John Sayers' Recording Studio Design Forum Archive

Hello everyone,

So I've just moved to a small apartment and did a quick makeshift studio setup. Just wanting to treat my living room to the best of my ability. I've attached a drawing to illustrate what I'm working with. Please don't mind the mess I've still got a lot of work to do. Goals are just acoustic treatment, no real ability to do any isolation here. I'd appreciate any feedback, tips or ideas. I know its not a perfect situation, but the room is decently sized and not a perfect square at least. So far I've centered the speakers and placed them pretty close up against the windows, in order to conserve space. I could probably move them further back off the wall but maybe it would be best to ditch the stands and get a desk they could sit on. Would this be compromising clarity in the interest of space? I will probably build a more functional desk at some point as well.

Room Dimensions:
Length: 18ft
Width: 13ft
Height: 8ft
Speakers:
Yamaha HS80m
Speaker stands are made of 4" ABS/PVC pipe filled with 25lbs of sand each.
Speaker height is currently 48.5" to center of tweeter. Just realized this being almost dead center of the floor to ceiling.
Is this an issue? I could lower them (by cutting the ABS pipe) or raise them with some paver stones.
Broadband traps
2'x4' x 4" Roxul AFB Quantity 4 (I'll be adding 2 more panels and can build more)
16"x4' x 2" Roxul AFB Quantity 4
Concerns and questions:
-Windows are not centered so the front wall isn't symmetrical. Right speaker is closer to drywall while the Left is directly in front of a window. If my understanding is correct the window shouldn't be too much of an issue, but the symmetry could be as well as the proximity to walls?

-Bass trapping the front wall left corner with the window.
Super chunks would be tricky given the window on the left which I would like to be able to open. I could always find a way I suppose. I was thinking of building a movable stand for the broadband panels to stradle the corners, as well as 4 triangular shaped traps to hang above and below straddling the 3-wall corner points. Does this sound like a good plan?

-Same thing with rear wall symmetry.
For example, should I bass trap the corner by the hallway door? (Left side of rear photo.)

-Left wall is a partial wall that divides kitchen and living room area.

- Couch and tv stand are probably not ideal, but its a living room after all.

- Hanging the ceiling cloud. The ceiling is an acoustic/popcorn ceiling, building is built in 1962 so possibly contains asbestos. I will probably buy a test kit before I hang anything. I may be able to suspend a cloud off the front wall since the speakers are close to the front wall currently.

-I've sort of placed the broadband panels, it seems the side reflection points are quite close to each other and one 2'x4' x4" panel covers both points. I could place two traps on each side for good measure. Should my speakers and I should be further apart? Currently the speakers are about 46" apart and 46" to the listening position.

-REW testing. I've sort of read about this, a while ago and will freshen up on the subject.
1. Does the room need to be completely empty to test, or should i test with what is going to be in the room, as it currently is? (hope so cause that would be a pain haha)
2. If I remember correctly, I place a speaker in the corner and fire off a frequency sweep. Then adjust the reference mic to find the best frequency response for listening position. Can I just try moving the speakers and listening position a couple inches forward to find the best compromise of space and frequency response, and also try different sizes of the "listening triangle"? I should probably just reread the HOW TO TEST YOUR ROOM thread, so my apologies if these are redundant questions.

Photos:

I could probably move them further back off the wall but maybe it would be best to ditch the stands and get a desk they could sit on. Would this be compromising clarity in the interest of space?

You should keep your speakers ~4" from the windows and fill that space with 4" of insulation to help with SBIR. Try to place your head around the 38% mark in the room.

Speaker height is currently 48.5" to center of tweeter. Just realized this being almost dead center of the floor to ceiling

That sucks but it's a common problem. Unless you buy a special chair that allows you to kneel lower than a regular sitting chair, that could be a solution.

but the symmetry could be as well as the proximity to walls?

You seem to realize that this room/set up is not ideal but at least you have a place. Just make sure your speakers and head are in centered between your side walls.

