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#1660370 - 11/20/06 06:41 PM Perforated Acoustic Panels
whomadewho Offline
Member

Registered: 11/20/06
Posts: 2
Hi Ethan,
I have just begun my research on making my sound room the best it possible can be and your name comes up a lot through my research. I am hoping you can answer some questions for me as I do see a real passion in you through your site and your work through the videos you have made and placed on your real traps web page.

I have done some research on perforated acoustic panels and would appreciate your expert advice on the following questions.

Do I need an air space between the perforated hardboard and the fiberglass or should I just place the fiberglass directly on the back of the hardboard in the frame?

Do I need to have the panel completely sealed against the wall (i.e. in a sense a 12" deep sealed box) or can I just mount it 10 to 12 inches
out from the wall?

If I have to build a sealed box should I fill the entire box with rigid fiberglass for best results?

If the spacing is 10 to 12 inches out from the wall should I use more than 3 sheets of Type 703 fiberglass board?

For best results should I fire my subs directly into the panels or just place them as close to my main speakers as possibly (i.e. along side my
mains firing in the same direction)?

I have 6 corners in my room due to it's shape. Should I use the perforated panels in the front corners and use panels with no perforated
hardboard for the back (i.e. just 3 inches of Type 703 fiberglass board in a frame mounted in each corner)?

Is 3 inches of rigid fiberglass board enough?

Are there any other things I need to keep in mind when building and installing perforated panels that I have missed in my questions above?

Thank you for your time Ethan and I look forward to your responses.

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#1660371 - 11/21/06 06:09 AM Re: Perforated Acoustic Panels
bpape Offline
Platinum Member

Registered: 05/18/05
Posts: 1763
Loc: Wildwood, MO (St. Louis)
Welcome to the forum.

So many questions. I'll give it a shot.

Frst of all, you don't specifyt the rom size or what you're going to be using it for. Without those 2 things, specific correct answers for overall treatment will be impossible. In general, broadband soft bass absorbers are a preferable solution. Perforated ones ar for when you have very very specific problems that require tight tuning of the absorber.

As for how to build them, yes, they need to be sealed. No, they shouldn't be filled full. No, no gap needed between the perf panel and the absorbtion.

For the straddling corner panels, don't use perfs, use at least 4-6" of thickness, and do not under any circumstances put a back on it or you defeat the gains of corner mounting.

Bryan
_________________________
I am serious and don't call me Shirley.

www.gikacoustics.com

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#1660372 - 11/21/06 11:46 AM Re: Perforated Acoustic Panels
Ethan Winer Moderator Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
Quote:
I have done some research on perforated acoustic panels
I'm not an expert with that type of tuned trap. I almost always recommend broadband traps, rather than tuned, especially for smaller rooms. But as Bryan said, without knowing the size of your room or your intended use, it's difficult to be very specific.

Also, sealed traps such as wood panel bass traps need to be placed flat on the wall - not spaced away as shown in the forum FAQ. Porous absorbers like rigid fiberglass do benefit from being spaced away. Either way, I would not place a subwoofer so it fires directly into a trap.

--Ethan

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#1660373 - 11/21/06 06:10 PM Re: Perforated Acoustic Panels
whomadewho Offline
Member

Registered: 11/20/06
Posts: 2
Thank you gents.

The room size is 23.5 feet long, 14 feet wide, and 8 feet high.

The panels are designed based on a particular perforation of .79% and 8.9 % to cover off a lot of the low frequency range. I do not have any fancy measuring gear so I went with what I believed to be the best coverage of the low frequency range. The room is not a true rectangular box as it has a total of 6 corners. Two of which are half into the room on either side of the room where the room bends at a 90% for two feet and then goes out on the other side of the room by the same measurement. Almost like a perfect twist one way.

I have read a lot about many different types of panels and the perforated made the most sense. I am a newby in the high end and have just bought some Bryston gear with Dynaudio speakers. I want the best possible sound.

