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
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
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
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
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/Pioneer/CDA/HomeProducts/HomeProductDetails/0,1422,590,00.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)
Attachments
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
Ian
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.
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.
I think it was the Celestion SL700 which was the first with the Aerolam lightweight, honeycomb cabinet.
I've dug up: SL700 review in Stereophile, which makes interesting reading.
There are some definite advantages to lightweight cabinets. I believe that the main one is that they store less energy.
Please keep posting if you go this route.
Steve
PS: 35 years ago, I made an early speaker experiment by making car speaker cabinets out of expanded polystyrene - they fitted into the door pockets of a mini. They sounded awful but there could have been several reasons for this. I seem to recall that precious little attention was payed to dimensions (other that they should fit into the door packets). There was no serious attempt to match the drivers to the cabinets and they were held together with sellotape.
I've dug up: SL700 review in Stereophile, which makes interesting reading.
There are some definite advantages to lightweight cabinets. I believe that the main one is that they store less energy.
Please keep posting if you go this route.
Steve
PS: 35 years ago, I made an early speaker experiment by making car speaker cabinets out of expanded polystyrene - they fitted into the door pockets of a mini. They sounded awful but there could have been several reasons for this. I seem to recall that precious little attention was payed to dimensions (other that they should fit into the door packets). There was no serious attempt to match the drivers to the cabinets and they were held together with sellotape.
I've also been looking at designing low-mass speakers for some time now. The obvious candidate would be some form of honeycomb, but although the strength is high when forces are distributed over a wide area, it doesn't resist concentrated forces well (unless solid inserts are used for local reinforcing and as "entry points" to allow forces to smoothly enter and be distributed throughout the entire structure). On top of that, fabricating complicated shapes requires specialized and skilled craftsmanship, gluing areas are small, and probably as a consequence, manufacturing consistency of the cabinets tends to be spotty. I feel that even the Celestions suffered from uneven consistency in production, and some of the SL600 and 700 cabinets certainly appeared to be better-sounding than others (notice that the recent Kingston designs no longers use any form of Aerolam?).
Honeycomb is theoretically very good, and carefully-made prototypes can have outstanding performance, but maintaining that performance in production may prove to be a challenge. Of course, if a manufacturer of F1 cars or America's Cup yachts is locally available, this may not be an issue.
My present opinion is that fiberglass, carbon or aramid skins over expanded foam may lead to less grief when put into practice (production). In other words, surfboard technology.
regards, jonathan carr
Honeycomb is theoretically very good, and carefully-made prototypes can have outstanding performance, but maintaining that performance in production may prove to be a challenge. Of course, if a manufacturer of F1 cars or America's Cup yachts is locally available, this may not be an issue
.My present opinion is that fiberglass, carbon or aramid skins over expanded foam may lead to less grief when put into practice (production). In other words, surfboard technology.
regards, jonathan carr
Well over a year ago there were two threads-one about concrete enclosures someone built, the other about lightweight alernatives-and I searched for them.
Didn't find them, but came up with these other threads in the search.
Still trying to find those original threads. Anyway, these threads might prove useful. Apparently this subject has received some attention on this board:
http://www.diyaudio.com/forums/showthread.php?threadid=8241&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=6119&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=3720&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=2656&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=2574&highlight=concrete
Didn't find them, but came up with these other threads in the search.
Still trying to find those original threads. Anyway, these threads might prove useful. Apparently this subject has received some attention on this board:
http://www.diyaudio.com/forums/showthread.php?threadid=8241&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=6119&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=3720&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=2656&highlight=concrete
http://www.diyaudio.com/forums/showthread.php?threadid=2574&highlight=concrete
The problem is.....
that a light-weight speaker would have to be securely mounted to something if it were to have any chance of producing reasonable bass.
Its all to do with actions and equal and opposite reactions, F=mass x acceleration etc, so if you attempt to move a lot of air using a big driver (which good bass generally requires), you will move the light-weight cabinet as well, which is not desirable at all. So added mass will always be needed.....
that a light-weight speaker would have to be securely mounted to something if it were to have any chance of producing reasonable bass.
Its all to do with actions and equal and opposite reactions, F=mass x acceleration etc, so if you attempt to move a lot of air using a big driver (which good bass generally requires), you will move the light-weight cabinet as well, which is not desirable at all. So added mass will always be needed.....
How about building a Translam or something from Andy's curved enclosures site and using it as a mould for a lightweight fibreglass (or whatever) skin and then spraying in the expanded polystyrene?SY said:
Steve
Making molds and requiring spray equipment sounds pretty advanced for me...I'd rather try winding my own chokes!
I always think in terms of "can I buy it at a store in town". In this case, some kind of foam, shaped with a bread knife, and with a skin made of laminating fibreglass cloth with epoxy resin would do the trick. If a rigid foam were chosen, driver mounting would be handled by just using T-nuts on the inside of the baffle to distribute the fastener load.
In fact, this enclosure screams "use me for 2 push-push TangBands" ala planet10!
I always think in terms of "can I buy it at a store in town". In this case, some kind of foam, shaped with a bread knife, and with a skin made of laminating fibreglass cloth with epoxy resin would do the trick. If a rigid foam were chosen, driver mounting would be handled by just using T-nuts on the inside of the baffle to distribute the fastener load.
In fact, this enclosure screams "use me for 2 push-push TangBands" ala planet10!
i think 7V said it best, if it aint heavy, it aint hi-fi.
i work in the industry, and i have to say, whenever new gear comes in, EVERYONE does one thing first, pick it up and see what it weighs. if its heavy, we smile. if its HEAVY AS #^&*@#, we giggle . there is just something to be said about heavy components. i just dont think "lightweight" has much place in audio.
i work in the industry, and i have to say, whenever new gear comes in, EVERYONE does one thing first, pick it up and see what it weighs. if its heavy, we smile. if its HEAVY AS #^&*@#, we giggle
. there is just something to be said about heavy components. i just dont think "lightweight" has much place in audio.- Status
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