[ttan98]

The local speaker store is offerring a 15" bass driver  at a very good price, about US$80 each.
As I am new to th OB design I welcome any comments on the suitability of this driver as an OB bass driver. The spec as shown below:

SPECIFICATIONS:
=============

This series of loudspeakers feature Rolled Rubber Surrounds and high rigidity, fibre impregnated Poly Emulsion Coated Cones (PECC).

All voice coils are wound on Aluminium Formers, and magnet pole pieces are vented for heat dissipation. Bump back plates are employed to prevent voice coil over-excursion.

Specifications:

Rated Input Power: 100W RMS
Max Input Power: 150W
Impedance : 8 Ohms
Frequency Resp: 28Hz-1.5kHz
Resonant Frequency: 28Hz
Sensitivity 1W @ 1m: 94dB
Voice Coil Diameter: 49.5mm
QMS: 4.29
QES: 0.44
QTS: 0.4
VAS: 314.6L
Nett Weight: 5kg
Magnet Weight: 1.4kg
Cutout Diameter: 355mm
Mounting Depth: 160mm

Suggested Vented Enclosure
(Tuned to 45Hz)
Volume: 100L
Port: 2x 100mmø x 100mmL

Suggested Sealed Enclosure
Volume: 80L


I notice the Qts is a little low, does it have any significant effect on the sound quality, possibly by adding a series resistor with it increase the Qts to say 0.6. Is this a viable option?

Any comments are welcomed.

Thanks in advance.

[hasselbaink]

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The woofer has a desirable Fs of 28 Hz and the Qts of 0.4 is OK, but what is the Xmax?
Do you intent to drive the woofer with active filtering? It would be nice to see a frequency and impedance chart too. It can tell you a lot about the quality of the driver. It has a good sensitivity of 94 db, but here is the kicker; how sensitive is it below 100 Hz? That would be nice to know.
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[ttan98]

thanks for your interest, I am afraid I don't have any more additional info. They are made in China like most drivers nowadays.

another query, will a dual 12" woofer give suffcient performance or only 15" woofer  a necessity?

[scorpion]

ttan98,

I have looked around at Altronics and Australian ebay. There is one company Etone that sells a 12" unit with some suitable parameters.
It is presented like this: NEW etone 12" 100w RMS Hi-Fi Speaker made in Australia and sells at this ebay shop: http://stores.ebay.com.au/etonesound_W0QQcolZ4QQdirZ1QQfsubZ0QQftidZ2QQpZ2QQtZkm . Ask this seller for Xmax, if it is 4-5 mm two per side would be quite alright for a bass-dipole. Giving almost 100 dB att 40 Hz. One 15 " unit would give about the same performance. With a Qts of 0.4 you will have to boost
bass to get a level response and then you also need 6 - 8 mm Xmax.

/Erling