-Bass trapping the front wall left corner with the window.
Super chunks would be tricky given the window on the left which I would like to be able to open. I could always find a way I suppose. I was thinking of building a movable stand for the broadband panels to stradle the corners, as well as 4 triangular shaped traps to hang above and below straddling the 3-wall corner points. Does this sound like a good plan?

You need bass traps so if that means making them movable to open the window, then do that for sure.

-Same thing with rear wall symmetry.
For example, should I bass trap the corner by the hallway door? (Left side of rear photo.)

If I were you, I'd investigate the idea of building a partition wall so that you can block off of the kitchen. The kitchen will ruin your acoustic response. The rear wall symmetry isn't super super important, but you should block off the kitchen. Like every other control room design, make sure you put as much deep absorption on your rear wall as possible.

Should my speakers and I should be further apart? Currently the speakers are about 46" apart and 46" to the listening position.

Speakers between ~28% and 34% (20% min and 40% max) width of the room away from the side walls. 25% is BAD! This is a frequency null point! Also don’t put them on the 45 degree line from the corner however put them as far apart as possible.

1. Does the room need to be completely empty to test, or should i test with what is going to be in the room, as it currently is? (hope so cause that would be a pain haha)

Read the REW instructions here on the forum and you'll see that you need to take baseline tests with an empty room.

I look forward to seeing your progress!

Greg

Hi Victor, and Welcome to the Forum!

Adding to what Greg already said:

Length: 18ft
Width: 13ft
Height: 8ft

That's a nice sized room, with good potential. The recommended minimum size for a control room is about 210 ft2, and yours is bigger, so that's a good start!

So far I've centered the speakers and placed them pretty close up against the windows, in order to conserve space.

Excellent, because that's the best placement for speakers: as close to the front wall as possible, with just a small gap of 4" or so (10cm) where you can insert an absorption panel.

I could probably move them further back off the wall but maybe it would be best to ditch the stands and get a desk they could sit on

Absolutely NOT a good idea! Speakers should never be placed on the desk, or on the console meter bridge, for many reasons. Of course, that doesn't stop silly people from doing it anyway, as you often see in photos of studios (even pro studios! ), but there are very good acoustic reasons why speaker should never be on the desk or meter bridge. On stands behind the desk, close to the front wall, is the best spot. Why? One of the reasons is called SBIR, which stands for "Speaker Boundary Interference Response". That refers to how low frequency sound behaves. The high frequencies emitted by your speaker travel more or less in straight lines, or more accurately in a narrow cone, that shoots out from the front surface of the speaker towards you. But lower frequencies spread out more, in a wider cone, and very low frequencies wrap all the way around the speaker, going out behind it too, expanding as a sphere, not a cone. That means that some frequencies will hit the wall BEHIND the speaker, and bounce back towards you... but then they interfere with themselves! As the waves go past the speaker again, they interfere with the next wave that just came out, partially cancelling it, or partially enhancing it, depending on the frequency. So there will always be one specific frequency where the wave cancels itself out completely, and that's the "SBIR dip". If you look at the resulting frequency response, there's a large drop in the intensity at that specific frequency, as well as related dips and peaks further up the spectrum. The frequency where that "lowest dip" occurs depends on one thing only: the distance from the speaker to the wall. That dip occurs at the frequency whose wavelength matches one quarter the distance from the front face of the speaker to the wall. Why four times? The wave goes "there and back", hitting the front wall and returning to the speaker face, so you'd think it would be just half the distance... but that's a full wavelength for the wave, so the wave that completes a full cycle on that round trip arrives in phase with itself again, and thus increases the amplitude, not cancelling it. However, if the wave only managed a half a cycle on the "there and back" trip, then it arrives back at the speaker face exactly out of phase with itself, so it cancels itself completely. Thus you get a null in the frequency response for the quarter-wavelength distance: So multiply the distance from the speaker face to the front wall by four, and that's the wavelength of the SBIR dip frequency. Here's a few easy ones: If your speaker is 2 meters away from the front wall, the wavelength for the SBIR dip would be 2x4=8 meters, so the frequency is 43 Hz: you'd get a dip at 43 Hz. But of the distance is only 1m for the wall, then the wavelength is 4m, and the frequency is 86 Hz. And if the distance is only half a meter then the wavelength is 2m and the frequency is 172 Hz. If the distance is a quarter of a meter, then the wavelength is 1m, so the frequency is 344 Hz.

