Hi guys.
Hopefully someone can shed some light on this subject.
I'm about to install a pair of Full range Audio Nirvanas in a new set of cabinets.
The AN specs call for sound damping material on the upper half of the cabinet, no more than 1 inch thick.
Now, other than fiberglass, which I am not going to use, what other damping material will not hurt the bass response?
The AN people say NOT to use the egg crate type foam because it eats up the low frequencies. No good.
Would anyone have an online source?
Many thanks for any help.
Retro Rick
Hopefully someone can shed some light on this subject.
I'm about to install a pair of Full range Audio Nirvanas in a new set of cabinets.
The AN specs call for sound damping material on the upper half of the cabinet, no more than 1 inch thick.
Now, other than fiberglass, which I am not going to use, what other damping material will not hurt the bass response?
The AN people say NOT to use the egg crate type foam because it eats up the low frequencies. No good.
Would anyone have an online source?
Many thanks for any help.
Retro Rick
Hi ,
In my DIY pair I used DYNAMAT in the wall behind the driver. You can take a look about DYNAMAT here : http://www.dynamat.com/index.html
costas
In my DIY pair I used DYNAMAT in the wall behind the driver. You can take a look about DYNAMAT here : http://www.dynamat.com/index.html
costas
Attachments
Re: AN
Rick-
I did just the top half, as per the suggestions from David at commonsenseaudio. I don't trust myself to detect much in the way of differences without setting up an A/B type of test, so I haven't experimented much with different materials (not having a 2nd pair of enclosures and speakers).
I'm happy with my AN10s- but again I don't have a wall of speakers for comparison.
Which AN speakers do you have? Which enclosure did you build?
Cheers
John
Retrosonic said:
Rick-
I did just the top half, as per the suggestions from David at commonsenseaudio. I don't trust myself to detect much in the way of differences without setting up an A/B type of test, so I haven't experimented much with different materials (not having a 2nd pair of enclosures and speakers).
I'm happy with my AN10s- but again I don't have a wall of speakers for comparison.
Which AN speakers do you have? Which enclosure did you build?
Cheers
John
Hello all-
I have used this type of material, made by Owens Corning, in quite a bit of acoustical treatments over the years:
SelectSound Acoustical Board
This material seems to work very well for "broadband" absorption, and I see no reason why it could not be used inside of a speaker enclosure as well. I have seen folks use what is commonly called "duct board" for this type of things as well, but that is a semi-rigid yellow "fiberglass" product that seems too dense (to me) to be of much use in broadband absorption applications.
A lot of the pro-audio speaker enclosures I have had apart over the years seemed to have a white, fluffy type of filling either loose or in blanket form inside. Some people seemed to call that stuff "Dacron fill", from what I remember.
I was able to order a minimum amount of that Owens Corning material from my local lumber yard, they deal in Owens Corning products.....
HTH
I have used this type of material, made by Owens Corning, in quite a bit of acoustical treatments over the years:
SelectSound Acoustical Board
This material seems to work very well for "broadband" absorption, and I see no reason why it could not be used inside of a speaker enclosure as well. I have seen folks use what is commonly called "duct board" for this type of things as well, but that is a semi-rigid yellow "fiberglass" product that seems too dense (to me) to be of much use in broadband absorption applications.
A lot of the pro-audio speaker enclosures I have had apart over the years seemed to have a white, fluffy type of filling either loose or in blanket form inside. Some people seemed to call that stuff "Dacron fill", from what I remember.
I was able to order a minimum amount of that Owens Corning material from my local lumber yard, they deal in Owens Corning products.....
HTH
AN
Hi John.
I have the AN 10 inch cast frames. Right now they are in a pair of old advent cabs and I am NOT impressed, BUT I hear that in the right cabinet they can be great. The are certainly great in the mids. The bass is what I'm trying to get right.
I had the big 5.6 cabs built per their spec by a professional cabinet builder.
Hi John.
I have the AN 10 inch cast frames. Right now they are in a pair of old advent cabs and I am NOT impressed, BUT I hear that in the right cabinet they can be great. The are certainly great in the mids. The bass is what I'm trying to get right.
I had the big 5.6 cabs built per their spec by a professional cabinet builder.
Hey Retro-
Hey, I totally get what you are saying there in your last post. From what I thought I knew about speaker acoustics, bass response is lost in a speaker enclosure by two things: either poor design geometry producing standing wave interference inside the enclosure itself, or "diaphragmatic absorption" which is produced by the actual flexing of the enclosure material itself. Don't think I got a fancy term like "diaphragmatic" all by myself, it's used in the classic tome by F. Alton Everest "The Master Handbook of Acoustics". I am sure everyone here knows this info anyway, I am just saying all this to sort of "think out loud" if you will, I'm certainly not trying to "instruct" anyone at all I assure you! Maybe I just totally missed the request you were actually making in your post, sorry if that's the case!
A dense material (like "egg crate" foam) that takes up a lot of air volume inside the enclosure would have the effect of reducing the internal volume of the enclosure and therefore dropping the Q of it, which kills the bass response as well. If it's foam an inch thick, you can just subtract one inch from the speaker box inner dimensions for every surface you put it on. I assumed since the Owens Corning material is both fairly thin (you can get it in 1" thickness), as well as not very dense it would not affect the tuning of the enclosure very much at all. The specs give it a rating of only 0.10 in absorption below 125Hz, that being just 10%. And there's certainly no demand to totally cover the entire surface area inside the box either, correct? Still, I see you said you were NOT using fiberglass, and that's exactly what the stuff I suggested is made out of inside its core. Sorry I missed that in your post! Mr. Weems suggests some kind of material called "Acousta-Stuf" in his book, saying it was a crimped type of long tri-lobal fibers. This material is known to be quite superior to ordinary Dacron "pillow fill", from what I have read.
