Does anyone have experience putting a hard floor over carpet? I'm considering putting something over most of the carpeted area since I found out on this very forum that carpeting my music room floor was a bad idea, but I want to avoid damaging the carpet.
If I do this, I'm considering putting 2x2 down to act as joists, then screw plywood subflooring into that and cover with something simple like linoleum.
How badly does this idea suck? If very, what are some alternatives?
Thanks.
Tim
Hard floor over carpet?
Originally posted at johnlsayers.com, topic 17463.
You might just be able to lay thick plywood or OSB directly on top of the carpet, and put your flooring on top of that. Not sure if that would be OK. Brien can probably give you a thumbs up or thumbs down on that. But I certainly would not build any type of frame! You don't want any air gap under the plywood!
- Stuart -
OK. Does the air gap create a different acoustic problem, or do you think it could lead to a moisture problem under the new plywood? The problem with laying plywood directly on the carpet is that it will still give a bit, so adjacent pieces won't be level.
The problem with any air gap on the other side of any large and reasonably rigid, reasonably massive surface is that it creates a resonant system that will resonate in sympathy with certain notes, thus sucking energy out of the room for those. That's the basis of how a panel trap works (membrane trap). So if you place your plywood over a wooden frame, basically you are creating a drum head for your floor: It will "ring" at it's own natural resonant frequency, and all related harmonics. It's not a good idea to build a room on top of a drum head! :)
There would only be a moisture problem if you already have a moisture problem!do you think it could lead to a moisture problem under the new plywood?
Why? What is under the carpet that might give? If it's a concrete floor, then there's no reason why it would give. If it is a wooden floor of some type, supported on joists that give, then it will give anyway, regardless of how you put the plywood deck on top. If you have a concrete subfloor, and you build the deck itself correctly, then there won't be any problem with it giving. We are talking about two layers of 3/4" plywood here, laid crosswise with respect to each other, and screwed together, so there would have to be one very large load to make that lot give! But the big question is: Why not just take out the carpet? If it was installed properly, then it should be possible to take it out without causing too much damage to it. - Stuart -The problem with laying plywood directly on the carpet is that it will still give a bit, so adjacent pieces won't be level.
2 layers of plywood laid crossways so no seams match makes sense. I was imagining only one layer in my framed scenario. Not looking to put my drummer out of a job, though.
As far as removing the fairly new carpet, I may come to that conclusion but I want to exhaust other possibilities. If I have a reasonable chance of remedying my problem without damaging the carpet, I'd rather explore that.
"As far as removing the fairly new carpet, I may come to that conclusion but I want to exhaust other possibilities."
Guess what happens to fairly new carpet when you cover it...and penetrate it with fasteners? It becomes fairly useless carpet with holes in it with no redeeming qualities.
I never had any intention of putting fasteners through the carpet. No worries, though. I'm going to take Ethan Winer's suggestion and put pieces of plywood on the carpet just during recording and mixing."As far as removing the fairly new carpet, I may come to that conclusion but I want to exhaust other possibilities." Guess what happens to fairly new carpet when you cover it...and penetrate it with fasteners? It becomes fairly useless carpet with holes in it with no redeeming qualities.
To be fair, what your remedy is has nothing to do with the topic you started. It is a pretty easy control device to place a hard barrier (plywood or MDF or OSB) underneath the microphone to remove the mid range absorption of the carpet. It is something different altogether to ask "Does anyone have experience putting a hard floor over carpet?" The short answer is this. When you take carpet and encapsulate it with upper and lower hard boundaries, you trap this material, now if it has been there for some time, the ability to trap contaminants is high. The acoustic side is that you reduce the TL of this floor because you introduce a small air space, and the flanking you introduce is not going to help you.I never had any intention of putting fasteners through the carpet. No worries, though. I'm going to take Ethan Winer's suggestion and put pieces of plywood on the carpet just during recording and mixing."As far as removing the fairly new carpet, I may come to that conclusion but I want to exhaust other possibilities." Guess what happens to fairly new carpet when you cover it...and penetrate it with fasteners? It becomes fairly useless carpet with holes in it with no redeeming qualities.
