guitar amp room

[fitterbkw]

Hello all,
This is my first post. I work construction and am very good with tools so the building of what I am going to ask about does not scare me. My question is, and this may be a weird one. How big of a room do I need to build to use a room mike on a guitar amp to get a good room sound. I have a Gibson GA-8T that sounds gorgus when played. I just can't catch the sound when I record it. I have tried a shure 57, & a cheap condenser mike in a small soundproof box I've built. Noise is not a problem, because I live out in the woods away from other people. I can also build a seperate room in my shop. Just need some technical info on size to help me out. Thanks in advance, fitterbkw

P.S. Using SX 2.0, with a delta 44 card, and I have captured good sounds, but by only going direct to the soundcard. My guitar amp is all that will see this room. One more thing, western red cedar is the wood I would like to use. Easy to get here in the pacific northwest.

[frederic]

This was the major reason for choosing the fender "cybertwin" amp I bought when I was amp shopping - it has a digital out thats always "full volume", i.e. the master volume control doesn't change the s/pdif level out - so i can record "direct" without having to set up microphones and deal with volume level issues in a small console room.

Anyway, to your question, I personally don't like recording guitar amps in small rooms (with mics) because "air" is part of what makes amps sound a certain way, for their signature sound. Some amps are open back, some are ported, some are sealed, and if you change the environment of the amp (ie shove it in a closet) it will sound very different.

Generally, you can get a decent recording from a guitar amp by changing its positioning in the room, meaning don't record it on the floor. Q-lock scissor stands are good for this - you get the amp into the air, off the floor, maybe at an angle to the floor, and try different mic positions, and you'll have a better recording. Putting the amp "in the air" eliminates fast reflections off the floor that the mic won't see (hear) anymore.

Since you live in the woods, you could even face the amp out the back of the garage door and mic it that way. Depending on the mic, if it has a tight pattern, it will pick up the amp and not the ambient reflections from other buildings if you're truly "in the woods".

I did that once with a drumkit about 10 years ago... we recorded it literally in the woods, on a top of a hill, on a homemade folding drum platform. Not one reflection was recorded, just the initial "thwap" of the sticks on the drumheads and associated head ringing to generate the drum sound. We used tight cardiod pattern mics, I believe. We did this because our other option was a cement, untreated basement, and the echo's and flutter between the parallel cement walls were totally hosing the drum tracks. That and we were getting headaches really quick.

Hope you don't mind a weird reply.

[RICK FITZPATRICK]

Hope you don't mind a weird reply.

Doggone frederic, your back. I thought you were going to be gone for a week? I was going to return your call on Sunday, but didn't really have a moment to do it till late at night. My folks were here and we were runnin all over the place. They gave me a car, and went for rides in it. Cool. Now I have something to drive that actually is fun!!

Hey, theres nothing weird about your reply. I did an hours worth of typing last night for this thread. But decided it was late and I was rambling, so I saved it untill someone else replied, JUST so I could see how weird MINE was OK, now I'll post it. Low and behold, you said a lot of what I said, and then I erased it cause I was sure as hell it was SO dumb. But here it is, after modifying it 10 times. Ha! Doesn't even give a real answer. So much for typing late at night.......

"Hello fitterbkw. Where you at in the pacific northwest. I'm in Coos Bay Oregon. Western Red Cedar huh? Cool. Nice stuff. I deal with Port Orford Cedar. Nice stuff too! Well now, size huh? Lets figure some things out.

You already said you LIKE what you hear at some point because it sounds GORGEOUS> right? But when is that? When you are playing AND recording? Or playing with the amp in a ROOM and just listening? Or does it sound gorgeous in the soundproof box, while using headphones, but you are not capturing it on tape? That tells me you've already solved one big problem though. Getting a gorgeous sound in the first place. The problem is..... WHEN and WHERE does it sound gorgeous?

Personally, I would guess not capturing it to a recording has to do with three things.

#1Monitoring while recording. How do you monitor? If you like what you hear as you are recording it, that tells me you are listening with HEADPHONES, correct? If so, they fool you. If not, how DO you tell what you are recording WHILE you are recording it?

