How many more panels do I need to build?

[geotungz]

Hi,

The room I record vocals in is 9 x 11, 8 feet high, if I count the entrance with the door, that wall is 13 feet long.

I built 8 absorbtion panels, 3 inch thick, 4 feet by 2 with safe and sound rockwool or roxul depending on where you live, I notice a very significant improvement when it comes to the reverb and echos being reduced in my room but it still isnt satisfactory to me. Yet most sites with calculators recommended a minimum of 2 panels or 4 total. yet I am not yielding results that I like.

I built a temporary vocal booth in the room with the panels, mounted on furniture etc it is 4 ft by 4ft six feet high, but I find the sound is too dead or seems to have a boomy and slightly too dull sound for my liking. I dont know if the boomy sound is because the back wall of the booth is the room wall and lacks absorption, or if it is simply too small. Ideally, I would like to have a room that is as dead as the booth, but less boomy.

Hence my next question, how many more panels would I need to build to achieve the goal I mentioned? Note I am only going to record vocals and mix in the cans as I dont have monitors.

Thanks

 

[keith.rogers]

I'd guess your booth is reflecting a lot off that untreated wall, and maybe you're just on top of the mic too much, but hearing would help.

It's a small room, and while you're not recording low frequencies or monitoring, it doesn't mean that low frequencies won't still build up, so I'd say you need bass traps in the corners, too - maybe not massive ones, but you could double your panels, stacking pairs in the corners, and have a couple panels as clouds over where you'll stand to record. It's more or less what I did, though I have double-thick Roxul in the corner traps (only 3 corners). I used 2 bundles (12ct ea) of Roxul for everything, one bundle in the bass traps, and the rest around the room with 2 on the ceiling. It's pretty effective, but I don't shout when I sing and only record acoustic instruments in a small room. (A bit smaller than yours, and I used 16"x48" Roxul, so the panels/traps are narrower.)

 

[geotungz]

Do you think one more pack of roxul safe and sound would do the job? I need to do this in the weekend with the weather here changing it will be too cold soon.

 

[geotungz]

it is 8 sheets per pack.

3 inch thick 4 x 2 panels would be okay as clouds?

 

[geotungz]

here are two clips

one is processed with de-essing, couple of EQ low end roll offs, compression and some volume adjustments.

sorry for the hiss or air in the background, I recorded it pretty hot.

 

[miroslav]

...how many more panels would I need to build to achieve the goal I mentioned?

What goal is that...dead but not boomy...?

Add more low end traps. Your room is too small for LF to be easily controlled.

If you're just trying to control your vocal boom....step back from the mic and/or try a different mic.

 

[geotungz]

Am I condemned by the size of the room no matter what?

 

[geotungz]

What goal is that...dead but not boomy...?

Add more low end traps. Your room is too small for LF to be easily controlled.

If you're just trying to control your vocal boom....step back from the mic and/or try a different mic.

do you find the audio clip I posted sounded dead and boomy?

At one point I am even 4 feet away from the mic and it sounded bassy. Mind you I recorded those clips in the make shift booth I built to remove the reflections of the room.

If I undo the booth and put the panels on the walls, in the corners as well, the sound is not boomy at all but I still hear reflections. My question is, if I build 8 more 4 x2 panels, 3 inches deep, if it will remove the reflective sounds and will it sound as boomy as my booth takes I posted.

Will those 8 more panels I build handle the low end issue? If not, how much money would I have to put into treating the room to get the best results out of it

 

[miroslav]

Am I condemned by the size of the room no matter what?

Up to a point...yes, no matter what you do, it won't change the size of the room, which is not favorable for the low end.

That said, my feeling has always been that with small rooms, go for dead...it gives the illusion of a large room, meaning, it takes the room out of the equation and allows you do add artificial ambience...however, to control the low end in a small room in order to take it out of the equation, you need some focused bass control, which is not easy in a smaller room.

You might want to do at least four 2'x4'x 6" or greater depth panels for the low end...at least for the corners.
The 3" are also going to help. You don't need to cover the walls end to end to make the room dead...but definitely something on each of the walls and also the ceiling.

I think that small booth was adding more boom than helping you. Once you have your room decently treated...just stick the mic at like 1/3 from the back wall, and face into the longer end...and that end you are facing are where you really want the most treatment, and the side walls where you have your first reflections.

All that said...if you are just doing vocals and nothing else...not even mixing with monitors...you may need to go real massive with bass traps, since the human voice will not really go down into the low end. So low mids to upper mids are where the typical voice resides. Of course, if you plan to abandon the headphones for mixing at some point and get monitors...then go ahead and treat the room for the full bandwidth which you will have when mixing.

Don't feel bad about building traps and the cost...I just spent over $3k on materials to build acoustic panels, but I've got over 50 panels, and my room is like 4 times as large, so lots of surfaces to cover.