I have no data on the actual cabinet construction you're currently using, since none was given anywhere. But, if you're simply trying to damp the cabinet resonances, then the already suggested DYNAMAT is the absolute best way to do that. I remember the subject of cabinet filler was covered very well in David B. Weems classic "Great Sound Stereo Speaker Manual" on page 50 of the 1990 1st edition....
I guess I am feeling pretty old now, looking at all these books I bought way back when they were ALL 1st and 2nd edition printings! At least mostly are on solid-state circuitry and not all tube, though. That would REALLY make me feel old! BTW - Is it as cold in NY as it is in Michigan right now? We're at about 8 degrees F right now, THAT temp would certainly damp some speakers, wouldn't it?
Hey, I totally get what you are saying there in your last post. From what I thought I knew about speaker acoustics, bass response is lost in a speaker enclosure by two things: either poor design geometry producing standing wave interference inside the enclosure itself, or "diaphragmatic absorption" which is produced by the actual flexing of the enclosure material itself. Don't think I got a fancy term like "diaphragmatic" all by myself, it's used in the classic tome by F. Alton Everest "The Master Handbook of Acoustics". I am sure everyone here knows this info anyway, I am just saying all this to sort of "think out loud" if you will, I'm certainly not trying to "instruct" anyone at all I assure you! Maybe I just totally missed the request you were actually making in your post, sorry if that's the case!
A dense material (like "egg crate" foam) that takes up a lot of air volume inside the enclosure would have the effect of reducing the internal volume of the enclosure and therefore dropping the Q of it, which kills the bass response as well. If it's foam an inch thick, you can just subtract one inch from the speaker box inner dimensions for every surface you put it on. I assumed since the Owens Corning material is both fairly thin (you can get it in 1" thickness), as well as not very dense it would not affect the tuning of the enclosure very much at all. The specs give it a rating of only 0.10 in absorption below 125Hz, that being just 10%. And there's certainly no demand to totally cover the entire surface area inside the box either, correct? Still, I see you said you were NOT using fiberglass, and that's exactly what the stuff I suggested is made out of inside its core. Sorry I missed that in your post! Mr. Weems suggests some kind of material called "Acousta-Stuf" in his book, saying it was a crimped type of long tri-lobal fibers. This material is known to be quite superior to ordinary Dacron "pillow fill", from what I have read.
I have no data on the actual cabinet construction you're currently using, since none was given anywhere. But, if you're simply trying to damp the cabinet resonances, then the already suggested DYNAMAT is the absolute best way to do that. I remember the subject of cabinet filler was covered very well in David B. Weems classic "Great Sound Stereo Speaker Manual" on page 50 of the 1990 1st edition....
I guess I am feeling pretty old now, looking at all these books I bought way back when they were ALL 1st and 2nd edition printings! At least mostly are on solid-state circuitry and not all tube, though. That would REALLY make me feel old! BTW - Is it as cold in NY as it is in Michigan right now? We're at about 8 degrees F right now, THAT temp would certainly damp some speakers, wouldn't it?
Update
In my AN 2.8 enclosures, I just replaced the 1" yellow fiberglass board with 3" of pink fiberglass insulation (upper 1/3 of enclosure) - the bass 'seems' a bit better (ie louder,lower) now.
Nice thing about larger drivers (10" in this case) is that you can work through the speaker cutout- this job only took about 25 min start to finish.
Cheers
John
In my AN 2.8 enclosures, I just replaced the 1" yellow fiberglass board with 3" of pink fiberglass insulation (upper 1/3 of enclosure) - the bass 'seems' a bit better (ie louder,lower) now.
Nice thing about larger drivers (10" in this case) is that you can work through the speaker cutout- this job only took about 25 min start to finish.
Cheers
John
advice needed
I am currently building this
http://www.troelsgravesen.dk/JA8008_DTQWT_cabs.htm
What do you think about this material?
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=5011&spr=EN&typ=full
Would it kill the low frequencies?
I am currently building this
http://www.troelsgravesen.dk/JA8008_DTQWT_cabs.htm
What do you think about this material?
http://www.monacor.de/typo3/index.php?id=84&L=1&artid=5011&spr=EN&typ=full
Would it kill the low frequencies?
For the environmentally friendly and conscious, there was discussion of bamboo fiber fill a while back. It comes in a bag like polyester fiber fill for pillows and sold in big box fabric stores for craft projects..
Other current recommendations for those who don't want to mess with fiberglass or worry about closed vs open foam products like egg crate is the hard to find 3/4 felt used as carpet underlayment.
I see the advantage of the felt as being able to be stapled in to keep it where you put it.
Mcmaster Carr also sells a product like this called F-13 grey wool felt.
www.mcmaster.com
I am hoping to find some locally though.
Other current recommendations for those who don't want to mess with fiberglass or worry about closed vs open foam products like egg crate is the hard to find 3/4 felt used as carpet underlayment.
I see the advantage of the felt as being able to be stapled in to keep it where you put it.
Mcmaster Carr also sells a product like this called F-13 grey wool felt.
www.mcmaster.com
I am hoping to find some locally though.
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