What would be the ultimate cabinet materials?
For example if you could mould yourself a cube of some state-of-the-art tons per square inch concrete, would it be worth it?
If you pick up some pvc barrels from a building site, would it sound good? if you mould yourself a round concrete ball and stuck 2 didgeridoos out of the top? Would that be the best thing?
anyone come across some good article comparing speaker cabinets musical instruments or about theories of fluid dynamics across cabinet materials ? it sounds really confusing.
For example if you could mould yourself a cube of some state-of-the-art tons per square inch concrete, would it be worth it?
If you pick up some pvc barrels from a building site, would it sound good? if you mould yourself a round concrete ball and stuck 2 didgeridoos out of the top? Would that be the best thing?
anyone come across some good article comparing speaker cabinets musical instruments or about theories of fluid dynamics across cabinet materials ? it sounds really confusing.
High-mass uniform building materials are ,by themselves, no longer the choice material in todays high-tech speaker designs. ie, concrete/cement, hardwood, chipboard, fibreboard, polymers, metals, etc.
A speaker 'box' is designed to contain and dissipate the rear-wave energy, the drivers chassis vibration, and provide a stable mount for the driver. A highly rigid and heavy material will do most of this, but is very inefficient at dissipating energy. For this you need some sort of damper, and constrained layer building techniques can give you this.
Also, just as in a cars suspension, the damper has to work harder if the mass to be dampened is high. For this reason, it's best to keep the speaker structure as light (and rigid) as possible, and let the damper dissipate the vibrational energy.
Some searching for 'constrained layer' will bring up lots of information, but some materials could be.
Thin high-grade plywood (baltic birtch, marine, aircraft, furniture), 1/8 or 1/4" masonite or fibreboard, aluminum, steel. These materials are only for structure.
For damping you need some viscoelastic material. Such as:
3M™ Vibration/Sound Damping Products
http://products3.3m.com/catalog/us/...ytapes_3_0/command_AbcPageHandler/output_html
Dynamat
http://www.dynamat.com/spec_pages.htm (good/quick information about damping)
WSU (Waterproof Shingle Underlayment) = "self-adhesive ice and water barrier" = Roofing Material
-such as-
Peel & Seal
http://www.mfmbp.com/peelseal/index.htm
Grace Ice & Water Shield
http://www.na.graceconstruction.com/product.cfm?mode=a&id=74&did=8
WEATHERMASTER™ DG ICE & WATER PROTECTION
http://www.atlasroofing.com/residential/sm_dg.asp
etc, etc, etc... see your local roofing supplier.
A speaker 'box' is designed to contain and dissipate the rear-wave energy, the drivers chassis vibration, and provide a stable mount for the driver. A highly rigid and heavy material will do most of this, but is very inefficient at dissipating energy. For this you need some sort of damper, and constrained layer building techniques can give you this.
Also, just as in a cars suspension, the damper has to work harder if the mass to be dampened is high. For this reason, it's best to keep the speaker structure as light (and rigid) as possible, and let the damper dissipate the vibrational energy.
Some searching for 'constrained layer' will bring up lots of information, but some materials could be.
Thin high-grade plywood (baltic birtch, marine, aircraft, furniture), 1/8 or 1/4" masonite or fibreboard, aluminum, steel. These materials are only for structure.
For damping you need some viscoelastic material. Such as:
3M™ Vibration/Sound Damping Products
http://products3.3m.com/catalog/us/...ytapes_3_0/command_AbcPageHandler/output_html
Dynamat
http://www.dynamat.com/spec_pages.htm (good/quick information about damping)
WSU (Waterproof Shingle Underlayment) = "self-adhesive ice and water barrier" = Roofing Material
-such as-
Peel & Seal
http://www.mfmbp.com/peelseal/index.htm
Grace Ice & Water Shield
http://www.na.graceconstruction.com/product.cfm?mode=a&id=74&did=8
WEATHERMASTER™ DG ICE & WATER PROTECTION
http://www.atlasroofing.com/residential/sm_dg.asp
etc, etc, etc... see your local roofing supplier.
