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Lionel PAUTY
10-08-2003, 01:06 PM
Hello,

I would like to build a JBL 4688 subwoofer, but I don't know how the internal construction is.
I know it's probably a variation of Isobaric, but I don't understand how the loudspeakers are laid out.
If some body has an idea or the plans :)

Thank you for your help.
sa660
10-13-2003, 07:30 AM
Go to ebay.co.uk
You can't get cheaper than this.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=3051692078&category=21145

Good luck
Lionel PAUTY
10-13-2003, 10:17 AM
Thank you,
but I've two 2240 JBL already and I want to build my sub himself. I've send a mail to subwoof in Marketplace forum, who sell a 4688, but I d'nt have any answer:mad:

Best regards
Lionel
sa660
10-14-2003, 05:25 AM
the box are with precision device 18"
tu peux revendre les 46cm PD et installer les bon vieux HP jbl 2240.

bon courage. J'ai essayer de trouver les plans et puis j'ai abandonne de plus avec un bon caisson bass reflex tu peux deja faire beaucoup de bruit.
subwoof
10-15-2003, 05:17 AM
" Thank you,
but I've two 2240 JBL already and I want to build my sub himself. I've send a mail to subwoof in Marketplace forum, who sell a 4688, but I d'nt have any answer "

I replied 2 days ago....:)

No plans are drawn - it would take hours and I cannot afford the time right now...:(

sub
Lionel PAUTY
10-15-2003, 01:15 PM
I understand. There are no problems :cheers:

Thank you for your answer.

Best regards
Lionel
Alex Lancaster
10-15-2003, 01:35 PM
Lionel:

Out of curiosity, I went to "vintage" in JBLPro, but there are no plans; in my opinion, get some 2245īs, or recone the 2240īs (same motor, diff cone suspension and coil), and build vented boxes, that should give You deeper bass, and be easy to build.

Alex.
4313B
10-15-2003, 01:52 PM
I'll second that suggestion Alex :)

Or you can buy a pair of 2242HPL's from me and build a pair of 4645C's ;)
I'm selling them two for one :eek:
Alex Lancaster
10-15-2003, 02:03 PM
I guess You could force electrically the 2242's (they handle a lot), to get below 35Hz?

Alex.
4313B
10-15-2003, 02:43 PM
"I guess You could force electrically the 2242's (they handle a lot), to get below 35Hz?"

Well, check this out and see what you think. 4645C (http://www.jblpro.com/pub/cinema/4645c.pdf)

I've got my pair of 2242HPL's and can confirm first hand what G.T. has stated. "They aren't even of this planet!"


The Synthesis S1S originally used the 2245H and was tuned to the "usual" 30 Hz. It now uses the 2242HPL and is tuned to 25 Hz just like the 4645B and 4645C. The original 4645 used the 2245H.

Another link:
Technical Notes, Volume 1, Number 22 (http://www.jblpro.com/pub/technote/tn_v1n22.pdf)