Re: Corian.
I haven't much experience when it comes to plastic; wood lots, but very little on plastic and usually UHMW (which isn't much good for speakers). I'll have to buy a couple of pieces & some glue and try things out. I'm very excited! I'm guessing the two part glue is just a proprietary two part expoxy. Wow, this has potential; if I can finish renovating my kitchen & put in a Corian countertop myself than I can likely build a new set of speakers without having to consult my local divorce lawyer! Perfect. Do you have any informative web-sites you can recommend? Dupont's is just about useless.
Thanks again,
Vince
MJL21193 said:
I haven't much experience when it comes to plastic; wood lots, but very little on plastic and usually UHMW (which isn't much good for speakers). I'll have to buy a couple of pieces & some glue and try things out. I'm very excited! I'm guessing the two part glue is just a proprietary two part expoxy. Wow, this has potential; if I can finish renovating my kitchen & put in a Corian countertop myself than I can likely build a new set of speakers without having to consult my local divorce lawyer! Perfect. Do you have any informative web-sites you can recommend? Dupont's is just about useless.
Thanks again,
Vince
Re: Re: Corian.
You might try calling some local counter top places. Corian should be nearly as common as granite, I would think. I personally have been wondering about using soapstone. It can also be cut with standard carbide tools. Seems like it might be an interesting option.
I ran across this awhile back: http://www.hsi-luidsprekers.nl/Kastmaterialenonderzoek.htm . I can't read it, but there's enough info that you don't need to read much. Babelfish should do well enough for you.
A couple questions of my own...
Has anyone looked at other marine grade plywoods? I've looked online for marine grade baltic birch and I keep running across other things that look good. Okoume plywood seems to come up quite a bit as well as luan based stuff like Aquatek and Hydrotek. Do you need marine grade plywood, or does standard AA grade baltic birch work just fine? Besides marine grade, there seems to be exterior, cabinet, and airplane grade plywood available from different sources. All the plywood I've looked at locally in hardware stores seems badly warped, while the mdf is perfectly flat. Does that matter?
The other question is whether anyone has messed with damping compounds, especially in a constrained layer configuration. It seems to me, based on what I've read, that constrained layer's effectiveness would be drastically reduced the more braces you used.
vincentrubble said:
You might try calling some local counter top places. Corian should be nearly as common as granite, I would think. I personally have been wondering about using soapstone. It can also be cut with standard carbide tools. Seems like it might be an interesting option.
MJL21193 said:My experiment is panel resonance only, not listening. It will be a MLS signal. Listening is a subjective thing. I just want to see the differences between materials.
Exact same set-up, same driver. Small sealed box with small sized panels(don't want to waste too much of my precious MDF)
If someone has already done this, point the way to the data please.
I ran across this awhile back: http://www.hsi-luidsprekers.nl/Kastmaterialenonderzoek.htm . I can't read it, but there's enough info that you don't need to read much. Babelfish should do well enough for you.
A couple questions of my own...
Has anyone looked at other marine grade plywoods? I've looked online for marine grade baltic birch and I keep running across other things that look good. Okoume plywood seems to come up quite a bit as well as luan based stuff like Aquatek and Hydrotek. Do you need marine grade plywood, or does standard AA grade baltic birch work just fine? Besides marine grade, there seems to be exterior, cabinet, and airplane grade plywood available from different sources. All the plywood I've looked at locally in hardware stores seems badly warped, while the mdf is perfectly flat. Does that matter?
The other question is whether anyone has messed with damping compounds, especially in a constrained layer configuration. It seems to me, based on what I've read, that constrained layer's effectiveness would be drastically reduced the more braces you used.
Hi Azrix,
I don't think bracing would reduce the effectiveness of CLD. What seems to be important is that the two layers have the same stiffness and the damping layer has the right properties.