If you could mold 'Corian' or some similar material as some have done it works better than concrete. It is very dead, do not crack, is not porous, machines well, and even looks good(any color you like) but it is very heavy, extremely expensive, and hard to get a hold of the raw material to cast yourself.
There is something that Martin Q said that is not realy clear for me about mass.
You say that the cabinet need to be rigid and light. But it seems like i would rather have a infinitely heavy cabinet than an infinitely light one. Because a light cabinet cannot keep the frame of the woofer in place as well as a heavy one.
It seems to me that a good cabinet should be massive, rigid and well damped. What do you think
F
You say that the cabinet need to be rigid and light. But it seems like i would rather have a infinitely heavy cabinet than an infinitely light one. Because a light cabinet cannot keep the frame of the woofer in place as well as a heavy one.
It seems to me that a good cabinet should be massive, rigid and well damped. What do you think
F
Gary F: Mass is better 'spent' for damping than just for the sake of mass. The structure should be light and rigid to make the best use of the damping. As a system, it can still be quite heavy, but more effective than mass alone.
A effective system can be intelligently built/designed to produce less noise than a strictly massive one. Yes, infinte mass would produce good results ... and a black hole.
Most drivers have enough mass in the motor/basket assembly as it is, and this can easily be backed up with putty, loaded paint, constrained layers, etc. if needed. But, if the driver chassis is rigidly fixed to the speaker box structure, then you also get an effective transmission of those vibrations to the structure where they will most likely be amplified.
Nip it at the source and minimize transmission. The enclosure has to deal with the rear wave as it is.
A effective system can be intelligently built/designed to produce less noise than a strictly massive one. Yes, infinte mass would produce good results ... and a black hole.
Most drivers have enough mass in the motor/basket assembly as it is, and this can easily be backed up with putty, loaded paint, constrained layers, etc. if needed. But, if the driver chassis is rigidly fixed to the speaker box structure, then you also get an effective transmission of those vibrations to the structure where they will most likely be amplified.
Nip it at the source and minimize transmission. The enclosure has to deal with the rear wave as it is.
Member
Joined 2004
This pops up every so often. You clicked the "Have you Searched?" option, correct?
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Does anybody know if there are effective adhesives for wood that have beneficial damping properties, and if their use could be recommended? I've been attracted to the translam method of cabinet construction for various reasons, and the need for many layers of adhesive might present an opportunity to incorporate damping into the structure itself. Or perhaps laminating wood with a damping adhesive would be of little value compared to the more common practive of simply lining or spraying the inside of the box. Any thoughts?
For very rigid, yet reasonably lightweight construction, I like:
to make up high quality cabinet material sandwiching about 1/16" inch of high solids contact cement between two 3/8" sheets of plywood. Add internal lead sheets and viscoelastic damping material to suit.
For bracing, I like 2 1/2" x 3/4" oak glued & screwed on edge to the inside of external panels, as well as rabbetted plywood circumferential ribbed bracing, particularly between driver cutouts. You can go the extra yard by screwing 1/8" thick steel strapping to the inner brace edges, although I haven't yet.
You can brute force also with double shell & sand or lead shot filled or just plain old concrete construction (maybe air entrained or with perlite aggregate to keep weight down a bit).
to make up high quality cabinet material sandwiching about 1/16" inch of high solids contact cement between two 3/8" sheets of plywood. Add internal lead sheets and viscoelastic damping material to suit.
For bracing, I like 2 1/2" x 3/4" oak glued & screwed on edge to the inside of external panels, as well as rabbetted plywood circumferential ribbed bracing, particularly between driver cutouts. You can go the extra yard by screwing 1/8" thick steel strapping to the inner brace edges, although I haven't yet.
You can brute force also with double shell & sand or lead shot filled or just plain old concrete construction (maybe air entrained or with perlite aggregate to keep weight down a bit).
