604 8hpln

**maxserg** · November 26th, 2011, 03:59 PM

Hi to all!

I have only one 604-8hpln that have been reconed with original parts in the 80's (cone and hf diaphragm). It is since then in a "cabanon" sleeping there in a 3,5 cu. ft. box with a generic passive x-over. It sounds quite shouty even with the l-pad. It was designed for active biamplification for hi-power output.

Does GPA offer a passive solution or I should go for active. I would use it for center channel, L&R would be provided by JBL K-145 for the lows/low-mids and a JBL 2420 in a small Mc Caully horn-lens that look alike the JBL 2391 or the bigger JBL 2390 with the 1" throat adapter.(I have both horns sets)

The problem I see with the 2390 plus the adaptor and the driver is that it goes quite deep to integrate with the box.

It is for music/cinema use.

I don't want for the moment to have subs. Good bass is sufficient for music, and I know not for movies.

Thanks for your suggestions.

**RonSSS** · November 26th, 2011, 04:08 PM

I believe the 904-8A is the same speaker.
Stock crossover for the 604-8K or the 904-8A (I believe they are the same) should work well.
You can adjust both MF and HF response.

Ron

**Ronald Lee** · November 26th, 2011, 08:20 PM

I would go "active crossover," and you will never look back. Your woofer will feel the full dampening effect from the output of your amplifier because your amplifier won't see all of those inductors, resistors, & capacitors and it will cut down on the dampening. Of course it will cost a bit more, but I personally think will be well worth it.

I bet if you scrounge around, you can find some amps. You don't need much power especially in home type setting. When you bi-amp, the power is actually doubled. is actually double, ie if you have 60watt power amp for the woofer and a 30watt amp for the tweeter, the sum is 90 watts, but the effect is like 180 watts. more than adequate for a home.

**bowtie427ss** · November 27th, 2011, 09:37 AM

I believe the 904-8A is the same speaker.

Not quite. No argument intended Ron. But, if we're talking about these drivers in original form, there are as many differences as similarities beginning with one being built on alnico motors and the other ferrites. With the switch to ferrite came the new model number 604-168X

an original 904 uses a coil, former, and cone very similar to if not the same as 421 to acheive it's 150watt power handling at the cost of steeper LF roll-off.

The HPLN 604 uses a "604" cone with minor modifications to the coil and former to increase the power handling to 80 watts while retaining as close as possible the true sonic signature of a 604. The HF section uses a standard aluminum diaphragm. However, the HF section uses a 16 ohm voice coil to increase power handling.

If the OP's HPLN was re-coned faithfully, then no stock Altec network is going to be plug n play without modifications to compensate for the 16ohm HF load. It's not a big issue, but should be considered.

Just my .02.................

**RonSSS** · November 27th, 2011, 01:07 PM

You butthead, I'm right and you are wrong.......just kidding!

Thanks for correcting me.
The op could then just change the HF diaphragm to an 8 ohm version, and use the mentioned x-overs.
I really do think those are the same, unless I've completely lost my mind......which is a possibility. Note that I'm selling most everything. Or at least trying to.

Later!

Ron