My attempted goal remains the same as when I posted the original question - keep the carpet intact, but create a non permanent hard surface for recording/mixing. I came up with a crackpot plan as a remedy, but I said up front I didn't know if it was a good idea. As soon as I got the responses from soundman2020 about the resonance problem created by the air gap, I dropped that idea and started asking about others. I think the EW plywood idea is similar to what soundman suggested, only more easily moved when needed. If this forum is for pro/semi-pro studio owners or musicians, I probably made a mistake posting here. I thought it was also for people like me who are just starting to learn about acoustics. My room has been perfectly fine for band or solo practice. Recording and mixing will be limited to a few weeks at a time with long stretches in between. That's why I can't justify ripping up $700 worth of fairly new carpet and spending another $400-500 on hardwood. EW's comment about temporarily using plywood seemed tailor made for people in my situation. I understand that I shouldn't leave anything like that on the carpet for long. Thanks.To be fair, what your remedy is has nothing to do with the topic you started. It is a pretty easy control device to place a hard barrier (plywood or MDF or OSB) underneath the microphone to remove the mid range absorption of the carpet. It is something different altogether to ask "Does anyone have experience putting a hard floor over carpet?" The short answer is this. When you take carpet and encapsulate it with upper and lower hard boundaries, you trap this material, now if it has been there for some time, the ability to trap contaminants is high. The acoustic side is that you reduce the TL of this floor because you introduce a small air space, and the flanking you introduce is not going to help you.I never had any intention of putting fasteners through the carpet. No worries, though. I'm going to take Ethan Winer's suggestion and put pieces of plywood on the carpet just during recording and mixing."As far as removing the fairly new carpet, I may come to that conclusion but I want to exhaust other possibilities." Guess what happens to fairly new carpet when you cover it...and penetrate it with fasteners? It becomes fairly useless carpet with holes in it with no redeeming qualities.
Another option might be to do a "drum riser" type of thing, where the plywood deck would sit on top of a layer of 703, or something similar. Try searching the forum for "drum riser", and see if there's something that might work for you.
- Stuart -
Thanks, soundman. I'll check it out. I have a related question, but I need to think it through a bit before I post.
Tim
"I thought it was also for people like me who are just starting to learn about acoustics."
Learning is an 8 letter word, it does not happen in one session.
It is like this. You crawl, you walk. You run. You fall. You get up. You walk with caution.
There is no quick fix...learning is a difficult process...
Holy Frijole! Where have I indicated that I expect to learn everything about acoustics at once? I stated clearly that I'm just starting to learn. I even asked if I had joined a pro forum by mistake."I thought it was also for people like me who are just starting to learn about acoustics." Learning is an 8 letter word, it does not happen in one session. It is like this. You crawl, you walk. You run. You fall. You get up. You walk with caution. There is no quick fix...learning is a difficult process...
Mistake or no, you are being coached by professionals who adhere to the professionalism that John Sayers is. I recognize this seems like an easy question/answer session to you, but it never is. :) Never, or at least seldom. And I stick by what I said, you do not want to encapsulate the carpet. Now if all you are trying to do is add some reflection that this carpet has reduced, yes, do that with a piece of hard (pick your poison) it really does not matter what it is. The goal is to terminate the absorption of the carpet and get some reflections back although reflections from the floor in a poorly designed room only record the poorly designed rooms response...so everything matters :) Pull up the carpet....pull up the carpet and use area rugs if needed and add a soft ceiling/cloud for this room that we know nothing about other than it has carpet. Your options are now exhausted.[I even asked if I had joined a pro forum by mistake.
Yup, that's how it sounded to me, too. Thanks.Now if all you are trying to do is add some reflection that this carpet has reduced, yes, do that with a piece of hard (pick your poison) it really does not matter what it is.