I sometimes read a magazine called soundonsound that has a section on the acoustics and emulations of musical instruments. Bowed instruments have one-dimensional properties and are easy to emulate, drums which have two-dimensional skins are less easy to emulate and the skins vibrations have inflection points arrayed in quarters and hexagons and pentagons with more inflection points along concentric circles of the skin. That's why electronic drums don't sound very realistic yet. Simple flutes are easy, being one-dimensional, but convoluted brass instruments are also complicated.
Originally, I thought speakers were like musical instruments, but I guess the more this is the case, the more the sound is coloured. So rocks cement and extra rigid weighted PVC sounds like the best plan. I was kind of thinking of cement eggs moulded around balloons and cement shapes with wood front panels to make the bass reverberate frontwards.
Any ideas on some sources of interestingly shaped PVC, for example sixties style garden chairs and strange vases and flowerpots.
Originally, I thought speakers were like musical instruments, but I guess the more this is the case, the more the sound is coloured. So rocks cement and extra rigid weighted PVC sounds like the best plan. I was kind of thinking of cement eggs moulded around balloons and cement shapes with wood front panels to make the bass reverberate frontwards.
Any ideas on some sources of interestingly shaped PVC, for example sixties style garden chairs and strange vases and flowerpots.
It's also important to consider that the proper cabinet materials will change based on the frequency range in question. In Martin Colum's book he points out that there are three vibrational ranges and three different techniques to deal with them: Mass, damping and stiffness.
Mid to High frequencies are best combatted with mass - picture a tweeter trying to set up a resonance in concrete for example. Upper bass, lower midrange is best treated with damping, and low bass is best dealt with using stiffness.
I don't have the book handy right now, and I can't remember the break points for the transitions, but I'm sure they aren't critical, as the transistion between these ranges is fairly gradual.
One other aspect that is important is the absorption of the backwave inside the cabinet. The choice, and amount of volume damping can also have a huge impact on sound.
I know I haven't provided any specific materials yet, so I'll throw a suggestion of skinned composites: for a bass mid cabinet, metal/honey comb nomex/carbon fiber, laminated with high damping glue. and damped with your favorite damping material in a constrained layer.
Mid to High frequencies are best combatted with mass - picture a tweeter trying to set up a resonance in concrete for example. Upper bass, lower midrange is best treated with damping, and low bass is best dealt with using stiffness.
I don't have the book handy right now, and I can't remember the break points for the transitions, but I'm sure they aren't critical, as the transistion between these ranges is fairly gradual.
One other aspect that is important is the absorption of the backwave inside the cabinet. The choice, and amount of volume damping can also have a huge impact on sound.
I know I haven't provided any specific materials yet, so I'll throw a suggestion of skinned composites: for a bass mid cabinet, metal/honey comb nomex/carbon fiber, laminated with high damping glue. and damped with your favorite damping material in a constrained layer.
Sand
I worked with the same 2 drivers in different cabinets some years back. The best, and the difference was huge, was a double wall mdf cabinet with around 1 inch of sand in between. The main diff. was a lot more fine details and microdynamics.
I also tried a cabinet with tiles (around 1/4 inch thick) glued on. It also gave more microdynamics but also a hard annoying sound. And I prefered the plain mdf cabinet to the tile version. These cabinets was all made in mdf of the thickness.
At that time I also listened to some speakers made of some kind of concrete, two different brands, and they had this hard annoying sound also. On the other hand, the sandfilled cabinets had more dynamic and slam but were also more relaxed ind their presentation.
BTW sandfilled cabinets are quite heavy, so I wait to make my current Lowthers (plywood) into sandfilled horns until I live a place where I will stay many years.
Cheers, sorry for my English
I worked with the same 2 drivers in different cabinets some years back. The best, and the difference was huge, was a double wall mdf cabinet with around 1 inch of sand in between. The main diff. was a lot more fine details and microdynamics.
I also tried a cabinet with tiles (around 1/4 inch thick) glued on. It also gave more microdynamics but also a hard annoying sound. And I prefered the plain mdf cabinet to the tile version. These cabinets was all made in mdf of the thickness.