 

[rob aylestone]

Sometimes you just got to let your ears do the work and to hell with the calculations. In my audio studio, during lockdown, I needed to do some green screen, so I decided what the hell, and I stripped two walls back to the panels, and put MDF in, including a curve to span the corner. This means my room is now a. unsymmetrical down the long axis, and b. has a focal point where there's convergence. Video completed, I was going to remove it and put the room back, as the real green screen is now built in the new studio half a mile away, but I have decided to keep it, as it does interesting things. My studio is over damped - deader than the 'deal', because I like that, but now I can adjust the liveness of the room by small movements in the green screen area. I can liven up a guitar, or create more live sounding voice.

I'm leaving the 'bad' treatment in place because I like how it works. I can move to the other end and record very dead. I'm really happy with this totally 'wrong' approach to acoustics.

If you have a space that sounds bad to you - it's bad. If it sounds good and what you want, surely that's the decider. If you find it too dull/boomy/dead. Take a panel or two out, or move them around and see what happens?

 

[Orson]

Line the walls a ceiling with something possibly acoustic foam?. It will stop the 'bounce'.

 

[mjbphotos]

Safe and Sound is not as dense as Roxul 60 or 80, so not absorbing anywhere near as much low end as if you were using 4" thick panels of of it or OC703/705.

 

[keith.rogers]

Safe and Sound is not as dense as Roxul 60 or 80, so not absorbing anywhere near as much low end as if you were using 4" thick panels of of it or OC703/705.

I think this is a myth. I've googled the specs enough time.

If it's the 3" thick batts, its specs are not very different from 2" or even 3" OC703/705. It's certainly adequate for broadband.

 

[geotungz]

he coefficients for safe and sound are

Thickness
3”
6”
125 Hz
0.52
1.11
250 Hz
0.96
1.28
500 Hz
1.18
1.15
1000 Hz
1.07
1.06
2000Hz
1.05
1.03
4000 Hz
1.05
1.01
NRC
1.05
1.15

2.4 lbs per sq ft density

 

[miroslav]

Sometimes you just got to let your ears do the work and to hell with the calculations.

Exactly.

 

[keith.rogers]

Sometimes you just got to let your ears do the work and to hell with the calculations. ....

Exactly.

Well, yes, but, if you're still training your ears, it's nice to know if you probably 8 or 16 or 64 panels to get close. And, it's a small room, probably not comparable to the spaces you are used to (guessing).

That Amroc calculator has some ideas that can be used. If you enter your room dimensions, you get total square footage (518 for OP's 9x11x8) room. Then, you can pick from a couple different types of rooms to get an average absorption coefficient, and they even give you a square footage of coverage (it doesn't explain how *that* is calculated). But, you can try some arithmetic of your own. E.g.

If the 3" (thick) 2'x'4' panels are surface mounted, they'll have a coefficient of 1.05 (average, per the spec sheets). 8 panels is 8x2'x4' of coverage, or 64sf. Times the average coefficient is 67.2. Divided by total square feet yields 0.13, or something that might meet a "music room" number (i.e., a place you might listen to your hi-fi), assuming you place the panels optimally, let's say. But it's well shy of any recording use.

So, for OP, to get to something like a "speech" room would require twice the number of panels. Now, this makes a lot of assumptions about placement, but pure arithmetic gets you something, at least that's how I look at it.

Of course, the room size is below the minimum for any actual use (30sqm is the smallest room), so that suggests you probably would not be wrong going that number of panels or more. My room is up to about 0.2 something with panels, but I've got a large, heavy quilt (5'x5') on a wall, a couple small bookcases/cubbies and rugs, so it's "close enough" for me to know that so long as I'm under the clouds, I can get away with a fair amount. (My room is just shy of 30sm, but square, so hopeless by all accounts...)

P.S./Edit: Attaching acoustic specs from some common products (if I didn't make a typo). It's interesting that less density seems to actually improve LF absorption, though at the higher density of the Rockboard 60/80 products, you can probably make up for that by doubling or tripling thickness without ending up physically deeper. And, there may be cases where availability of thinner or more rigid material is important. But, if you can source Safe'n'Sound locally, it appears to be almost as good as the others. (I just found shipping cost of materials to be a big deterrent to using anything else.)

 

[miroslav]

Well, yes, but, if you're still training your ears, it's nice to know if you probably 8 or 16 or 64 panels to get close.

Ahh...you rarely get that info from measuring.
People have stuffed their rooms with panels...and the measurements still show some of the same issues with few or many panels, especially in the low end.
Which kinda underscores the point that you can only do so much with smaller rooms...there is no magic number of panels what will transform them into something special...so the best approach IMO is to just go for a dead sound in smaller rooms (which your ears are quite good at measuring), using a variety of panels types...and that's about as good as it will get.

I spent hours...days...playing around with the measurement tool...moving panels, trying out different things, and there was never a point where the readings suddenly went from one extreme to the other...which basically confirms that your space, the size/shape, is not going to be dramatically changed.
Still, it was nice to do some measurements just to see what I had...but I couldn't guesstimate from that how many panels I needed.

