An Enticing Marketing Story, Theory Without Measurement?

[jazzendapus]

Correct. This is why it is important for at least the mastering, if not the mixing, of recordings be done in spaces that approximate average domestic listening rooms. This sometimes happens, but not always. This is a component of the circle of confusion.

Hello Dr. Toole, a question on this point:
Isn't trying to achieve average recording studio acoustic conditions at home would be a more correct approach if the goal is to get as close as possible to reproducing artist's intention? Sure, the studios vary a lot, but my intuition tells me that those graphs from Sean Olive's blog post would look a lot wackier if the same research would have been conducted in domestic listening rooms...

 

[Soniclife]

I have never experienced room treatment not being a huge upgrade. However, a lot of treatment out there today are poor.

Can you expand on this a bit please, are there any simple pointers to good not poor treatment?

 

[Floyd Toole]

Hello Dr. Toole, a question on this point:
Isn't trying to achieve average recording studio acoustic conditions at home would be a more correct approach if the goal is to get as close as possible to reproducing artist's intention? Sure, the studios vary a lot, but my intuition tells me that those graphs from Sean Olive's blog post would look a lot wackier if the same research would have been conducted in domestic listening rooms...

Have you been in recording studios lately? They are all over the map acoustically - from totally dead (the "Non Room"), through variations of live and dead ends, a few outliers that are totally diffusive, and many that are variations on "normal" - as in acoustically similar to a typical domestic room. Tracking and mixing rooms can be quite different from mastering rooms, which should in a rational world be similar to domestic spaces, if that is the intended customer.

So, from the get-go, in spite of all possible variables, there is more "standardization" in domestic rooms and in professionally designed listening rooms than in professional control and mastering rooms. This is illustrated in Figure 10.1 in the 3rd edition of my book.

Fortunately - and this is truly fortunate - in spite of differences in rooms, it is the loudspeakers that dominate perceived sound quality. Most of my book explains that, and the fact that human listeners are perceptually able to separate the sound of the source from that added by the room. This is true in live unamplified music and in sound reproduction. So, the fundamental requirement for controlling the "circle of confusion" is to ensure that all loudspeakers from recording to playback radiate similar sounds. As increasing numbers of loudspeakers adhere to the rational design goals that science has provided, things are definitely improving.

BTW I know of no listening tests by me or by Sean Olive (together or separately) that were not conducted in rooms designed to resemble typical domestic rooms. To do otherwise serves no purpose. In fact an elaborate test was conducted that showed that listeners rated loudspeakers similarly in four very different real rooms - Section 7.6.2 in the 3rd edition. This is good news. Buy truly good loudspeakers, relax and enjoy them.

 

[Soniclife]

Fortunately - and this is truly fortunate - in spite of differences in rooms, it is the loudspeakers that dominate perceived sound quality. Most of my book explains that, and the fact that human listeners are perceptually able to separate the sound of the source from that added by the room. This is true in live unamplified music and in sound reproduction.

How much does this vary from person to person? I think my ability to do this has degraded over the years, but I have no test to prove it disprove it.

 

[Floyd Toole]

How much does this vary from person to person? I think my ability to do this has degraded over the years, but I have no test to prove it disprove it.

There is remarkably little variation from person to person, including differences in experience, culture, country of origin, etc. The critical factor is that the listening tests must be blind or double-blind - sighted tests cannot be trusted. It was this observation that, back in 1966, caused me to take on the challenge of identifying measurements that described what we hear. Without consistent, reproducible sound quality ratings that could reliably be extrapolated to large populations of listeners such a venture was doomed to fail. The listeners who demonstrably differ from the easily identifiable population trends are those with hearing loss. This is explained in detail in Section 3.2 in the 3rd edition.

 

[Bjorn]

Can you expand on this a bit please, are there any simple pointers to good not poor treatment?

It depends obviously on what you can do in regards to aesthetics. But generally speaking treating broadband is crucial for a great result. That implies dealing with ringing and resonances of low frequencies effectively and treating specular energy with something that works well down to at least the Schroeder frequency.