2#The listening envirinment. WHERE to you play the recording back? One of the most difficult concepts for home recording enthusiasts to grasp is the ROOM colors the sound. Many things can account for this delima. The SIZE, SHAPE, and furniture. Not only that, but electronics, speakers, placement of speakers, etc etc all have a bearing on the validity of what your hearing. HOW do you know that the speakers are telling you the truth. What kind do you monitor with? Do you use a graphic eq in the room? These kind of things will totally distort your perception if they are not up to par. Lets put it this way. How do you really know your not capturing the sound you want, if you are comparing what you heard in the headphones(if thats what you monitor with while recording)with what you hear when played back on the speakers. Make sense? Either one may be lying. Get my drift? Not only that, have you played back the recording on more than one system? That is called "translation". If it sounds good on your system, but sounds like shit on another, it is NOT translating. But since you have already heard it sound "gorgeous" at some point, but does not sound good on your system, well thats why I suggest looking at other reasons.
Man, building a room just for an amp, sounds really like overkill. I would suspect the real problem is a combination of the above. However, IF you insist on building a room just for mic'ing an amp, well, what kind of space do you have available? You may do better to use the cedar as slats on a slot absorber wall, but that is getting into room acoustical design. Oh oh, crap, now we've opened pandoras box!
OK, heres the deal regarding size. First off, there are what is known as optimum room dimension RATIOS. These ratios determine the most evenly distributed room "MODES". A simplistic explanation would be that the dimensions of the room coincide with the wavelength of sound, and given these dimensions, certain things happen with them. Like cancellation among other things. "Acoustical theory" states that parallel surfaces cause whats known as standing waves to occur at frequencys determined by the distance between them. And each dimension of the room determines the frequencys which are affected.
So size is one thing, which will determine how LONG the sound takes to decay, but the ratio of the dimensions is far more important. And this is EXACTLY what your existing listening space consists of. Dimensions that for the most part, alter what you are hearing. Which causes you to try and cure it with MORE and MORE EQ, which in turn, is telling you even a bigger lie. For instance, a perfectly square room is a BIG no no as each dimension affects the same frequencys. Rectangles are more favorable for even distribution of the modes. And the ratios of Width, Length, and Height will determine by way of mode analysis, what SET of dimensions to use. But a good starting point is your limitations.
What are they? Once we know that, then we can recommend a starting ratio to you. Ok? Well, thats about all I can offer at the moment, other than just say "12' long, 9' wide, 8 1/2' high. But that doesn't mean a thing untill the dimensions meet your limitations, and then if you really want something correct, run through the mode analysis. Which if we are lucky, will be offered by other members here or wait untill another forum that is down at the moment comes back on line. Then we can link you up to some people there. OR, just build any old size and treat it! Ok thats my .02 for now."

Thats what I wrote last night. Please don't laugh too loud or I'll KILL ya!! Hahahaha!
Man, what a rambling moron. Hey fitterbkw, just trying to help. Your question is interesting.

fitZ

[frederic]

We were away from last sunday to 11pm last night... back home finally. Soon, off to dinner with friends!

Spent most of the day futzing with valve cover gaskets... got one in

I'll be back around tomorrow...

[RICK FITZPATRICK]

Spent most of the day futzing with valve cover gaskets... got one in

Well I hope you didn't catch a case of frostbite Frederic And now, with no oil trail, don't get lost

[frederic]

Originally posted by RICK FITZPATRICK
Well I hope you didn't catch a case of frostbite Frederic And now, with no oil trail, don't get lost

It was 50 today, which is why I started to tackle the job. Anyway, got one in, drove it around, no more leaks on the driver's side.

Passenger side is going to be an ordeal, because the EFI intake is the ford "chef hat" design, it flops over the passenger valve cover, so I essentially have to tear up the top of the engine to get to it.

