I have a 40 x 18 room with a 8"6 ceiling. The floor ceiling node is of course the big issue. I also have no choice but to carpet it. Soooo I cover the entire ceiling with 6 inches of oc703, hung 6" below the surface. Sounds ok, but dark. At least the FC node is not annoying. Now my dilemma: I need a new rug. Absorption specs on rug+pad run from almost none (short pile, hard back, hard pad), to significant (thick pad, thick pile, soft back). So: All things considered: Shall I reflect as little, or as much as possible from the floor, assuming the ceiling is absorbing a lot? I do have the option of little wooden stages in the room for occasions when I want the wood floor sound. Thanks for your help.

Why?

Covering the floor with carpet is usually a bad idea. Especially since your room is probably already quite dead in the highs due to the absorptive ceiling. Do you have any measurements?

agreed with Jens

What type of room is this: CR, TR or combo? I'm not seeing why you're covering ~800 sq ft of ceiling with 6" 703 +6" gap??? I know you mentioned floor to clg mode...again, what's the function of the room.

+1 too.

Andre

I have to agree with everyone - and ask the question:

Why do you feel the need to install carpet?

Rod Gervais
GIK Acoustics
Director of Education
Gik Acoustics USA
Gik Acoustics Europe
Tel.(US)1.888.986.2789
Tel.(UK)+44(0)20.7558.8976

Because what's under it is uneven, painted concrete, and I don't like the sound of cement much. Prefer wood. I tied to do wood, but the only way to do it right is furring strips and a false wood floor ... giving up almost 3 inches of headroom. Maybe I should reconsider. In the current config (thick rug/pad/ceiling) there is not much reflection at all... but, its pretty even and FC node is a non factor unless there is a high db source (like a guitar amp). With that stuff, I use ribbons or close mics so the FC node can be controlled.

Anyway, that's why. . More help needed.t

3 inches???? Sorry, that's off message... A resilient/supportive/absorptive underlayment and possibly a subfloor or the floor itself (depending upon the construction could be done for well under 2-2.25 inches (Max).)

Just a general comment.

I am fascinated with the all too common idea of people liking the sound of (fill in the blank: cement, wood, macaroni, vinyl tile, ceramic tile, avocados (in season), stone tile, etc.) in regards to a 'solid' reflective surface.

They are all reflective.

The only 'sound' that is imparted is if they are resonant, which is an error, not a feature; or absorbent; or if they have some surface patterning sufficient to effectively diffuse or scatter energy... And still, that is not integral to the material itself.

But then I can understand so many believing that, as acoustics is just toooo complex for science to get a handle around it.

The sad fact, you would be better off putting up egg-cartons instead of carpet. (well, except for the paper ones as the Styrofoam units sound like Styrofoam peanuts...sorry, couldn't resist after my 'complaint'...) ...And egg-cartons are near worthless as well.

Yeah I know, burn the witch, as I am stepping on a very common, yet flawed, sacred cow. (Of course I guess that means that the cow must be relatively small in order to be stepped upon..., but nevertheless....)

T,
I still agree that it is a bad idea to put carpet down... The absorption peak of carpet is around 2-3kHz and not helpful at all...

Wood sounds the same as concrete (close) - as SAC explains, it's reflective.

We still don't know what you are using this room for - and that will dictate the flooring procedure & yet, I believe that we will all still recommend the painted concrete over any carpet.

We usually put a wood floor in studios because it makes the humans 'feel' better - but does not have much to do with the sound. People have all kinds of other subjective reasons for doing it, but it's reflective just like concrete, linoleum, brick, heavy wood paneling, etc...

A reflective floor is preferred in a recording situation as that is how we usually 'hear' an instrument. - With the floor reflections and associated comb filtering which make up the 'natural' sound of that instrument (the natural way we are used to hearing it).

Objectively,
- John

I guess it's time once again to link to this:

Surface Reflectivity

BTW, I prefer the sound of macaroni over avocado.

--Ethan

________________
The Acoustic Treatment Experts

Easy solutuion.... skim coat / patch any major imperfections in the concrete floor - and lay down some affordable, click-in, laminate wood flooring. Easily around $2/sq. ft.

Laminate Floors at Warehouse prices - Discount Laminate Flooring

It can't be much thicker than 3/8" - and has the foam underlayment attached to each piece for easy install. The foam will also help even out and surface imperfections.

Then add area rugs for modular deadening. I really don't think wall to wall carpet is your only option - and it certainly is not the best idea acoustically.

geeLo

You could do a lightweight gyp-crete floor just 3/4" thick that is self leveling and would solve your floor problem......

gyp-crete is available in many different strengths - and will provide a great surface for any finished flooring you want to install.

BTW - I am in agreement with the rest here - there is no way I would install carpet and pad on the floor in this room......

It really is going to just suck the high frequency life out of it......


Rod Gervais
GIK Acoustics
Director of Education
Gik Acoustics USA
Gik Acoustics Europe
Tel.(US)1.888.986.2789
Tel.(UK)+44(0)20.7558.8976

Yep, I do get it that the concrete will reflect evenly, but I also think wood sounds better, even if its an illusion, ... certainly my drum stage in the drum room, which has a cement floor, improves the sound reflecting up to the overheads. But.. you have changed my mind. Its very scary to change the basic sound of my tracking room so severely... but I think between having the option to add carpets selectively, and use a cheap laminate with leveling for bad spots, there's a way to make it look decent and sound better. Thanks.