In the past I've tried to implement CLD using silicone, asphalted felt and water based latex contact cement none was very effective. I'm currently building an open baffle speaker using Green Glue http://www.greengluecompany.com/understandingDamping.php . This stuff seems to work amazingly well . I am using 15mm birch ply and 12mm Viroc (a cement / wood fibre board), the baffle is both stiff and very well damped, it even seemed to soak up all the vibration from the power sander.
Would definitely recommend CLD with Green Glue as the way to go for building speakers.
Regards
Khush
tinitus said:
BTW ... fore a violin you use ahorn for bottom, sides and neck
The deck is made of spruce
Thickness varies and every surface is curved
Bottom and deck is connected with a small pin, to make the ressonanse louder
To clarify a few translation difficulties
ahorn = maple
deck = top (most commonly)
"small pin" = sound post
There's also a shaped strip of wood (spruce) glued to the underside of the top on the 'bass' side of the instrument = bass bar
... thanks, its a long time ago since I have read about violin building in englishBTW ... I agree with soft glue .... a matrix(bracing) structure is also working at the best if glued soft with "thin" absorbing wood .... otherwise you just get a very hard box with a nasty hard undampened ressonanse
A good material fore matrix is called massonite in danish and is made of high pressured paper and oil
But resently I have used 12mm MDF matrix in a bigger box, glued with polyurethane, and a loose fit
Many thick and stiff materials are very difficult to dampen .... a light, thin and soft material is a much yeasier task
As often is the case .... overdoing it often makes it even worse
I like the old method of reinforcing all corners with wooden lists, but glued with acrylick compound or something alike
Green Glue sounds interesting... what is this stuff ?
Hey you crazy Northman - don't tell all our secrets !
Masonite is definitely being abused when used as rear panels of cheap cupboards (I don't want to mention a well known Scandinavian brand here). These people try to hide the fact that it makes building midrange horns real fun. Two layers glued together will keep true to the craziest horn contour you want, and three or four layers are as stiff as stiff can be and will have a resonance decay like nothing else.
But as I said, that's our secret - don't tell.
Pit
P.S. And let's keep it another secret how cheap that stuff is, and how easy to paint.
!Masonite is definitely being abused when used as rear panels of cheap cupboards (I don't want to mention a well known Scandinavian brand here). These people try to hide the fact that it makes building midrange horns real fun. Two layers glued together will keep true to the craziest horn contour you want, and three or four layers are as stiff as stiff can be and will have a resonance decay like nothing else.
But as I said, that's our secret - don't tell.
Pit
P.S. And let's keep it another secret how cheap that stuff is, and how easy to paint.
khush said:
Wonderful. Everything I've read about CLD makes me think that it needs to have large, freestanding panels to work properly, which you wouldn't have in a well braced box. But if it still works that's great.
I've been looking at Green Glue as well. There are a few other glues that look usable for CLD too - Quiet Solution's Quiet Glue, North Creek's speaker glue, as well as Liquid Nails for Projects.
Damping and Speaker materials
've been hanging out reading the DIY pages for almost a month and found a thread where I could throw in some tips.
.
I've been doing some research and have the following to offer. You have to use your imagination as to how you would mount or tie the MDF/HDF/Solid wood cabinet or two component fiberglass -w- male and female molds together with the following components placed in between the "shells." I do not know the minimum purchase quantity/cost. For general damping you have:
.
Daubert V-Damp
http://www.daubertchemical.com/
.
Elastomeric and Polyurethane
http://www.epoxysystems.com/elastomeric.htm
.
Green Glue...and I saw that already mentioned
http://www.greengluecompany.com/soundproofingDampingOptions.php
.
Sorbothane
http://www.sorbothane.com/
.
3M Automotive, Marine and Aerospace : 3M™ Body Schutz™ Rubberized Coating Black, 08864, 1 Quart (US), 6 per case
http://products3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSYQLRLTGTgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_PSM6K102PFbl/gvel_6DTWTJQPBBgl/theme_us_aad_3_0/command_AbcPageHandler/output_html
.
