[dgator]

I'm way over my head here but have an idea prompted by the recent OB thread.

I have a pair of 15" Altec 604e coax drivers in need of an enclosure. They are suited for a vented 9 ft box - but I don't want to do that and my wife really doesn't want that.

I was thinking about an OB with the 604e on top with two Eminence Alpha 15s to augment the bass. The 604e is not ideal in a narrow baffle (20"-22") OB - it's QTS is .21. So, from what I've read I would get an early rolloff especially on a narrow baffle - hence the two Alpha 15s. I understand that the Alpha (qts >1.0) is well suited for an OB.

This concept is kind of a cross between the Jamo 907, http://www.stereophile.com/floorloud..._loudspeaker/# and the Emerald Physics 2.3.

[Badwater]

Give it a try.  Drive the Alphas with a plate amp. If you want to see how it will do buy Martin's mathcad worksheets and model it. 

I did something similar using a EVSP12B.  It's a great system. 

http://gallery.me.com/marilynladieu#100295

[PaulFolbrecht]

A lot of people like the 604 on an OB with no bass augmentation at all.

[panomaniac]

See my thread here: http://www.audiocircle.com/index.php?topic=79439.0

It's a 605 in that rig, but I've tried the 604-8K on OB, too.
So you are on the right road with your 604 and a helper woofer.  Either the Alpha 15 or the cheap Goldwood 18" will be easy to use.

The tricky part is going to be the crossover, as always.

[audiotone]

See my thread here: http://www.audiocircle.com/index.php?topic=79439.0

It's a 605 in that rig, but I've tried the 604-8K on OB, too.
So you are on the right road with your 604 and a helper woofer.  Either the Alpha 15 or the cheap Goldwood 18" will be easy to use.

The tricky part is going to be the crossover, as always.

I would run the full rangers full range and drive the helper woofers with a reckhorn:
http://www.reckhorn.com/index.php?ln=en&prod=a403
cheap and it does the job...

Tony

[panomaniac]

The Rekhorn looks like it would do the job.  A plate amp will also do.  No high pass on the coax 15".

[audiotone]

The Rekhorn looks like it would do the job.  A plate amp will also do.  No high pass on the coax 15".

FWIW: I connect the the Reckhorn at high level input ( from the speakers output of the main amplifier) best result imo...

[panomaniac]

Have you found a difference doing it this way?

I was running a strange sort of system in Dallas.  300B tube amp on the Altec coax, and a Virtue amp on the 18" subs.  I took the signal off the speaker lines of the tube amp and ran into the balanced inputs of a DCX2496 as the sub crossover/EQ.  I made banana to XLR cables for that.  Worked well and allowed me to use the remote volume of the tube amp for everything.  It worked pretty well.

Running the Rekhorn like this out to work well, too.

[audiotone]

Have you found a difference doing it this way?

I was running a strange sort of system in Dallas.  300B tube amp on the Altec coax, and a Virtue amp on the 18" subs.  I took the signal off the speaker lines of the tube amp and ran into the balanced inputs of a DCX2496 as the sub crossover/EQ.  I made banana to XLR cables for that.  Worked well and allowed me to use the remote volume of the tube amp for everything.  It worked pretty well.

Running the Rekhorn like this out to work well, too.

It sound more as 1 like this...

My setup is very simple: altman dac to altman amplifier...so no preamp...that is why I do it like this...
I also have a very tube fine preamp, but the sound with is as good as without the preamp (so good preamp and good altmann stuff) and I like to keep things as simple as possible...so the preamp is in standby for the moment....

[panomaniac]

It sound more as 1 like this...

Yes, I know what you mean.  That works for me, too.