Room renovation. Questions

[Mishaiger]

Hello, I'm doing some renovations in my home theatre room. Basically i want to soundproof room from neighbors. I live in apartment.

Recently finished floating floor. But whenever i walk on it i hear a loud booming sound. And i personally don't mind it, but it will affect sound.


Floor consists of several layers:
1) Crooked concrete floor
2) Soft concrete heaps with insulation in-between.
3) OSB nailed down to heaps.
4) 10cm of insulation. Insulation is specifically designed for floating floors. Its density is about 115kg/m3.
5) 2 layers of OSB. Total heigh is 24 mm.


I've brought some subwoofer and measured it on this floor.
Red is subwoofer sine sweep. Orange is me stomping on the floor. They are practically the same. I think this means that subwoofer excite floor, but when subwoofer comes to a halt almost instantly, floor continues to play that frequency for some time.

Decay is very bad. When i stop subwoofer playing specific frequency i still hear this decaying sound for about a second.

I thought about some EQ. Here is result:
While things definitely became better, still there are some decay. And it doesn't solve the root of the problem, floor. At least, i think it is floor, but with bare concrete walls and ceiling... i don't know.

So, with all that in mind i have some questions.

There will be a lot of mass near walls in finished renovation.
1) Will adding more mass to the floor improve the situation?

I'm planning on making walls and ceiling from this same OSB. But unlike floating floor they will be fixed to metallic profiles.
2) Will walls and ceiling also vibrate/resonate and add decay?

I'd really preferred to keep this floor since its doing its job of isolation perfectly. Subwoofer is blasting on floating floor and there are absolutely no vibrations in the rest of apartment.
3) Theoretically, will different type of floating floor will be better for decay times?
I'm thinking about something like rubber joist isolators for wooden planks*. But i think they are way less effective isolators than insulation.

4) Any way to improve situation with this floor?

5) Is floor even at fault here?
I have bare concrete walls and ceiling, maybe they amplifying sound from floor...

6) Will fully treated room be free of this problem to some extent?

7) Should i even worry?
I have some measurements from this same room before starting renovations. Fully treated.
It still had some decay, but i was totally fine with it.
Then again, this is with concrete walls and hard fixed wooden floor.

Also, observation.
I tried stomping on... ceramic? tile on concrete screed floor. I could barely hear any booming sound at all. But the measurement is somewhat really close to the new floating floor:

Maybe questions are not in the right order... but anyway, i think that's all. Any help/advice/sorting out will be appreciated.

 

[olieb]

5) Is floor even at fault here?

This probably is the most important question. Many of the answers to the other questions depend on this one.

Is your room rectangular? If so you can try to model it with REW "Room Sim". There is a good possibility that it is mainly room modes that are responsible here.

I tried stomping on... ceramic? tile on concrete screed floor.

This was in the same room? FR is somewhat similar to the subwoofer before but with less pronounced peaks. My guess is that is again the room response to a sonic excitation, not so much the floor resonating.

To reduce floor resonances from the subwoofer you could isolate the sub from the floor in a similar way you isolated the concrete floor form the OSB: an elastic (and dampening) layer.

 

[kemmler3D]

It does sound to me like resonances from the floor might be a factor. That decay looks pretty bad. If resonance is the problem, putting furniture and other heavy items on it may help. Possibly adding a damped layer on top of the current floor could also help? Redoing with another type of floor - sure, but I would also be reluctant to give up isolation before I tried other ways of eliminating resonance.

 

[Prana Ferox]

Hello, I'm doing some renovations in my home theatre room. Basically i want to soundproof room from neighbors. I live in apartment.

Recently finished floating floor. But whenever i walk on it i hear a loud booming sound. And i personally don't mind it, but it will affect sound.

 

[Mishaiger]

Is your room rectangular? If so you can try to model it with REW "Room Sim". There is a good possibility that it is mainly room modes that are responsible here.

My room is almost square. About 3.05x2.98 m and heigh with new floor is about 2.4 m
Thanks for the idea about REW room sim. I tried different settings. While they are pretty close to my measurements, only about half of them match.

