John Sayers' Recording Studio Design Forum Archive

Ah good to be back. John had helped me design a small studio online for my home in Illinois years back. It was a great success for us for writing music and recording. Well... I just moved to another state and had to setup a new room for video/audio editing and mixing. The room is 11.3 x 13.5 feet and ceiling height is 11 feet. It has French doors on one of the long walls and outdoor windows with curtains on a small wall. Floor is unfortunately shag carpet but doesn’t seem to kill any highs. Ears do get a bit fatigued while listening though in a short time. I just purchased jbl lsr 305s and desk is sitting on the 11.3 smaller wall. Desk is also glass.Speakers are 1 ft away from wall on stands. Not much slap back in room at all but there are a few bass frequencies that stand out a bit on playback of pro recordings. This is a room with no treatment at all for the moment. Typical drywall room that I cannot really go construction crazy on. You know the wife would kill me after fixing up our other home to sell . Should I stay on the short wall or try the long wall instead for the bass response? Or start looking into room treatment like corner bass diffusers and behind speaker treatments which I know I will add a little bit for mids and highs in the end.

Hi David, and Welcome Back!

Congratulations on your second studio!

The room is 11.3 x 13.5 feet and ceiling height is 11 feet.

The high ceiling is nice, but that's not such a good ratio of dimensions. You'll have serious modal issues at around 50 Hz, 66 Hz, 83 Hz, 100 Hz, 110 Hz, 120 Hz, and the second harmonics of all of the above. Of the three critical acceptance tests that the BBC uses, that ratio fails two. The biggest issue is that the height and width are practically the same, so their respective axial modes line up almost perfectly.

Floor is unfortunately shag carpet but doesn’t seem to kill any highs

That's probably because the room isn't treated yet! It is certainly killing the highs, but you just can't hear that yet because the high frequency response of the rest of the room is still there, masking the effect of the carpet. Once you get the ceiling treated correct, that will change, and you'll lose the psycho-acoustic "reference" of the floor plane. I'd suggest that you either remove the carpet or if that's not possible then cover put a thick layer of plywood on top, and lay laminate flooring on that. You need to have a nice solid, hard, reflective surface for the floor, to give your brain a known reference to work with.

Ears do get a bit fatigued while listening though in a short time.

Yup. Not surprising... see above for the reason...

Desk is also glass.

Dimensions? Location in room?

Speakers are .... on stands.

On stands is the best way to have them (OK, make that "second best", but still much better than "on the desk" or "on the meter bridge").

Speakers are 1 ft away from wall ....

Not so good. Here is how your low frequency response will look, due to SBIR from the front wall:
That assumes that your speakers are about 10 inches deep, meaning the front face is about 22" from the wall. That's not a pretty situation.

On the other hand, if you push them right up against the wall, then you can improve things to this situation:
Now you just have a simple bass-rise that can eb dealt with using the speaker's own EQ controls, plus the SBIR artifacts have now moved up above 1kHz, where they are much easier to treat.

On the other-other hand, if you really want the smoothest response possible, then the very best way to set up your speakers is flush mounted (soffit mounted), so you can get this response:
Simple bass roll-off fixes that perfectly: it's just a power imbalance thing now, piece of cake to fix.

That's just SBIR off the front wall: Add in the side walls, the floor, the ceiling, and the modal response, and you can see why you are hearing ... :

there are a few bass frequencies that stand out a bit on playback of pro recordings.

... which is absolutely as predicted by theory.

Should I stay on the short wall or try the long wall instead for the bass response?

Your bass response on the long wall would be worse, not better, as you'd be in a huge SBIR null from the back wall. (Note about that: You have your diagram marked wrong: you have the wall in front of you labeled "back wall", but it is actually the "front wall". The wall behind you, at your back when seated at the mix position, is the "back wall". The one in front of you is the "front wall".)

There's also the issue of the Haas time: with speakers firing across the short axis of the room, the first reflections off the rear wall would be coming in well inside the Hass window, messing up your perception of directionality and also the overall ambiance of the room. Keep the back wall as far away as you can.

So stay with the setup you have now: speakers on the short wall, firing down the long axis. However, you do need to flip the room around completely, so the window is in front of you, with the speakers. Right now, you have that glass behind you, where it is doing a great job of being a massively effective sound reflector, and I'm assuming that you don't want to cover up that window entirely with the necessary back wall treatment, so it makes sense to face the window and only cover part of it with the front wall treatment. That way, you'd be free to put the bass traps that you need in the rear corners, and cover the entire rear wall with enough absorption to get the room usable.

Or you could leave the room in the current orientation, as long as you don't mind covering the window with a 6" depth of OC-703.

Or start looking into room treatment like corner bass diffusers

Bass diffusers are huge! Way too big to fit in your room. It just isn't big enough to have diffusers that work down to low bass frequencies. What you need in there is bass trapping, not bass diffusion. I'd suggest at least doing Superchunk style bass traps in all four vertical corners, as well as some of the horizontal ones, if you can swing that.

and behind speaker treatments which I know I will add a little bit for mids and highs in the end.

Yes, you will need treatment between the speakers and the front wall, bit it needs to be absorption for the mids and highs (see above graphs for the reason): It does not need to add any mids and highs. You already have plenty of mids and highs.

So overall I'd suggest first getting the room geometry correct, with the speakers and listening position in the right locations, then add the basic treatment that a small room like that needs (vertical corner bass trapping, thick rear wall absorption, first reflection point absorption, and absorption between the speakers and the front wall), then add a hard-backed, angled, ceiling cloud to help with the modal issue, and see how that works out. Do a REW test before and after, to see what is working, what isn't, and what still needs to be done. Then design the second round of treatment based on the REW results.

