woofer with high Qms/Qes

MCPete

Member
2005-11-01 1:00 am
Does anyone know of a currently-sold woofer with 0.3 > Qes > 0.2 and Qms about 30 times Qes? I need this type of woofer to test a bass extending network.

I've had some success with Pioneer DVC 8" B20FU20-52D with Qes =0.23 and Qms= 4.05. My calculations show that a higher Qms/ Qes ratio will improve the amount of extension possible.

The size of the woofer at this point isn't of concern to me, but I would like to limit the unit cost to maybe $60. or less because I'm not absolutely certain that I can achieve success with it.

A woofer that fits the bill that I can't locate is Pioneer 6-1/2" woofer C16LU20-51F. This woofer has Qes = 0.23 and Qms = 7.63, so Qms/ Qes = 33.

I don't think that it would be easy to modify a woofer to obtain a higher Qms.

Any help is appreciated,
Pete
 
Does anyone know of a currently-sold woofer with 0.3 > Qes > 0.2 and Qms about 30 times Qes? I need this type of woofer to test a bass extending network.

I've had some success with Pioneer DVC 8" B20FU20-52D with Qes =0.23 and Qms= 4.05. My calculations show that a higher Qms/ Qes ratio will improve the amount of extension possible.

The size of the woofer at this point isn't of concern to me, but I would like to limit the unit cost to maybe $60. or less because I'm not absolutely certain that I can achieve success with it.

A woofer that fits the bill that I can't locate is Pioneer 6-1/2" woofer C16LU20-51F. This woofer has Qes = 0.23 and Qms = 7.63, so Qms/ Qes = 33.

I don't think that it would be easy to modify a woofer to obtain a higher Qms.

Any help is appreciated,
Pete

Hope you are measuring the TS specs for your drivers, as the published ones can be (often are) significantly different. Ocassionally, the differences are compensatory, so that the design works fine anyway. If your design is relatively insensitive to TS parameter variation, then you are likely ok.

Regards,

Bob
 

MCPete

Member
2005-11-01 1:00 am
Thanks for the responses. I'll look into the Selenium and Chiare woofers. Those brands are unfamiliar to me, but maybe they are available from some company in N. America.

Bob- Measured and published parameters is a real problem for me. In the case of one woofer that I purchased and returned to PE, the impedance at Fs was drastically less than what would be the case for a Qms/Qes equal to about 30. I'm fairly certain that I do need that high ratio for what I'm doing to be significantly effective.

Thanks again to all,
Pete
 

MCPete

Member
2005-11-01 1:00 am
Flaesh, I have no previous experience at all in doing the mechanical things that you suggest. Also I would think that if I could increase Qms, undoubtedly I would change other characteristics of the woofer at the same time, probably in ways that I wouldn't like.

Thanks for the reference to SB acoustics, Ron. As I said in my post #5, I found a big discrepancy between the specified and measured Qms/Qes of one woofer that I bought. Do you think that I could trust the specs of a pro woofer manufactured by Goldwood, the GW-10120 10", sold by Parts Express?

Best Regards,
Pete