So what's the point of all this? Well, first, major nulls in the lowest frequencies are VERY audible! You can hear that you have "no bass" across the range of that dip (it can be quite wide). And second it's really, really hard to treat very low frequencies precisely because the wavelengths are so long. On the other hand, dips in the mid range are less audible, and it's a lot easier to treat those frequencies, because the wavelengths are so much shorter. Thus, if you have your speakers far from the front wall, you get a big dip that is very noticeable and untreatable... but if you put the against the front wall, the dip is much less noticeable, and much easier to treat.

That's the reason!

Would this be compromising clarity in the interest of space?

Yep! see above...

I will probably build a more functional desk at some point as well.

When you do, make it as small as possible, and as open as possible, with as few flat surfaces as you possibly can. All desks affect the acoustic response of the room. The larger it is, the greater the response. The more flat surfaces it has, the worse the response. So make it small, low profile, and open. Do not put any shelves above the desk: they interfere with the path from speaker to ear...

Speaker stands are made of 4" ABS/PVC pipe filled with 25lbs of sand each.

Great! Those will work fine. Just make sure that they are the correct height. THe acoustic axis of your speaker should be at least 1.2m (47 1/4") above the floor. That's the "standard" height. You can go a bit higher of you need to, but not so high that your ears are off-axis from the speaker. Maybe up to 5cm or so higher.

Speaker height is currently 48.5" to center of tweeter.

Contrary to popular internet lore, it's not the tweeter than matters: it's the ACOUSTIC AXIS of the speaker. Most manufacturers publish that information, but if you can't find it for your speaker, then the simple rule of thumb is this: For a two-way speaker, draw an imaginary line from the center of the woofer to the center of the tweeter: the acoustic center of the speaker will be half way along that line. The acoustic axis is an imaginary line that pokes out form the front face of the speaker at that point, perpendicular to the front face. That's the point you should be concerned about for most acoustic measurements related ot eh speaker: that's the "axis".

Just realized this being almost dead center of the floor to ceiling.

Yup! That often happens. But to be honest, what you should be most concerned about in that sense, is the woofer, not so much the acoustic axis. This sound strange, after I just told you all about the acoustic axis, but there's two things going on here: th acoustic axis is the spot where sound appears to emanate, theoretically. Sort of the "average" point for all frequencies. And it only applies of you are far enough away form the speaker that the sound fields from the woofer and tweeter have merged, IN THE DIRECTION TOWARDS YOU! In reality, lows still come from the woofer, and highs from the tweeter. It's only when you get a certain distance away, along the axis, that the merge into a single sound field... ON AXIS! But for OFF axis, the individual drivers play a larger and larger role. At 90° off axis, the tweeter plays no role at all. Nothing. It's only the woofer that is doing anything out there, because once again we get back to the issue of high frequencies traveling rays, or cones, but lows travel as spheres. The cone from the tweeter faces towards you at the mix position, but the sphere form the woofer faces in all directions equally. In the direction "towards you", those two merge into a single field at some distance away from the speaker, but the merging is less and less perfect the further you get off-axis, and at 90° off axis, there is no merging because there are no highs going out sideways, so the "axis" isn't really any use here. It's the location of the woofer you are worried about for effects that are a long way off axis. So even though your speaker axis might be at exactly half room height, the woofer is not! It is lower than the axis by a few inches, and therefore is not at half the room height.

Is this an issue? I could lower them (by cutting the ABS pipe) or raise them with some paver stones.

