JBL Control SB-5 Project?

[Surtsey]

I'm considering acquiring JBL Control SB-5 box. I assume it's unloaded. At the moment I've got 6.5" woofers coming out of my a$$. I've no experience with 6th order. Can I throw in any four (matched) drivers and adjust the port tuning accordingly?

 

[Brian Steele]

Doesn't the SB-5 use 5" drivers...?

Looks like it uses four of them in a triple chamber isobaric 6th order bandpass. Not sure what was the thinking behind that, because the bandpass should provide decent acoustic filtering anyway.

I built something like that YEARS ago. We're talking at least 25 years ago. It worked well. Too well. Didn't know the woofers were being over-driven until... no woof :-(.

 

[Surtsey]

According to the specs it uses 4 x 6.5"

 

[Michael Chua]

I may be wrong but I think they are the same 6-1/2" drivers in the JBL Control 5.

I had the SB-5 and the Control 5 in the 90s. Never liked them then, still don't like them now.

 

[weltersys]

Can I throw in any four (matched) drivers and adjust the port tuning accordingly?

If your drivers have the same bolt pattern as the JBL C5003 ( 6.625″/168mm diameter) you could "throw them in", wiring the inner pair the opposite polarity as the outer. If the bolt pattern does not match, you will need a right angle drill.

As JBL says "The SB-5 has a frequency response hump at 80Hz and falls rapidly below that".
The SB-5 is at least -10dB at 45Hz compared to it's output at 80Hz, and below 45Hz drops like a rock.
Hardly an octave of range, but tuning the outer chambers lower (lengthening the ports) would reduce the low frequency output even more.