Small enclosure for Altec 515b
Danny Bekhor
Can I place an Altec 515b driver in a small cabinet ?
I have a pair of these extremely efficient woofers and I would like to
use the in a small cabinet which will still give good results. Comments
will be appreciated.
Danny
Scott Dorsey
No. These are not like modern woofers. They are intended to be used
in bass horns, and the T-S parameters reflect that.
Xmax = 0.18 inch.
Re = 12 ohms
Vd = 23 cu in.
Fs = 24.7 Hz
Vas = 19.70 cu ft.
Ref = 4.60%
Qts = 0.17
Qms = 7.50
Qes = 0.17
Vid = 0.22
No, those Q values aren't typos. They really are like that.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Gordon Waters
>Can I place an Altec 515b driver in a small cabinet ?
>I have a pair of these extremely efficient woofers and I would like to
>use the in a small cabinet which will still give good results. Comments
>will be appreciated.
My specs for that woofer are very sketchy, but here's the scoop as I see it:
The standard ported box alignment for the 515b (you do have the 16 ohm
one, right?) is about 3.5 cubic feet each, with a port tuned to 45 Hz.
This will give you bottom end down to a rolloff (f3) at 60 Hz... ie, no real
low bass...
Alternate alignments are:
7 cubic feet ported, port tuned to 40 Hz, f3 of about 45 Hz (this would
give you a little low bass, and would probably be OK for a PA main speaker)
2.2 cubic feet SEALED (NO port), with an f3 of about 88 Hz. This would be
percieved by most people as having very little bass at all; a subwoofer
would be needed for this to really sound "full range"...
Also, the sealed box would have reduced power handling in the bass
compared to the ported boxes; it might be possible to damage (double-up
or deform the cone, or bottom out the voice coil) the speaker on a bass
note that might be OK in one of the ported boxes...
Regards,
Gordon.
--
GALAXY convention --------- Anime Weekend Atlanta 5- October 8-10,1999
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//|| ||//||// //|| ./ //_// //_// //_// --- http://www.anime.net/~awa
//~~|| |/ |/ //~~|| / ,,_// ,,_// ,,_// Gordon Waters-...@crl.com
Danny Bekhor
putting it into a huge box ?
Gordon Waters
Danny Bekhor <danny....@radguard.com> wrote:
>Wow, I am amazed. Isn't there any way to get bass fron this great driver without
>putting it into a huge box ?
Nope.
Basically, there's two ways to get loud low bass output: big boxes, or
big amps.
On one hand, the 515 is a driver from a day when amps were tiny, and boxes
were huge.
OTOH, we now live in an era when BOXES are tiny, and AMPS are huge.
Completely different speaker designs are required for THAT, versus the
above...
Not only will the driver have problems with low bass in anything other
than huge boxes, it will ALSO have problems even if you DO manage to
generate an alignment for low bass (such as the 7 ft^3 box I
mentioned)... in that the suspension is simply NOT made for the massive
excursion required to get low bass without the HORN that this driver was
made for.
My suggestion? Find somebody who will trade you a good pair of JBL 2231s
or 2235s, or a pair of the Eminence Beta/Gamma extended-LF series, or
something of that ilk, for the 515s. It's simply a physical
IMPOSSIBILITY to get the simultaneous trio of high efficiency, low bass
extension and small box size from the same speaker and box. Simple
physics dictates otherwise... so if you really need low bass in a small
box, you need to simply knuckle down, buy the big amp you'll need, and get
some speakers that will handle the power and give you the low end
extension you need in a workable box size...
Scott Dorsey
Danny Bekhor <danny....@radguard.com> wrote:
>Wow, I am amazed. Isn't there any way to get bass fron this great driver without
>putting it into a huge box ?
Is there any way to get great performance out of a Porsche without
putting an engine into it?
The 515 just isn't designed for what you want to do. It's a totally different
kind of device.