What is the best way to go about measuring the room without spending a ton of money to do it (i.e. just bought very expensive gear)?

Ethan - I thought of firing the subs into the panels because I read somewhere that the effectiveness of the panel has something to do with the angle in which the wave hits it. I figured straight on was the best although I know bass waves are non-directional. It just made sense in my mind. Should the subs be right up front sittying beside the main speakers if possible?

By the way how many sheets of fiberglass should I use to get the best effects (i.e. 6 with an 8 inch space behind them)? By maximum allowable distance from the wall is 12 inches in 3 corners but not directly in the corner crossing over two wall only right in the cornerlike the wall goes into the corner. Or should I just mount the panels in all corners?

I can easily change the panels from perforated to non-perforated if the xperts believe the non-perforated to be the best. The Handbook sounded like peforated was the way to go.

Look forward to your reply gentlemen.

Bill

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#1660374 - 11/22/06 06:49 AM Re: Perforated Acoustic Panels
bpape Offline
Platinum Member

Registered: 05/18/05
Posts: 1763
Loc: Wildwood, MO (St. Louis)
Perforated panel absorbers can be finely tuned, but are effective over a VERY VERY narrow range - like less than 1/2 octave.

Is this for a 2 channel listening room or a studio? In either case, the Dynaudios are an excellent choice.

Do not fire the subs directly into the absorbers. Set the subs where they balance best with the mains and provide the smoothest response. I'd start with dead center on the front wall and dead center on the back wall - that's usually a good start.

Bryan
_________________________
I am serious and don't call me Shirley.

www.gikacoustics.com

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#1660375 - 11/22/06 09:55 AM Re: Perforated Acoustic Panels
Ethan Winer Moderator Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
Bill,

> I thought of firing the subs into the panels because I read somewhere that the effectiveness of the panel has something to do with the angle in which the wave hits it. I figured straight on was the best <

You want bass traps to absorb the reflected sound coming back from the walls, floor, and ceiling. But not the direct sound.

--Ethan

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#1660376 - 11/22/06 10:02 AM Re: Perforated Acoustic Panels
Ethan Winer Moderator Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
Bill,

> What is the best way to go about measuring the room without spending a ton of money <

I use the ETF software. See here and here:

http://www.etfacoustic.com
http://www.realtraps.com/art_etf.htm

In truth, it almost doesn't matter what you measure because the solution is always the same: Broadband absorption that works well to as low a frequency as possible. That, and first reflection treatment.

> Should the subs be right up front sittying beside the main speakers if possible? <

There are a lot of opinions about that. Many sub makers recommend a front corner because that's where the bass output is loudest. But it's not the flattest unless you have a lot of bass traps. I have my SVS sub in the front left corner of my living room and it's fabulous there. But I also have 40 traps.

> By the way how many sheets of fiberglass should I use to get the best effects (i.e. 6 with an 8 inch space behind them)? <

For corner trapping four or more inches is good.

--Ethan

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#2919082 - 04/03/18 11:29 PM Re: Perforated Acoustic Panels [Re: Ethan Winer]
normale Offline
Member

Registered: 04/03/18
Posts: 1
Loc: Center
Some panels do not attach well to the wall, so if you need to have a panel completely sealed against the wall? I recommend you to visit this site on Perforated Wall Panels , you can find your solution.


Edited by normale (04/03/18 11:34 PM)
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ABDOU

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#2954932 - 10/27/18 10:14 PM Re: Perforated Acoustic Panels [Re: whomadewho]
ChengHou Offline
Member

Registered: 10/27/18
Posts: 1
Loc: South Carolina
I find perforated acoustic panels very useful, I recently moved into an apartment and needed soundproofing to record my songs. The perforated acoustic panels I bought were aesthetically pleasing, trust me I have kids running their hands over it every opportunity they get. They are cheap and easy to install, I followed the installation and help guide which I found really convenient.
_________________________
ChengHou Lam

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Moderator:  Ethan Winer