which 10" drivers

[Akira]

i am building dual 10" compression subs. the design is simple: separate 10" reflex enclosures aimed at each other, housed in the same box, firing through a narrow slot. this is a trick used in sound reinforcement systems designed to give more kick and impact verses smooth low end response.
this sub need only reproduce 30Hz to 60Hz.
what drivers should i use, new (prefered) or vintage.
i don't want to go any larger that a 10" driver for three reasons-- size, diaphram motion speed and tightness. (no over hang common in 18" drivers)
Akira

[speakerdave]

Interesting idea. I would suggest you consider going to 12". Study the information on the woofer in the LSR32/LSR6332, the 252G. This woofer is available new for something around $250, as I recall. Also available in a 2-ohm version, the 252F, which JBL uses in a sub for the LSR series.

David

[whgeiger]

…your design strategy, as it is based on false premises:

A,

Remarks {...} follow your text.

Regards,

WHG

)snip( this sub need only reproduce 30Hz to 60Hz.

{A one-note boomer! Why? It must also perform well for at least one octave into the crossover overlap region(s).}

what drivers should i use, new (preferred) or vintage.

{Those with large [Vd]=[Xmax]*[Sd] and low [Qts] <= 0.3 (this is not typical vintage performance). Whatever driver you choose to use, enclosure acoustics will need to be tweaked to match its TSP’s.}

i don't want to go any larger that a 10" driver for three reasons-- size, diaphragm motion speed and tightness. (no over hang common in 18" drivers)

{“size” (Presume in regards to enclosure footprint required) - It is possible to have a larger driver in an enclosure of a footprint smaller than that of the one you are considering. For an example of this, see products from Velodyne }
http://www.velodyne.com/velodyne/products/specs/DigitalDrive.html

{“diaphragm motion speed” - Presume slower is what you are after; but, for equal output, a smaller [Sd] diaphragm must move further in the same time frame (same frequency) than that of one with a larger [Sd]. So the larger [Sd] driver moves slower over a smaller distance, but weighs more. So?}

{“tightness” - has everything to do with [Qts] and little to do with [Sd] other than the associated increased mass of the larger diaphragm. Here the mass increase is typically compensated for by use of a larger (stronger) motor. Also, mass roll-off and the upper limit of the driver’s piston range are non-issues at the frequencies of interest even when they are extended several octaves into the crossover overlap region.}

[JuniorJBL]

simi 5th order. Tune (port) the center chamber then it is a fifth order. Tune the 2 outside chambers (as well as the 3rd) and you will have a 7th order. I think JBL made a control series sub in the early 90's with this design, but I think they were 6" drivers. Also this is a Bose approach. Used alot in car audio designs.

IMO they are not quite as responsive as a sealed or 4th order box

They do make some lowend tho....

[Zilch]

http://www.jblpro.com/mpro/PDF/MP255S.pdf

http://www.jblproservice.com/pdf/MPr...ies/MP255S.pdf

More like triple-chamber bandpass, actually:

http://audioheritage.org/vbulletin/s...ead.php?t=3922

Try 123A-1, maybe. They cheap....

[johnaec]

This too: http://www.jblproservice.com/pdf/Sou...tor/SF22SP.pdf

John

[JuniorJBL]

The Control SB-5
http://www.jblpro.com/pub/obsolete/Control_sb-5.pdf

[Mr. Widget]

Isn't that the triple chamber bandpass design that Bose has the patents on and forced JBL to stop making them?

Widget

[JuniorJBL]

Isn't that the triple chamber bandpass design that Bose has the patents on and forced JBL to stop making them?

Widget

I was not aware that that had happend.

They (bose) had one for a car and we called it the Bose Hose
It had 2 hoses comming out of it to go into the cab of the car.

[Zilch]

See the thread I referenced above in post #5. The Bose patent has long since expired, and JBL is "dabbling" in multi-chamber bandpass subs again.

Gordon discloses a cool design using 123A-1's there.

See also 4682 (12" 2206), 4685 (15" 2225), and 4688 (18" 2240) "push-push" TCB designs:

http://www.jblpro.com/pub/obsolete/4682.pdf

http://www.jblpro.com/pub/obsolete/4685.pdf

http://www.jblpro.com/pub/obsolete/4688.pdf



And "slot" array alignment of PD125 at bottom here:

http://www.jblpro.com/pages/pd_series/pdf/PD125.pdf

There's more info on subwoof arrays on the JBL pro site in various application manuals. Use "Search" there to find it.


Nobody's come up with the subject Tech Note, though, Volume 1, #19.

C'mon, guys, I KNOW somebody's got it out there....

[speakerdave]

Could somebody sketch the inside of one of these things for me?

thanks,

David

[Zilch]

Huh?

Inside of SB-5 is shown in the link provided by JuniorJBL above. That's a dual isobaric (push-pull) triple-chamber configuration. The two outer chambers are tuned to the high-pass frequency, and the common center chamber to the low-pass frequency. The frequencies can be determed from the impedance curves.

The layout of the push-push 468X series is unknown here, thus far. Subwoof was gonna sketch one up for us.

[With pics and dimensions, please.... ]

[JuniorJBL]

You da Man

[Zilch]

You da Man

Subs is just plain FUN stuff.

Control SB-5 knocks me out when I put the cover on.

I can just imagine what one built with REAL drivers would sound like....

[JuniorJBL]

We used to build lots of boxes. The best one(s) was in an Ford e350 extended van
with 14 12's in 2.5cu ft boxes with 4 Hifonics Collosus (1000w per ch@4ohms) It did 171db. It felt like your chest was gona cave in and your head was gona explode. It used to pop the windshield out if you did not leave the doors open

I was a bit younger then

P.S. I should say no one was in the van when we did the reading
C weighted