Axiom Home Page Forums General Discussion Technical Questions Why small (diameter) bass drivers

My old (20+ years) speakers have 13-inch bass drivers. Now the norm seems to be 6.5-inch bass drivers and the larger drivers are reserved for subwoofers.

Do form and looks (narrow, sleek appearance) dictate the size of the drivers rather than function? Now 2 or 3 small bass drivers are in a system when it used to be one large bass driver was sufficient.

Simple -
The bigger the driver, the sloppier the sound for any particular material... ie: bassists that like a tight punchy sound use 8" or 10" arrays in their cabinets, whereas the sloppy bassists (I'd post names but every time I do I offend someone) usually play through 15" arrays.

So next time you see some kid on the street with one of those farty cars with the 20" basket sub... give the bass a listen alone, it'll sound like bean night in Attica.

Bren R.

! ! ! ! ! ! ! ! Now there's a simile you don't hear too often. Unbelievable, Bren!

Bean night in Attica. First I heard of that one. HA, HA, HA!

Hey Bren,

Maybe you should try writing for some of those comedy shows that were still on when I left Canada. "This Hour Has 22 Minutes..." Royal Canadian Air Farce"? Are those still on the CBC? Bean night in Attica!

Back to the woofer thing. The motive force--the voice coil--is at the apex of any cone woofer, so the larger the cone, the greater the tendency of it to flex as it moves rapidly back and forth. It should operate as a perfect piston, but with big cones, they don't. This in turn produces break-up modes of unwanted resonances that color the sound. It's a form of distortion, in effect.

So by keeping woofer cones much smaller, and using lightweight rigid materials like aluminum, as well as several woofers, you largely eliminate breakup and the resulting resonances. Smaller and stiffer, as the actress said to the bishop. . .

Regards,

In reply to:

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Maybe you should try writing for some of those comedy shows that were still on when I left Canada. "This Hour Has 22 Minutes..." Royal Canadian Air Farce"? Are those still on the CBC? Bean night in Attica!

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They are... some changes in lineups: John Morgan is off Air Farce, replaced by Jessica Holmes - who had a terrible show on Comedy for a while... and Shaun Majumder has joined This Hour... still some of the funniest sketch comedy ever.

If you don't mind my prying, Alan - you're a born Canuck, but moved to NY and occasionally commute back to Dwight, ON?

Bren R.

Bren - Bean night in Attica has me chuckling. I love that kind of turn of a phrase!

But the downside to small woofers is you need four 6.5-inch woofers to equal the air moving capacity of one 13-inch.

Area=(pi/4)*D*D

Hence the subwoofer!

Which probably also has a great deal to do with the lack of ginormous drivers in modern speakers.

Personally, I probably would veer away from subs with drivers of greater than 12 inches, just because of that percieved sloppiness. 'Course, if they sounded great, bring 'em on!

Exactly... more smaller drivers will move the same air and do it more efficiently and with less slop.

I finally convinced my neighbour to ditch the 12" sub in his truck for dual 8"... after fighting with him on "nah, man, I want a lot of bass... BIG bass, man!"... he was, as can be expected, a lot happier with the tight bass sound. And he got to return the expensive R1pPin'-BaSs-XPloZion brand sub and got money back on top of the dual 8s.

(BTW, it's slightly more complicated than the overall surface area of the cone - the physics majors can explain that part better)

Bren R.