It's also very important that if you use absorption, that you treat areas surgically and don't just spray treatment around the room that will overdampen and possibly make the room too dead. This can be done either by measurements (best way) or by finding early reflections points with a mirror. Late arrival specular reflections are best to diffuse IMO.

Practically this means quality bass trapping that actually works (absorption material is generally inefficient at low frequencies unless it's extremely thick), absorbers that absorb with high efficiency down to 200-300 Hz and diffusers that are broadband with good polar data.

Type of treatment is depended on room size and placement. There are several ways to skin a cat. There's isn't one type of solution to every room and situation.

 

[Bjorn]

Isn't trying to achieve average recording studio acoustic conditions at home would be a more correct approach if the goal is to get as close as possible to reproducing artist's intention? Sure, the studios vary a lot, but my intuition tells me that those graphs from Sean Olive's blog post would look a lot wackier if the same research would have been conducted in domestic listening rooms...

Absolutely in my opinion. Just because the studio acoustics varies, doesn't mean that there are no answers here.
Quite the opposite: If you want to hear the mix as accurate as possible treatment is necessary.

This can be done by making the early arriving reflective energy audibly anechoic or at least close to it. And if you can also treat later arriving high gain reflections that is a great benefit, and so is dealing with room modes and long decay in the lower region. But most important part is treating the early arriving reflections by attenuating them as much as possible. This has a great effect on clarity, intelligibility, localization, pin-pointing and tonality. You will be able to hear the mix with much greater accuracy.

 

[Juhazi]

Wheez, Floyd's two last posts made me sentimental... I have not yet retired, but have practiced my academic profession for 36 years so far and I find many similarities here to my own thinking and views of my expertice. Having gained knowledge and experience, seen many fashions and dogmas come and go, so gradually one's own thinking, rationalizing and conclusions start to crystallize. Basics tend to be simple and basic, really

Hifi is "popular science", many people are interested in it without specific education and understanding of basic electronics, mechanics, acoustics and psychoacoustics. Most of us don't know much of music theory or history either, or of music business, but we just like it and are afficionados of music and hifi. This (mis)leads easily to strange paths of pseudoscience, myths and dogmas of "absolute hifi", search for the perfect or absolute truth/fidelity of reproduction. But there are so many turns, bricks and holes on the road that we need and must accept guidance and we really must accept the uncertainties and imperfections that we must live with every day!

But oh how I love this hobby, have been reading and learning since early '70s! And still I learn more every day...

 

[Floyd Toole]

It is noticeable in audio forums that there are biases. Some people argue that the room is the critical ingredient. It dominates at low frequencies (absolutely no argument there!) and there are several approaches to alleviating bass colorations, all of which are discussed in Chapter 8 of the 3rd edition. They range from aggressive bass trapping, through to multiple subwoofer solutions that are capable of eliminating need for such trapping - a huge advantage when visual aesthetics matter. There are choices, but something must be done.

However, at frequencies above the transition frequency things change. The traditional "kill all early reflections" approach was entirely justified in past years when almost all loudspeakers exhibited degraded performance off axis, thereby coloring the reflected sounds. See 50 years of loudspeaker measurements in Chapter 18 for persuasive evidence. Early in my own double-blind evaluations, which were in a room that did not address first lateral reflections (deliberately), loudspeakers with the flattest, smoothest on axis (direct sound) performance rose in the rankings. Further, it quickly became evident that loudspeakers that exhibited relatively uniform performance both on and off axis achieved higher subjective ratings than those that did not. The off axis angles involved go beyond those measured by many in the business - it is simple geometry but many have failed. So, it seems that the subjective effect of those reflections became more desirable if they exhibited timbre similar to the direct sound.

Much later we learn that part of this is the precedence effect in action. When the direct and delayed sounds are similar the localizations are more precise, and timbre is less degraded. What happens when these reflections are simply absorbed - eliminated? It depends on the musical repertoire and the personal preference of listeners. All of this is discussed in Chapter 7 in the 3rd edition. We quickly learn that many common acoustical treatment materials do us no favors in how the reflected sounds are modified. They are never "eliminated".