Should take less than 12 hours

[fitterbkw]

Guys,
Thanks for the responses. I'll start by answering your questions. First Fredric, I also have a cyber twin. Thats how I know going direct I can get the sound I want back thru the moniters. The garage is out of the question. Not because of noise, its because of the cold weather we have here. Also the garage is full of my other toys.
Rick, when I am playing thru the gibson ga-8t amp I am in the same room I record in. Thats when it sounds gorgus(I have tried it in other places,still sounds good). When I'm just playing. I do not use headphones to monitor. I have peavy monitors, model-HKS 8. I do not use any eq. And as far as my limitations for building a room, I have a heated room in the shop down below the house. Its dim. are roughly 8' tall, 14' long, & 12' wide. Concrete floor. I could always make it taller, or wider. Kinda stuck in the length though. I don't want to dive into this with the amount of work it will take, then not be happy with the results. Thanks guys, looking forward to your opinions. fitterbkw

P.S. Rick, I live Northeast of Vanc., Wash. Northeast of Battleground wash., Then 9 miles in the woods Northeast of Yacolt Wash. Towards Mt St. Helens. Thanks again

[knightfly]

Fitter, if you can get a sound you like in the room you're using, but can't get it recorded, then it's NOT the acoustics or you wouldn't like the sound in the room. It's that simple.

What this means is that you need a better recording chain, not a different room. I would look harder at a separate mic preamp used first with the 57, and possibly the "cheap condenser" - the trick is, get a sound you like, then move your ear out of the way and put the mic there. Anything you don't like after that is either bad gear or bad engineering. Make sure your levels are as hot as you can make them without sounding distorted, checking this all the way through the chain of gear into your sound card, and if your hardware supports it record in 24 bit mode whether you use high sample rates or not. That should get you as close to the original sound as you can get.

A lot of killer guitar tracks have been done with 57's, but if you like EXACTLY what you're hearing in the room then a flatter frequency response mic will probably come closer to your liking.

Bottom line though, if your room is really crap you won't hear what you like no matter what. I'd look closer at gear and techniques... Steve

[RICK FITZPATRICK]

Thats what I like about you Steve. No bull, get to the point. Hey

Fitter, if you can get a sound you like in the room you're using, but can't get it recorded, then it's NOT the acoustics or you wouldn't

I thought he said he was using a soundproof box ? So.....let me get this straight.

IF you are playing in the same room as the soundproof box, are you monitoring it through the Peavys ? And it sounds good? I want to understand whats going on here. If your monitoring as you play, and it sounds good through the monitors, but not on the recording playing back through the SAME monitors, then what Steve said about the room is confusing me as you are not mic'ing the amp in a room. You are mic'ing the amp in the box. So, I don't know how you could put your ear where it sounds good. Then you say it sounds good in other places. Whoa, which is it. The room or the box? Thats what had me confused in the first place. Hence my reply that I thought it was issues other than the box/room.

fitZ

[fitterbkw]

To all,
I do my recording during what I like to call the dregs of the day. Thats the last hr or two before bedtime. This seems to be the only time I have to myself. When I say it sounds good in the room I record in, I mean when I get the rare chance (during the day) when my wife is gone to take the amp out of the soundproof box then plug in and listen to it. I have to use the soundproof box at night because my wife is in bed by then. If I waited till nobody was here to record in the same room I would never get anything done. Does that make sense? I just want to build a good room just for my amp. I'm sure I will have to step up to a better mic, but thats a completely different subject that there is tons of info about on the web. It may seem like a waste just for an amp room but I am working on a CD. The other players are long distance with their own studios. When it is done all tracks will be taken to a proper place for mixing. Only intersted to capturing best sound. Thanks again guys, fitter

[knightfly]

OK, now that we're probably all clear about WHEN you get a sound you like, you're right - the box is killing the vibe, so you need to kill the box. I ran your dim's of 14/12/8, and they would cause some modal problems - if you could raise the finish ceiling to 9 feet and narrow it to 11 feet (14x11x9) the modes balance out much better.

However, since you're wanting to build this room so your wife can sleep while you rock, you'll probably want the room pretty isolated while it's sounding good inside -

So, since you're a builder this next part should be easier than usual - I need to know exactly what and how your shop room is built, outside to inside, including floor and ceiling, roof, ventilation, rafters or trusses, actual dimensions, what layers of which kind of material are where, etc, just as if you were asking me to build it from scratch. Include details like windows, doors, insulation, anything you can think of that would affect soundproofing measures.

