Cabinet materials - why not more diversity?

[Ian J]

Hi all,
Most speaker cabinets are made from Mdf or ply as this is good solid stuff that's not too hard to work with, and has the mass to attenuate the sound. But is this mass necessary? There has been at least one attempt (Acoustic precision) to make a cabinet with expanded polystyrene (styrofoam in the US?). This used a single Jordan JX92 and got good reviews, though it apparently lacked bass. Polystyrene is light but rigid, and the lack of mass means it stores less energy therefore there's less colouration of the sound from that energy turning into panel resonances. Aren't there other materials that might offer similar benefits of being lighter and easier to work with than wood? Mind you I've no idea how you would actaully mount a driver in a polystyrene baffle, presumably that has to be something stronger. And too little mass might reduce the dynamics due to movement under Newtonian force... I'll stop here before I demolish my own argument.

IJ

[peranders]

Concrete
Marble
Stone of other kinds
Glass
Lumbercore
Plexi
Metal with damping
Lot's of materials.....

[faustian bargin]

here's a thread

Mr. Pass has some with granite front baffles. or is it marble...one or the other anyway.

i want to see some speakers made with Corian. anybody got any pictures?

/andrew

[uli]

Wilson uses porprietary VERY heavy materials...

Uli

[Bricolo]

how do you assemble cabinets made of stone?

[Tazzy]

Originally posted by Bricolo
how do you assemble cabinets made of stone?

Euhm, like a real pro?

[Da5id4Vz]

i want to see some speakers made with Corian. anybody got any pictures?

There is this one, but I was thinking it might be fun to try a Corian composite dipole. (Smallish to min. $$):

http://www.pioneerelectronics.com/Pi...22,590,00.html



System Center Channel Speaker : TZ-MC09 : $350.00
The Elite TZ-700 system speakers prove that an elegant and interesting design can be combined with high performance. The system includes a 3-way subwoofer with a 7-ply cabinet and integrated 300-Watt amplifier. The slim surround speakers allow you to re-position the tweeter for better room coverage. And the center channel speaker- which reproduces center-stage action like movie dialogue- is designed to sit on or near the television and complement its shape. All together, an elegant and powerful surround sound system.


Corian Material Construction
Bass Reflex cabinet, Satellite / Bookshelf Style
Linear Power Response Technology
2 Way 3 Speaker System
3 " LPR Woofer, 1" Tweeter
Frequency Response: 70Hz to 60 kHz
Sensitivity 86dB / 1 watt / 1 meter
Maximum Power: 150 watts
Crossover Frequency: 8,000Hz
Video Shielded
Speaker Terminals: Banana Plug Ready
Cabinet Color: Corian Stone Finish (05)

[Ian J]

yes, all this 'heavy' stuff is interesting, but I was more interested to see if anyone has tried light materials/composites for the cabinet. Is there a real physical reason why there has to be alot of mass in the cabinet to attenuate the rear wave? I remember reading somewhere that there are frequencies where mdf is much more 'transparent' to sound than at others, do all materials behave similarly?
Ian

[7V]

Didn't Celestian come out with some lightweight cabinets some years ago? Aerolam or something?

Call me old fashioned but I reckon that if you can lift it easily, it ain't hi-fi.

Steve

[EC8010]

Yes, light materials can be used, but they tend to be quite difficult to work with. You probably remember the Celestion SL600 which was effectively an SL6 in an Aerolam aluminium honeycomb cabinet. Light materials have the attributes you describe but jointing is tricky, and a special bayonet mount was needed to spread the load when fitting the drivers. Another composite possibility is Formica/expanded polystyrene/Formica. Again the problem is the jointing and driver mounting.

It is possible to make a light, rigid box that has its structural resonances much higher in frequency than the standard MDF shoebox, but it's trickier.