ceiling and floor treatment

[taxman]

I have a new studio in a finished basement which is 12x13 with 7ft ceilings. I intend to record acoustic and electric guitar and vocals. The ceiling and walls are sheetrock and the floor is tile.

Should I put acoustic tile on the ceiling, and if so, should I go with Home Depot .55 sound reduction rating or shoud I special order Armstrong .90? Should I put carpet on the floor?

I understand that this will not alter isolation because there is no change in mass.

[Joel DuBay]

taxman,

Welcome!

Using a thick carpet on your floor to tame early reflections and add "some" bass absorption will likely be a must. I love tile areas for acoustic guitar recording, however if you'll b using this room for things other than that, the natural reverberation of the (acoustically) untreated space might not sound very good and will make mixing an ugly task.

So, carpet = yes.

Additional ceiling treatment with rigid fiberglass (think OC703) or rockwool wrapped in fabric will help alot.

Now, even though you mentioned a limited use for this room, it will require bass absorption to enhance your stereo imaging and to capture offending modes. Straddling a 4-6" thick broadband bass trap in your vertical corners will work well. If you can make something ( a DIY traps)that is 7ft in height, then 4" of absorption will do the trick.

I hope this helps.
Enjoy,

[Groff]

Using a thick carpet on your floor to tame early reflections

So what about the floor-reflective / ceiling–absorptive rule?

[MadMax]

Joel, carpet has absolutely not realistic effect on low frequency absorbtion!!! It will only tame some of the high frequencies! So to say that carpet will add "some" low frequency absorbtion is misleading. Yes, it may address reflections, but it doesn't effect low frequencies.

So, carpet=maybe

To address the point that Groff brings up...

And that "carpet=maybe" is from the apect that to achieve a soundspace that sounds "natural", the ear "prefers" to hear hard floors and soft ceilings. This comes (IMHO) from the classic performace hall environment.

So, carpet=reversed soundspace... provided you have hard ceilings.

Joel's right, you could definitely benefit from adding bass absorbtion to the vertical corners. You should also add bass absorbtion to the ceiling/wall corners as well.

To address the question of which ceiling tile... By adding all that low frequency absorbtion, you may find that the Armstrong .90 isn't necessary.

I'd add all of the trapping first, then make the decision as to which tile, or even considering going with some other type of "soft" absorbtion on the ceiling.

HTH,

Max

[Ethan Winer]

The ceiling and walls are sheetrock and the floor is tile. Should I put acoustic tile on the ceiling?

I wouldn't use ceiling tile, but your basic idea is correct. A reflective floor is especially useful for recording acoustic instruments. Even if the room is too small to get any sort of quality ambience, floor reflections can add a nice sense of "being there" in a recording. This is why all stage floors are reflective, and every pro recording studio you'll see on the cover of Mix magazine has a reflective floor. The text below is from my Acoustics FAQ, and sums up the issues nicely.

--Ethan

The following is from an exchange that took place in the rec.audio.pro newsgroup in May, 2003:

Bill Ruys asked: Why it is recommended to have bare (un-carpeted) floors in the studio? One web site I visited mentioned that a bare floor was a prerequisite for the room design with diffusors and absorbers on the ceiling, but didn't say why. I'm trying to understand the principal, rather than following blindly.

Paul Stamler: Carpet typically absorbs high frequencies and some midrange, but does nothing for bass and lower midrange. Using carpet as an acoustic treatment, in most rooms, results in a room that is dull and boomy. Most of the time you need a thicker absorber such as 4-inch or, better, 6-inch fiberglass, or acoustic tile, and you can't walk around on either of those. Hence the general recommendation that you avoid carpet on the floor and use broadband absorbers elsewhere.

Lee Liebner: the human ear is accustomed to determining spatial references from reflections off of side walls and floor, and a low ceiling would only confuse the brain with more early reflections it doesn't need. Everywhere you go, the floor is always the same distance away from you, so it's a reference that your brain can always relate to.

John Noll: Reasons for having wood floors: they look good, equipment can be rolled easily, spills can be cleaned up easily, provide a bright sound if needed, sound can be deadened with area rugs.

