Small Bedroom with Sliding Glass Door

[Josek]

Hello! I am seeking advice on my room setup and acoustic treatment.

My wife and I own a house, and I currently have a room that I use as a multipurpose music room I'm not looking to do any heavy construction, as we might need this room for another child. It started with band practices and jamming, but I've focused more on mixing and possibly recording. My neighbors don't mind the music (a drummer lives across the street) so isolation is not a priority. I have ordered a dB meter.

Floor Plan measurements.png

The room has a narrow closet area that is covering what used to be a fireplace, and a large, sliding glass door that reaches the corner of the room which I would still like to have accessible. I have built some shelves on one of the walls toward the corner.

Corner 2 rsz.jpg

Window 1 rsz.jpg

Window 2 rsz.jpg

Until a few days ago, my setup was oriented so that my front wall near the speakers was against the closet wall. I've since moved to in front of the sliding glass doors, so that my speakers could be equidistant from the side walls, and so that I don't have glass on one side of me. ( speakers are40.5 inches from the side walls and 26 inches from the back wall/glass, measured form the center of the front top edge of the enclosure)

Would this be the best way to set up? I know everyone says to set up so the sound is traveling down the length of the room, but I've also heard that you don't want glass on one side of you. I'm planning on getting some heavy curtains soon. Would this alleviate some of the issues with the sliding glass door?

I haven't been able to find cases on this site (fabulous resource btw, forcing me to rethink EVERYTHING I'm doing!) or across the web similar to mine, so I'm hoping for some advice on how I should tackle mixing in this room, while keeping it functional for the occasional band practice and recording, so these are my motivations for creating this (my first) post. So thank you for any time and advice that could be thrown my way.

I have about US$700 I had been saving for a Thunderbolt Interface but I realize I should probably tackle my room first. I have instead ordered several Rockwool sheets for making traps and some panels (the carpet squares and crates will come down). I get about $200 spending money per month.

More details:
There is carpet in the room.
The wall dividing the closet and rest of the room is 4 3/4" thick built with 2x4 studs and sheetrock.
I'm not sure about insulation in the walls other than my current back wall (11'6"), which needed drywall replacing when the heater (above the room, yay!) leaked exhaust water all down it. It was filled with old blown insulation and was replaced with pink fiberglass insulation rolls. I can only assume that either the other walls have blown insulation or none at all.
I know that this room was once part of the living room and the wall to the right of my current setup position was put up to make another bedroom, so might not be insulated. There is a crawlspace underneath the house.

Closet 1 RSZ.jpg

Closet Ceiling RSZ.jpg

Closet Floor RSZ.jpg

and in this last picture,

Door Corner rsz.jpg

to the left of a door is another corner that raises another question. Does this corner need to be trapped up as well?

Once again, thank you for any time or advice!
Alex

[Soundman2020]

Hi Alex, and Welcome!

It started with band practices and jamming, but I've focused more on mixing and possibly recording.

You probably already know by now that "recording" and "mixing" are two rather different acoustic scenarios. Mixing requires absolutely neutral acoustics: the room cannot color the sound at all, in any way: it can neither add anything to, nor subtract anything from, the clean direct sound coming out of your speakers. Response should be as flat as possible, especially in the time domain, but also in the frequency domain. But a neutral environment like that is not very interesting for tracking live instruments: it sounds too dry, dead, controlled, stifled, for most instruments. It can be fine for things like vocals and acoustic guitar, but not so fine for drums, brass, strings, etc. It is possible to design the room with variable acoustics, such that you can swing, slide, rotate, open, close etc. parts of the treatment panels to change the acoustics of the room, but that won't be possible on your budget.

So, you should be certain that you really want to prioritize mixing in this room, realizing that it will be at the expense of having a good tracking room. The room is very small in any case, so it's unlikely that it would ever be amazing for tracking. It's a bit small even for mixing, but you stand a better chance of getting it usable for serious mixing than you do of getting it usable for serious tracking. As long as you are OK with that, then make the decision consciously: turn this into a mixing room, and forget about high quality tracking.

Assuming that you decide to do that, here's a few comments on your post:

My neighbors don't mind the music (a drummer lives across the street) so isolation is not a priority.

That's good, because your budget doesn't stretch far enough to get you good isolation AND good acoustics. As long as you are OK with not being able to mix during those times when outside noise is interfering with your ability to hear things clearly in the room... EG: Wind, rain, hail, thunder, aircraft flying over, sirens, helicopters, neighbors mowing their lawn, dogs barking, phones ringing, traffic on the street, noises inside the house as well: toilets flushing, radio, TV, people talking, dishwasher running, vacuum cleaner, etc. It's one of those things that you need to take into account. When you are on a tight budget, there's compromises to make. If your number 1 priority is to have the best possible mixing environment, then that's where all your attention should be focused, but you still should be aware that the room won't be so good in other aspects.