 

[keith.rogers]

Ahh...you rarely get that info from measuring.
People have stuffed their rooms with panels...and the measurements still show some of the same issues with few or many panels, especially in the low end.
Which kinda underscores the point that you can only do so much with smaller rooms...there is no magic number of panels what will transform them into something special...so the best approach IMO is to just go for a dead sound in smaller rooms (which your ears are quite good at measuring), using a variety of panels types...and that's about as good as it will get.

I spent hours...days...playing around with the measurement tool...moving panels, trying out different things, and there was never a point where the readings suddenly went from one extreme to the other...which basically confirms that your space, the size/shape, is not going to be dramatically changed.
Still, it was nice to do some measurements just to see what I had...but I couldn't guesstimate from that how many panels I needed.

Yeah, I have not gone to the point of measuring after I put the panels in. I just listen to what gets recorded. And, even if I happen to be in the right place, all I have to do is put the mic in the wrong spot, and the room ceases to be a problem, anyway .

So, to be clear, I am not arguing that numbers beats ears, ever. [I think] We all agree you can't go into a small, untreated room and have much hope of getting a good recording, and while you could cover all the surfaces with absorption and diffusion to create an anechoic chamber, that is overkill (and will make you crazy to spend time in, by all accounts). I'm just saying it's a way to get an idea where to start, i.e., the calculator gives you a way to take some guesswork out of the minimum required.

If you look at the calculated surface area for the rehearsal room, targeting about 0.12-0.13 average absorption, it specifies ~65sf, which is essentially 8 2'x4' panels, and the calculation using those panels and the Safe'n'Sound spec came out as 0.13. IOW, it all adds up . I think OP just needs to get more treatment in there and start figuring out what works. With more treatment, the corners can be trapped, and first reflection points for recording, and maybe even monitoring, if they get to the point of setting up monitor speakers. Or, put another way, I think trying to make it work with 8 panels only is going to be more frustrating than 16 panels (about half of which should be bass traps).

P.S./Edit: Perhaps a corollary here is that treatment alone cannot be guaranteed to make a space sound good, and is not always required (for recording, at least). It really helps to have a space that is large, and, ideally, lacking in parallel walls. I've been very happy with recordings done in our 20'x15' family room, which is big, open to the kitchen, front hall, stairway (to an open upstairs) and has a vaulted ceiling. Not a bit of treatment!

 

[miroslav]

If you look at the calculated surface area for the rehearsal room, targeting about 0.12-0.13 average absorption, it specifies ~65sf, which is essentially 8 2'x4' panels, and the calculation using those panels and the Safe'n'Sound spec came out as 0.13. IOW, it all adds up .

I never got that much into the numbers...too much work.......so all I did the measurements for was to see the response of the room, but I didn't use any of them to suggest the type/size of trap (this was when I set up my old studio space)...and it was after the room was already set up and well treated, and I wanted to add some more bass traps...so I measured.
I then moved and measured those traps around...and I couldn't get any real significant differences in the readings...and I think much of that was to do with the size of the room.
I see people putting up endless measurements and asking how to improve on them...meanwhile their space is small, so at that point I say just put up some low end and some broadband treatment...get the room fairly dead (but not so that it feels like it's sucking the sound up before you can hear it)...and then move on, and forget the measurements.

With my new, much large studio...I have not done any measurements yet, and I just went ahead and started building panels.
After the room is completely set up and all my panels are in position...I'll check then to see what I have, but AFA how many traps and where to put them...I'm just going with common sense, and also there is an esthetic consideration, as everything is for me when I lay things out.
I'm not just hanging the panels everywhere, end-to-end.

Except for a few key spots for panel placement...the main point is to just reduce total reflectivity by some amount (there are numbers for that too)...and pretty much all the hard surfaces are game, so you don't need to overthink where to place each of the panels, which makes more esthetic considerations possible.
I've seen some spaces that looked absolutely hideous with all the homemade panels just lining the walls and ceiling...and still, the room wasn't measuring well...so it's bad enough it has acoustic issues...but then to also look hideous!

 

[GoodTimesRec]

I will echo the importance of bass traps. I cut 4" Rockwool/Roxul panels into 16" tall fabric coated triangles and then stacked them in two corners of my room. There are two doors on the other corners so it's not really possible to have all four corners trapped like that. however I built some 4" panel gobos and while I am still too lazy to construct small feet for them, they tend to stand on their own just fine and lean on the wall just fine too. When I shut the doors I put a panel in each corner as a pseudo trap/additional baffle. I have more baffles in the amp recording closet in the middle of one of the long walls, so I leave that door open to help some, I hope. At the least there's a panel hanging on the door that helps some.

I also echo that with small rooms I'm finding it's helpful to make it pretty dead and add room flavor later. But that just means you can make it into whatever room sound you want!

Last weekend I added ceiling panels and those help a lot too. If you're in the wrong place in the room, like by the wall on the non-bass trapped side, I still hear some weird echo/verb but for so much of the room now it's improved the clarity of what I record in it