Sorry, I should have clarified my comment way earlier than this. What I meant was that with 2 pieces of plywood sitting side by side on carpet or other semi-soft surface, when you step on one piece close to the edge that's butted up to another piece, it would create a trip hazard. That's why I liked your idea of joining pieces together. Yes, I am that klutzy. :lol:Why? What is under the carpet that might give?The problem with laying plywood directly on the carpet is that it will still give a bit, so adjacent pieces won't be level.
I'm just wondering out loud here: How is that carpet attached? If it's done in the usual way, it will only be attached around the edges of the room, maybe on some type of strip, or perhaps nailed(!) through. But either way, if you work carefully you could take it out without damaging it, and simply roll it up and store it. Then, if you "undo" the room for whatever reason, and want to put it back like it was, then you can simply roll it out and install it again.
So what was the "other thing" that you were mulling over a bit before asking? You got me intrigued... :)
- Stuart -
That's true, and I think it's just using tack strips. I have a feeling it would be a lot more difficult in practice (as so many things are).I'm just wondering out loud here: How is that carpet attached? If it's done in the usual way, it will only be attached around the edges of the room, maybe on some type of strip, or perhaps nailed(!) through. But either way, if you work carefully you could take it out without damaging it, and simply roll it up and store it. Then, if you "undo" the room for whatever reason, and want to put it back like it was, then you can simply roll it out and install it again.
OK, I've already dismissed because I can imagine a lot of unforeseen problems, but here goes. My understanding is that the floor should serve as the one large reflective area because you have to have one like that. If you make the ceiling or any wall the reflective surface, then the floor has to be absorptive, but you can't walk on that, right? But since my recording needs are for limited amounts of time, I wondered if I could leave the ceiling reflective and put my bass trap panels on the carpeted floor with just enough space between a few to be able to walk where I need. Allow me to pause while you laugh your butt off. OK, so with that out of the way, here's my current plan. I've got some 703 panels and a tascam 122 on the way. I'm going to make some 4" traps to put in the corners where the walls meet, then measure. Add traps according to measurement results, then measure again. At this point, I would expect bass more balanced through the room, but high frequencies to be sucked out by all the absorption, right? Last, lay some plywood on the floor and measure again to see if the highs are more evident. Is that reasonable?So what was the "other thing" that you were mulling over a bit before asking? You got me intrigued... :) - Stuart -
There's actually quite a few reasons why it's better to have a reflective floor and absorptive ceiling, including the ones you mentioned, but for me, the most important reason is the psycho-acoustic one: All your life, wherever you go, your head is always the same distance form the floor, so your brain gets used to the sound of reflections coming off the floor. Distances to walls and ceiling change, by the day, hour, minute and second, as you move around, but the distance to the floor is pretty much constant, and so is the "sound" of the floor. Your brain uses it as a sort of reference. If you make the floor very absorptive and the ceiling or one of the wall reflective in your studio, then your brain has to deal with a new and different reference: The distance and timing are no longer what your brain expects, and it just doesn't sound quite right in there. Very subtly perhaps, but the effect is there. Your aural reference is flipped, and the room doesn't "feel" right. For critical listening, that's not a good situation. If you try to track in there, then of course the mic is picking up the same slightly "wrong" sound of the room, and it will be imprinted into the recordings, just as surely as room reverb gets imprinted. And once its in, it's realy hard to get it out! Like too much salt in your soup, there's not much you can do about having too much room sound in your recordings. You could probably position the mic carefully and overcome this to a certain extent, but why make your life harder than it needs to be? Micing is already hard enough without adding another twist! This is also one of the reasons why rooms with very low ceilings sound strange: your ears and brain are getting conflicting signals, and the floor seems closer than it should be, so your brain is mildly derailed by the strange experience. And of course, if you try to mic drums in a room with a low ceiling, it sounds like crap, as you get all kinds of weird artifacts from having the mics so close to the ceiling and so far from the floor. Like I said, all of this is subtle, not really noticed consciously, but it it there, nevertheless, and is a little bit disconcerting, Trying to make mix decisions in a room that sounds inverted, or lopsided, is not going to bring out the best in you. You might tend to compensate, subconsciously, for a problem that isn't really there, or to not compensate for one that is. That's one of the reasons why the general recommendation is to have a hard, reflective floor: to reinforce the effect of the "floor constant", and make it easy on your brain. If you were to also have a hard, reflective ceiling, then you run the risk of having a modal issue in the vertical axis, or flutter echo problems, so the associated general recommendation is to have a "soft" ceiling opposite your "hard" floor. And the soft ceiling also helps the psycho-acoustic thing too: Putting thick, deep absorption on it, makes it "disappear" somewhat, acoustically, so the room can sound higher than it really is, which once again helps to reinforce the "hard floor" sound.My understanding is that the floor should serve as the one large reflective area because you have to have one like that. If you make the ceiling or any wall the reflective surface, then the floor has to be absorptive, but you can't walk on that, right?