I have ordered a dB meter.

A decent one, with both "A" and "C" weighting, as well as both "Fast" and "Slow" response?

The room has a narrow closet area that is covering what used to be a fireplace,

The room is very challenging! There's no obvious "best" orientation or layout. The closet is one issue, the door is another. The sliding glass: not so much. Is there any chance at all that you can remove that closet, such that the room becomes pretty much rectangular? I mean, take out the wall marked 4' 9" in your diagram? If you could do that, then there's a simple, clean, easy layout that would work well. If not, then it's going to be really hard to get a good layout.

sliding glass door that reaches the corner of the room which I would still like to have accessible.

Do both panels of that door slide, or only one of them? If both slide, then I would suggest leaving the one towards the corner permanely locked, and use only the other side (more towards the middle of the room). That will at least allow you to put treatment in that corner.

Until a few days ago, my setup was oriented so that my front wall near the speakers was against the closet wall.

That probably wasn't a good layout. The symmetry would not have been much good, and the closet likely wasn't helping you at all!

I've since moved to in front of the sliding glass doors, so that my speakers could be equidistant from the side walls,

That's a better location, but still not good. The best would be to remove the closet and use that far end of the room as your the front.

and so that I don't have glass on one side of me.

That's not too much of a problem, and certainly not your biggest problem.

( speakers are40.5 inches from the side walls

How far apart are they from each other? And how far away from the glass is your head? In other words, if you measure from your head straight forward to the sliding glass door, what is that distance?

and 26 inches from the back wall/glass, measured form the center of the front top edge of the enclosure)

What is the distance between the rear corner of the speaker and the glass?

I know everyone says to set up so the sound is traveling down the length of the room,

Correct, but sometimes you do have to compromise. That seems to be your case: there's no way to get your orientation working with the room facing either up the page or down it, so the only real options are facing towards the glass, or facing towards the opposite wall.

but I've also heard that you don't want glass on one side of you.

Myth. The specific material does not matter. What DOES matter is that the materials on either side are similar, acoustically. Drywall and glass are not exactly the same, but they aren't that far off either. It would be possible to have drywall on one side and glass on the other, as long as the room is treated accordingly.

I'm planning on getting some heavy curtains soon. Would this alleviate some of the issues with the sliding glass door?

Perhaps it will help a little, but it won't go far enough to do what you need. The issue is something called "SBIR", which stands for Speaker Boundary Interference Response. It's a fancy term that just means the sound waves that go out BEHIND your speaker will bounce off the front wall, then head back towards you, and because there's a slight delay, that "bounced" wave will interfere with the direct wave coming out of the speaker, causing a pattern of peaks and nulls in the room. The first null will be VERY deep, but there will also be a series of other nulls repeating all the way up the spectrum, in a "comb filter" pattern, which really messes up your sound. You can only treat SBIR successfully if the frequency of the first null is fairly high (higher than around 150 Hz, if possible), and even then it needs very thick insulation between the speaker and the front wall. If the frequency is much below that, then it can't be treated properly. The lower it is, the worse it is, and for anything under about 100 Hz your chances are pretty much zero. So curtains won't do the job, as they are not thick enough. A 4" thick panel of OC-703 will do the job.

I haven't been able to find cases on this site ... or across the web similar to mine,

That's because you have a rather unique situation! Don't you just hate that type of comment? Like when you take your car to the mechanic, and after he looks at the problem, he says "Wow! I?ve never seen THAT happen before!"... OK, so your situation is a problem. There are solutions, but the simplest, easiest, fastest, cheapest, best solution is to get rid of the closet.

so I'm hoping for some advice on how I should tackle mixing in this room, while keeping it functional for the occasional band practice and recording

If you remove the closet, it can certainly be decent for mixing. It can still be usable for rehearsal/tracking but it will NOT sound optimal, since it will be tuned "neutral". "Neutral" is not a sound that musicians like: they say it has no life in it, no character, no warmth, no "feeling"... and they are right! Because that's exactly what you want for a mixing room: no life, no character, no warmth, no "feeling" at all. Just "neutral".

I have about US$700 I had been saving for a Thunderbolt Interface but I realize I should probably tackle my room first.

