Creating a symmetrical mix space in an asymmetrical room

All about acoustics. This is your new home if you already have a studio or other acoustic space, but it isn't working out for you, sounds bad, and you need to fix it...
SeattleSound
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Creating a symmetrical mix space in an asymmetrical room

#1

Postby SeattleSound » Thu, 2020-Oct-15, 02:20

Hello! I'm so glad to find that you are doing this forum. Using the advice you gave to countless others, I was able to convert my garage into an MSM design with great success. I am able to play drums and play music with others at any time of day/night without disturbing any of my neighbors in a fairly quiet neighborhood in Seattle - so thank you!

My issue now is that I would like to create a decent mix space in this room if possible. The dimensions of the room after internal construction (in inches):

Length: 270
Width: 173.5
Hight Left Wall: 122
Hight Right Wall: 93.5

I would like to be able to keep the majority of the room set up to play with other musicians - as was intended. I also record drums for other people's projects, so I have the drums in the best position in the room for that (according to my ear). I have my desk facing a short wall where the ceiling is angled overhead. This has not been an issue for what I have been using the room for so far, but I am now moving more into sound design and need to deliver finished mixes (mostly consisting of my own work, and without budgets to outsource). I realize the asymmetrical ceiling is going to be a huge obstacle to ever getting a true stereo image, so I am thinking about building a loft above the mix position. This would put the ceiling above the mix position at just under 8ft. If I put my monitors right up against the wall, my listening position would be around 4ft from the wall.

The questions:
Is this a viable option?
If this is an option, how deep would the loft need to be? Could it be as shallow as 6ft?
Would it be better to move the desk to one of the longer walls (it would put the back wall about 10.5 ft behind me).

I'm not looking to turn this into a commercial studio, but would like to be able to mix as much as possible without using headphones. I use SonarWorks to compensate now, but it still feels off to me when mixing through my monitors (Focal Solo 6Be). If there is a way to make this situation better, I would love your advice.

I've included some REW tests done yesterday with the room in its normal state. I moved a few things out of the way to explore the loft option so the pics reflect that. I have built some bass traps in the corners and along the wall/ceiling connections (OC 703 mostly), and absorption along the walls just to get the sound in the room to feel better for playing. I realize that no matter what, more treatment is needed, but before doing that, I would like to know if the loft option can be figured into the equation.

Thanks for taking the time to read this and for all of the great work that you do - it's very appreciated!
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Soundman2020
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Creating a symmetrical mix space in an asymmetrical room

#2

Postby Soundman2020 » Fri, 2020-Oct-30, 18:52

Hi there "SeattleSound", and a big Welcome to the forum! :thu: :)

I've been a bit busy on some projects recently, hence the delay in responding to your thread. Nice looking place, by the way!

Using the advice you gave to countless others, I was able to convert my garage into an MSM design with great success. I am able to play drums and play music with others at any time of day/night without disturbing any of my neighbors in a fairly quiet neighborhood in Seattle - so thank you!
That's wonderful to hear! I know a lot of folks do use the info on the forum to build their places, without actually starting a thread to tell us about it, so it's really good to hear from someone who did that and got great results. Thanks for letting us know! An I'm glad that it worked out well for you, achieving your isolation goals.

Length: 270
Width: 173.5
Hight Left Wall: 122
Hight Right Wall: 93.5
For metrically minded people, that works out to:
Length: 685.8
Width: 440.7
Hight Left Wall: 309.9
Hight Right Wall: 237.5

That's a nice size: roughly 30m2 (323 ft2). That's 50% larger than the minimum recommended size for control rooms, and the high ceiling is a nice touch, even though it isn't symmetrical, left/right. But that can be fixed.
I would like to be able to keep the majority of the room set up to play with other musicians - as was intended. I also record drums for other people's projects, so I have the drums in the best position in the room for that (according to my ear).
That can be done too, but there's an issue you should be aware of: the acoustic response needed for a control room (mixing) is quite different from the acoustic response needed for a live room / rehearsal room / music room.

