JBL 4682 TCB triple chamber band-pass

[JBL 4645]

Last year got some cheap x2 JBL 4682 the smaller professional duel 12" inside a triple band-pass chamber. Heavy they where, almost killed me getting these up the stairs and I was thinking of not wanting them, but I struggled and managed to get them up two floors and they are Heavy! The largest is 4688 18" the mid size is 4685 15".

I like them. I have done the frequency sweeps seen them I still like them.
They not the only ones in the room JBL 4645 home made over 23 years ago and JBL 4645C.

What I don't like about the 4682 is they are heavy!

What I like is the sound the feel of the low frequency.
I have them running each on a Behringer inuke 3000D.

I recently placed the second 4682 behind the cinema seat to smooth out sub bass or fill in where there is typical room snags where frequency dips down and is now restored to a fuller smoother range.

I had to replace new 2206 in the cabs and test and check wiring was okay and polarity.

Anyone else have the 4682 or 4685 and 4688?

 

[papasteack]

Common high freq chamber/port, separated low range chambers/port, push-push, that's a interesting parrallel 6th order bandpass.Thanks for the discovery.

JBL Technical Notes Volume 1 Number 19

 

[JBL 4645]

Not an easy JBL 4682 to move around the THX cinema.

 

[JBL 4645]

JBL 4682 TCB behind the screen. wow they thump low!

 

[SpeakerBob]

I've got a fair bit of info saved about the double 18 version, I wanted to build a low tuned version to cover 12Hz to 30Hz.

I notice you had trueRTA running do you have an in room measurement of your sub/s we could see ?

Cheers,
Rob.

 

[JBL 4645]

I've got a fair bit of info saved about the double 18 version, I wanted to build a low tuned version to cover 12Hz to 30Hz.

I notice you had trueRTA running do you have an in room measurement of your sub/s we could see ?

Cheers,
Rob.

Hello. Yes I have x6 Behringer ECM8000 / Room EQ Wizard REW / TrueRTA full version / winRTA 1/3, till June as its trail version.

I have done some tuning in past to see what I can or can't get more out of the 4682 12.

So what have you got in mind then?

 

[SpeakerBob]

A trueRTA sweep of the sub without any EQ or crossovers applied taken at 3 or 4 locations around your listening seats would be nice to see.

Thanks,
Rob.

 

[JBL 4645]

A trueRTA sweep of the sub without any EQ or crossovers applied taken at 3 or 4 locations around your listening seats would be nice to see.

Thanks,
Rob.

I think I can do that with TrueRTA and REW. But I'm sure I did a sweep graph months ago but can't find the one for the 4682 so I do it again. I like frequency sweeps.

 

[SpeakerBob]

trueRTA or REW would be fine. I use both here so whichever is easier for you.

(These days I tend to use REW more as the mic I use is calibrated to it for spl.)

Thanks,
Rob

 

[JBL 4645]

That's just the two 4682 TCB not including the other JBL. I think I do some tuning.

 

[SpeakerBob]

Is there a low pass filter on the sub ?

 

[JBL 4645]

Yes and for protection but its at the usual 120Hz and the system has a lot on it. So there's the graph I can do and it can be altered which I doing now. tuning.