Light weight speaker system

[amirmk]

I was asked to build custom speakers for some guy to use in his Raytheon Hawker 800. The speakers should be as high quality as possible, while limited to very little weight and size. Because of the rather small cabin, I want to use ~5" midbass or 6" woofer with an 1" fabric tweeter. At the moment, I'm considering Morel 621 with A Scan Speak d2905/9500. The cabinet is the bigger problem. I want to build it from Carbon fiber and balsa and vynil cover. I'm also considering Balsa sandwich.
Can you please share your thoughts with me about both cabinet and drivers?

[Mr Evil]

The cabinet doesn't have to be very light before the heaviest part becomes the woofer's magnet.

[Kittle]

I built some cabinets out of cardboard recently.
1 was just flat walls with some fiberboard glued on. Annoying vibrations and so-so performance.

the other was a honeycomb like effect where the walls were 1 1/4" thick. no fiberboard. Pretty decent performance.. but the 8" driver weighed more than the whole cabinet, so it was prone to falling over on its face.
Probably preventable with legs or some other creativity in place.

[johninCR]

Since this is going in a jet, size, weight and shape are definitely a concern. Molding something out of fiberglass with a carbon fiber layer may be the way to go, then gel coat to get a sleek finish.

Due to the changing cabin pressure, I'd stay away from sealed. Ported results in a larger cab. If there isn't a bulkhead to mount them IB, then I think an aperiodic box is the way to go and you can have a box size as small as the driver will fit in. With aperiodic you might even be able to find space in a corner for sub driver.

Regarding drivers, I'd go with the new 4" driver from CSS with the XLB technology. Plenty of bass for it's small size and extension well above 10K makes integrating a tweeter for the top end simple.

Since size, weight, and power consumption are concerns, you need a chip amp to drive the speakers.

[bilorn]

I just finished some dipole panels, I used 1 1/2 " hard polystyrene insulation board skinned with 1/4 " oak plywood glued to both sides and framed with oak. Not as ridgid as I hoped, but still pretty good.
Another problem you may have. Sealed tweeters and changes in elevation will cause the dome to bulge out as elevation increases.
This happened to me, I sent a pair of speakers to my son in Klamath Falls Or. from Indiana, One of his tweeters had very little output. It was visably bulged also. I had him poke a tiny hole at the edge of the surround with a needle. The problem cleared. This was a Morel Mdt30. If your using a chambered tweeter it would be a good idea to poke a small hole in the plastic chamber. Don't us a drill bit, it will wind up the damping material around it. A heated needle will do the trick. a hole this small won't affect the tweeters performance.
Good luck
Bill Horn

[thomas997]

If you can find a decent speaker that uses a Neodyium magnet, it should be very light.