My goal has been to make life simpler for consumers. If satisfaction can be attained with minimal or no deliberate acoustical intervention that is a good thing. It runs counter to the business interests of purveyors of acoustical materials and associated designers. So be it. All empty rooms are huge problems, so an intelligent combination of absorption and scattering (which makes absorbers work harder) is needed. In my experience satisfaction can be achieved in rooms that have a "normal" appearance and in those that are aggressively "technical" in appearance - this is a personal taste issue. Again, there are choices.

EDIT: The book has much of the material, but an open-access companion website contains more: www.routledge.com/cw/toole. Click on the titles at the top of the webpage to download material.

 

[Bjorn]

Multiple subwoofers don't work in the region where we are the most sensitive to resonances and ringing. So only choosing this method is a mediocre solution, which is obviously fine if that's the goal and what's practical possible. Multiple subwoofer isn't a solution that works in every room either and setting it up well integrated requires skill and time.

For the region above Schroeder what you do depend on the goal and taste. Accuracy requires attenuation of early arriving reflections no matter how the speaker measures off-axis. A uniform directivity gives less coloration from the boundaries. But an accurate stereo image still suffers. If you don't care much about an accurate imaging with great clarity and localization and prefer the more diffuse result, you can have the side walls contributing and it will enhance spaciousness.

A middle way here is diffusion or a hybrid product that absorbs the lows and diffuses the highs. IMO some kind of treatment, as long as it's sufficiently broadband and of good quality, is always better than no side wall treatment but your mileage may vary.
But it's interesting that it seems almost no one that have lived with broadband side wall treatment for a while, don't go back to purely reflective side walls. I'm uncertain if short listening studies really tell us what we prefer over time with different music material. Best is really to experiment and listen to both over time.

Take note that absorption treatment needs to be done surgically and this will avoid making the room lifeless. Absorption can also be completely avoided.

 

[daftcombo]

Some people argue that the room is the critical ingredient. It dominates at low frequencies (absolutely no argument there!)

Even our host says so:
https://www.audiosciencereview.com/...surements-of-onkyo-m-282-amp.6165/post-137977
;-)

But how can the room be "used" without adding distortion to the signal?

 

[Floyd Toole]

Multiple subwoofers don't work in the region where we are the most sensitive to resonances and ringing. So only choosing this method is a mediocre solution, which is obviously fine if that's the goal and what's practical possible. Multiple subwoofer isn't a solution that works in every room either and setting it up well integrated requires skill and time.

For the region above Schroeder what you do depend on the goal and taste. Accuracy requires attenuation of early arriving reflections no matter how the speaker measures off-axis. A uniform directivity gives less coloration from the boundaries. But an accurate stereo image still suffers. If you don't care much about an accurate imaging with great clarity and localization and prefer the more diffuse result, you can have the side walls contributing and it will enhance spaciousness.

A middle way here is diffusion or a hybrid product that absorbs the lows and diffuses the highs. IMO some kind of treatment, as long as it's sufficiently broadband and of good quality, is always better than no side wall treatment but your mileage may vary.
But it's interesting that it seems almost no one that have lived with broadband side wall treatment for a while, don't go back to purely reflective side walls. I'm uncertain if short listening studies really tell us what we prefer over time with different music material. Best is really to experiment and listen to both over time.

Take note that absorption treatment needs to be done surgically and this will avoid making the room lifeless. Absorption can also be completely avoided.

You said:"Multiple subwoofers don't work in the region where we are the most sensitive to resonances and ringing. So only choosing this method is a mediocre solution, which is obviously fine if that's the goal and what's practical possible. Multiple subwoofer isn't a solution that works in every room either and setting it up well integrated requires skill and time."

Well it seems that you have not read my book because, there is evidence that humans do not "hear" the ringing (European research not mine - see Section 8.3). It is counterintuitive, but so are other aspects of psychoacoustics. Yes, multi-sub solutions only work in the sub frequency range, but the most energetic room modes tend to be below 80 Hz, and these can be very well controlled. Above 80 Hz we are into the adjacent boundary region (Chapter 9) and equalization is effective because this is a sound power radiation issue and it should be used certainly up to the transition frequency, and sometimes a bit higher - 400 -500 Hz. BTW the Schroeder frequency calculation is for large reverberant auditoriums, not small listening rooms - his definition, not mine - see Section 6.1.