Smart move! The best interface in the world, and the best speakers in the world, and the best DAW in the world will still all sound awful in an untreated, lousy room. And the converse is true: a not-so-great DAW with not-so-great speakers and not-so-great interface can all still sound rather good in a good room that has been well treated.

I have instead ordered several Rockwool sheets

Which ones!?!?!?! Rockwool is a brand name, and they make MANY different products. Some are good for acoustics treatment, some not so good.

(the carpet squares and crates will come down)

Yep. They are not actually doing anything useful for your room, and are likely making it worse, not better.

There is carpet in the room.

Really, that should go. Take it out if you can, and leave a hard, solid, reflective floor. If you take it out carefully, you will be able to re-install again in the future, if you ever do need to use the room for some other purpose. That carpet is doing the exact opposite of what you need, acosutically.

The wall dividing the closet and rest of the room is 4 3/4" thick built with 2x4 studs and sheetrock.

Good! Then it come come down easily! But before you take it out, do check that it is not structural (load-bearing).

to the left of a door is another corner that raises another question. Does this corner need to be trapped up as well?

For maximum performance, yes it does. Control rooms ("mix rooms") always need a lot of bass trapping. The smaller the room is, the more trapping it needs. Your room is VERY small, so it needs a LOT of bass trapping: as many corners as possible (every room as at least 12 corners...), and as deep as possible. We'll get to trapping after we figure out how to orient your room, but basically all your corners should be trapped, or as many as possible.

So, first of all let's look at your options based on what you can and can't do with that closet. If the closet can go, leaving you a roughly rectangular room, then there's a good chance you can get decent acoustics in there, for good clean mixes, and good mix translation. If that closet cannot be touched then your chances are rather less...



- Stuart -

[Josek]

Thanks Stuart for the seemingly instant reply and the warm welcome!

You probably already know by now that "recording" and "mixing" are two rather different acoustic scenarios. Mixing requires absolutely neutral acoustics: the room cannot color the sound at all, in any way: it can neither add anything to, nor subtract anything from, the clean direct sound coming out of your speakers. Response should be as flat as possible, especially in the time domain, but also in the frequency domain. But a neutral environment like that is not very interesting for tracking live instruments: it sounds too dry, dead, controlled, stifled, for most instruments. It can be fine for things like vocals and acoustic guitar, but not so fine for drums, brass, strings, etc.

Indeed. My priority is mixing for sure.

It is possible to design the room with variable acoustics, such that you can swing, slide, rotate, open, close etc. parts of the treatment panels to change the acoustics of the room, but that won't be possible on your budget.

Do you think removable panels would be a good solution? This was my initial idea. After all, mixing is priority, but if it might help a little, I'm willing to make it work!

I have ordered a dB meter.

A decent one, with both "A" and "C" weighting, as well as both "Fast" and "Slow" response?

Yes and yes, and apparently it records the sound changes over time.

Is there any chance at all that you can remove that closet, such that the room becomes pretty much rectangular?

Sadly, no.

sliding glass door that reaches the corner of the room which I would still like to have accessible.

Do both panels of that door slide, or only one of them?

Only the one closest to the corner. The other is stationary..

( speakers are40.5 inches from the side walls

How far apart are they from each other?

54" from tweeter to tweeter

And how far away from the glass is your head? In other words, if you measure from your head straight forward to the sliding glass door, what is that distance?

about 70"

What is the distance between the rear corner of the speaker and the glass?

17"

but I've also heard that you don't want glass on one side of you.

Myth. The specific material does not matter. What DOES matter is that the materials on either side are similar, acoustically.

I've recently heard that from listening to Bobby Owsinski, I think that's what I meant to say, sorry!

Drywall and glass are not exactly the same, but they aren't that far off either. It would be possible to have drywall on one side and glass on the other, as long as the room is treated accordingly.

That's good to know!

I have instead ordered several Rockwool sheetsWhich ones!?!?!?! Rockwool is a brand name, and they make MANY different products. Some are good for acoustics treatment, some not so good.

I wasn't aware that Rockwool was a brand name. These: Roxul 40320 Insulation from Ebay

So, first of all let's look at your options based on what you can and can't do with that closet. If the closet can go, leaving you a roughly rectangular room, then there's a good chance you can get decent acoustics in there, for good clean mixes, and good mix translation. If that closet cannot be touched then your chances are rather less...

As of now, it can be still used as a functional "closet," so my wife would like to leave it there for another child we may or may not have in the very near future.

Once again, thank you for your quick and informative response. I hope I have answered your questions with enough information and look forward to your reply.

Alex

[Soundman2020]

I wasn't aware that Rockwool was a brand name.