As far as pure sound waves and acoustics are concerned, yes, you could do that. The acoustics would be the same as if you did it the other way around, with the absorption on the ceiling.. Sound waves don't care which way is "up" or "down"! So from the pure acoustically approach, that would work. HOWEVER, even though the sound waves don't care about up and down, our brain does, and that's where you'll most likely run into the psycho-acoustic sensations mentioned above. So your idea ain't dumb at all, if the only issue were acoustics. Unfortunately, our brains care too much about "up" and "down"...But since my recording needs are for limited amounts of time, I wondered if I could leave the ceiling reflective and put my bass trap panels on the carpeted floor with just enough space between a few to be able to walk where I need.
When you do those measurements, you MUST get the mic back to the exact same position in the room every single time. So figure out a way to mark or measure that position very accurately. If you put the mic in a different location, then you cannot compare that reading with others: they will be invalid as they show the response for two different positions, and two different patterns. So make sure that the mic is always in the same place, give or take a half inch or so in any direction. Also, the changes between readings as you add things and move the around probably won't be as big as you might think on the graphs. Don't expect to see huge differences, as the changes are more likely to be small than large. And make your first measurement in the empty room, with nothing in it at all, so you have a valid "baseline" against which you can compare all the changes.Add traps according to measurement results, then measure again.
Yes on the "sucked out highs", but not necessarily on the lows. There will be a difference, for sure, but if you have a major modal issue then a couple of 4" traps is not going to make a huge difference. Some difference, yes, but not earth-shattering. And depending on which mode(s) is (are) causing issues, you might not see any change at all! For example, if you have a modal problem on the side-to-side axis of the room, but you put the absorption on the back wall and the ceiling (which is a good plan!), then you won't see much change at all, since the absorption is not very much in the path of the "problem". If you were to then move some of it to one of the side walls, then you'd see a difference. In other words, it helps if the absorption is in the path that the wave is traveling! And if you want to put the highs back in the room, then just cover your 703 panels with plastic sheeting, or something thin like that. That will reflect the highs back, but still allow the lows through. Please post your graphs here, as I think it would be very instructive to see how things change in your room as you play around with 703 panels and plywood! It would be neat to see some real-world data on how these things actually affect a room. - Stuart -At this point, I would expect bass more balanced through the room, but high frequencies to be sucked out by all the absorption, right?
Thanks for the very thorough response, Stuart. Yup, plenty of things there I would not have anticipated, so I really appreciate you setting me straight. I've ordered 24 of the 2" panels from a local supplier, and can get more if I need to. I'm planning to pick up some fabric over the weekend and hope to get started on the traps next week.
I can place my spl meter on a tripod at my listening position and should be able to get the measurements for the exact location. My room is 15'x19'x8, by the way. I used one of the online room calculators to give me an idea of where I should expect to start with traps, but I know measuring is the only sure fire way to know.
Thanks again.
Tim