustments (EQ) in the analog amp stage of the chain. I like a bit (just a tad) of high-end boost, as I am over 50 and so that might be why. But then again even as a much younger listener I liked hearing a crash cymbal crash with some sizzle. Horns too, love them a touch sharp and some "there-ness" to them.

So no, no digital anything done to the signal. But I am aware that if you are working with 24/192khz then the signal degrading should be very minimal, possibly inaudible.

Audiophile Neuroscience · August 24

I accept the question as being in good faith and my answer in given in kind. I fully accept that my experience also mainly relates to my situation of a dedicated listening room which has been acoustically treated.

I have had limited experience of a handful of implementations of DRC including a couple of paid professional implementations but that experience has produced different SQ but not necessarily a preferred difference. In general less preferred. That accords with a greater but not exhaustive experience with DSP in general, in my own hands.

I like near field listening and I fancy I can hear any altered speaker's direct response before room response.

For me there are also conceptual issues that follow on from from the above. The direct sound from the speakers will always arrive before any room contribution. Speakers first then room response. I do understand about summing and combining sound waves, Precedence/Haas, flat FR, but the ringing that occurs in rooms holding on to bass frequencies lingers well beyond the time the signal has ended. Reducing amplitude of the bass frequency reduces the level of ringing but at what cost. I remain open to possibility, especially in an untreated room, that there is software that makes allowances for early direct speaker response and somehow only alters the room contributions and can do so in the time domain but I do find that puzzling. If the room is the problem treat the room is my feeling but as said, not always practical.

PeterG · August 24

I use the DSP built into my subwoofer (but don't delete me yet! haha), but returned a McIntosh MEN220 which provided comprehensive(?) room correction. I found that it improved the bass, but at the price of high end detail (sparkle?). I concluded that it may have helped if I had a more problematic room, but with my room/system/ears, it was not worth the trade off.

I considered Josh's convolver(?) briefly, at your recommendation, but at least at the time it was not compatible with my Naim Uniti Core server. If Josh had a plug and play box, I probably would have bought one.

I have since moved to analogue as my favorite source, which based on a comment or two above, probably raises the bar again

CG · August 24

OK, I'll toss in my unprofessional opinion.

I tried DRC. It didn't last long, even though I wanted it to be magic.

Here's why, I think.

The peaks and valleys in amplitude in sound across the audio spectrum at the listener's position is a function of the speaker itself and interference between direct sound and reflected sound. (No kidding, right?) When you use DRC, you essentially predistort the sound coming from the loudspeaker in amplitude and time so that the interference is minimized at the listening position. But, that means that the amplitude and time relationships at other spots in the room, or on the sofa, also get modified. Maybe in a good way, maybe not.

That's the part that didn't work as well for me.

I found that lowering the effective Q of the listening room by adding bass traps in the corners to minimize bass peaks and nulls worked better. For me. That, along with some diffusion at the right places and proper placement of the listening sofa and the speakers was more effective. Fix the room as best you can, in other words. That solution also makes for better human speech quality in the room, too. (I'd guess that's not a consideration for a lot of audiophiles.)

I have also found that I personally prefer so-called time aligned and phase correct sound. You can only get that from a small number of speaker manufacturers. That doesn't seem to be a factor for the majority of audio enthusiasts - everybody is different. DRC messes that up.

There's also the question of what raising or lowering the amplitude of a particular frequency band does in regard to the distortion output spectrum from a power amplifier.

Finally, I am not convinced that absolute flatness provides a better listening experience. What concert hall is flat? My wife the music major told me that in the performance halls at her alma mater different professors had different preferred seats that they "reserved" because of the sound qualities right there. From what I have read, part of the spatial perception we like to enjoy is due to us subtly moving our heads to get preferred wave patterns into our ears. That allows for better localization. (That's why I don't love headphones, I think, despite all their clear advantages.)

That's my two cents worth, which isn't much these days. Can't even buy Bazooka bubble for anywhere near that price. No comics with that, either.

The Computer Audiophile · August 24

Thanks for all the details so far guys.

One and a half · August 24

Only real exposure to DRC was with HT receivers, Sony & Yamaha. The receivers were somewhere upper mid-tier, and both flattened the sound to loss of excitement. The bass really took a huge hit, and wasn't pleasant even the highs lost their brilliance, the response would have been flat, so was the music!

Is DRC trying to correct for distortion, or it can't see past the distortion from the speaker, nulling out and boosting frequencies perhaps with a sledgehammer and not a fine brush.

Since then, haven't used any DRC in 2CH setup, just room treatments here and there, rugs, plush couches, painted brick walls. I don't expect a room could ever be treated perfectly, heck even if it was, the recordings we listen to 95% suck badly so is it worth the exercise? The other issue is that another component is in the chain, even digital could add timing errors, and there's the processing issue as well contributing to noise and masking critical details.