3M Automotive, Marine and Aerospace : 3M™ No Cleanup High Coverage Body Schutz™ Coating, 08964, 22 fl oz, 6 per case
http://www3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSHNZC3CRWgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_TFQHXJDFN8bg/gvel_6DTWTJQPBBgl/command_AbcPageHandler/theme_us_aad_3_0
.
Solid Solutions, Polyurethane Solutions
http://www.solidsolutions.com.au/polyurethane_systems.php
.
E-A-R Specialty Composites Isoloss® HDF Polyurethane Elastomer
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=PEARC24
.
.
MJL21193 mentioned that Wilson Audio speakers were made from Corian. I read that they were made from other materials. I have a components list for many speakers and the Wilson Watt/Puppy is one. I got the quotes from off the Internet for the methacrylic & phenolic resin from three locations. Not sure if that material is equal to Corian....I've never seen the chemical components of Corian so it may be the same. Quoted materials: Watt Puppy 6 - Home Audio Equipment Review; Wilson Audio Specialties WATT Puppy 7 - Ultra Audio Review; Wilson Audio Specialties WATT/Puppy 7 loudspeaker - Stereophile.
/QUOTES/
Before the WATT 7, all WATTs were made of ceramic-filled methacrylic. The 7 is made of M material, which is made of multiple layers of nonsynthetic pulp and mineral-based material. Each layer is hard on its surface and soft in the center. "M" has more uniform particle size throughout compared to MDF; the result is a material claimed to be both harder and better damped than MDF or methacrylic
.
Wilson told me that M transmits about 10dB less noise when excited than methacrylic, resulting in far less "group delay jitter" than the previous cabinet. The new material's hardness better matches the flanges of the drive-units, resulting in better energy transfer and quicker "settling" in the midrange.
.
The Puppy cabinet is a combination of M and X material, the latter a high-density mineral and phenolic resin said to be as hard as steel and twice as hard as M, yet with outstanding damping characteristics. X is used for the front baffle and the cabinet's top and bottom. Wilson claims the material is extremely difficult to mill. Milling X takes about 12 times as long as milling MDF, and time is money; and because X is such an excellent insulator, it sends heat back to the milling tool instead of absorbing it, thus destroying the tool far more quickly than other materials.
.
Overall, Wilson told me, making the cabinets of M and X costs 15 times more than MDF.
/END of QUOTES/
.
For products like Wilson's you might be looking at something like the following:
.
DuPont Plastics
http://plastics.dupont.com/myplastics/Mediator?id=0
.
.
A manufacturer similar to Wilson is the EgglestonWorks Andra II loudspeaker and according to Stereophile the EgglestonWorks measure better than the Wilsons.
've been hanging out reading the DIY pages for almost a month and found a thread where I could throw in some tips.
.
I've been doing some research and have the following to offer. You have to use your imagination as to how you would mount or tie the MDF/HDF/Solid wood cabinet or two component fiberglass -w- male and female molds together with the following components placed in between the "shells." I do not know the minimum purchase quantity/cost. For general damping you have:
.
Daubert V-Damp
http://www.daubertchemical.com/
.
Elastomeric and Polyurethane
http://www.epoxysystems.com/elastomeric.htm
.
Green Glue...and I saw that already mentioned
http://www.greengluecompany.com/soundproofingDampingOptions.php
.
Sorbothane
http://www.sorbothane.com/
.
3M Automotive, Marine and Aerospace : 3M™ Body Schutz™ Rubberized Coating Black, 08864, 1 Quart (US), 6 per case
http://products3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSYQLRLTGTgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_PSM6K102PFbl/gvel_6DTWTJQPBBgl/theme_us_aad_3_0/command_AbcPageHandler/output_html
.
3M Automotive, Marine and Aerospace : 3M™ No Cleanup High Coverage Body Schutz™ Coating, 08964, 22 fl oz, 6 per case
http://www3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSHNZC3CRWgs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_TFQHXJDFN8bg/gvel_6DTWTJQPBBgl/command_AbcPageHandler/theme_us_aad_3_0
.