Basically, a control room MUST have a completely neutral, transparent, natural sound: it must not have any sound of its own. In the sense that it must not "color" the sound coming out of the speakers in any way: it cannot add anything to that sound, and it cannot take anything away from the sound. When you think about it, this is logical and obvious! The entire pointing of a control room is so that you can clearly hear the mix in your speakers, and nothing else! You need to hear the truth: your tracks must be clearly heard, in all their ugliness, so that you can do something to make them sound good. If the room already makes them sound good, then you won't be able to mix in there! You will think that your mixes are already great, and don't need any adjustment, when in reality they're are not so great... and when you take them out to your car, living room, club, church, radio, TV, or even cellphone earbuds, they will sound awful! In technical terms, your mixes will not "translate", because the room is hiding the truth about them: You cannot mix what you cannot hear. In fact, the acoustic response needed for a critical listening room is well defined in a couple of documents: ITU BS.1116-3, and EBU Tech.3276. You can find both of those in the document library section of the forum, here: viewtopic.php?f=9&t=4

So the control room MUST have a totally neutral acoustic response. But that is lousy for tracking, rehearsing, and playing music! Musicians need to have some feedback from the room about how their instrument or voice sounds: They want "warmth" and "air" and "life" in the room, so they can "feel" the music, and "get into the groove", as they saying used to go. Put a musician in a lifeless room, and he/she won't like it very much... and won't be able to play well in there. Thus, the room needs to have some character to it: it cannot be neutral lifeless, and transparent.

So, you have two conflicting acoustic needs here. There's a couple of ways of dealing with that, but the best method is to have variable acoustic treatment in many places around the room: several panels that can be rotated, flipped, slid, opened, closed, or whatever, to expose different types of acoustic treatment to the room, as needed. Thus, with one arrangement of the panels, it would be just right for mixing, and with a different arrangement it would be just right for playing / tracking / rehearsing. Here's an example of that: What is variable acoustics? How do I do that?
I have my desk facing a short wall
Good! That's the best stup. With plenty of space behind you, to the back wall. Ideally, the mix position should be about 1 third of the way from the front wall to the back wall. Theoretically, the "best" spot is at 38% of the room depth, but in reality that's just a starting point: it is not a rule! And most engineers prefer a spot that it s bit closer to the front wall than that. So 1/3 of room length is another good starting point, and easier to remember.

where the ceiling is angled overhead.
Not so good, but that can be fixed, or at least improved.

I realize the asymmetrical ceiling is going to be a huge obstacle to ever getting a true stereo image,
Right. It also messes with the definition and center of the sound stage, as well as with your ability to accurately determine directionality and true frequency response. Your ear pinna creates a very specific interference pattern inside your ear canal for each angle that sound waves arrive (that's the purpose of the folds and wrinkles on your ear itself), then your inner-ear and brain use those clues to help determine which way the sound was coming from. But since the interference patterns also affect the frequency response, your brain automatically "corrects" for that, so you don't hear it any more. However, if those intricate interference patterns are messed up by ANOTHER interference pattern, such as from a strong early reflection arriving at a strange angle, then your brain now thinks that the sound came from a slightly different direction, and it "corrects" the frequency response in the wrong way: thus, your directionality AND frequency response are messed up. Yes, the effect is very small, but if you are wanting a high precision mixing environment, then you should do whatever you can to get a symmetric acoustic "signature" around you, that is the same on both sides, and interferes as little as possible with this psycho-acoustic issue.

so I am thinking about building a loft above the mix position.
That would be one solution, yes. There are others, but that would be the simplest. Your room is large enough that you can afford to lose a little air volume without too much detriment. You would probably be able to get away with making the loft a little higher, so that it does not come all the way down to 8', even if that means leaving the ceiling slightly asymmetrical right out at the wall edges. Reflections from so far out will likely not come close to your ears, so the effect would be minimal, but you'd need to do some "ray-tracing" to figure out how high you can make it. The higher, the better.

If I put my monitors right up against the wall, my listening position would be around 4ft from the wall.
The location of the speakers does not determine the location of the mix position: the room acoustic response in the low end is what determines the location of the mix position. And you are indeed correct that the best location for your speakers, is tight up against the front wall. Or rather, that's the SECOND best location: even better is to flush-mount your speakers in "soffits" standing up vertically on either side of the front wall.

You might find this article interesting, abut speaker positioning: Speaker setup, and the equilateral triangle

There's a method for determining the best location for your mix position, using the REW software (free!). How to calibrate and use REW to test and tune your room acoustics That's the first part you need to do, then you do the "walking mic" test, outlined here: The "walking mic" test, using REW That will help determine the best spot for your mix position, in the room, and this will not be related very much to the location of the speakers. The speaker location does have an effect, yes, but it is not the main driver behind locating your mix position. That is driven my the modal response of the room, which affects the overall frequency response of the entire spectrum in your room, regardless of the speaker location, or even of the speaker itself. The acoustic response of the room is largely independent of the speakers, and it is the room response that determines where you should sit: the smoothest spot, with the least variation, especially in the low end.

