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Posted By: jbmjr Why small (diameter) bass drivers - 05/11/04 04:25 AM
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.
Posted By: BrenR Re: Why small (diameter) bass drivers - 05/11/04 04:49 AM
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.
Posted By: Ajax Re: Why small (diameter) bass drivers - 05/11/04 02:21 PM
! ! ! ! ! ! ! ! Now there's a simile you don't hear too often. Unbelievable, Bren!
Posted By: littleb Re: Why small (diameter) bass drivers - 05/11/04 02:25 PM
Bean night in Attica. First I heard of that one. HA, HA, HA!
Posted By: alan Re: Why small (diameter) bass drivers - 05/11/04 07:53 PM
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,
Posted By: BrenR Re: Why small (diameter) bass drivers - 05/11/04 08:28 PM
In reply to:

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!



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.
Posted By: Ray3 Re: Why small (diameter) bass drivers - 05/12/04 12:29 AM
Bren - Bean night in Attica has me chuckling. I love that kind of turn of a phrase!
Posted By: jbmjr Re: Why small (diameter) bass drivers - 05/12/04 06:12 AM
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
Posted By: Ken.C Re: Why small (diameter) bass drivers - 05/12/04 06:16 AM
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!
Posted By: BrenR Re: Why small (diameter) bass drivers - 05/12/04 06:25 AM
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.
Posted By: jbmjr Re: Why small (diameter) bass drivers - 05/12/04 06:36 AM
I am talking about regular speakers, not subwoofers.

For example, the Paradigm Studio 100 uses three 7-inch bass drivers for a total area of 115 sq. inches. A single 12-inch bass driver has the same total area.
Posted By: jbmjr Re: Why small (diameter) bass drivers - 05/12/04 06:44 AM
But I hear that SVS and Hsu subwoofers with 12-inch drivers are excellent. Do you know subs at similar price points with 8-inch drivers that are better?
Posted By: BrenR Re: Why small (diameter) bass drivers - 05/12/04 08:02 AM
In reply to:

I am talking about regular speakers, not subwoofers.



They're all speakers... the idea is the same.

In reply to:

But I hear that SVS and Hsu subwoofers with 12-inch drivers are excellent. Do you know subs at similar price points with 8-inch drivers that are better?



A single 12" is bigger than a single 10", so it will move more air, and it is cheaper than a dual 8" or 10" setup.

I'm almost tempted to build a cylinder sub like the one I helped a buddy build in high school... but, nah... all I need is another unfinished project.

Bren R.
Posted By: Ken.C Re: Why small (diameter) bass drivers - 05/12/04 02:34 PM
And at the time many speakers were coming with 12-18 inch drivers, subwoofers were not common. Also, I imagine that excursion also plays into it, not just total area.
Posted By: alan Re: Why small (diameter) bass drivers - 05/12/04 06:58 PM
Hi,

And it isn't just the cone area of the drivers, it's box size that is also an essential part of the equation. In other words, if you stick a 12-inch woofer into a ported floorstanding speaker enclosure of insufficient interior volume, then you won't get deep bass out of it no matter how hard you try.

The formulae for ported box volume, driver diameter and desired bass extension, were worked out by a couple of physicists, Thiele & Small some years ago (Thiele no relation to the Thiel speaker company in the US).

Regards,

Posted By: alan Re: Why small (diameter) bass drivers - 05/12/04 07:02 PM
Bren,

Yes. Lived in Toronto for 30 years and moved to NYC in '96 to work at Audio Magazine, which ceased publication in 2,000, then Ian C at Axiom called me. I'd known him since Axiom was founded in the early 1980s, when I was editing a magazine called Sound Canada and writing occasionally for Stereo Review in New York.

Regards,
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