The Computer Audiophile · August 26

Who else wants to share why they don't use room correction? There are no wrong answers, and in this thread any responses that don't address the topic are removed. It's a win-win :~)

StephenJK · August 29

On 8/23/2024 at 11:30 AM, The Computer Audiophile said:

Members of the Audiophile Style community know that I use digital room correction and have talked about it many times in these pages. Now, I have an honest question for those who don't use it. Please don't read into this question or assume anything, that doesn't help anyone. There is absolutely zero judgement here. Whatever people prefer is all good with me. If people are happy without DRC, I'm happy for them.

Question: Why don't you use digital room correction?

P.S. There are no wrong answers :~)

I looked into it. I had a brief conversation with Mitch and the service he can provide, that being a few years ago.

I bought a mic and did a bit of testing on my own with basic DRC, but I suppose the bottom line is that it just wasn't that important to me.

I do have a system with KEF blades and Devialet Expert Pro 440 amplifiers, and suspect that they do a good job with the Devialet/KEF profile to optimize the sound for any room.

I don't have an optimized "man cave" that's exclusive to a stereo system, and never wanted one. I think most of us want the best from the hardware we have, but we all live with a budget and within our means.

For me, I think the main reason was that so much music is recorded so differently, whether good or bad, that trying to optimize any recording to sound great just wasn't possible. You know, the "You can't make a silk purse out of a sow's ear" school of thought.

I continue to enjoy all forms of music, but do recognize that a poor recording is exactly that.

If you have a system in a room where you want to have that optimized to be the best it can be, then yes, DRC would certainly be one of the tools you would want to use.

The Computer Audiophile · August 29

Thanks @StephenJK

sdolezalek · August 29

In a word: "Complexity." But complexity is really a combination of:

a) I'm not capable (short of doing an amount of learning I'm too lazy for or cannot afford the time for) to do it myself (I have bought the necessary microphones and software)

b) I'm too cheap to pay to have a real expert do it for me, but a big part of that is not being sure my "expert" actually knows what they are doing

c) Because what I ultimately would want is a set of corrections that are doing all of:

(i) fixing speaker frequency anomalies

(ii) fixing room-based anomalies

(iii) doing both of the above while preserving time domain accuracy of the sound at my ears

(iv) giving me a result I'm as happy with on day 90 as on day 1 (too many changes sound like an initial improvement only to become fatiguing over time)

(v) do what they do seamlessly in the HQPlayer/Roon/Tidal/Qobuz environment I deploy

The Computer Audiophile · August 29

Thanks @sdolezalek

Chris A · August 29

On 8/23/2024 at 10:30 AM, The Computer Audiophile said:

Question: Why don't you use digital room correction?

My answer to your question isn't based on simple ideas such as "I don't like it", "it doesn't do 'X' that I want it to do, custom for my tastes", "the music itself isn't consistent enough to bother with this", etc. These are simple answers to your admittedly simple question.

The truth is that I've used these firmware packages initially to only set channel delays and initial channel gains (due to the combination of loudspeaker placements in-room, differing loudspeaker configurations--including 21 ft internal path lengths for subs, differing insertion delays and gains of the three different DSP crossovers used in series with a preamp/processor, etc.)--because these packages do those two functions fairly well and more quickly than I can do it manually. I manually copy these two (vector) settings from the "room correction" app, but discard the rest of the most important parts: amplitude and phase corrections, i.e., the transfer function corrections.

I've found that all of these packages are telling the user to place the measurement microphone much too far from the loudspeaker front baffles in-room--at the listening positions (LPs)--and therefore are mixing significant amounts of non-minimum phase artifacts from room acoustics with the minimum phase response in their upsweep measurements. Then the app's internal algorithms fail to separate out the non-minimum phase portions (by using techniques like non-flat excess group delay response to avoid trying to correct these frequency band areas, etc.) and are trying to EQ/phase correct non-minimum phase room reflections--that cannot be EQed. To date, all the apps I've tried have this disease. The loudspeakers I use in a 5.1 array all have full-range directivity, i.e., the ratio of direct to reflected acoustic energy is above some threshold that the human hearing system needs to hear phase fidelity in-room, above the room's so-called Schroeder frequency--where the concept of direct-to-reflected energy has meaning.

I tried an experiment once with a fairly capable commonly used app on my manually dialed-in setup. The experiment would show that the apps would do nothing to the transfer function response if it was successfully rejecting non-minimum phase in-room reflections. This is the first criterion necessary to prove that the app could successfully use the measurement microphone distances so far away from each loudspeaker's front baffle (thus mixing in significant levels of room reflections). The apps uniformly failed this test miserably, and they all failed precisely where the physics says they will fail: right around and slightly above the room's Schroeder frequency. All the apps try to correct this region via attenuation of amplitude response, leaving the setup sounding overly (and unacceptably) "thin".

It's interesting that the apps I've used all apparently fail this test at the same points in the frequency spectrum, and none allow the user to move the measurement microphone to do one loudspeaker at a time at 1m distance, then later combine with measurements at the LPs to get accurate channel delays and channel gains.

Chris Askew

The Computer Audiophile · August 29

3 hours ago, Chris A said:

My answer to your question isn't based on simple ideas such as "I don't like it", "it doesn't do 'X' that I want it to do, custom for my tastes", "the music itself isn't consistent enough to bother with this", etc. These are simple answers to your admittedly simple question.