Solid Solutions, Polyurethane Solutions
http://www.solidsolutions.com.au/polyurethane_systems.php
.
E-A-R Specialty Composites Isoloss® HDF Polyurethane Elastomer
http://www.matweb.com/search/SpecificMaterial.asp?bassnum=PEARC24
.
.
MJL21193 mentioned that Wilson Audio speakers were made from Corian. I read that they were made from other materials. I have a components list for many speakers and the Wilson Watt/Puppy is one. I got the quotes from off the Internet for the methacrylic & phenolic resin from three locations. Not sure if that material is equal to Corian....I've never seen the chemical components of Corian so it may be the same. Quoted materials: Watt Puppy 6 - Home Audio Equipment Review; Wilson Audio Specialties WATT Puppy 7 - Ultra Audio Review; Wilson Audio Specialties WATT/Puppy 7 loudspeaker - Stereophile.
/QUOTES/
Before the WATT 7, all WATTs were made of ceramic-filled methacrylic. The 7 is made of M material, which is made of multiple layers of nonsynthetic pulp and mineral-based material. Each layer is hard on its surface and soft in the center. "M" has more uniform particle size throughout compared to MDF; the result is a material claimed to be both harder and better damped than MDF or methacrylic
.
Wilson told me that M transmits about 10dB less noise when excited than methacrylic, resulting in far less "group delay jitter" than the previous cabinet. The new material's hardness better matches the flanges of the drive-units, resulting in better energy transfer and quicker "settling" in the midrange.
.
The Puppy cabinet is a combination of M and X material, the latter a high-density mineral and phenolic resin said to be as hard as steel and twice as hard as M, yet with outstanding damping characteristics. X is used for the front baffle and the cabinet's top and bottom. Wilson claims the material is extremely difficult to mill. Milling X takes about 12 times as long as milling MDF, and time is money; and because X is such an excellent insulator, it sends heat back to the milling tool instead of absorbing it, thus destroying the tool far more quickly than other materials.
.
Overall, Wilson told me, making the cabinets of M and X costs 15 times more than MDF.
/END of QUOTES/
.
For products like Wilson's you might be looking at something like the following:
.
DuPont Plastics
http://plastics.dupont.com/myplastics/Mediator?id=0
.
.
A manufacturer similar to Wilson is the EgglestonWorks Andra II loudspeaker and according to Stereophile the EgglestonWorks measure better than the Wilsons.
My Bad
"A manufacturer similar to Wilson is the EgglestonWorks Andra II..."
I was wrong on this. The speaker that I was thinking about which has the most dead cabinets was the Rockport Technologies Antares loudspeaker. From Stereophile:
The cabinet's measurements
http://stereophile.com/floorloudspeakers/644/index6.html
The quote
http://stereophile.com/floorloudspeakers/644/
/QUOTE/
A female mold is sprayed with an industrial-strength version of Pam (the actual chemical bears no resemblance to aerosol vegetable oil, but serves the same purpose), to keep the cast from sticking, then layers of resin reinforced with glass fiber are laid up, much like a Corvette body. Each layer is allowed to harden before the next is applied, until there is a 12mm-thick shell of "high tensile strength." (Payor loves to lard his descriptions with sexy tech terms.) When finally pulled from the mold, the seamless, five-sided shell weighs around 100 lbs.
The same glass-fiber-reinforced resin process is applied in reverse to a smaller, male mold. When that 60-lb shell has hardened, it is pulled off the mold and inserted into the larger shell. Then, 240 lbs of high-density, high-hysteresis-loss, mineral-filled epoxy goo specially developed for Rockport is poured in between the two, to form a 30mm-thick core that bonds the two skins together.
The result is a five-sided monocoque cabinet with internal braces built into the molds, and separate sealed chambers for the tweeter, midrange, and bass units.
/END QUOTE/
"A manufacturer similar to Wilson is the EgglestonWorks Andra II..."