What you'll need to accomplish good isolation is two separate centers of mass, called leaves in acoustics, separated by a single air/insulation gap, with no hard contact between the inner and outer leaf. Each leaf can consist of one or several layers of paneling, such as sheet rock, particle board, OSB, etc - when using multiple layers in a leaf, they should be attached only by screws over studs, with one side pretty stiff and the other side more flexible.

Ceilings can be trickier, since the outer layers usually are vented at soffits and so do NOT count as one of the two leaves of mass needed. The trick here is usually to get the outer wall, which normally IS NOT vented, to connect with the upper leaf of your new ceiling so that the two form a complete outer shell that's isolated physically from the inner shell. You can see where some of this can get kind of wierd when dealing with existing construction, but usually there are ways to get there with just a bit of thought.

On top of all that, there is the way the room will sound inside once it's sound proofed (I prefer the term isolated, since sound proof is kind of like bullet proof - got a bullet proof vest? I got a bigger gun...) Anyway, one way to handle both goals at once is to make the outer mass leaf quite a bit heavier than the inner one, then make the inner wall frames at some distance from the outer wall frames and at angles that eliminate parallel walls in the room - filling most of the cavity between the two wall frames with insulation (each frame with only ONE side paneled, so you have only two leaves of mass total) - if there's room, you can also slope the ceiling to avoid parallel floor/ceiling. Doing all this helps smooth out modal response caused by dimensions between pairs of walls.

All that may be enough to absorb for now, but it should give you an idea of what's necessary for a good sounding, quiet room - if you can let us know some of your details including a rough idea of budget, we can probably make more detailed suggestions to help you get there... Steve

[RICK FITZPATRICK]

So, a BIGGER "isolated" box it is. Hey Steve, just out of curiosity, what is the SMALLEST box with balanced modes, that sounds good? I mean, if all this is for is recording an amp, why does it have to be this big? WHAT determines it is going to sound good besides the modes? Like, at what point in shrinking size does it start to "kill the vibe"? BTW fitter, Steve is the gentleman I was referring to when I said we might get lucky! Thanks Steve. Good luck fitter. Your in great hands now. Steve is the best of the best.
Cheers
fitZ

[knightfly]

Rick, as usual your apparently simple question needs a pretty complex answer - generally, though, the smaller the room the further apart the low frequency modes are - you could take the same set of "ideal room ratios", one with all dimensions cut in half, such as one of Sepmeyer's favorites, 10:16:23.3 - if you were to build a room with 20 foot ceiling, 32 feet by 46.6 feet, the modal response would get tighter together and smoother in response at an octave lower frequency than the same ratio room built with a 10 foot ceiling, other dimensions of 16 x 23.3 feet. Cut the dimensions to 80%, making a room that was 8 x 12.8 x 18.64, and you raise the lowest frequency that will have a smooth response by even more.

I've recently been reading a couple of books by Phillip Newell, and he goes into this a little bit but not enough to get some concrete numbers - I'm hoping to get some time to play with a couple of new spreadsheet models, one of which will examine the modal spacing of a room, considering ALL three types of modes, and plot a curve based on proximity of neighboring modes - if I'm right, this would show how low a frequencies would be evenly supported by any room. Realistically, this could take a few months before I get time.

Basically, what it comes down to is using the largest room you have available in order to get the best sound. When you get into pretty large rooms, even the air volume needs to be taken into account when figuring reverb times and absorption, point being that there are 'way too many variables to make this an easy answer.

If forced to use a small room, say smaller than maybe 25 feet in its longest dimension, then you just need to be aware that lower frequencies won't behave smoothly. The only way around that I'm aware of, is to absorb enough bass to help even out the response, then absorb enough of the rest of the frequency range to make things even. Sometimes, you just get lucky with a combination of room modes, instrument harmonics, etc, and it just "works" -

Wes LaChot over at RO goes so far as to pick dimensions for rooms that do NOT reinforce musical notes, but interleave between them - he claims (and I tend to agree) that this does more to smooth out a room's response. So if you want to get really picky, you would choose your room's finish dimensions based on NOT coinciding room modes with standard musical notes. I've not found time to figure out just what this would entail yet, but it's an interesting thought.