The questions:
Is this a viable option?
If this is an option, how deep would the loft need to be? Could it be as shallow as 6ft?
Yes it is viable, and it would need to extend from the front wall at least as far back as the mix position, but preferably a bit further. I would also suggest that you build in some of the treatment that the ceiling will need anyway: leave the joists exposed to the room, so you have a flat floor in your loft, then you can use those joists and the bays between the, for acoustic treatment. That maximizes the use of space.

Would it be better to move the desk to one of the longer walls (it would put the back wall about 10.5 ft behind me).
Not necessary. I would not do that. Yes, your room is big enough to do that, but it would also limit your options for tracking/rehearsal.

I use SonarWorks to compensate now, but it still feels off to me when mixing through my monitors
Right! Because "room correction" cannot actually correct a room! :) I'm working on article to explain that in detail, but it's not ready yet. The manufacturers of these room correction products (hardware and software) conveniently forget to tell you that it is physically impossible to "correct" the acosutic response of a room that has poor acoustics. In simple terms, "room correction" (sometimes also referred to as "DSP") is just a fancy name for equalization.

Room correction products apply EQ to the signal just before it gets to your speakers, and they tell you that this will even out the response, because it places a cut at just the right frequency spot in the spectrum to reduce some problems that are too loud, and a boost in other locations to increase the level where it is not loud enough, to get the response "flat" again. It sounds good on paper and in the marketing hype, except for one thing: it does not work!

Here's why: it changes the level of the signal for certain frequencies BEFORE the sound leaves the speaker, but AFTER the sound has left the speaker and started bouncing around the room, there is nothing that it can do any more! It cannot fix the "time domain" of the sound, only the "frequency domain". Once the sound has departed from the cone, then the "room correction" software has no more influence on what happens, because the sound wave is now in the real world, moving very slowly, and affected by "things" that it meets. It is no longer just an electrical signal moving at close to the speed of light along a wire: now it is a psychical wave that consists entirely of pressure variations in air. So, if that sound wave happens to excite a resonant mode in the room, which then "rings" for many milliseconds after the wave has already STOPPED.... well then, that mode will carry n ringing just like it always did! The room correction product CANNOT stop that from happeneing, because it is a ROOM problem, not a signal problem. Sure, you can reduce the level a bit at that specific frequency, so the mode is triggered to a lesser extent, but it is still there, in the room: You can't fix it with EQ, because EQ is all about the electrical signal going to the speaker, not the real sound wave after it left the speaker.

Room correction also cannot fix a reflection, because reflections are not related to signal intensity at a frequency: they are related to phase changes at a frequency, and there is nothing that the product can do to the sound wave phase AFTER it leaves the speaker. A reflection is just the interference pattern between two sound waves at the location where you ears are in the room: if you move your head a bit, you will be in a different part of that interference pattern. At some points in that pattern, the two waves cancel each other out, and you have an acoustic null: that frequency seems to disappear from the sound, or it is greatly attenuated. At other locations in that pattern, the two waves reinforce each other, and you have a peak: that specific frequency is louder at that spot. EQ cannot do anything about this, because once again it is a room problem, not a signal problem.

Ditto for SBIR, edge diffraction, and a bunch of other things: EQ cannot fix them. The ONLY thing that EQ can fix, is problems in the signal chain that cause one frequency to be louder than another, purely in intensity, not related to phase or time.

The manufacturers seem to "forget" to mention this, in their glossy brochures...

Don't get me wrong: EQ most certainly does have a place in room tuning, and I use it extensively in rooms I design. I prefer to call it "digital tuning" to make sure there is no confusion about what it is that I am doing. But it can ONLY be used in a room that has already been treated acoustically as far as it possibly can. It cannot be used successfully in an untreated room, or a partially treated room. The treatment must already be taking care of things like damping modes and other resonances, killing strong speculator reflections, reducing or eliminating phase changes in the room, and things like that. The problem that are left over AFTER all those issues have been dealt with, are mostly just level issues, which can be dealt with by EQ.

So that's what you are hearing: your room correction software is telling you that it did a wonderful job, and your curves do indeed look flatter, but you can still hear that things are not right: because your ear and brain are very sensitive to the time-domain issues, and the phase issues, which have not been corrected. In fact, your ears are not really that sensitive anyway, to pure level issues in the frequency domain....