Setting up a multi-sub system is straightforward in a rectangular room (Welti papers and Section 8.2.6) but Sound Field Management, if you have access to it (JBL Synthesis), is also straightforward, but requiring some measurements and the optimization algorithm. The results are predictable Section 8.2.8), and improvement is possible in any room we have yet encountered. Without SFM or a functional equivalent, you are right that setup takes a lot of trial and error.

You said: "Accuracy requires attenuation of early arriving reflections no matter how the speaker measures off-axis." Now we part company. Stereo is mono left, mono right and double mono amplitude panned for all images across the soundstage. To this basic set of images is incorporated some amount of poorly correlated real or synthesized reflected sound in the two channels to create a sense of space. In studio mixes different instruments and voices of the mix can be put in different spaces. Stereo is not an "encode/decode" system, it is merely a two channel delivery system and there are enormous variations depending on how the channel information is utilized in the miking and mixing processes. In many stereo recordings sound will be heard emerging only from the left or right loudspeaker, in which case the sound quality evaluations are very similar to those in mono presentations. Section 7.4.2. In those cases there is evidence that listeners prefer to have a sense of space around the point-source loudspeaker. It seems that you prefer "pinpoint localizations" - and you have company, but it is not the only preference. Chapter 7 includes a lot of information on the effects of lateral reflections on image location and other aspects.

I think I describe in the book, certainly elsewhere, that very early in my experiments I set up a room with heavy lined drapes that could be moved forward or back to vary the amplitude of the side-wall reflections. Among my group of volunteer listeners there was one who was sufficiently enthused to set It up in his personal room. He concluded what was quite clear from our in-house evaluations (which were not short term sessions) that preference was significantly program dependent. There was a "classical" setup and a "rock/pop" setup.

In the end I will offer that unless one begins with fundamentally well-designed loudspeakers no amount of Room EQ or acoustical fiddling will save the day. With good loudspeakers the job is much easier, and intelligent manipulation of acoustics devices may or may not lead to greater satisfaction. Bass MUST be fixed and that includes adjacent boundary effects below the transition frequency.

But so long as one stays stuck in the stereo groove, there can not be one physical solution for all listeners. It is inherently a directionally and spatially deprived format, with everyone seeking a "solution", when there is none that does not involve multiple additional channels. I live with 9.4.6 and use them all from time to time.

 

[Kvalsvoll]

I have to agree with @Bjorn here. As long as we want the best possible quality, room acoustics must be up to a certain standard, and that means acoustic treatment beyond a couple of thin absorber plates and some furniture.

To me, room acoustics are more like a requirement to allow the speakers work their best, and in a good room better speakers sound even better.

With good speakers with decent on and off axis response, tonality can be perceived as good, even in a lesser room. But the difference compared to a good room where decay is quite short and linear across the frequency range, early reflections are attenuated - also across the whole frequency range, no resonances in upper bass and lower midrange, well, the difference is huge. Clarity is improved, location of instruments are far better, soundstage is wider and deeper, room information from the recording is much stronger, instruments appear like individual objects. The same level of performance simply can not be achieved in a room where decay is too long and there are too strong early reflections.

Many enthusiasts have dedicated listening rooms, where this can be achieved. In ordinary living rooms, it will be more challenging. and then the story about acoustics that are not so important is very welcome. Also, when trying to give some useful advice in to a world that believes a piece of wire can improve sound, you have to start somewhere, and that is at the very beginning.

 

[amirm]

But it's interesting that it seems almost no one that have lived with broadband side wall treatment for a while, don't go back to purely reflective side walls.

Oh, I see people do this all the time on forums. The most ardent advocates of "block side reflections" come back a year or two later and say: "I removed all of that and was surprised how much better the sound was!"

