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View Full Version : Altec 3156 + JBL 2426J?



gjm
12-20-2012, 11:09 PM
I have the opportunity to acquire a pair of 8256s. Now, this is obviously only part of the story - the 3156s are rated as far as 2kHz.

I also have a pair of JBL 2426Js, and a pair of the complementary Bi-Radial horns - the 2370As. This looks, in frequency response terms, to be a good match.

There is an obvious impedance mismatch, but as I was planning to use tubes for the 2426Js, and a class-D amp for the bass, would this be less of an issue? Or is this a fundamentally bad idea?

Ultimately I would probably look to use the 15" drivers in a different way; one driver in a cabinet underneath the horn, and the other in a second cabinet above. A sort of d'Appolito pair of smaller 8182s or 8184s, sandwiching the horn. Something like this:

https://lh6.googleusercontent.com/-BWqye4Hy6U0/UNQKmSAmXWI/AAAAAAAAAak/TRmlEKFkCKI/s781/Tatsu+speakers.jpg

Perhaps a little smaller than these... And I'm not going to be trying for a curved baffle! These were made by a friend in Japan.

Thoughts? Comments? Suggestions for strong medication?

Thanks,
Graham

grumpy
12-21-2012, 11:31 AM
Hi Graham,

That's a lot of nice looking wood grain! It would be interesting to hear a bit more about the
pair in the pic (OB/sealed/ported/compression driver/...?), but to respond to your question...

I'd suggest not trying to use the 3156 drivers up so high... Perhaps just over 1KHz would
blend the drivers and horns together a bit better. One could live with the 2470 horns and
they can sound reasonably good, but there are other choices that often cost a bit more
but also are a bit less "in your face", i.e., 2344(a). Both horns have examples of passive
crossover/EQ circuits that work well, although you might need to scale values for the 16
ohm diaphragm (or emulate the transfer function in an active crossover).

Thanks for you post/welcome aboard.

gjm
12-21-2012, 12:27 PM
I'd not use the 3156s to 2kHz... I think that's a theoretical upper end.

I should point out that I know a little about speakers and so on, but not much! The 2426Js may not quite go low enough to properly make a compete system with the 3156s, but I've not spent time checking (yet).

I know little about the speakers in the pic other than that they took 12 years to build (!), are made from Bubinga, and use Sony drivers. And they are very big!

Given the 2470s are available and cheap, I may opt to use them for now. Any build will more than likely be in plywood, both for availability and for economics, but I would like to use 'proper' wood later. To give you an idea, at present it looks as though using some parts I have I should be able to put this together for about NZ$1000.


Edit: Where are my manners?! Thank you for the welcome! I'm fairly active on a couple of other hifi forums, but this is something very specific. :)
There may be something on YouTube regarding my friend's speakers - I'll check and post a link if I find it. He is a craftsman of the first order and pictures don't really do justice to the speakers. The sound, too, is something I would be very happy with, for a very long time.