This was in the same room? FR is somewhat similar to the subwoofer before but with less pronounced peaks. My guess is that is again the room response to a sonic excitation, not so much the floor resonating.

This was in a different room.

To reduce floor resonances from the subwoofer you could isolate the sub from the floor in a similar way you isolated the concrete floor form the OSB: an elastic (and dampening) layer.

Subwoofer was already on some sort of yoga mats...

 

[olieb]

Subwoofer was already on some sort of yoga mats...

I See. The more I would guess that it is not the floor but the room.
In the picture you have dry walls?
In Room Sim that would translate in a higher surface absorption. Your graph seem to be made with very little absorption.

While they are pretty close to my measurements, only about half of them match.

In the picture you have dry walls?
In Room Sim that would translate in a higher surface absorption. Your graph seem to be made with very little absorption.
Did you place sub and mic in the positions of the measurement?
But already like this it is rather obvious that there are room modes involved quite a bit.

I do not know whether the positions match but the FR does not look too bad. Moving the mic around might give an even better match.
I used 5% absorption for floor and ceiling and 10% for the walls.

 

[Mishaiger]

In the picture you have dry walls?
In Room Sim that would translate in a higher surface absorption. Your graph seem to be made with very little absorption.

2 walls is concrete about 20 cm. Another 2 walls is mix of concrete and gypsum or something like that, about 8cm.
I set all absorption to 0.01 to better show peaks.

I do not know whether the positions match but the FR does not look too bad. Moving the mic around might give an even better match.

Positions match. In simulation i moved it around a little. When one peak match others don't...

 

[olieb]

When one peak match others don't...

You will never get a perfect match. The influence of the window or door and the (unknown) absorption coefficients (frequency dependent) of the different walls change the room FR.
But there is still a very good correlation if you ask me and I only guessed the position of sub and mic and the absorption.

I set all absorption to 0.01 to better show peaks.

This gives you sharp peaks but not a realistic result.
Here is the overlay of your curves and the REW sim.

 

[ozzy9832001]

The floor slaps. That's what they call it. Was the concrete slab leveled properly before the entire process began? I would have started with a self leveler if it was really out of sorts, and then check for level. Then I would have either laid a framework of 2"x4"s drilled into the concrete or 2"x3"s if you want the raised floor to be slightly less high. From there lay down the plywood, 3/4 in thick. I would screw it in with floor screws, not nails. Nails can create some give. You also may want to have placed a few screws in the wood and let it settle for a few days so they are nice and straight, and then begin the process of screwing it down completely -- starting from the center of the boards and working your way out, so you don't end up with any humps.

Even if you used a insulative pad on top of the concrete and then placed the floor you'd probably still have places where it slaps. This is one of the draw backs to a floating floor as the substrate has to be perfectly level.

Because you're on a slab, the sound won't penetrate the concrete, it will reflect back up and probably run along the underside of the floor (especially if there is a cavity there).

 

[DVDdoug]

I'm not an acoustics expert...

I wouldn't expect the floor to have much effect on the sound in the room, except the surface or floor covering (carpet, etc.). But floating the floor should help to isolate from any neighbors below.

Soundproofing is a lot different from room treatment except that absorption, especially bass traps, that reduce standing waves can help with both.

But whenever i walk on it i hear a loud booming sound. And i personally don't mind it, but it will affect sound.

I'd guess the floor is not stiff enough and I'd guess the booming isn't going-through to neighbors below. It's probably less noise-vibration going-down than the original floor. But the "resonance" might go-through to any neighbors on the sides or above.



...I read Geoff Emrick's book. He was the engineer for most of the Beatles recording and he built (actually re-built) the Apple studio. The Apple studio was below ground and double-walled, etc. When he was almost done building it, there was an terrorist bombing (IRA?) a couple of doors down. He didn't hear anything. When he came out, the police and fireman wondered where he came from and he was wondering what was going on, and I think he was very proud of his soundproofing! (Geoff Emerick's book isn't a how-to book. It's just a book about his life in the recording world. He also didn't have any architectural, acoustics, or engineering education... Just a ship-load of practical experience.)

 

[kemmler3D]

You will never get a perfect match. The influence of the window or door and the (unknown) absorption coefficients (frequency dependent) of the different walls change the room FR.
But there is still a very good correlation if you ask me and I only guessed the position of sub and mic and the absorption.

This gives you sharp peaks but not a realistic result.
Here is the overlay of your curves and the REW sim.
View attachment 310429

You know, this looks like a smoking gun to me.

OP, look into bass traps, membrane absorbers, etc.

But things should also improve somewhat once the room is furnished.

 

[Mishaiger]

Here is the overlay of your curves and the REW sim.

Was the concrete slab leveled properly before the entire process began?

I would screw it in with floor screws, not nails. Nails can create some give.

You also may want to have placed a few screws in the wood and let it settle for a few days so they are nice and straight, and then begin the process of screwing it down completely -- starting from the center of the boards and working your way out, so you don't end up with any humps.

Concrete slab was not leveled by itself, instead new 15mm osb subfloor was leveled properly.
I used dowel nails if that makes a difference.
There was no humps in subfloor. And even if there was a minor one, insulation would have smoothed it out somewhat.

I'd guess the floor is not stiff enough and I'd guess the booming isn't going-through to neighbors below. It's probably less noise-vibration going-down than the original floor. But the "resonance" might go-through to any neighbors on the sides or above.

I'm actually more worried about neighbors below. There will be walls and ceiling which will absorb at least some of that sound, but below is simply 10 cm of unknown 115 kg/m3 density insulation, then osb subfloor and finally about 5 cm same insulation.

OP, look into bass traps, membrane absorbers, etc.

But things should also improve somewhat once the room is furnished.

My plan is to use [10 cm insulation - 2.4 cm osb - 10 cm insulation] on walls and ceiling. And not some unknown insulation like with the floor, but this:
Yes, i want room very dead.
My wishful thinking is that 10+10cm of insulation will combine to 20cm even through 2.4 cm osb walls at 125 hz and lower. And higher frequencies will use absorption coefficient of only 10 cm.
I don't know much about membrane absorbers. Is this what you are talking about?

Can i fit them in between metallic profiles and outer wall, which is 10cm?
And if so, how to create them? I was planning on filling that 10 cm with insulation.
My best guess is to attach limp membrane (metal?) to metallic profile and anyway fill all space with insulation... will that even have any effect?
I attached pdf, if someone is interested.

You will never get a perfect match. The influence of the window or door and the (unknown) absorption coefficients (frequency dependent) of the different walls change the room FR.
But there is still a very good correlation if you ask me and I only guessed the position of sub and mic and the absorption.

This gives you sharp peaks but not a realistic result.
Here is the overlay of your curves and the REW sim.
View attachment 310429

I guess this is what i've been looking for for now. This gives me hope that all my efforts wasn't in vain.

Thank you all, i will continue on doing renovations. I'm still interested about that membrane absorbers for bass, since basically my dream is anechoic chamber. Of course, that is not an option. But this can still be semi-semi-anechoic, not typo, room with almost totally absorbing walls and ceiling and basic floor. And since its diy project, door and window, when closed, quite literally almost becomes part of the wall (with all that insulation).

Once again, thank you all for replies, i really needed those.

 

[kemmler3D]

Concrete slab was not leveled by itself, instead new 15mm osb subfloor was leveled properly.
I used dowel nails if that makes a difference.
There was no humps in subfloor. And even if there was a minor one, insulation would have smoothed it out somewhat.
View attachment 310443


I'm actually more worried about neighbors below. There will be walls and ceiling which will absorb at least some of that sound, but below is simply 10 cm of unknown 115 kg/m3 density insulation, then osb subfloor and finally about 5 cm same insulation.

My plan is to use [10 cm insulation - 2.4 cm osb - 10 cm insulation] on walls and ceiling. And not some unknown insulation like with the floor, but this:
View attachment 310446 Yes, i want room very dead.
My wishful thinking is that 10+10cm of insulation will combine to 20cm even through 2.4 cm osb walls at 125 hz and lower. And higher frequencies will use absorption coefficient of only 10 cm.
I don't know much about membrane absorbers. Is this what you are talking about?
View attachment 310447
Can i fit them in between metallic profiles and outer wall, which is 10cm?
And if so, how to create them? I was planning on filling that 10 cm with insulation.
My best guess is to attach limp membrane (metal?) to metallic profile and anyway fill all space with insulation... will that even have any effect?
I attached pdf, if someone is interested.


I guess this is what i've been looking for for now. This gives me hope that all my efforts wasn't in vain.

Thank you all, i will continue on doing renovations. I'm still interested about that membrane absorbers for bass, since basically my dream is anechoic chamber. Of course, that is not an option. But this can still be semi-semi-anechoic, not typo, room with almost totally absorbing walls and ceiling and basic floor. And since its diy project, door and window, when closed, quite literally almost becomes part of the wall (with all that insulation).

Once again, thank you all for replies, i really needed those.

You are on the right track with the membrane absorbers, yes.

10/20cm insluation won't help much with the modes you've identified since it does very little below 125hz, as you noted. Your problem areas are mostly below that. Since you have some obvious modes, you can get membrane or limp mass traps tuned to those frequencies and it should help more than porous absorbers. They're a little tricky but when done right are more effective.

I am not sure if you can fit them into the wall. I think they need to be open to the room... But attaching a limp mass to the metal profile/frame could work... I am not sure if 10cm is enough depth though.

A fully anechoic chamber is a nice idea... or even semi-semi-.... but keep in mind that fully absorbing low frequencies is disproportionately hard and almost impossible in a normal sized room. (if you can hear 20hz through a concrete wall... what chance does 20cm of insulation have?) As such, your goal should simply be to absorb as much of the bass modes as you can, and then match the RT60 of higher frequencies to the bass region, so it's even. What you don't want is a room that is totally dead in some frequencies but not others.

 

[olieb]

I'm still interested about that membrane absorbers for bass, since basically my dream is anechoic chamber.

I am not so sure that is really what you want. Stereo is not working so good in anechoic conditions.
But in the bass region you can hardly have too much absorption. Membrane absorbers work in bass without overdamping mids and treble.

Acoustics-Insider-The-Complete-Guide-To-Bass-Traps-And-Bass-Trapping-V2.pdf

This is a very nice overview!

What you are building on your walls is actually some sort of big membrane absorber. The problem is, with stiff membranes (OSB) and sealed air it will have rather specific frequencies (resonances) where the absorbtion is best. But how to tune this to your room? If the absorption is max where the room has a null they do not do much.
On the other hand, being so big it will still be working. Dry walls are generally advantageous for bass reproduction (not so great for neighbors though).
You could try wooden fiber board instead of OSB.

 

[bert stoltenborg]

Hello, I'm doing some renovations in my home theatre room. Basically i want to soundproof room from neighbors. I live in apartment.

Recently finished floating floor. But whenever i walk on it i hear a loud booming sound. And i personally don't mind it, but it will affect sound.

View attachment 310378
Floor consists of several layers:
1) Crooked concrete floor
2) Soft concrete heaps with insulation in-between.
3) OSB nailed down to heaps.
4) 10cm of insulation. Insulation is specifically designed for floating floors. Its density is about 115kg/m3.
5) 2 layers of OSB. Total heigh is 24 mm.


I've brought some subwoofer and measured it on this floor.
View attachment 310381 Red is subwoofer sine sweep. Orange is me stomping on the floor. They are practically the same. I think this means that subwoofer excite floor, but when subwoofer comes to a halt almost instantly, floor continues to play that frequency for some time.

View attachment 310385 Decay is very bad. When i stop subwoofer playing specific frequency i still hear this decaying sound for about a second.

I thought about some EQ. Here is result:
View attachment 310387 While things definitely became better, still there are some decay. And it doesn't solve the root of the problem, floor. At least, i think it is floor, but with bare concrete walls and ceiling... i don't know.

So, with all that in mind i have some questions.

There will be a lot of mass near walls in finished renovation.
1) Will adding more mass to the floor improve the situation?

I'm planning on making walls and ceiling from this same OSB. But unlike floating floor they will be fixed to metallic profiles.
2) Will walls and ceiling also vibrate/resonate and add decay?

I'd really preferred to keep this floor since its doing its job of isolation perfectly. Subwoofer is blasting on floating floor and there are absolutely no vibrations in the rest of apartment.
3) Theoretically, will different type of floating floor will be better for decay times?
I'm thinking about something like rubber joist isolators for wooden planks*. But i think they are way less effective isolators than insulation.

4) Any way to improve situation with this floor?

5) Is floor even at fault here?
I have bare concrete walls and ceiling, maybe they amplifying sound from floor...

6) Will fully treated room be free of this problem to some extent?

7) Should i even worry?
I have some measurements from this same room before starting renovations. Fully treated.
View attachment 310388 It still had some decay, but i was totally fine with it.
Then again, this is with concrete walls and hard fixed wooden floor.

Also, observation.
I tried stomping on... ceramic? tile on concrete screed floor. I could barely hear any booming sound at all. But the measurement is somewhat really close to the new floating floor: View attachment 310389

Maybe questions are not in the right order... but anyway, i think that's all. Any help/advice/sorting out will be appreciated.

1. You describe a lightweigth floating floor. Such a floor can, when executed correctly, help to decrease impact noise and even airborn noise. Problem is the resonance frequency. A wall has a comstant load, a floor has a varying load when people are in the room. So the way a floating floor is suspended has to be calculated but the top floor always has to be heavy, like 120 mm concrete for a minimum. A lightweigth floor will always act as a drum head.
You also are mixing up absorption and isolation. For an isolating construction you will always have to choose the resonance frequency as low as possible, for isolating music 8 Hz or lower is standard. When a construction is tuned higher it will absorb low frequencies dependiung or the tuning frequency but it will also have a dip in the isolation, transmitting sound as if there is no floor.

2. As already explained, a wall is another animal. It is, like the floor, a mass-spring-mass construction with a resonance frequency that has fit the .

Hello, I'm doing some renovations in my home theatre room. Basically i want to soundproof room from neighbors. I live in apartment.

Recently finished floating floor. But whenever i walk on it i hear a loud booming sound. And i personally don't mind it, but it will affect sound.

View attachment 310378
Floor consists of several layers:
1) Crooked concrete floor
2) Soft concrete heaps with insulation in-between.
3) OSB nailed down to heaps.
4) 10cm of insulation. Insulation is specifically designed for floating floors. Its density is about 115kg/m3.
5) 2 layers of OSB. Total heigh is 24 mm.


I've brought some subwoofer and measured it on this floor.
View attachment 310381 Red is subwoofer sine sweep. Orange is me stomping on the floor. They are practically the same. I think this means that subwoofer excite floor, but when subwoofer comes to a halt almost instantly, floor continues to play that frequency for some time.

View attachment 310385 Decay is very bad. When i stop subwoofer playing specific frequency i still hear this decaying sound for about a second.

I thought about some EQ. Here is result:
View attachment 310387 While things definitely became better, still there are some decay. And it doesn't solve the root of the problem, floor. At least, i think it is floor, but with bare concrete walls and ceiling... i don't know.

So, with all that in mind i have some questions.

There will be a lot of mass near walls in finished renovation.
1) Will adding more mass to the floor improve the situation?

I'm planning on making walls and ceiling from this same OSB. But unlike floating floor they will be fixed to metallic profiles.
2) Will walls and ceiling also vibrate/resonate and add decay?

I'd really preferred to keep this floor since its doing its job of isolation perfectly. Subwoofer is blasting on floating floor and there are absolutely no vibrations in the rest of apartment.
3) Theoretically, will different type of floating floor will be better for decay times?
I'm thinking about something like rubber joist isolators for wooden planks*. But i think they are way less effective isolators than insulation.

4) Any way to improve situation with this floor?

5) Is floor even at fault here?
I have bare concrete walls and ceiling, maybe they amplifying sound from floor...

6) Will fully treated room be free of this problem to some extent?

7) Should i even worry?
I have some measurements from this same room before starting renovations. Fully treated.
View attachment 310388 It still had some decay, but i was totally fine with it.
Then again, this is with concrete walls and hard fixed wooden floor.

Also, observation.
I tried stomping on... ceramic? tile on concrete screed floor. I could barely hear any booming sound at all. But the measurement is somewhat really close to the new floating floor: View attachment 310389

Maybe questions are not in the right order... but anyway, i think that's all. Any help/advice/sorting out will be appreciated.

1. You describe a lightweigth floating floor. Such a floor can, when executed correctly, help to decrease impact noise and even airborn noise. Problem is the resonance frequency. A wall has a comstant load, a floor has a varying load when people are in the room. So the way a floating floor is suspended has to be calculated but the top floor always has to be heavy, like 120 mm concrete for a minimum. A lightweigth floor will always act as a drum head.
You also are mixing up absorption and isolation. For an isolating construction you will always have to choose the resonance frequency as low as possible, for isolating music 8 Hz or lower is standard. When a construction is tuned higher it will absorb low frequencies dependiung or the tuning frequency but it will also have a dip in the isolation, transmitting sound as if there is no floor.
A mass-spring-mass construction like here described can, by absorption, color sound reproduction in the room, when it actually adds decay something is horribly wrong.

2. As already explained, a wall is another animal. It is, like the floor, a mass-spring-mass construction with a resonance frequency that has to fit the required isolation. But it has a fixed load, so has to be considered in another fashion as a floor.

3-6. Don't think it is all straightforward & intuitive, but I already explained that.

 

[bert stoltenborg]

1. Yes, adding floor mass can improve the situation. Mass helps absorb sound waves, so the more mass, the fewer sound waves will reflect off the floor. In your case, adding OSB floor mass will help reduce sound transmission from the floor to the walls and ceiling.

2. Yes, walls and ceiling can also vibrate and resonate and increase decay. However, if the walls and ceiling are attached to metal profiles, this will help reduce vibration. As for the walls, I recommend making soundproofing, and then covering the walls with interior wall murals. It will look cool and the room will have better sound.

3. Theoretically, another type of floating floor may be better in decay time. For example, a floor using rubber wood plank insulators may have a shorter decay period than a floor using mineral wool. However, as you already noted, rubber insulators are less effective as insulators.

4. There are several ways to improve the situation with this floor. You can:

Add a layer of compound on top of the existing floor. This can be done by adding a layer of OSB or other high-density material.
Increase the thickness of the existing insulation layer. This will also help reduce sound transmission from the floor to the walls and ceiling.
Use other soundproofing methods such as sound-absorbing panels on the walls and ceiling

5. The floor may be the culprit, but it is also possible that the bare concrete walls and ceiling also amplify the sound from the floor. To determine what is the root cause of the problem, you need to take measurements.

6. A fully treated room will be free of this problem to some extent. However, if you want to achieve the best results, you will need to use a combination of soundproofing methods.

7. Whether you should worry depends on how much the problem bothers you. If you hear echoes or other unwanted sound reflections, you should take steps to eliminate them.

Nothing of what you say here makes sense.
When I read this kind of sillyness I wonder why this forum is named audio SCIENCE review

 

[ozzy9832001]

5) Is floor even at fault here?
I have bare concrete walls and ceiling, maybe they amplifying sound from floor...

This is part of your problem. Concrete is highly reflective because it's so dense that it only allow extremely low frequencies to pass through it. On one hand, properly treated it would sound amazing, but without treatment it will sound very oppressive because of all the extra energy stored in the room.

While the floor could be problematic as concrete as well, the walls and ceiling would be even more so. Everything is feeding off one another because there is no place for the sound to escape.

 

[AdamG]

Nothing of what you say here makes sense.
When I read this kind of sillyness I wonder why this forum is named audio SCIENCE review

He was a Spambot and is gone now. Next time you see something like this please Report it to us. Your instincts were spot on Sir!