Sit in your favorite chair: the one that you use for mixing. Get comfortable, in the posture you normally use when you are mixing. Get somebody to measure the height of your ear hole above the floor. That's the height that your acoustic axis on your speakers should be. It really is that simple. Because the speaker produces the cleanest, flattest, best response "on axis", so your ears should also be "on axis" to the speaker. Thus, put your acoustic axis at the same height as your ears! Or a little higher, for other reasons. But try not to ave your speakers lower than your ears, if you can avoid it. Same height or up to a couple of inches higher is fine.

-Windows are not centered so the front wall isn't symmetrical. Right speaker is closer to drywall while the Left is directly in front of a window. If my understanding is correct the window shouldn't be too much of an issue, but the symmetry could be as well as the proximity to walls?

Probably not too much of a problem. In both cases you will have a large panel of absorption between the speaker and the wall/window, to help with the SBIR and other issues. If there are issues here in the end, then there are ways of dealing with those.

Super chunks would be tricky given the window on the left which I would like to be able to open

You don't have a lot of choice here: you can either give priority to having great acoustics response in the room, or you can give priority to having a window there. Pick whichever you think is most important!

For example, should I bass trap the corner by the hallway door? (Left side of rear photo.)

Treat the entire rear wall. If you can't put bass traps in the "normal" locations, then put them in other locations: the horizontal ceiling/wall corner across the top of the wall is just as valid for superchunks as the vertical corners.

-Left wall is a partial wall that divides kitchen and living room area.

That's a problem. Your room is going to have two different acoustic response curves: one for the room itself, the other for the room combined with the kitchen. So there will be two sets of decay times: the initial decay will be just from the room, then that will be followed by a longer, slower, lower decay coming back form the kitchen. The two spaces are acoustically coupled.

- Couch and tv stand are probably not ideal, but its a living room after all.

Ummmm.... symmetry! Problem... The couch could go on the rear wall, instead of the right wall, and maybe have the TV inside one of those cabinets where the screen slides down inside the cabinets when it is not being used, then pops up where you need it. The cabinets could be positioned just behind your chair at the mix position. Something like this: https://www.touchstonehomeproducts.com/ ... t-cabinets

I may be able to suspend a cloud off the front wall since the speakers are close to the front wall currently.

The main purpose of the cloud is to deal with reflections for the ceiling to the mix position. Thus, it needs to go on the ceiling about half way between the speakers and the mix position, because that's roughly where the reflection will happen. So if you have the cloud against the front wall, it won't be doing anything useful for that. The cloud has other purposes too, but that's the main one.

Should my speakers and I should be further apart? Currently the speakers are about 46" apart and 46" to the listening position.

Ahhh! So you fell in the trap! You followed the myth! The famous "equilateral triangle" myth. You are probably thinking that I must be crazy to say that it's a myth when you see it EVERYWHERE, even in the manuals soft speakers, and all over the inernet, and in text books on acoustics... but it's still a myth! Not a myth in the sens that it is false, or doesn't work, bu in the sense that it is the best setup for every room and every speaker. It isn't. It works, but isn't optimal. That's why you see it everywhere! Because if you set up your speakers and mix position like that in most rooms, you will get acceptable sound. Not optimal, but at least acceptable. It's the "lowest common denominator", so that's why everyone tells you about it. A speaker manufacturer wants to make sure that his speakers at least sound OK, in your room, so that's why he tells you to do that: because they will sound OK. Not great: just OK.

The truth is that all rooms are different, and there's always a better spot in any give room, than the one dictated by the "equilateral triangle". Most studio designers ignore that "rule", and place the speakers in the best spot for the room, and also place the mix position in the best spot for the room. The problem is that the "best spot" is different for every room, and hard to find! There are methods for doing that, if you really do want your room to be the best, but it's a bit more complex to do and explain than simply publishing a picture of a triangle in the speaker manual. I don't have the time right now to figure it all out for you, but your speakers need to be further apart in that room, and your mix position needs to be further back, and the toe-in angle on the speakers will need to be less than the "standard" 30° angle. It takes time to figure out the best starting point, then it takes more time to optimize that, but the improvements can be quite convincing when you do it right.