 

[March Audio]

Multiple subwoofers don't work in the region where we are the most sensitive to resonances and ringing. So only choosing this method is a mediocre solution, which is obviously fine if that's the goal and what's practical possible. Multiple subwoofer isn't a solution that works in every room either and setting it up well integrated requires skill and time.
.

Well this is my experience going from 1 to 4 subs. Just dumped in the corners but with levels matched. Bass was also significantly more even around the room.

 

[amirm]

With good speakers with decent on and off axis response, tonality can be perceived as good, even in a lesser room. But the difference compared to a good room where decay is quite short and linear across the frequency range, early reflections are attenuated - also across the whole frequency range, no resonances in upper bass and lower midrange, well, the difference is huge.

One of the best experience I had was setting up my Revel Salon 2 speakers in a bare highly reflective room and playing classical/orchestral music. It sounded amazing. I did have to modify that once I listened to rock and pop music and did so with usual furnishings. This is a living space and acoustic products have no business being there.

At madrona we have a highly treated theater room. It is for multichannel playback. Here is a shot of it:

There is about $25,000 worth of acoustic products in there, some that we built and some that we bought off-the-shelf. The room was designed by Keith Yates. What you see are all behind acoustically transparent fabric that then is backlit using LED lights. There is a lot more on the other surfaces and the ceiling. It all sounds incredible.

However, when we put even high-end stereo speakers in there (e.g KEF Blade 2, Revel Salon 2, etc.) they all sound extremely dead and dull. I remember the KEF people who brought the Blade 2 and after hearing it in this room, they wanted to slash their wrists. I agreed and we took them out and put them in our larger, untreated space and they sounded far better.

So no, I am 100% with Dr. Toole here. Fancy acoustic products is not a ticket to excellent sound. And reflections are not the thing we should fear. Too much is a problem and bare rooms like above do need some but there is no measure of more the better.

There are of course exceptions. My chief designer loved both the KEFs and Salon 2s in our theater. He mixes and records music so likely has adapter his hearing to a) hear the effect of reflections more ab) prefer them that way. Not so for most of us.

 

[Kvalsvoll]

Well this is my experience going from 1 to 4 subs. Just dumped in the corners but with levels matched. Bass was also significantly more even around the room.

View attachment 25317


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I suspect Bjorn meant the range around 80-200hz. Where at least up to around 150hz you can still see improvements with bass-system/subwoofers, because they are (usually) placed close to boundaries. it starts to get more difficult to achieve excellent results in the time domain.

Here it seems you cut off right above 60hz, which is fairly low, for a bass-system, and the improvement is huge - both in frequency and time.

 

[Kvalsvoll]

One of the best experience I had was setting up my Revel Salon 2 speakers in a bare highly reflective room and playing classical/orchestral music. It sounded amazing. I did have to modify that once I listened to rock and pop music and did so with usual furnishings. This is a living space and acoustic products have no business being there.

At madrona we have a highly treated theater room. It is for multichannel playback. Here is a shot of it:

View attachment 25320

There is about $25,000 worth of acoustic products in there, some that we built and some that we bought off-the-shelf. The room was designed by Keith Yates. What you see are all behind acoustically transparent fabric that then is backlit using LED lights. There is a lot more on the other surfaces and the ceiling. It all sounds incredible.

However, when we put even high-end stereo speakers in there (e.g KEF Blade 2, Revel Salon 2, etc.) they all sound extremely dead and dull. I remember the KEF people who brought the Blade 2 and after hearing it in this room, they wanted to slash their wrists. I agreed and we took them out and put them in our larger, untreated space and they sounded far better.

So no, I am 100% with Dr. Toole here. Fancy acoustic products is not a ticket to excellent sound. And reflections are not the thing we should fear. Too much is a problem and bare rooms like above do need some but there is no measure of more the better.

There are of course exceptions. My chief designer loved both the KEFs and Salon 2s in our theater. He mixes and records music so likely has adapter his hearing to a) hear the effect of reflections more ab) prefer them that way. Not so for most of us.