I was wrong on this. The speaker that I was thinking about which has the most dead cabinets was the Rockport Technologies Antares loudspeaker. From Stereophile:
The cabinet's measurements
http://stereophile.com/floorloudspeakers/644/index6.html
The quote
http://stereophile.com/floorloudspeakers/644/
/QUOTE/
A female mold is sprayed with an industrial-strength version of Pam (the actual chemical bears no resemblance to aerosol vegetable oil, but serves the same purpose), to keep the cast from sticking, then layers of resin reinforced with glass fiber are laid up, much like a Corvette body. Each layer is allowed to harden before the next is applied, until there is a 12mm-thick shell of "high tensile strength." (Payor loves to lard his descriptions with sexy tech terms.) When finally pulled from the mold, the seamless, five-sided shell weighs around 100 lbs.
The same glass-fiber-reinforced resin process is applied in reverse to a smaller, male mold. When that 60-lb shell has hardened, it is pulled off the mold and inserted into the larger shell. Then, 240 lbs of high-density, high-hysteresis-loss, mineral-filled epoxy goo specially developed for Rockport is poured in between the two, to form a 30mm-thick core that bonds the two skins together.
The result is a five-sided monocoque cabinet with internal braces built into the molds, and separate sealed chambers for the tweeter, midrange, and bass units.
/END QUOTE/
Re: Damping and Speaker materials
Hi. This is a DIY forum. I used the trade name for a product that has very similar properties to the stuff used by Wilson. My point was not for exact composition, but superior stiffness. I'm not sure if you can pick up a sheet of X material at the local lumber yard...
showflash said:
Hi. This is a DIY forum. I used the trade name for a product that has very similar properties to the stuff used by Wilson. My point was not for exact composition, but superior stiffness. I'm not sure if you can pick up a sheet of X material at the local lumber yard...
Dave
I just discovered this great thread.
Maybe I’m a bit dense, it’s been a while since I had caffeine, but can you explain when you said in post #64 www.diyaudio.com/forums/showthread.php?s=&postid=1168015&highlight=#post1168015
I’m trying to work out how much benefit there is from pushing resonances up:
. . I’ve seen figures that the energy of a large orchestra live by octave, eg over 125-250 hz is about 4 dB more than 1-2 kHz, loosely suggesting a modest benefit in pushing panel resonances up 1khz plus.
The rock/ pop/ blues I listen to is probably more bass dominant, so the benefit in pushing resonances up should be more. OTOH most if it is so compressed, maybe this compresses the differences & benefit over octaves too(?)
I was surprised when you said
www.diyaudio.com/forums/showthread.php?s=&postid=1168198&highlight=#post1168198 :
By air space, do you mean just the air volume alone – I think of the spring effect in a sealed box, but don’t think you’re referring to this?
Isn’t most of the benefit from pushing resonances up, they are then more easily effectively tamed by damping or stuffing eg with fiberglass, ie this might attenuate a further eg 4-6 dB?
Tthanks
I just discovered this great thread.
Maybe I’m a bit dense, it’s been a while since I had caffeine, but can you explain when you said in post #64 www.diyaudio.com/forums/showthread.php?s=&postid=1168015&highlight=#post1168015
I’m trying to work out how much benefit there is from pushing resonances up:
. . I’ve seen figures that the energy of a large orchestra live by octave, eg over 125-250 hz is about 4 dB more than 1-2 kHz, loosely suggesting a modest benefit in pushing panel resonances up 1khz plus.
The rock/ pop/ blues I listen to is probably more bass dominant, so the benefit in pushing resonances up should be more. OTOH most if it is so compressed, maybe this compresses the differences & benefit over octaves too(?)
I was surprised when you said
www.diyaudio.com/forums/showthread.php?s=&postid=1168198&highlight=#post1168198 :
By air space, do you mean just the air volume alone – I think of the spring effect in a sealed box, but don’t think you’re referring to this?
Isn’t most of the benefit from pushing resonances up, they are then more easily effectively tamed by damping or stuffing eg with fiberglass, ie this might attenuate a further eg 4-6 dB?