As already stated, wood does not sound any different from concrete (or any other dense material) IF thick and solid. If not (usually more or less), it will absorb sound depending on mounting condition, mass, and other variables. Let me give you an example:

An empty concrete room measured with and without an inexpensive laminate floor (IKEA “Tundra”, 7 mm thick, 6,7 kg/m²:


With only this stuff (Cheap leveling polyethylene) underneath:




Mic and speaker (DPA 4006-TL with nose cone & Genelec 8250A) in the same position (corners) before and after:





Measured “Reverberation times”:



A quick Sabine calculation gives us these theoretical absorption coefficients for the floor:




The floor is actually behaving a bit like the opposite of a carpet (absorbing the low midrange but not the high range) and this is naturally a good thing since carpets are just about the worst thing that can happen to a control room. Even better would be if the absorption took place even lower (in frequency), but remember that this is a very inexpensive floor (thin) and no sub floor was used. If heavier floor and perhaps a sub floor is used, the absorption peak would probably drop considerably in frequency.


Sincerely Jens Eklund

+1

Very nice work, Jens! Thank you!
- John

What is "this stuff?" More important, does it prevent the wood from bonding solidly to the concrete below?

--Ethan

IKEA | Flooring | Floor accessories | NIVÅ | Floor liner

Cheap leveling polyethylene.

Always glad to contribute.

If the wood is not free to vibrate, where does the absorption at 500 Hz come from?

--Ethan

As a studio builder/owner... I gotta tell ya' that a concrete floor is SO much better than anything else you can put down.

It's low maintenance, sounds fine, it's low maintenance, easy to clean, and it's low maintenance.

When you get the first big scratch in your laminate flooring, and you WILL get many... you'll spend hours agonizing over the fact that you'll have to pull up ALL the adjoining flooring just to get at the damaged piece. Then you'll agonize over having to match the flooring... or buying all the extra flooring for repairs. (Go ahead and buy enough to cover your floor 2-3 times over the years.)

If you put down a standard 3/4" T&G flooring, you'll still have maintence issues with scratches and eventually sanding and resurfacing the floor. Which, you'll be shut down for two to several weeks while you do that, and no work can be done in the room while the sanding and finish work happens.

I've been open for a tad over a year, and yes, I do need to do some concrete stain/sealant maintenance... a little stain work and some sealant... but I'll only be shut down for less than a week while the sealant dries.

I agree, Max.. and I especially love the triple 'low maintenance'.

Cheers,
John

I never said that the floor is fixed. Also the leveling stuff is naturally a bit elastic so the floor can (and obviously does) vibrate a bit and as I said; if it couldn’t, the result would have been very similar to the measurement without the floor since wood does not have a sound in itself as we all agree on.

Hey Max,
God I hate laminate flooring. You've pointed out one of the reasons. When you get a scratch in something as artificial as a laminate surface it just screams out at you. (actually laminate floors scream out at me even before they are scratched "Look at me, I am fake, but I'm smooth and so perfect. Oh, and I'm squishy too, don't you like that?)
As an owner of a studio with 3/4" T&G wood floor for many years I've learned to embrace the scratches as "badges of honor". They mellow with time and just add to the overall ambience......unlike laminate .

To all the laminate adopters......Yes, I'm sure that there are some forms of laminate that must be better than the usual standard but so many I see and walk on are absolute crap.

OK, I feel better now.

I am pretty certain that I can hear the difference between finished concrete and wooden floors. Particularly if the area is big. That said, depending on the actual paint/resin or whatever, I have often liked finished concrete. The layer of hard shiny lacquer on relatively soft wood creates a harsh sound to my ear. Concrete painted with a really pro industrial material seems to have a more even response. Hi Fi even. Great for drums.
The quality of the finish is important IMHO.
FWIW I also prefer the sound of those imitation wood effect vinyl floors over the typical varnished wood.
DD

I also have a hard time "absorbing" the idea that two solid floors that are different materials...which have...different thickneses, densities and finishings (amongst a whole other bunch of differing properties)...will sound the same.

or are you guys suggesting that all frequencies reflect evenly off these two surfaces?



PS Had a look at Ethan's graph...and if even if we assume that this data is 100 % correct, it is clear that all the various materials reflect Differently...because they are NOT the same...within the margin of one dB is beside the point...the way they each reflect various frequencies in relation to one another is DIFFERENT...ever eq'd a mix by adding .3dB 10K ...and cutting .3 dB 100 Hz ...would you suggest that you couldn't hear the difference bypassing the eq? a crude example but similar in nature....doesn't matter how small the difference is...you will percieve it especially if there are a number of differences.

and your ears are much more finely tuned than ANY measuring microphone and software...and sense all things sound differently than any microphone.

Assuming that the two materials compared are mounted the same way, have the same mass, same flexural modulus (if mounted with an air gap) and are relatively smooth (in relation to the frequencies considered), they will reflect sound in the same way.

I think its safer to assume no two materials are the same, but some are SIMILAR....as will be the reflective properties.

No, mine aren’t and I would be surprised if yours are. heh

Mine certainly are and so are yours. Microphone see things in a very different way and don't adjust and compensate the way your ears do.

This discussion is doomed so I’m getting of here. God night.

PS. read up on the Haas / precedence effect.

anyway...on topic...different materials reflect differently...therefore it is a safer assumption that a room will sound different given two different flooring materials....but perhaps a lot more similar than you might expect.

I'm finding the other position a wee bit shocking actually.