If the room is too damped - i.e. has too much absorption - it will sound dull. In that room this may be intended, for its purpose. Too much high-frequency absorption and too little low-freq absorption can also give this impression of dull sound, but as this was a pro-design, that is not likely.

Room size plays a big part in this, too. If your highly reflective room was quite large, it will sound better than a smaller room, because the distance to first reflection surfaces are greater.

But I think you already knew that.

I am fortunate to have access to different speakers - in the meaning really different. Size, capacity, and - most important - different radiation pattern. Listening to those speakers in the best room, my impressions does not match yours. Why? Preference, speakers, room, I am stubborn?

First, I have had visitors in there, and at least one of them has totally rebuilt his own room now. All visitors prefer the sound in the best room over the lesser room.

The room is quite small, and that plays a big part for the ordinary "hifi"-speakers with little radiation control. The distance to the speakers is quite small, and since the room is small, the distance to the reflective surfaces - particularly at the back of the room - is not too large. This thing about distance is important here, because different radiation causes differences in how the frequency response changes as you move away from the speaker. While the hifi-type (dome, small mids) falls off at higher frequencies, the larger speakers (horn) have a much more even response when the sound hits the back of the room. This causes differences in amount and frequency distribution of later reflections and decay. If the room had been much larger, this difference would be greater.

The room is far from "dead", it just has a much more even decay response because absorption works down to the bass range, and there are reflective surfaces intended to maintain life at higher frequencies.

All speakers maintain their own sound signature, they just sound better. Moving the same speaker to a different room reveals this - a lesser room puts more of the room's own signature to the sound. Soundstage is wider, deeper, more precise, more room information, more clarity especially lower mid and down. And a better speaker - especially off-axis response - sounds better, better acoustics can never do magic for a bad speaker.

 

[b1daly]

Have you been in recording studios lately? They are all over the map acoustically - from totally dead (the "Non Room"), through variations of live and dead ends, a few outliers that are totally diffusive, and many that are variations on "normal" - as in acoustically similar to a typical domestic room. Tracking and mixing rooms can be quite different from mastering rooms, which should in a rational world be similar to domestic spaces, if that is the intended customer.

So, from the get-go, in spite of all possible variables, there is more "standardization" in domestic rooms and in professionally designed listening rooms than in professional control and mastering rooms. This is illustrated in Figure 10.1 in the 3rd edition of my book.

Fortunately - and this is truly fortunate - in spite of differences in rooms, it is the loudspeakers that dominate perceived sound quality. Most of my book explains that, and the fact that human listeners are perceptually able to separate the sound of the source from that added by the room. This is true in live unamplified music and in sound reproduction. So, the fundamental requirement for controlling the "circle of confusion" is to ensure that all loudspeakers from recording to playback radiate similar sounds. As increasing numbers of loudspeakers adhere to the rational design goals that science has provided, things are definitely improving.

BTW I know of no listening tests by me or by Sean Olive (together or separately) that were not conducted in rooms designed to resemble typical domestic rooms. To do otherwise serves no purpose. In fact an elaborate test was conducted that showed that listeners rated loudspeakers similarly in four very different real rooms - Section 7.6.2 in the 3rd edition. This is good news. Buy truly good loudspeakers, relax and enjoy them.

This is absolutely the case, there is no standardization at all in studio design.

I can share some experience from the production side that folks here might find interesting.

I worked for a while in a studio designed by a top designer. We struggled for years because both the recording space and control room were unbelievably damped. It sounded nothing like any room I'd ever been in. It was designed to meet specific criteria for frequency response and reverberation times. But the space was small. The designer managed to meet the "paper specs" at the cost of a sub-optimal working space. It wasn't terrible, but there were some challenges. Eventually someone got frustrated and just took out some of the treatment down. It was a wonderful improvement.

There are aspects of recording/mixing that I find easier to do in a "normal" room, as opposed to a typical studio environment.

For example, I find getting the basic level balances between elements of the mix easier to do in a regular room. And this is the most important part of the mix! One would think balancing the relative levels, the voice, the drums, the instruments, would be easier on a nice studio monitor in a controlled space, but it's not that simple.

