DIY 4320

[Woofer]

OK, just to confuse the issue, I now have two different measurements for the 'net' 'front to back' dimension (depth).
One of 14 3/4" (as stated by Zilch) and the other of 15 1/4"
(as worked out from Heather's specs)

If the overall depth is 20 1/4" and the front overhang is 3 1/2" and the back and baffle thickness total 1 1/2" (3/4" each) then therefore the inside measurement should be:
20 1/4" - 3 1/2" - 1 1/2" = 15 1/4", right?

Yet Zilch, you state that particular measurement is 14 3/4".
How is that extra 1/2" accounted for?

[Zilch]

Heather and I both provided the same dimension, from the inside of the rear baffle to the outside of the front baffle, which is 3/4" thick. 15.5 minus 0.75 gives 14.75" inside depth of the cabinet.

The missing 1/2" from the exterior dimensions is the the inset of the rear baffle in back. It's not flush with the sides, top, and bottom....

[Woofer]

Heather and I both provided the same dimension, from the inside of the rear baffle to the outside of the front baffle, which is 3/4" thick. 15.5 minus 0.75 gives 14.75" inside depth of the cabinet.

The missing 1/2" from the exterior dimensions is the the inset of the rear baffle in back. It's not flush with the sides, top, and bottom....

Ahhhhh.....
Got it.
I didn't know about the back inset.
Cheers heaps for that Zilch.

[Zilch]

What're ya gonna put in them homebrew 4320s, Woofer?

[Woofer]

What're ya gonna put in them homebrew 4320s, Woofer?

I have a pair of 2215A's, a pair of 2470's but with 2421 8 ohm diaphragms, and a pair of 2307 Horns, (but I've misplaced the lenses and I'm still looking for them,) and a pair of 077 Slots, using a 3105 crossover for the slots and a Crown VFX-2 for bi-amping from Lo to Mids. (I'm not really happy with the 3105 as I think it crosses at 7K, and I think that's too low considering the 2470/21's will go up to 20K anyway.)
To power up with I have a Phase Linear 700 Claire Bros. model but I'm also trying to find a PL 400 II for the Horns and Slots to replace the Crown D75 I'm using on them at the moment.
It's taken a while to find everything.
All I have left to do now is build the boxes.

[Zilch]

Low pass in 3105 wants 16 Ohms, I believe.

I just did an 8.5 kHz highpass for the slot. You should be able to extract it and rework the lowpass (right of LPad1) for 8 ohms:

http://audioheritage.org/vbulletin/s...246#post130246

[Woofer]

Low pass in 3105 wants 16 Ohms, I believe.

I just did an 8.5 kHz highpass for the slot. You should be able to extract it and rework the lowpass (right of LPad1) for 8 ohms:

http://audioheritage.org/vbulletin/s...246#post130246

What, just change R6 to something like 10 ohms, or will the choke and capicitor have to be changed also?
This is way out of my league, so forgive me for asking.
I'm an old school sound guy that knows where to kick 'em to restart 'em, but I'm afraid my technological understanding is a tad wanting.

[Zilch]

Leave the 20 Ohms. Halve the choke and double the capacitor.

If I get a chance later this week, I'll try that for you, as I still have the breadboard here....

[Woofer]

Leave the 20 Ohms. Halve the choke and double the capacitor.

If I get a chance later this week, I'll try that for you, as I still have the breadboard here....

I knew I'd get it round the wrong way...
Thanks for clarifying, and thanks for the offer. Don't go to too much trouble though. If you can, great, if you can't, it's OK too. I'm open to experimentation at the moment.
Alternately, I might seriously reconsider just running another active crossover, and power amp for the 077's
Furman 24dB crossovers are quite good and they seem to be cheap and in abundance 'downunder' at the moment.
They feature Phase Reversal, Limiting on each output, Compression driver/horn EQ switches on high outputs and a Slope switch gives Linkwitz-Riley/Butterworth choices. (for what it's worth)
I'll just have to remember to add some blocking capacitors to the mid and hi drivers just in case any of the amps go DC.

UPDATE:

I've just pulled the 8 ohm diaphragms out and replaced them with 16 ohm aftermarket ones (my original ones before I got the new JBL replacements), and the problem is solved for now. (certainly doesn't sound any worse)

[Zilch]

I confirm LE85 on 2312 (H92) is 14-5/8" long (what Toddalin calculated, exactly,) and fits in 4505WX (what Chas said.)

There's only 1/8" to spare, so you have to bolt the driver on with the horn in place; don't bolt the horn to the baffle until after that's done, so it can rotate to make attaching the driver easy: