Super Soundproofing Community Forum

Soundproofing Forum Topics => Acoustical Questions? Ask here about Sound absorbsion, Reflection, ETC => Topic started by: orenharel on September 02, 2009, 01:03:38 PM

Title: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 02, 2009, 01:03:38 PM
Hi there,
I have a storage room that I would like to convert into a home theater room. It is small - 15x14ft (4.5x4.2m) - and is basically a concrete box (walls, ceiling and floor all thick concrete).

That being said there are two issues that I still need to deal with:
1) Ensure that no sound escapes through the walls and ceiling, and especially the door and pipes (there are no windows)
2) The sound inside doesn't echo and sounds great

I was planning to put thick curtains around the wall, and carpet with underlay on the floor. That being said, I'm assuming that I will still need to put soundproofing material behind the curtains as well as a false ceiling with soundproofing material between it and the concrete ceiling?

I was thinking of two options - either acoustic foam (egg carton shaped foam) or special soundproofing insulation. Any thoughts? Is there a cheaper/easier way of doing it? Thanks.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 03, 2009, 04:42:13 PM
Fabtec panels will work fine for this job.
http://www.soundproofing.org/sales/flameresistant.htm
First product on this page.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 04, 2009, 07:24:55 AM
Thanks very much!
1) Am I correct to say that this would fall into the category of "sound absorbers" rather than "sound blockers/barriers"? I understand that these two categories need to be tended to separately as materials differ. If I have the thick brick/concrete walls, is it fair to assume that sound blocking will be inherently covered and that I therefore only need to worry about sound absorption?
2)Would I cover all the walls (and ceiling) with this material, or only part of the walls? I heard that there is a danger of creating too much of a "dead sounding room" by "over-absorbing" - is there any truth to this or is it better to over-absorb than under-absorb?
3) I'm assuming that this means that the curtains will not suffice - is there a benefit in using the soundproofing foam over soundproofing insulation (such as rockwool), or is it simply an effort vs cost issue?

Thanks!
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 04, 2009, 03:53:22 PM
Thanks very much!
1) Am I correct to say that this would fall into the category of "sound absorbers" rather than "sound blockers/barriers"? I understand that these two categories need to be tended to separately as materials differ. If I have the thick brick/concrete walls, is it fair to assume that sound blocking will be inherently covered and that I therefore only need to worry about sound absorption? That is correct it is referred to as acoustical conditioning.
2)Would I cover all the walls (and ceiling) with this material, or only part of the walls? I heard that there is a danger of creating too much of a "dead sounding room" by "over-absorbing" - is there any truth to this or is it better to over-absorb than under-absorb? Placement is very important, room dimensions, speaker placement and other variables are considered when acoustical conditioning. Dead rooms are normally 100% coverage with high NRC rated material (cones and max wedges). These panels will not deliver that NRC value.
3) I'm assuming that this means that the curtains will not suffice - is there a benefit in using the soundproofing foam over soundproofing insulation (such as rockwool), or is it simply an effort vs cost issue? effort vs cost plus aesthetics.

Thanks!
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 05, 2009, 12:31:02 AM
I can see the quote but it seems to not have posted your reply?
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 05, 2009, 11:34:19 PM
oops, sorry, I just noticed that your reply was in the quote, I was looking for a reply under it  ;D

Thanks very much.

Also, regarding the doorway, which of these two options would do a better job soundproofing:
1) One standard solid core door
2) Two hollow core doors on the same door frame (double hinged) with soundproofing material in the space between the two of them

I am trying to decide which way to go. Either way I will put weather sealers around the door (or both doors) to prevent sound leakage. Thanks.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: supersoundproofing on September 08, 2009, 03:59:45 PM
solid core door is best. stay away from hollow core doors, they are a headache.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: johnbergstromslc on September 08, 2009, 09:00:19 PM
solid core door is best. stay away from hollow core doors, they are a headache.

'Headache' is an understatement.  A hollow-core door, even with seals, rates an STC 15 - completely worthless!
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 09, 2009, 07:20:07 AM
Thanks for your replies, that is very helpful. As a follow-up to your replies:
1) Is a solid timber door sufficient for these purposes, or is it worth forking out the money for a special door that is basically filled with soundproofing material?
2) It sounds like one solid core door is better than two hollow doors on the same frame. That being said, there might be an option for me to put one solid core door and one hollow door on the same frame (double rebated - one door swings into the room and the other out of the room), which is probably even better than a sole solid core door, especially if I include soundproofing material between them. If this is the case, would it be better to use the solid core door as the inner door and the hollow door as the outer one, or the opposite? Maybe it doesn't make a difference?
Thanks.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 09, 2009, 06:38:46 PM
Ok answer to #1- Yes a solid core door is sufficient, if you want to beef it up then add MLV w/PSA to the door.
#2 Stay away from the hollow core door, if you want to have 2 doors then use 2 solid core doors.
Note: any space between two hard surfaces that is less than 2" apart and empty can and will create a resonence chamber.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 09, 2009, 10:34:18 PM
Just to clarify:
1) MLV w/PSA =  mass loaded vinyl with pressure sensitive adhesive, is that correct?
2) I am not sure if the door frame will support two solid core doors, that's why I was considering one solid one and one hollow one. I must admit that I am not familiar with the term resonance chamber - is that a good or bad thing? Can you please elaborate? Would it be beneficial to the space between the two doors with sound blocking material?
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 10, 2009, 05:01:08 PM
#1 - Yes MLV w/psa is mass loaded vinyl with pressure sensitive adhesive
#2 resonence chamber = bad thing (A resonance chamber uses resonance to amplify sound. The chamber has interior surfaces which reflect an acoustic wave. When a wave enters the chamber, it bounces back and forth within the chamber with low loss (See standing wave). As more wave energy enters the chamber, it combines with and reinforces the standing wave, increasing its intensity (volume).

Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 10, 2009, 10:36:14 PM
Thanks, the space between the 2 doors will be appr 2.5", so I assume that resonance might still be a problem. I will fill the space between the two doors with sound absorbing material if that is the case to prevent it from bouncing back and forth. I'm assuming that should fix it?

By the way, I found out something very interesting that I was not aware of (although you probably knew). I found a website with a table titled “Noise Reduction Coefficients (NRC) for Common Building Materials”. I originally thought that fibreglass batts were inserted into the cavity of a (false) wall due to their ability to improve STC ratings, but based the mentioned table they also have an extremely high NRC rating of between 0.9 to 1.

As mentioned previously, I was planning to hang thick curtains around the concrete walls and stick sound absorbing foam (wedges or egg cartons) on the concrete walls so that it is hidden behind the curtains (ie between the concrete walls and curtains). But if fibreglass batts have a greater NRC rating then them, it sounds like it will be a more effective and a less expensive option to use fibreglass batts instead? Plus, I’m assuming that the heavy curtains will already absorb part of the sound before it reaches the fibreglass batts.
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 14, 2009, 09:39:02 AM
Anyone?  :)

Perhaps the question is too tricky!
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 14, 2009, 04:39:58 PM
Sorry, had a couple days off...

Yes, by filling the space you will solve the problem.
Let me fill you in on a little information about NRC, what you found is very informative based on material exposed to sound. This is based on ASTM 423, which is when this material is exposed to sound, not in the wall assembly. ASTM E 90-02 is the test for performance in the wall when the material is not directly exposed to sound.
So this is why we recommend Cotton fiber insulation, It performs both in the wall for added STC value and it has a High NRC when exposed to sound 1.15 NRC.

Use this, it is less mess and no itch!.
http://www.soundproofing.org/infopages/natural_fiber.htm
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 15, 2009, 01:45:08 AM
Sorry, I just wasn't sure if anyone saw my reply so I was checking just in case.

I think that I am learning a lot thanks to you and others so far, so I am feeling closer to the confidence level I need to begin the project.

So to summarize and make sure that I understand correctly (sorry for the length!), please tell me if you agree with the following conclusions:

1) Walls - Although certain materials improve STC ratings when inserted into a cavity of a wall, some of these materials actually have a high NRC rating when exposed (i.e. when not behind a solid reflective material). Regular 2.5" fiberglass insulation batts for example don't have an STC rating but have an NRC rating of 0.9-1.0, making it more effective than the typical foam-based sound absorbing material, not to mention a much a cheaper alternative. In my situation, as the fiberglass batts (or cotton-based ones you mentioned) will be located between the concrete wall and the heavy curtains (which are absorptive rather than reflective), the combined NRC values of the curtains and fiberglass batts should suffice for my sound absorption purposes. This coupled with the sound blocking properties of the brick/concrete walls should probably cover my total soundproofing needs.

2) Doors – Two solid core doors on the same door frame with wether stripping around the inner part of the frame to seal them properly is the best way to go rather than dealing with hollow core doors. The faces of the solid core doors are reflective, therefore two things needs to be done: i) the surface of the door facing the inside of the room needs to be covered with sound absorbing material to avoid sound waves reflecting back into the room and; ii) if the two doors are less than 2” apart (or even 2.5” as in my case) a resonance chamber will be created, and therefore sound absorbing material will be needed to fill in this space.

Did I get it right?  :)

By the way, regarding the process I discuss in point 1 above, do I still need to worry about an excessively “dead sounding” room or would this still be O.K.?
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 15, 2009, 04:44:26 PM
1) Agreed, as long as you do not exceed certain db, sp levels and lets not forget frequencies under 125hz.
I would like to explain this to you in further detail, so that you can have a true understanding on how acoustical conditioning is addressed.


2) yes, and you can use SSP foam mat for this.
 
Give me a call when you get some time, here is my contact info.

Randy S.
760-752-3030 ext 104
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: orenharel on September 18, 2009, 02:38:50 PM
Hi Randy,
Sorry, just a quick follow-up question to our discussion. Regardless of whether I use cotton-fibre or fibreglass batts as my sound absorption material on the walls, would 2.5" thick material be sufficient (especially since the curtains in front of it will do part of the work) or is it still recommended to go at least 3" thick?

Also, I have read online in a few places that dense styrofoam (i.e. or basically any generic polystyrene foamin sheet form) has even greater sound absorption ability (i.e. higher NRC rating) that cotton-fiber or fiberglass - is there any truth to this or is it just a myth? If true, is it therefore an even cheaper and more effective alternative? Yes, my questions are always complicated, sorry...

Thanks again for all your help!
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on September 21, 2009, 04:13:26 PM
2.5"-3" shouldnt be a noticable difference, remember placement.

Im not buying in on the styrofoam myth...sorry...thermo sure...
Title: Re: Soundproofing Storage Room (concrete box) to Convert to Home Theater
Post by: Randy S on May 23, 2012, 07:28:40 PM
You can stop reporting this post...I will not remove it because you keep spam flagging it...

Find somewhere else to play your games.

If you are the original poster you can send me an e-mail direct and I will remove the post.

Our forum is for providing honest information about soundproofing.