There is something that Floyd said about engineers using bad speakers while working that I would like to clarify.

Many engineers, whether recording, mixing, or mastering do use bad speakers in the process. But the use is not based on the theory that if it sounds good on these speakers it wIll sound good anywhere. That is simply not the case. Relying on a bad speaker when producing music will basically give you the inverse pattern of its deficiencies in your mix.

Checking the mix on the bad speaker gives the engineer information about the mix that is not always apparent on the main studio monitors. By checking on different speakers, the engineer can get a sense of how well the mix will translate to other systems in the "real world."

One of the shocking things when you start out trying to make recordings is that just making your mix sound good on your studio monitors does not suffice to make a mix that translates well across other playback systems. This is a complex subject. It's taken me years to get a handle on this, and it's still a challenge. (I've been working in pro audio 30 years of so. I'm a slow learner

I have a "cognitive framework" that I have come up with to help with all aspects of music production, and it addresses the issues with working on bad speakers, as well as the issues of working in imperfect studios. I've dubbed it:

The Principle Of Listening

In a nutshell, it's a suggestion that all changes that are made to a recording as it moves through the production process should be made based on how the change affects the sound of the recording. That means the change is made by ear. This sounds ridiculous at first, because it seems obvious. What else could you do?

It turns out that anyone making a recording can be easily led astray and make decisions about the signal on criteria that are not based on how the change effects the sound of the mix.

For example, music is produced mostly on the computer these days, and there is a lot of onscreen visual stimulation. A listeners attention is inevitable drawn to focus on the screen, which has a profound effect on auditory perception (and not a good one.) Even if you are working and trying to ignore the visual "noise" in the workspace.

Another common side-track is to make decisions about which piece of equipment or software to use based on its reputation: Oh, so and so famous mixer uses this DSP compressor plugin on every mix! So I'll use that on all my mixes too!...Or... this mic is advertised as being great for vocals, so that's the ticket to making our smash hit record!

Another common example is the use of spectrum analyzer to assess your mix. A tool like this can tell you where you might have problems in the mix, but at best these serve as clues. You cannot fix the issue shown on the frequency analyzer by just making changes with global EQ until the shape of the frequency response looks like what you are going for. Such an approach will mess up the artfully created musicality of the mix.

So the frequency analyzer can give you information about your mix. But how does the engineer/mixer use this information?

This same issue presents itself when you check your mixes on other speakers. For example, a practice with a very long pedigree is checking the mix on a car audio system. Say you listen in the car, and the mix sounds totally off! You can't hear certain instruments, it has boomy low midrange, uneven dynamics! Very disappointing to everyone working on it.

How do you fix these newly perceived issues? Suppose you could bring your mix system right out to the car, plug it in to the audio system and fix the problems right there. (And you can do this now-a-days because it's trivial to mix on a laptop.)

But if you sit in the car, making adjustments to your mix until it sounds great, you will have made no progress, and probably made your mix much worse! Such an approach to mixing will result in a mix that will probably not translate to other systems at all.

To use the Principle of Listening you have to be able to perceive the issue you noticed on another system on your main studio monitors. And if the monitors and room are at least decent, you usually can. You can hear those very same issue on the studio monitors, but it will take concentration and critical listening skills.

This paradoxical issue is exacerbated in part because modern studio monitors have great dynamic range, and are utilized in the overly deadened spaces Floyd mentioned.

In a dead room, this "perceptual dynamic" range is enhanced far beyond a regular listening environment. Such a monitoring environment can be so clear, that it becomes very hard to judge relative volume of signals. You can mix a loud instrument with a soft one, and both will be perfectly perceptible in the studio. But in an average playback environment, the loud signal can "mask" the quite one dramatically, so the balance of the instruments is way off.

A regular room is more reflective and the sound is more diffuse. And the playback system is usually not so great. In such a space, the sound interacts with the speaker, reflects off objects, and energizes the physical space. This general "mixing up" of the sound makes the difference in the average sound energy level of different sounds in the mix much more apparent.