Hopefully I've managed to "dance around" your question enough so you won't realize I didn't answer it at all :=)... Steve

[RICK FITZPATRICK]

Hopefully I've managed to "dance around" your question enough so you won't realize I didn't answer it at all

Hahahahahahaha! On the contrary Steve. As usual, with few words you have written
my textbook for this semester. That will keep me at bay for quite a while. Add that to the electrical class, and you may not hear from me at all...... Ha! In your dreams

On second thought....

So if you want to get really picky, you would choose your room's finish dimensions based on NOT coinciding room modes with standard musical notes

Thats interesting. What does he consider "standard" musical notes? I didn't know there was such a thing. Unless you mean, none of the 1/4 and 1/2 tones etc. You know, when those damn guitar players stretch a string! Those kind of things?(just kiddin fitter, I'm a guitarist too!) Don't waste your time answering that one Steve. Its brain fart day. Plus my mind is on cuttin firewood today.....ARGGGGGGGRRR! Man, its all we have for heat and I've burned two cords since the middle of November! Come to think about it. I need to "burn" some other "chords" too. Like a E+9, or a G+5-9, or maybe a good ole A6/9! Man, I can feel the heat already. Ha!

Thanks for your explanation Steve. Have a great Sunday! You too fitter! Don't let the "dregs" git to ya .
Oh, btw Steve....."Sepmeyer 10:16:23.3".....sounds like a chapter in the bible. The "acoustics" bible!! Jeeeez, its Sunday, better study my "bible" too!

fitZ

[RICK FITZPATRICK]

I'm hoping to get some time to play with a couple of new spreadsheet models, one of which will examine the modal spacingof a room, considering ALL three types of modes, and plot a curve based on proximity of neighboring modes - if I'm right, this wouldshow how low a frequencies would be evenly supported by any room.

WOW! I just thought of something. Yesterday I downloaded a lisp program for Autocad that allows you to punch in an Excel or similar spreadsheet INTO a 3D drawing, and as you punch in the numbers, the drawing changes. I wonder if that would be any help down the road Steve? I'll play with it, as I've been tutoring myself on 3D stuff. Pretty cool. I downloaded TONS of texture maps that you assign to surfaces, such as wood, stone, etc. Real pictures of stuff. Man oh man, you should see some of the models people draw with this stuff. Mindblowing realism. Can't wait to do studio interiors. Here is some an acoustition by the name of Swist drew. I applied for a job with him a couple of weeks ago. He designs fixturing too. Hence the application. Anyway take a look at these CAD models. Too cool. Imagine punching in numbers into a spread sheet and the model changes with it.

http://www.lpswistdesigns.com/MixStages.html

fitZ

[fitterbkw]

Knightfly,
Wow, I had to take notes as I was reading the posts. I would like to clarify a few things. The shop I am refering to is about 150' away from the house. It is a steel master building, this type of building has no trusses. You can find it on the web to see what I mean.
What I did for storage of things that I did not want to get cold or wet was build a room (the one I described) inside of the shop next to the far end wall (away from the house) using typical construction mat. You know 2x6s, plywood, fiberglass insullation,The only thing I used different was I used all screws so if I wanted to change it later it would be easy to tear down. Heating is just a simple baseboard heater. Four elec. outlets. Three flouresent lights(I know these will have to go). The roof is flat because I am not worried about the elements.
When I come to terms with what I want to build I will take dim. to a mech. heating supplier I do a lot of business with tell him I want a quiet Heat, cooling, & humidity control for this sized room. Let him pick the options for me.
On the electrical side I will use some of the electritions who work for me to help with the design of quiet lights, grounding, & power.
I can raise the roof a foot . I can also change the width to 11'.
For the floor which is concrete I thought I would coat it with a good moisture sealer. Then install a strip cedar floor over that.
I have a buddy who has a small sawmill. I would like to leave the finish rough on the cedar. Love cedar
So knightfly you are saying I should build a room within a room. Using the dim. you said would work correct?
Also Ricks question about what is the smallest room you could build that an amp would sound good intrigued me.
You know I have looked all over the net trying to find out how to go about correctly, and this is the first place I have found that helps.Thanks, fitter