Tthanks
I don't know the exact math, but IIRC the amount of energy available to excite a resonance is inversly proportional to the square of the frequency... ie if i take a panel and split it in half (or approximately half which is better, then the amount of energy available to excite the resonance is now 1/4... and since i am aiming for a hi-Q resonance (ie the energy has to be at a very precise frequency) and have divided the panel into 2 dissimilar resonances the energy available is now 1/8.
Further if you are building a multi-way speaker and you can push the resonance above the cross-over the available energy is further attenuated by the XO.
As well because the resonances are high Q, if they do get excited they quickly release the energy, so that it is not stored up and released with a smooshing./masking affect on the low-level details.
Adding a damping material to the panel actually degrades this approach, by pushing the resonance back down in frequency & by broadening the Q making more energy available to excite it, which means more damping is needed, etc spiralling down towards the big heavy, monster box that has large energy storage....
Airspace damping is intended to halp kill off high-frequencies from bouncing around inside the cabinet (and in the case of QW designs to enhance the terminus low-pass function). A side effect is that if the panel resonances are pushed up high enuff it also helps attenuate the energy at frequencies required to excite the panel resonances.
Further important details like coupling the driver as effectively as possible directly to as much of the mass of the box as possible also helps spread around the mechanical energy as much as possible reducing the amount available to any one panel to excite its resonance. Taken to extremes this is exemplified by push-push loading which actively cancels energy that would be transmitted to the box.
Anyway, that is the theory. One only has to listen to one of our boxes (or maybe better to say not hear one of our boxes) to hear what i mean. I got here via a 30 year journey of trial, all started by John Greenbank when he described the rationale behind the Tangent speaker boxes which were a blinding flash of light in their day.
dave
Further if you are building a multi-way speaker and you can push the resonance above the cross-over the available energy is further attenuated by the XO.
As well because the resonances are high Q, if they do get excited they quickly release the energy, so that it is not stored up and released with a smooshing./masking affect on the low-level details.
Adding a damping material to the panel actually degrades this approach, by pushing the resonance back down in frequency & by broadening the Q making more energy available to excite it, which means more damping is needed, etc spiralling down towards the big heavy, monster box that has large energy storage....
Airspace damping is intended to halp kill off high-frequencies from bouncing around inside the cabinet (and in the case of QW designs to enhance the terminus low-pass function). A side effect is that if the panel resonances are pushed up high enuff it also helps attenuate the energy at frequencies required to excite the panel resonances.
Further important details like coupling the driver as effectively as possible directly to as much of the mass of the box as possible also helps spread around the mechanical energy as much as possible reducing the amount available to any one panel to excite its resonance. Taken to extremes this is exemplified by push-push loading which actively cancels energy that would be transmitted to the box.
Anyway, that is the theory. One only has to listen to one of our boxes (or maybe better to say not hear one of our boxes) to hear what i mean. I got here via a 30 year journey of trial, all started by John Greenbank when he described the rationale behind the Tangent speaker boxes which were a blinding flash of light in their day.
dave
BTW, syncronistically, i was talking to Bill Perkins just last night and he was talking about putting his panel material back in production. He did a lot of research into panel material (from the low-Q heavily damped point-of-view) which to this day is probably one of the very best of this kind of material today. If he ever gets it off the ground, i'll get a sample large enuff to build a box out of and we can do a real-world test of the theory above.
(he thinks i am out-to-lunch with my approach)
dave
(he thinks i am out-to-lunch with my approach
) dave
planet10 said:
Dave, in my rescent project:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99301
I did it your way. Used the right material, keep the panel sizes down, stay away from damping. I say the results are good, but is this due to the method or is it the product of better geometry?
I had trouble in the high midrange (as detailed in the thread), and had to add a piece of rubber backed carpet directly behind the woofer to reduce a midrange peak. Perhaps the divider panel is too close to the rear of the woofer (not enough breathing room?) Could this be contributed to by the un-damped panels? If by driving resonance up, it gets excited by the driver itself, how is this a good thing?
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