I'm running my 604's at a crossover point of 1150.

2.3 Inductor on the LF. 9.1 cap on the HF. 9.1 cap/15 ohm resistor for the LF zobel and a 2uf cap across the hf wires. It's the only choice I have short of having them not sound good. 515's are garbage much above 1000hz. Still deafening and still working. even being driven with my 90 watt SS amp.

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Edit: I changed the HF cap to 9.1uf

Original 604's were crossed at 1000(and are to this day perhaps the best sounding 604 particularly through the XO region).;)

I cross my g's at 1250, but I try to be very careful with the volume knob...

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Originally Posted by juniper

I cross my g's at 1250, but I try to be very careful with the volume knob...

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Unless you're running a mild slope like 6db/oct, you're probably safer than you think.;)

I'm not saying you should try to push your 300 watt amp to clipping on them, but i think your ears will tell you when you're stepping on the danger threshold.

Cradeldorf
I never did think of the 1600 XO freq as golden.To me the magic was how it sounds. If you would like to do some listening tests PM me.
Don

A buddy stopped over today and confirmed that they sound better than he's ever heard. Like I said over on AK if a 515 is indeed what the woofer section is, they are rated at 20-1000hz why they mated that with a horn that shouldn't be driven below 1600 is beyond me. Juniper All I'm gonna say is mine go well into the ear splitting level without batting an eye. I can almost hear them laughing. :D
Don they sound much more like they should this way. :)

I've read that 604 E to the last sectoral before the CD types were only providing driver loading to about 1900 Hz but the Altec standard Xover is 1600 Hz

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Originally Posted by zelgall

I've read that 604 E to the last sectoral before the CD types were only providing driver loading to about 1900 Hz but the Altec standard Xover is 1600 Hz

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I could never grasp the concept of loading since the phragm is barely moving in the first place and then every bit of air it is moving has to pass through 3 little human hair sized slits in the phase plug?
I can't imagine I could load the horn if I put my lips on the phase plug and blew as hard as I could. That is if my definition of loading means building some kind of back pressure from the air trapped in the horn tube and horn assembly itself. I would surely think the phase plug is what provides loading if there is to be any.

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Originally Posted by cradeldorf

I could never grasp the concept of loading since the phragm is barely moving in the first place and then every bit of air it is moving has to pass through 3 little human hair sized slits in the phase plug?

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Think of the diaphragm that is like a tuning fork.When you wrap on the edge of the tuning fork it puts out a lot of sound but you won't see it moving much.It is the tremendous amount of vibrations in such a short time that creates the output or (SPL).Or something like that.

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Originally Posted by Altec Best

Think of the diaphragm that is like a tuning fork.When you wrap on the edge of the tuning fork it puts out a lot of sound but you won't see it moving much.It is the tremendous amount of vibrations in such a short time that creates the output or (SPL).Or something like that.

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Okay, that draws a better picture in my head. Thanks.