[knightfly]

So, you're talking about a quonset hut type building then, one that looks like half a huge culvert? Or a different shaped but still corrugated steel design? Either way, am I correct in assuming that the steel building itself is not even close to hermetically sealed? If so, then you can still add the two leaves of mass that are needed for good isolation - you can also, if you want, do it in such a way that you need less acoustic treatment inside.

The things that help isolation are two leaves of mass separated by air and insulation, the two mass leaves NOT hard contacting each other, the more mass the better - the more air space the better, although after a while it's a diminishing return; more than about 12" of air space and you gain less and less with extra space between your mass leaves.

I've done some calculations that show that a double frame wall with 2 layers of sheet rock on the inner face of the inner frame, and two layers of sheet rock on the outer face of the outer frame (nothing but air and insulation between those leaves) - can be equalled in isolation by using 4 layers on the outer frame and only ONE layer on the inner frame - the advantage of this is that the room will need quite a bit less bass trapping in order to sound right, since this makes the inner wall leaf more flexible and more able to absorb bass without the sound being able to escape thru the outer, stiff, 4-layer wall. This construction costs you one extra layer of sheet rock but saves having to build so many bass traps to balance the room response.

If your existing construction is solid, I would consider leaving it as is and just adding more mass to the outer side of the frame as I mentioned, making sure you offset joints and mud all layers. If you've used screws for the inside covering of the frame, you can remove that paneling, add more insulation, and build a second frame inside the old one with at least 6 degrees of slant relative to the old walls, making your inside surfaces non-parallel. This gets rid of flutter echo without needing so much absorption, if any. Your inner frame should use 24" centers so the single layer of wallboard can act more as panel absorbers.

One way you can accomplish an inner and outer ceiling leaf that are isolated from each other - if your spans are good enough to support at least 4 layers of rock, you could first build your inner wall frames and sheath them inside, then put up Resilient Channel across your ceiling joists, leaving 1" space between ends of channels and the inner wall panels - then hang a layer of 1/2" rock on the channel, leaving 3/16" to 1/4" gap between the ceiling layer and the walls - finish this gap with real, acoustic rated caulk to hermetically seal it - do the same with all joints at floors, etc - the wallboard at the floor should also be hung with spacers under it, which are then pulled and caulked the same way. The other three layers of rock would go on the outside of your ceiling joists, and would be alternated between outer wall layer and outer ceiling layer, so you end up with a zig-zag joint between outer wall leaf and outer ceiling leaf, each joint caulked as you go.

To keep the upper part of your inner walls stable, you can build sway braces that are neoprene damped - Here is one way I've come up with -

[knightfly]

And here is another drawing, showing a way of using common framing all around and still isolating inner leaves from outer.

Both those drawings were done before I tried calculating for "having your cake and eating it too" - that's why I suggested putting two extra layers on the outside and using only one layer on the inside frame. This comes out almost identical in isolation, but with much better bass response inside the room due to the panel trap effect of having only a single layer of rock on the inside.

Note though, that in both drawings each leaf of mass is isolated from the other somehow. At least by using resilient channel, or (better) by using completely separate frames. Hermetic sealing is a must. Even when broken for ventilation, it must be done with enough bends and absorption in the ducting to keep the sound from getting in/out.

For recording, you'll want as quiet a HVAC unit as possible - if your HVAC guy hasn't done super quiet, post back and Rod Gervais will be the guy to ask, among others.

Gotta get some sleep - got two electrical licence update exams tomorrow... Steve

[John Sayers]

wow - so we have a resonable question regarding transfering a guitar sound and suddenly we are talking wall construction

hey guys!!

fitter - have you put your head where the mike is and listened to the sound from the amp?? start there.