So problem for the engineer is that they need to fix a problem in their mix that is not a problem on their main monitors!

The first part of using the Principle of Listening is to tune into perceiving the problem you heard in the car, for example, on your main monitors. You do this with critical listening. Once you can clearly perceive the issue in your monitors, you can make adjustments that correct the problem by listening, making sure the mix still sounds good while making the adjustment. Not just "blindly" changing something in hopes it fixes it.

Bass response is one of the biggest problems for monitoring environments, and the modern, dead-ish control rooms can absorb a lot of bass frequencies. This can result in mixes that are way too heavy in the low frequencies, which can be very disheartening. This is done to give the room a more even frequency response, but it comes with all sorts of costs.

Another big issue is that overly treated rooms, coupled with good monitors, can handle much bigger dynamic ranges than everyday systems. Our ear is not that sensitive to changes in levels. Most of the cues in a mix that communicate "loudness" are delivered by timbre, not level.

Another way we perceive dynamic sound level changes is by how the sound energy is transferred to the objects in the room, including the speaker itself, the walls, the floor, things that rattle. These level changes can be almost invisible in some control rooms. The speakers are very isolated from the structure of the room, the reverberation times are reduced (with attempts to maintain neutral frequency response), the amps for the speakers are very powerful and won't distort.

So some person out there is listening to your mix, sounds pretty good! But it has some very large low frequency dynamic hits, that on your studio monitors played just fine. The listener decides crank up the volume, and all of a sudden the speaker is distorting, the media cabinet is resonating, things are falling off the walls. Not so fun for the listener!

If you know you have an issue with some frequencies or dynamics, with critical listening, and some helper tools, you can address the problem. Making the changes by ear allows the engineer to gauge the type and amount of adjustments to while making sure those changes at the least don't detract from the musicality of the mix. Ideally the fixing "problems" in a mix ultimately results in better mix all around, no matter what system its played on.

Despite these observations, the thought of treating production environments more like regular listening environments gives me pause. As I've described, some issues in a mix can be much easier to perceive in a "real world" setting.

But...

Studio monitors enable a level of clarity that is essential in making the nuanced adjustments that a good mix needs.

The biggest problem is perhaps the challenge of accurately assessing the amount and color of the ambience in the recording, because the ambience of the working space will blend with the ambience in the recording, preventing you from hearing what you really have in your mix. It can lead to similar problems of mix translation.

This could be less significant in the mastering process, as the changes to sound there are usually broad changes to the whole mix, and one of the main goals of mastering is helping the mix translate well once it's released to the world. So working in an environment that more closely resembles real world listening environments might have a lot to recommend it.

The goal would be to try and standardize productions environments, and finding a happy medium between "live" or "dead" sounding spaces. This could probably be done, while keeping some of the qualities of the room that make it relatively "neutral" in it's overall sound.

I think it's a great idea, though it probably won't happen. Maybe at the highest levels of the audio post production system something like standardized room treatments can emerge. I think this practice is used to a degree for final mixes for movies. But a lot of music production is done in personal spaces, or small commercial studios that have been set up by an individual or small team. These endeavors are severely limited in budget. Yet they do contribute tremendously to the musical content that makes it out to the world.

The reason this problem is not more urgent is that the musical products we hear on a day to day basis, at home, in the car, playing in a store, wherever, are produced by highly skilled craftsmen, who have learned to create mixes in imperfect environments that translate well.

 

[March Audio]

I suspect Bjorn meant the range around 80-200hz. Where at least up to around 150hz you can still see improvements with bass-system/subwoofers, because they are (usually) placed close to boundaries. it starts to get more difficult to achieve excellent results in the time domain.

Here it seems you cut off right above 60hz, which is fairly low, for a bass-system, and the improvement is huge - both in frequency and time.

150Hz to 200Hz is beyond the normal usage range of subs. I would not use them within that range. Normally its below 80Hz due to the inability to localise below that frequency. I would suspect the majority of significant room modes for most domestic listening rooms are below 100Hz. I use Acourate FIR DSP for the crossovers so the time domain adjustment is also catered for