Room help please.

milesdf · Post by **milesdf** » Wed May 03, 2006 1:23 pm

that is going to be really really hard in this room and have it still be functional. is thier any way to get the same absorbancy in less space? we could probablly make the panels 5' long. i think in order to keep functionality we will not be able to eliminate too much of the corners, 1.5' out from the wall on each side is probablly the maximum we can do, and of course the one corner behind the door cannot be used. is there any way to still meet the original goal? i am sorry to have to say it, but this room doesnt have to be perfect, just be good enough for college radio work.

thanks for your help.

David French · Post by **David French** » Wed May 03, 2006 2:00 pm

Put one panel across each corner that you can. Also use 4" on the walls with as much airspace as you can. This will be ok.

1.5' out from each corner is juct about exactly how much you need to come out: sqrt(2) feet.

milesdf · Post by **milesdf** » Wed May 03, 2006 2:03 pm

David French wrote:Put one panel across each corner that you can. Also use 4" on the walls with as much airspace as you can. This will be ok.

1.5' out from each corner is juct about exactly how much you need to come out: sqrt(2) feet.

this is not taking into account the 4" of fiberglass though. can the edges of the fiberglass be cut so its frame would fit flush in the corner and be caulked? this would look pretty sweet as well.

David French · Post by **David French** » Wed May 03, 2006 4:29 pm

Yes, bevel cut is fine.

milesdf · Post by **milesdf** » Thu May 04, 2006 1:42 am

one more thing, how is fiberglass generally cut? pair of scissors?

thanks.

David French · Post by **David French** » Thu May 04, 2006 5:18 am

A serrated knife works well... also an electric carving knife or table saw if you have them.

milesdf · Post by **milesdf** » Thu May 04, 2006 9:25 am

great, it looks like this is going to happen. unfortunatley our advisor is probablly going to make us pay facilities to remove the old foam and adhesive, (which in my opinion is bullshit). it does look as able we will be able to build these panels discreetly and then call them purchased though. funny how it works when your involved with an organization, so much politics and bullshit you have to deal with.

it appears now that this room is going to switch places with the office, which has pretty much the same dimensions, except it has a window next to the door as well. I think what we will end up doing is 2'x5' 4" thick panels in 2 or 3 of the corners. we will then try for some 2" thick 2x4 panels on the walls in various places.

we also would like to make the main control room acoustically sound. I dont think I really have to make up schematics, its almost the same except that the side with the door is extended 4' and the door is on the extension on the right side. the desk is on the side of the door. the side next to the door is pretty much a window, unfortuatley. I am planning to put 2x5 sections of 2" thick panels in all four of the corners, on the window side they will have to be cut a little narrower. there will be a 4x6 2" panel on the wall behind the person talking into the mic. would it be benifical to use 4" foam on this panel? we are aiming for only medium volume vocals in this room, are corner absorbers neccesary? our mics are dynamic and very good at off axis rejection, so maybe only a panel in front of the mics (behind the speaking person) that can absorb down to 100 hertz?

knightfly · Post by **knightfly** » Sat May 06, 2006 7:31 am

Corner absorbers are necessary in virtually ANY room; volume is relatively unimportant, other than possibly exciting actual wall panels more (if they're not solid concrete) - first thing to consider in any room is positioning of the "instrument" (voices are instruments) - if the instrument is in a null at a particular frequency (in the case of voice, between roughly 100-3000 hZ) then that frequency won't be as loud in the recording.

So the first step (assuming you get to start from scratch) is laying out the room so the normal mic position is NOT at any even multiple of any dimension (not 1/2, not 1/3, not 2/5, etc) - same with any monitor speakers, other than stereo needing to be symmetrical left to right) - once this is done and tested for best frequency/tonal balance, THEN you add treatments to FURTHER smooth out the response that couldn't be helped by positioning of both source and mic.

Positioning of mic or source relative to any boundary will also color the sound by phase cancellations, so this needs to be kept in mind when deciding on layout as well.

If you START by placing all the treatments you THINK you need, you won't be able to hear what the room DIMENSIONS are doing to your sound as well, so likely won't get as optimum a setup.

If you're going to use foam, I'd recommend only using Auralex' PRO panels, not sure but possibly Illbruck now also makes denser panels (maker of Sonex); most other foams aren't as dense, so won't absorb to as low a frequency, leaving you with more of that "boxy" foam sound.

As to only having absorbent behind the speaking person, keep in mind that even a directional mic is still a pressure device; if the capsule of the mic is in a null caused by distance between mic and ANY wall, it will still affect the level of that frequency; so you need to absorb ANY close surface you don't want causing phase cancellations(comb filtering)... Steve

milesdf · Post by **milesdf** » Sat May 06, 2006 10:06 am

thanks for the reply. I am not for or against foam, infact i like the fiberglass panel idea because it is cheaper, and I am having bad expiriences with the current foam. im not sure if mic placement can really be set, these mics are on positionable booms, and they are generally positioned to location of greatest comfort. starting from scratch on the room is pretty much immpossible, and there has to be room for a couple people and a desk, and the windows still have to be mostly unobstructed. so perfection is immposible. how close to getting decent results can i get?

knightfly · Post by **knightfly** » Sun May 07, 2006 10:27 am

I know life is full of compromises, but it's easier to come up with workable solutions if you understand what the tradeoffs are; that's the main reason I posted. In any setup, acoustics will often be butting heads with practicality, such as the mic booms you mentioned, usable space, pieces of gear being within reach for adjustment and viewing, etc -

In this type of application, about the best you can do is to help make the people who will use the gear AWARE that moving the mic just an inch or two can make things better or worse. Like the old saying goes, first you learn WHAT the rules are, and WHY; then you'll know which rules you can break, and what will happen when you do.

The RE-20's I saw in the pix are typically used by radio "voices" because they make everyone sound "bigger" with their nice round bottom end; this can be either minimised or exaggerated by juxtaposition. Moving the mic will change boundary response between mic and walls/ceiling, etc, repositioning the speaker's head can do the same, as can distance between mouth and mic; aside from smoothing out the room (trapping any and all usable corners, patches on walls, "clouds" for floor/ceiling flutter, etc, the main thing to keep in mind is that the more aware people are that positioning can/will affect things, the more likely they can use this to improve their results.

For a room such as yours, that's about the best you can do; ideals are more something to keep in mind while you do what you MUST in order to do anything at all... Steve