Duplex in 828 cabinet

[jack6428]

I am currently preparing to setup my system to be a 4-way using a Rane AC24 active crossover, with four separate power amps per channel. The system levels and delays will be set with a Rane AC34.

I will be using one 828 cabinet on each channel and a separate subwoofer cabinet in the middle.

Each channel will have an 18 inch 3184 (one of the two in the separate sub cabinet) going to about 90 Hz, then a 515B going to about 400Hz, then a 390 driver (bought these from GPA) coupled to an 803 horn going to about 5KHz, and finally an 802G above that.

I?ve considered many horns for the 802G

- horn like that used in the center of newer Duplexes
- an MRxxxx (opening is 12 X 12)
- a small rectangular plastic Mantaray about 12 X 6

My problem is I?m not real happy with the look of these horns hanging off the 803. I could put the little Duplex horn in the 515 opening but not thrilled with that either.

Could I use a Duplex instead of the 515? Will the high frequency be OK propagating from the curved horn cavity?

[blakehoo]

Hi:

What you propose should be fine....but let an expert (or one who has tried the combo) comment on that.

Try this for the crossover:

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

It should simplify set-up and "tweeks" I really like it in 2 and 3-way. Also:

http://www.transcendentsound.com/Beast%20OTL.htm

Since you really care about "musical" bass ...by your choice of bass driver. This amp seems to be the best of all worlds for highly transient bass. I cannot wait to try this amp with the 3184. (The smaller OTL SET amps are fine for the 802's the 290's and would be for 604's.) The 3184 sounds much better in a larger cab. Someone, else on this board can help you better with that.

Good luck, with that neat set-up

[jack6428]

Your attachment for the Beringer crossover looks very cool. Does it do more than the 4-way Rane AC24. I haven?t used my Rane yet but in addition to crossovering, it also has level and delay features. I also have the Rane RA34 Realtime Analyzer to work with the AC24 during setup.

Your amps are also very cool. A little out of my price range though. I?ll have to make due with my two Dynaco ST70 tube amps and a couple of higher power transistor amps (one is the 9440A Altec, and an Aniversary series model ? Altec).

I think I will use the ST70s for the 802Gs and the 290s and the transistor amps for the 15 and 18 inchers. Any opinions on this choice (tubes for highs and xtors for lows)?

My subwoofer cabinet will be common to both channels. One 3184 wired to each channel. The cabinet is 32 sq-ft (4X4X2). It was tuned by someone who knows how to do this kind of thing (hopefully). Not sure what the lowest low will end up being.

I was thinking about getting some GPA 704-8A Duplexes. I?ve read some entries from people on this Board who say it may be better than the last Altec Duplexes. Any opinions?

[GM]

Greets!

Sure! Ideally you have to add some damping material to the top inside of the horn flare, but the dudes out in Japan usually don't bother. Neither did Altec for that matter.........

As always though, YMMV.

GM

[boltupright]

I tried the 604 8G in my 828 cabinets & it didn't sound very good, to my ears anyways, I had to make a special backboard for it so that the H/F driver would poke through, the chanfer of the H/F driver was sealed using a high density foam compressed against the chanfered edge to ensure a good seal.
But it still didn't sound as good as in the 620 cabinets, actually it didn't sound good to me at all.

[jack6428]

Regarding damping.

What type and thickness would be appropriate and still look OK?

Not glad to hear the 604 Duplex sounded bad.

I wonder if mine may fair any better since I am only putting 5kHz and up into the Duplex horn and the 515 only gets 90 to 400Hz.

jy

[Todd W. White]

Bil Hanushack designed Altec's 9864-8A and 9894-8A, both were BIG duplex speakers that worked really WELL!

Here's a link:

9864 Ad

And one more:

9894A

[boltupright]

Yeah, not to sound like a smart a$$, but it's obvious that the 9864 design to a 604 in an 828 cabinet is like comparing apples to oranges.

[jack6428]

Hi Todd,

Thanks for the info on the 9864/94 speakers. I never new about these.

Is the bass horn flare similar to the 828 cabinets?

If I was able to get the high-freq horn extender do you think this would solve my problem?

What can you tell me about the GPA 704-8A Duplex? How does it compare to the old stuff? Could you email me with a price?

jy

[Todd W. White]

Well, the idea with the 9864/94 is to apply the DUPLEX principle to a large-format design.

The cabinet is a modified (read: corrected/improved) Model 816 cabinet. It uses a larger diaphragm, true, but they do sound really good!

Jack - the e-mail link didn't work. E-mail me at [email protected] and I will get you your information.