Yup! Here's their website: https://www.rockwool.com/ The generic name for products made that way, is "mineral wool".

These: Roxul 40320 Insulation from Ebay

Cancel the order! That's not what you need. There's no acoustic specifications listed at all, but it does say the density is "8# ". I'm assuming that means "8 lbs per cubic foot", which is WAY too dense to be useful. You need much lighter stuff than that.

In reality, it's not the density itself that matters, but rather something called "gas flow resistivity", which is measured in the strange units of MKS Rayls per meter. It's actually a measure of acoustic impedance. However, the manufacturers of insulation usually don't bother measuring this parameter, since it isn't meaningful at all for the main purpose of the product: thermal insulation. It is only useful to us crazy folks who want to use the product for something entirely different: acoustic absorption. Fortunately, there is a very rough relationship between gas flow resistivity and the density of each type of insulation. But note: it is different FOR EACH TYPE. So for each specific acoustic application, you would need one density for mineral wool insulation, a different density for fiberglass insulation, something different again for polyester insulation, or cellulose, or etc, etc.

For bass traps, you need something that has a density of about 30 kg/m3 if it is fiberglass, and that works out to roughly 2 pounds per cubic foot (PCF), or if you want to use mineral wool then the density would need to be around 50 kg/m3, which is roughly 3 pounds per cubic foot. The stuff you ordered is nearly three times too dense (8pcf, which is 130 kg/m2), so it would perform very poorly as a bass trap. It might work for high frequencies, but it's no use for bass. Much too dense. So cancel your order, and get the right stuff.

Do you think removable panels would be a good solution?

It might be possible, to a certain extent, but the panels i your room will be BIG! You will need a place outside the room to store them while you are rehearsing. Lots of space...

Yes and yes, and apparently it records the sound changes over time.

That sounds like it has "Leq" capability, which is good. You can think of that as sort of averaging the levels over long periods of time (several seconds). Or it might just be a "peak hold" capability, that keeps track of the loudest sound, as well as telling you the instantaneous sound level. What brand/model did you get?

Only the one closest to the corner. The other is stationary..

Darn. That's backwards from what you need. Bass trapping performs best in corners, and since it has to be big, it will cover most of that panel. See if it is possible to reverse the two panels, so that the one in the corner is fixed, and the other can slide. Some doors allow you to do that.

What is the distance between the rear corner of the speaker and the glass?

17"

Too far away: your first SBIR dip will be around 100 Hz. Get the speakers right up against the glass, except for a 4" gap where you will insert a 4" panel of insulation.

How far apart are they from each other?

54" from tweeter to tweeter

What is the distance between the two sidewalls? From what you say, it seems to be 40.5 + 40.5 + 54 = 144 inches, but that doesn't make sense, because the entire room is only 12' 5" long (149"), and the closet takes up 1' 9" (21"), so something is wrong... The numbers don't add up.... In other words, as you are sitting at the mix position what is the distance between the face of the wall on your right, and the face of the closet wall on your left?

Is there any chance at all that you can remove that closet, such that the room becomes pretty much rectangular?

Sadly, no.

OK. Then you are stuck with a not-so-good situation. Basically, your only two options are to leave it as you have it, facing the glass, or to flip it 180° and face the wall opposite the glass. But that would leave the closet cavity next to your right ear, so that's not a good option. Your only option is to keep it like you have it now, but optimizing the layout.

First, you will need to get rid of those speaker stands you have right now, and replace them with something really heavy and solid. Massively heavy. Some people stack up bricks, or concrete blocks, others make a hollow steel stand and fill it with sand. The stand must be set to the correct height, such that the acoustic axis of the speaker is about 48" above the floor, or maybe a bit higher. I can't tell you yet where to put those stands, because the numbers don't add up (see above).

if you measure from your head straight forward to the sliding glass door, what is that distance?

about 70"

Too far back into the room. That puts your head pretty much smack in the middle of the first order modal nulls and peaks for that room! worst possible spot. Move your chair forward such that your ears will be about 46" from the glass. That's the theoretical best location in your room.

Once you clarify the number muddle above, I can give you more measurements.


- Stuart -

[Josek]

Cancel the order! That's not what you need.

I just sent the seller an email to cancel!

I'd rather not deal with fiberglass, so mineral wool would be best. Is there a well-known online source?

Do you think removable panels would be a good solution?

It might be possible, to a certain extent, but the panels i your room will be BIG! You will need a place outside the room to store them while you are rehearsing. Lots of space...