So, as you already figured out, your room correction is not doing what they told you it would do: you need to have proper treatment first, before you can even think of using that. Here's an example of what can be achieved in a good control room using both proper acoustic treatment and digital tuning: A fully treated and tuned professional control room: S3P

If there is a way to make this situation better, I would love your advice.
Yes! First, turn off your room correction system, set all of your EQ flat in the entire signal chain, and run REW. That will show you what is actually wrong with your room, in the frequency domain, yes, but much more importantly it will also show you the time domain problems, and the phase-related problems. Then you can design treatment to deal with each of those, attenuating them and minimizing them as much as possible. Then you can turn our your "room correction" software again, and re-run the process so it only tries to correct actual frequency domain issues, not the ones that it cannot fix.

I've included some REW tests done yesterday with the room in its normal state.
Great! Sorry: I only hadn't seen that you had included a REW test already, before I wrote the above.... But I wrote it already! So I'll take a look at your REW data ad see what I see.

But before I do that: did you have your Sonar Works turned off, and all the EQ set flat, before you did that REW test? If not, then please do that first and re-test.


- Stuart -



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shybird
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Creating a symmetrical mix space in an asymmetrical room

#3

Postby shybird » Tue, 2020-Nov-10, 00:36

I was wondering about your explanation on this issue Stuart so I searched for "Sonarworks" and found this amazing reply. And now it makes much more sense! So there totally is a time and place for using "digital tuning/eq" but not until the room has been treated as much as possible first. And then at that point it can potentially help a bit. Perfect. :ugeek: :D

Also, cool space SeattleSound!

Cheers
Trevor



SoundsSebastiany
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Creating a symmetrical mix space in an asymmetrical room

#4

Postby SoundsSebastiany » Sun, 2021-Jul-18, 19:08

Hi, I'm a new born to this site. I'm building a mixing studio on a tight budget which is much like the one on your post SeattleSound...I have an asymmetrical sloped ceiling (room is in half an A-frame house). I'm desperately trying to find someone who can point me in the right direction, ideally also a (paid) vid chat consultation. My question is whether to lower the ceiling...and whether to flatten/square the roof or to use the non parallel slope to my advantage by making the slopes symmetrical by creating an A-frame shape within this half A-frame, if that makes sense. I'm also considering a loft and also have focal speakers (6.5"). I cannot remove the closet beside door, so considering moving that door forward in line with the closet, again for symmetry. What materials (cheap) could I use to make ceiling? Tiles? All ideas desperately welcomed :P
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Soundman2020
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Creating a symmetrical mix space in an asymmetrical room

#5

Postby Soundman2020 » Sun, 2021-Jul-18, 21:56

Hi SoundsSebastiany, and WELCOME to the forum! :th: :) Can I assume your name is Sebastian?

General rule for small rooms: don't make it smaller, if you can avoid it! The smaller it is, the worse it will sound. So, don't lower the ceiling, and don't flatten it either. Perhaps make it symmetrical, by angling the left side similar to the right side, but even that might not be necessary in your room. I would suggest doing some tests first with REW (see here: How to calibrate and use REW to test and tune your room acoustics ), to see how much of an asymmetrical problem you have, then decide if it needs fixing, or not.
I cannot remove the closet beside door, so considering moving that door forward in line with the closet, again for symmetry.
Not necessary. Symmetry is important in the front one third of the room (from the speakers up to your ears, roughly), and not so important for the rear of the room. I would suggest some heavy bass trapping above that closet and on the face of the closet, plus perhaps some additional on the rear ceiling, along with the usual first-reflection-point treatment, and maybe a ceiling cloud. But be careful to not overdo the absorption: It's easy to suck the life out of a room with too much absorption, so you might need to cover some of it with plastic sheeting, slats, panels, etc.

One of the keys to treating a strange-shaped room (or any room, for that matter), is to do it one step at a time, and keep checking with REW at each step, to see if you are getting to where you want to be.

- Stuart -



SoundsSebastiany
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Creating a symmetrical mix space in an asymmetrical room

#6

Postby SoundsSebastiany » Wed, 2021-Jul-21, 02:42

Thanks so much for the swift n sound response Stuart! Yes my name is Sebastian and naturally I'm a Saint :lol:
That's the perfect advice to get me started. I shall P.M you ref zoom consultation..




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