-REW testing. I've sort of read about this, a while ago and will freshen up on the subject.

Try this link: How to calibrate and use REW to test and tune your room acoustics .

1. Does the room need to be completely empty to test, or should i test with what is going to be in the room, as it currently is?

Start with the room empty for the first test, so you can see the bare, ugly naked truth about the room response. Then start putting treatment in, and test again after you put in each piece, to make sure it really is doing what it is supposed to do,... and so you can see what needs doing next. Because the initially huge ugly mountains all over the first graphs will be hiding smaller mountains that you can't see yet, until you get rid of the bigger ones.

2. If I remember correctly, I place a speaker in the corner and fire off a frequency sweep. Then adjust the reference mic to find the best frequency response for listening position.

For a sub, yes. Sort of. But not for the mains. For the mains, start with the best theoretical positions (not the equilateral triangle! ), then move the speakers in very small incremental steps (further apart / closer together) to find the smoothest response. Then do the same for the mix position mic (move forwards/backwards along room center-line in small incremental steps), also looking for the smoothest location. Then add the sub, and move it around as well, in small steps, while checking with REW.

- Stuart -

Wow! Thank you both Greg and Stuart for the thoughtful detailed responses. I've just returned from a camping trip and still have a lot of work cut out for me as I'm still moving in and organizing.

While this room is decently sized the apartment is quite small unfortunately. I also cohabit the space with my girlfriend who has grown accustomed to music gear and is mostly on board with whatever I need to do to make the room functional for me. I don't want to take over the space completely and make it nonfunctional as a living space. That said I will definitely take your advice as far as I can, practically. This is going to be a process and likely will take several weeks if not months for me to complete. I also will likely have to compromise and live with the fact that this is apartment is a rental and not a perfect/ permanent room. Just want to do the best I can within reason.

A few more questions have come up, in regard to your advice.

Gregwor wrote: If I were you, I'd investigate the idea of building a partition wall so that you can block off of the kitchen. The kitchen will ruin your acoustic response. The rear wall symmetry isn't super super important, but you should block off the kitchen. Like every other control room design, make sure you put as much deep absorption on your rear wall as possible.

For making a partition wall. This would have to be modular/removable for the reasons listed above and Unfortunately the partial wall is perpendicular to and directly in front of the apartment entrance. So could a partition wall be made out of something like a gobo, also does a partition have to extend floor to ceiling or is 3/4 to the ceiling better than nothing? thinking I might not be able to make them as tall for storage purposes.

Soundman2020 wrote:Treat the entire rear wall.

A bit confused, as to where/how to treat the wall, In theory I could build a frame out of 1x6 in front of the wall and cover the entire wall with Rockwool or 703 and wrap it in fabric? is this an adequate way of doing things compared with straddling the corners with 6" bass traps and hanging panels at reflection points? I'll have to balance cost, function and appearance i suppose.

Soundman2020 wrote: Your room is going to have two different acoustic response curves: one for the room itself, the other for the room combined with the kitchen. So there will be two sets of decay times: the initial decay will be just from the room, then that will be followed by a longer, slower, lower decay coming back form the kitchen. The two spaces are acoustically coupled.

See partition wall question above^

Soundman2020 wrote:Ummmm.... symmetry! Problem... The couch could go on the rear wall, instead of the right wall, and maybe have the TV inside one of those cabinets where the screen slides down inside the cabinets when it is not being used, then pops up where you need it. The cabinets could be positioned just behind your chair at the mix position. Something like this: https://www.touchstonehomeproducts.com/ ... t-cabinets

This is an option! That tv stand is wild! I was planning to get a slightly bigger couch though, at 90" wide the side wall seems like the best spot for it. I guess the rear wall could work though. OR I could possibly place the couch in the middle of the room in front of the hallway door I think and get away with it. Though aesthetically it might make the room seem a bit smaller/ less open.