Now add room mike, may be try different places in the room, ??, not what hear in your head? well it's maybe the room. So how big a room do you need?? if you want the guitar to hang out - then a big room, if you want a short decay - a small room.

so what kind of sound do you want??

cheers
john

[RICK FITZPATRICK]

Man, this is gettin good. Fitter, you hit the jackpot Ok guys, when do we see some door and threshold details? (I'll be using this one myself fitter!) Hello John,
how are you? Nice to see you here again.

fitZ

[knightfly]

Hey John - I already tried that, appears you ALSO missed the part about his wife, sleep, etc - it wasn't too clear at first that the only way it sounded good was keeping his wife awake... Steve

[fitterbkw]

Guys,
Tired, day started @ 4:00 am, just now got home. Yes it is a style of quansut hut but with a better shape. I looked @ your drawings with the inside sheetrock isolated from outer studs with some kind of steel offset piece. I like the way that works. Doable. I propose that when I get time I will go down to the shop & get the actual dim. of what the inside room would be using this construction method. A couple of ques. Are you saying I should stay away from using cedar on the inside? Just go with sheetrock? Also I would have to put a final layer of something besides sheetrock on the very outside, the shop is not heated, so I'm afraid the cold, & humidity would destroy the sheetrock rather quickly. Where can I find info out about this steel you are showing to isolate the inner sheetrock? So I can work up the correct dim. for you. Gotta hit the hay, thanks guys. fitter

[knightfly]

Fitter, you can still use your cedar inside - you might want to build some slat absorbers in there to keep things bright and still lessen modal characteristics of the room - the cedar would be perfect for that.

As to the outside sheet rock, there's nothing saying you can't use OSB, T1-11, or even greenboard - just no air gaps except the one between the inner and outer leaves.

I've included another detail on the sway bracket showing more info. This bracket can also be used on the end of a longer 2x4 if you want wider air gaps between inner and outer wall frames. I've not yet drawn that scenario, but if it's necessary I will when I get time. The basic concept can be used to isolate either wood or steel framing with nearly any spacing. These types of brackets if bought readymade will run anywhere from $40 to $60 each, so someone who's handy with tools can save quite a bit by fabbing them.

If by "steel isolating the inner sheet rock" you're referring to the Resilient Channel the rock is hung on, that's a commercially available item - usually found at commercial drywall places but usually NOT found at Home Depot (although some HD's do carry it) -

One of the better versions -

http://www.dietrichindustries.com/bi...ccessories.htm

Dietrich's RC Deluxe is the recommended one from them, the double leg stuff doesn't isolate as well, and the standard stuff isn't recommended for ceiling use.

There are other sources of RC, depending on your area - some places it's harder to find than others. Basically, all of it stands off wallboard by 1/2" away from the studs. When you fasten wallboard to it, you need to be sure you don't put any screws where the studs are because just one screw will wipe out most of the gain in sound isolation the RC gives.

Anyway, gettin' late for me too, here's that other detail... Steve

[fitterbkw]

Hi guys,
Sorry it took so long to respond. I have worked some long hrs, we lost power at home, & had some terrible weather here. And the real truth is sometimes I just get lazy.
Anyway I went down to the shop & got good dim. If I put rc on the inside studs, & hang sheetrock my final dim. will be, W. 121.25" X L. 181.625" X H. 90.375". Would these dim. be condusive to getting a good sound? Thanks in advance, fitter



P.S. About the height dim. This measurment was from concrete floor to ceiling. I would like to put in a wood floor but not know exactly how to do it, so this dim. will change (gonna make for a short ceiling). Also I did not include the dim. change for angling the walls in 6 degrees on the sides as suggested. One more thing where should amp placement be? On the end with narrow sides, or @ the end with the wide sides? Thanks

[knightfly]

Fitter, I know what you mean about all the "fun" life dishes out - I'm off to my last 12-hour graveyard shift in a few minutes, then off for a few days (in which time I only have a few MONTHS of stuff that needs doing, like cleaning up all the broken limbs/foliage from the ice storm we just got through...

I'll get back to this probably tomorrow afternoon, when I've got time to give it a more thorough answer... Steve