Oh, and don't forget to take photos and post them! Lots of them! As the saying goes around here: "Pics, or it didn't happen"...

- Stuart -

LOL. Pics it is.
As usual. You guys are the best of the best. Cream rose to the top!!
I will give her a go over the weekend.
As far as bass superchunks. Would that be like the lenrd aurlex foam? Or is there a better way to make my own. I did this before but for the life of me cannot find the diagrams to make em. Yep. Moving does that.
I could turn it all around and face the window. Only hard part will be trying to figure where to put the 32 inch wall monitor lol. I just have curtains blocking the window right now.I also should ask. If I put on outdoor window wall. Treatment for the window would be curtains for absorbing? Hmm. I will work on this Stuart.
And again thank you sir!!

So here is a rough of what we discussed Stuart. My only questions was should I just use heavy drapery on the outside windows behind spreakers since absorbing panels are not going to work. And the French doors us heavy curtains as well and then absorbing material on the other side wall. Not 100% perfect on making walls identical eh? Also any ideas how to make a bass superchunk
Thanx Big S and others here!!

Would you consider this to be a good way to build these traps. Specially the super chunk? He uses only top and bottom and center is empty.
https://www.youtube.com/watch?v=fiJ6mI450c4

I once played at a church that had attempted to use heavy curtain material for absorption. I believe you will be dissapointed with the result. Have you considered building a rigid movable frame for a more standard absorption type of structure? Movable, if awkwardly so?

Thanx for the idea Johnnie. I will look at this as well as an idea. The window is off center so one speaker will get treatment and the other has the window right behind it. I am thinking I need to do bass chunk in all 4 corners of room. Sound right?

What if I cannot remove carpet? I know stuart suggested adding plywood then flooring ontop of the shag carpet but this would not be very practical since the floor is so big. Is it possible to do just the front area of room where desk will be?
Thank you for all your help!!
David

When you talk about doing only the front, what is that in reference to? Treatment? MSM construction? etc?

David17 wrote:Thanx for the idea Johnnie. I will look at this as well as an idea. The window is off center so one speaker will get treatment and the other has the window right behind it. I am thinking I need to do bass chunk in all 4 corners of room. Sound right?

I recall running across a post which I think John Sayers did, where he had kindly provided the plans for some cabinets that could be used for the front of a control room. I wonder if you could use something like that? I'd be less than thrilled to have one speaker with treatment and one with a reflective window behind it... symmetry is pretty important around the listening area. Maybe if you did this via cabinets, you could give yourself symmetry, but still have the option to remove and store if it was truly necessary.

I did a search yesterday for my own reasons looking for those, but I haven't been able to find them. Does anyone else happen to have a link handy?

So here is a rough of what we discussed Stuart. My only questions was should I just use heavy drapery on the outside windows behind spreakers since absorbing panels are not going to work. And the French doors us heavy curtains as well and then absorbing material on the other side wall. Not 100% perfect on making walls identical eh?

Your basic plan looks good, and on a tight budget, what you propose will help, but it would be better to invest in making some thicker acoustic panels for your first reflection points (instead of drapes), and also for your bass traps.

Also any ideas how to make a bass superchunk

The easiest way is to cut panels of OC-703 into triangles that measure 24" on the two shorter sides, and stack them in the room corners, floor to ceiling. Build a light frame to go in front of them, and cover it with fabric.

I am thinking I need to do bass chunk in all 4 corners of room. Sound right?

Right.

What if I cannot remove carpet? I know stuart suggested adding plywood then flooring ontop of the shag carpet but this would not be very practical since the floor is so big. Is it possible to do just the front area of room where desk will be?

If that's the only option you have, then yes, that would be better than nothing at all!

- Stuart -

It took forever to actually get this back up and running. I was working out of another studio for an indy label. So I am now back at my home room. Soundman and the gang were very helpful. Now I need to show you some pix and ask a few more questions. First off should I put some high frequency panels in front of window where my speakers will be right in front of. 2" acoustic panels? The window is off center from room so one window would be covered? The back of room will be 4" bass traps on back wall with corner traps in all corners. I have one 4" ceiling panel since I have a ceiling fan to abide by. Side walls would see 4" traps as well. Placement of traps about 2 feet from floor. Any suggestions at this point would fall mon open ears

I did make some stand alone gobos with 4" trap to place behind the speakers. Do you think this will help keep it equal across listening area? The off center window is killin me LOL.

First off should I put some high frequency panels in front of window where my speakers will be right in front of. 2" acoustic panels?

Definitely you need panels there, but not for high frequencies: you need broadband panels that get down into the low mids, to reduce the SBIR artifacts from the front wall. 4" of OC-703 would do the trick. Put that up against the glass, and your speakers tight up against the 703.

The window is off center from room so one window would be covered?

Partially covered, yes.

The back of room will be 4" bass traps on back

4" is not a bass trap. That's a broadband to low-mid trap at best. 6" would be more useful, but your real bass traps will be superchunks in the vertical room corners.

I have one 4" ceiling panel since I have a ceiling fan to abide by.

That's not much. I would suggest a custom-built ceiling cloud that fits around the fan. Make it big, angled, hard-backed, and centered over the area between the speakers and mix position.

Side walls would see 4" traps as well. Placement of traps about 2 feet from floor. Any suggestions at this point would fall mon open ears

Right, but make sure they are at your first reflection points!


- Stuart -

4" is not a bass trap. That's a broadband to low-mid trap at best. 6" would be more useful, but your real bass traps will be superchunks in the vertical room corners.

Perfect I have super chunks for corners. Could I just add about a 2 inch air gap on the 4" wall panels to make it work for bass traps? If not I can go with 6" and make a bigger panels for the walls. Ahhh! My room smells like I went to Lowes or home depot.