Is there a way to understand how much of a difference this kind of furniture placement will make? While testing the room should i test with both configurations as I add in and reconfigure the furniture? Will a sofa up against the wall act as a sort of bass trap?

I would think not everything will be symmetrical as I will have no doubt guitar amps/ bass amps against either side wall. I was thinking of building a small gear rack as well.
Any reading recommendations to help me understand the way furniture and gear affects acoustics?

I've completed my REW baseline test with the room empty.

https://www.dropbox.com/s/28r4e7uad4tvj ... .mdat?dl=0

Hopefully I did it correctly, cause I had to move all my furniture into my bedroom. If it's incorrect I'll have to try it again another week.

I was wondering how cars driving by could affect my test though. I can definitely hear them. Although I tried to do it when it was quiet, I live in the city and was a bit rushed today.

Any help understanding what I'm looking at would be much appreciated.

Best,
Vic

Hello again,

I am itching to get this room going and I definitely could use some guidance on my ideas.

Desk
So far I'm planning on a building smaller mixing desk about 30" wide (or maybe only 24" wide) on steel legs.
Also a low profile gear rack about 2 ft tall and angled upwards on casters so I can move it around and out of the way when not in use.
Rough drawing: Front wall
I think I am going to put 2'x4'x4" Left and right corner panels on stands straddling the corners.
Then build 2 ft high super chunks for the sections below the stands and straddle the front wall-ceiling corner with 4" bass trapping,

I will also have 2 - 4" traps on stands directly behind monitors.

Rear Wall:
The studio I work at has a small production room: fabric walls with about 2-3 inches of treatment up against the walls, it looks nice, but acoustically not sure it's very efficient. However with your approval I could do something like this by framing with 1"x3" along my entire rear wall, from the corner up to about where my front door begins, fill this frame with about 3" inches of insulation and wrap it in fabric. Would this be an efficient option for the rear wall? I could also straddle bass traps at the corners.

Should I add slats for diffusion?
what would be the best type of insulation/density for this? Something like owens corning 703 or roxul rockboard 40?

Or is this just a wasteful/bad idea?

My other plan is just to hang up 2'x4'x4" panels as well as straddling bass traps on the wall-ceiling and wall-floor corners of the rear wall.

Partial wall:
I could build 3 separate 3ft by 8ft sections of 2 or 3 inch thick gobos to act like a modular partition wall section when I am mixing. I could then tuck these along the right hand wall when not in use.
Something like this: I think thinner might be easier for portability.
One concern is this is still asymmetrical as the partial wall side will have a "gobo wall" while the rear right-hand wall will still be drywall and a door.
Imperfect solution, but perhaps better than leaving the partial wall space open at all times.

I'm also looking for a primer on how to analyze the room eq wizard measurements. I can see where the room has some peaks and nulls, but aside from the basic principals of adding bass trapping and treating first reflection points I am not exactly sure how to get more specific with things or understand my room's specific issues.

Hope to hear from you all.

Best,
Vic

Front wall

If you can't do full super chunks, then your plan will work, no doubt.

Rear Wall

I personally would never go thinner than 6" of insulation on the back wall.

Should I add slats for diffusion?

Hard to say what you should do until you take REW measurements along your journey.

what would be the best type of insulation/density for this? Something like owens corning 703 or roxul rockboard 40?

Any type that will effectively dampen low frequencies. 703 is worshiped in the acoustics world.

Partial wall:

That should work fine!

One concern is this is still asymmetrical

Do your best. The back of the room being asymmetrical isn't the worst.

I'm also looking for a primer on how to analyze the room eq wizard measurements.

REWs help document very clearly describes each portion of the software. If you're still confused about things, post pictures and questions so we can try and help the best that we can.

Greg