The truth is that I've used these firmware packages initially to only set channel delays and initial channel gains (due to the combination of loudspeaker placements in-room, differing loudspeaker configurations--including 21 ft internal path lengths for subs, differing insertion delays and gains of the three different DSP crossovers used in series with a preamp/processor, etc.)--because these packages do those two functions fairly well and more quickly than I can do it manually. I manually copy these two (vector) settings from the "room correction" app, but discard the rest of the most important parts: amplitude and phase corrections, i.e., the transfer function corrections.

I've found that all of these packages are telling the user to place the measurement microphone much too far from the loudspeaker front baffles in-room--at the listening positions (LPs)--and therefore are mixing significant amounts of non-minimum phase artifacts from room acoustics with the minimum phase response in their upsweep measurements. Then the app's internal algorithms fail to separate out the non-minimum phase portions (by using techniques like non-flat excess group delay response to avoid trying to correct these frequency band areas, etc.) and are trying to EQ/phase correct non-minimum phase room reflections--that cannot be EQed. To date, all the apps I've tried have this disease. The loudspeakers I use in a 5.1 array all have full-range directivity, i.e., the ratio of direct to reflected acoustic energy is above some threshold that the human hearing system needs to hear phase fidelity in-room, above the room's so-called Schroeder frequency--where the concept of direct-to-reflected energy has meaning.

I tried an experiment once with a fairly capable commonly used app on my manually dialed-in setup. The experiment would show that the apps would do nothing to the transfer function response if it was successfully rejecting non-minimum phase in-room reflections. This is the first criterion necessary to prove that the app could successfully use the measurement microphone distances so far away from each loudspeaker's front baffle (thus mixing in significant levels of room reflections). The apps uniformly failed this test miserably, and they all failed precisely where the physics says they will fail: right around and slightly above the room's Schroeder frequency. All the apps try to correct this region via attenuation of amplitude response, leaving the setup sounding overly (and unacceptably) "thin".

It's interesting that the apps I've used all apparently fail this test at the same points in the frequency spectrum, and none allow the user to move the measurement microphone to do one loudspeaker at a time at 1m distance, then later combine with measurements at the LPs to get accurate channel delays and channel gains.

Chris Askew

Thanks Chris

Jud · August 29

I do have a measurement mic, but life has been so busy I haven't got around to using it yet! (I'm president of our town's continuing adult education association and one of the instructors has experience as a record producer, so maybe I can get some good advice?) But both for my own measurements and any attempts at room correction that would follow, or for a professional service that would do this for me, I have the following concerns:

- I have Vandersteen speakers, that are time- and phase-aligned. What does this mean? It means (1) the drivers are located so the arrival times at the listening position of the frequency ranges they're responsible for are approximately equal; and (2) the crossovers are first order and linear phase, the linear phase again meaning various frequency ranges arrive at the listening position approximately simultaneously.

- This time and phase alignment produces beautiful soundstage and stereo imaging, sound quality characteristics I've learned to treasure after 35 years of owning Vandersteens.

- My general understanding of measurements for room correction software is that they involve first measuring quite near the speakers, then at listening position and comparing. However, if you've read what I've written above, the nearfield arrival times for the various frequency ranges with Vandersteens are intended to be different than arrival times at the listening position, and this is a feature, not a bug.

- In order to correct problems with frequency arrival times, all the room correction software I know of uses either minimum phase or intermediate phase filters. But here I sit with player software I've set to use linear phase sample rate conversion filters, and speakers with linear phase crossovers, that together result in wonderful soundstaging and imaging I don't want to mess up. (The Vandersteen owner's manuals go into great detail on positioning the speakers to achieve this.)

So I want to be quite cautious about thoroughly understanding what is going on with whatever room correction software I might decide to use - what the goals are, why those goals will result in improved sound, and exactly how we're going to achieve them.

The Computer Audiophile · August 29

Thanks for the thorough reply Jud.

amey01r · August 30

On 8/24/2024 at 1:30 AM, The Computer Audiophile said:

Question: Why don't you use digital room correction?

I'd love to. But so far, I've been unable to find anything close to an acceptable solution (for me). Here are my requirements. I don't have many, they're pretty basic. If anyone can tell me about something that can meet them, I'd be very interested.

1. Allow transparent passthrough - I want the option to have it ON or OFF

2. Before DAC - I don't want multiple AD/DA conversions.

3. Operate in digital domain with all my digital sources. That includes up to DSD x256, PCM 32/384, et al.

The Computer Audiophile · August 30

4 hours ago, amey01r said:

I'd love to. But so far, I've been unable to find anything close to an acceptable solution (for me). Here are my requirements. I don't have many, they're pretty basic. If anyone can tell me about something that can meet them, I'd be very interested.

1. Allow transparent passthrough - I want the option to have it ON or OFF

2. Before DAC - I don't want multiple AD/DA conversions.

3. Operate in digital domain with all my digital sources. That includes up to DSD x256, PCM 32/384, et al.

Thanks @amey01r

Why Don't You Use Digital Room Correction?

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