Perhaps in that closet

That sounds like it has "Leq" capability, which is good. You can think of that as sort of averaging the levels over long periods of time (several seconds). Or it might just be a "peak hold" capability, that keeps track of the loudest sound, as well as telling you the instantaneous sound level. What brand/model did you get?

Extech 407730

See if it is possible to reverse the two panels, so that the one in the corner is fixed, and the other can slide. Some doors allow you to do that.

These aren't those kind, unfortunately..

Get the speakers right up against the glass, except for a 4" gap where you will insert a 4" panel of insulation.

Will do!

What is the distance between the two sidewalls?

From closet inner wall to outer wall that faces me, takes 25 and 3/4 inches. From the closet wall on my left to the wall on my right is 11'5"

From what you say, it seems to be 40.5 + 40.5 + 54 = 144 inches, but that doesn't make sense, because the entire room is only 12' 5" long (149"), and the closet takes up 1' 9" (21"), so something is wrong... The numbers don't add up.... In other words, as you are sitting at the mix position what is the distance between the face of the wall on your right, and the face of the closet wall on your left?

Yep, something got messed up when I translated my pen-and-paper measurements to the drawing program. The closet takes up 25 and 3/4 inches, from there to the opposite wall is 137 inches for a total of 162 and 3/4 inches, so about 13 and a half feet? I'm not a numbers guy....

[Josek]

From left to right sidewall is 138.1875".

My order for the wrong mineral wool has been cancelled and refunded, and I've been trying to shop around for the right stuff. So far it has been difficult to source or find information on the products that certain brick-and-mortar stores carry so I am attempting to contact a place called IDI, who have warehouses across the USA, two of them within an hour of me. After initially talking to a salesperson and telling him how much insulation I wanted (a non-construction-sized amount) I think they might not want to sell to me (never called me back). I'll keep trying next week as I have vacation from work.

If I order 2" thick insulation, could I stack two to make the 4" thick pieces that need to go behind my speakers? How big should those be? Depending on how close together my speakers need to be (another thing I am unsure of), one might be in front of the door frame and the other in front of glass. I'm wondering how I could get some small panels up successfully behind those speakers. Maybe I should just put big panels behind them...

In the meantime I've gotten wood and made a few frames for the panels I am going to make (2'x4' with glued and screwed corners) and it went pretty smooth so far (im a novice at carpentry). I am researching a way to make some speaker stands that sit at 40.5" from the ground (my Yamaha HS5 speakers have 7.5" from the bottom to what I think is the acoustic axis*) from wood and PVC, filled with sand.

*could anyone clarify a little bit about the acoustic axis of speakers? I've read different things from different places about where this is and I'm so far guessing that it is between the LF and HF drivers, so someone please correct me if I am wrong!

My Extech meter has come in as well.

Happy Easter.

[Soundman2020]

If I order 2" thick insulation, could I stack two to make the 4" thick pieces that need to go behind my speakers?

YEs, you can do that. No problem. Just do not try to glue them together!

How big should those be?

From a little below the height of the desk top, up to a couple of feet above the top of the speaker, and at least a foot going out from each side of the speaker. If you can spare the space, then "bigger is better".

I'm wondering how I could get some small panels up successfully behind those speakers. Maybe I should just put big panels behind them...

Yup. Big. Take into account that the wavelength of those frequencies is several feet long...

*could anyone clarify a little bit about the acoustic axis of speakers? I've read different things from different places about where this is and I'm so far guessing that it is between the LF and HF drivers, so someone please correct me if I am wrong!

Your best bet is to contact the manufacturer and ask! If you happen to have a Genelec, then they have a document on their website that shows the location of the acoustic axis for every single speaker they make. Some other manufacturers do the same.

If you can't get a definite answer from the manufacturer (for some weird reason, some places seem to consider that ultra-high-super-major-stratospherically top secret!), then you can estimate it fairly well. For a typical two-way speaker, imagine a line that joins the center of the woofer cone to the center of the tweeter. The axis will DEFINITELY be somewhere on that imaginary line. It will be much closer to the center of the tweeter than it is to the center of the woofer: probably something like 80/20 or 90/10, give or take a bit. That's usually close enough for most reasonable purposes. It's not going to matter a huge amount if you are off by a half inch ir so. As longs as you set up BOTH speakers identically, and in mirrored positions in the room, you'll be fine. You'd only need to go better than that if you are building a very high end mastering suite with very high end, precision speakers... in which case you probably wouldn't be trying to do it yourself, and you would have hired a pro! For typical home studios, project studios, and even most professional studios, this method for estimating is plenty good.


- Stuart -