Ethan Winer: In a studio room, versus a control room, a reflective floor is a great way to get a nice sense of ambience when recording acoustic instruments. Notice I said reflective, not wood, since linoleum and other materials are less expensive than wood yet sound the same. When you record an acoustic guitar or clarinet or whatever, slight reflections off the floor give the illusion of "being right there in the room" on the recording. It's more difficult to use a ceiling for ambience - especially in a typical home studio with low ceilings - because the mikes are too close to the ceiling when miking from above. And that proximity creates comb filtering which can yield a hollow sound. So with a hard floor surface you can get ambience, and with full absorption on the ceiling you can put the mike above the instrument, very close to the ceiling, without getting comb filtering.

Dave Wallingford: I've always preferred wood floors for a few reasons: 1) It's easier to move stuff around, 2) You can always get area rugs if you need them, And the main reason: 3) Pianos sound like crap on carpet.

[taxman]

Well, its kind of like I expected. I should get a thick carpet, a medium carpet and no carpet! I guess I'll just play it by ear!!

[MadMax]

Well, its kind of like I expected. I should get a thick carpet, a medium carpet and no carpet! I guess I'll just play it by ear!!

You might be getting other recommendations for carpet from other forums, but here you've gotten 3 votes for no carpet.

Of corse your decision is your own, but think about this for a minute...

Have you ever been to any major performing arts venue where the actual performance area was carpeted? Go look at photo's of any theater in any major metropolitan area... I think you'll find that 99.something percent have NO carpeting. Look at photo's of every major recording studio in the world... The main rooms are anything but carpeted.

Ceilings are a bit different of a story... Depending upon the volume, shape and other physical characteristics of the space, you will find a wide variety of treatments... but generally, they will have softer ceilings than they do floors.

Why?!? In all honesty, all of the reasons Ethan's already mentioned and quite a few more that border on the "boring science calculations" frontier. All of it boils down to this; It sounds better... and isn't that what its all about?

Max

[taxman]

OK Carpet is definetly out, which is the easiest solution. I actually tried the space today for the first time, playing classical guitar, and the room sounds pretty good as it is.

Would the answer be different if I were using the room for mixing (which, because it is the only room, I will be doing with a pair of NS10Ms). Would I want a more passive room for just listening?

[MadMax]

OK Carpet is definetly out, which is the easiest solution. I actually tried the space today for the first time, playing classical guitar, and the room sounds pretty good as it is.

There ya' go! But I'd still recommend that bass trapping in the corners and along the ceiling/wall corners.

Would the answer be different if I were using the room for mixing (which, because it is the only room, I will be doing with a pair of NS10Ms). Would I want a more passive room for just listening?

In a word... no... well maybe... well yeah...

A mix/control room situation is somewhat different, and this may be a matter of semantics more than anything, but...

I'm WAY over simplifying here, but there's essentially three dominant types of control room designs. RFZ and LEDE. (There's a couple more, but lets not go there, yet.)

"Huh? but you said three."

Yes I did... LEDE is short for Live End-Dead End. There's two thoughts on LEDE - Which end is live and which end is dead. (This makes two schools of thought and the second and third types)

RFZ is Reflection Free Zone.

Regardless of the overall philosophy of a control room's design, the goal of each design is to create a listening environment that is accurate and free from coloration of the source signal, by the environment of the room. Ideally, this applies to the whole room, but at least at the primary position of the engineer... the famous (or infamous) "sweet spot".

When you use the word "passive", this is what I take it you mean, but just wanted to clarify.

What you really want to have is a room that is flat and free from any large frequency nodes or dips as you can achieve. The amount of reverberation in the room is minimal. Compare this to the "ideal" tracking room, and the ability to have one room doing double duty seems all but impossible.

Small rooms have excessive low frequency build up... primarily in the corners. You don't want that excess low frequency in either a tracking room or in a control room. By adding enough absorbtion to ALL of the corners in the room, you tame the acoustic to where it can be used quite adequately for both tracking and mixing.

Check out Ethan's article that both he and Wes Lachot co-authored on the one room studio. It's quite well written... (quite unlike this ramble I've written here)

Max