At that time I also listened to some speakers made of some kind of concrete, two different brands, and they had this hard annoying sound also. On the other hand, the sandfilled cabinets had more dynamic and slam but were also more relaxed ind their presentation.
BTW sandfilled cabinets are quite heavy, so I wait to make my current Lowthers (plywood) into sandfilled horns until I live a place where I will stay many years.
Cheers, sorry for my English
I like it!
cabinet couldn't be rigid and light and sound good...
do you know new Samsung and BBK HT, made of light metal?
do you hear it? I couldn't hear miserable sound before.
mass product being made of wood. it's just for price and technology. I wouldn't do my system of ramshackle furniture....
I made marble cabinets. and advise it for other. it's not realy expensive, not very heavy. you just have to use thin panel.
some sort of marble has ideal damping factor. of course you must to damp cabinet inside. but, view, sound, .... so, I like it
cabinet couldn't be rigid and light and sound good...
do you know new Samsung and BBK HT, made of light metal?
do you hear it? I couldn't hear miserable sound before.
mass product being made of wood. it's just for price and technology. I wouldn't do my system of ramshackle furniture....
I made marble cabinets. and advise it for other. it's not realy expensive, not very heavy. you just have to use thin panel.
some sort of marble has ideal damping factor. of course you must to damp cabinet inside. but, view, sound, .... so, I like it
Attachments
The requirements completely different for vented cabinets?
yury did you use a sealed cabinet and how did you glue the marble? I was thinking cement is good for gluing stone and making the interior chamber more round.
I spent about three hours last night looking for giant plastic vases, plastic amphora, plastic giant spheres, and I couldn't find very much! Even a few medium-sized spherical strong plastic vases cut and glued together could be neat.
I did find that you can get 30 litre Plexiglas biorb spheres from Goldfish bowls but these are prohibitively dear.
yury did you use a sealed cabinet and how did you glue the marble? I was thinking cement is good for gluing stone and making the interior chamber more round.
I spent about three hours last night looking for giant plastic vases, plastic amphora, plastic giant spheres, and I couldn't find very much! Even a few medium-sized spherical strong plastic vases cut and glued together could be neat.
I did find that you can get 30 litre Plexiglas biorb spheres from Goldfish bowls but these are prohibitively dear.
I use ceramics, Stoneware to high temperature. 1270 c, results are really good, most of all in treble.
Domingo.
http://personal.telefonica.terra.es/web/acusticaceramica/Web/Dejambe proyecto.htm
Domingo.
http://personal.telefonica.terra.es/web/acusticaceramica/Web/Dejambe proyecto.htm
I strongly recommend a sandwich of different materials, my preferred material at the moment is 12 mm (1/2") MDF then 9 mm (3/8") very fine dry sand then 9 mm (3/8") HDF (high density fibreboard) and finally 9 mm (3/8") granite or marble slates glued on the HDF with a 1 mm (1/24") layer of tar (really thick tar heated to make it liquid as in what is used for making tarmac).
Off course this probably works best for a bass cabinet as the total width of it is 40 mm (1 1/2"). And it's also best for anything but the front plate, which I make from alternating layer of 12 mm MDF and 9 mm HDF glued together with the same tar of used above.
Off course this probably works best for a bass cabinet as the total width of it is 40 mm (1 1/2"). And it's also best for anything but the front plate, which I make from alternating layer of 12 mm MDF and 9 mm HDF glued together with the same tar of used above.
Member
Joined 2004
adrikos,
yeah, you're right I should have explained that it's hinged in the edges and to the front plate only, so that the inner cabinet "floats" in sand all the way round except for the front, I also braced this inner cabinet with a matrix structure as in the B&W's.
Is it clearer now, or should I do a better job at trying to explain it.
yeah, you're right I should have explained that it's hinged in the edges and to the front plate only, so that the inner cabinet "floats" in sand all the way round except for the front, I also braced this inner cabinet with a matrix structure as in the B&W's.
Is it clearer now, or should I do a better job at trying to explain it.
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