Attenuating the HF on a 604

**juniper** · November 9th, 2011, 09:58 AM

Cradeldorf, What type of crossover are you using?

**bowtie427ss** · November 9th, 2011, 10:23 AM

I believe the 604 is a combination of 416-8B and an 806/804 HF drivers, if so, then they are 109 and 98 dB sensitive respectively.

That's actually closer to the recipe for a 605. The 604 uses 515 and 802 motors, basically.

**amandarae** · November 11th, 2011, 02:56 AM

Originally Posted by bowtie427ss

That's actually closer to the recipe for a 605. The 604 uses 515 and 802 motors, basically.

Uh-oh! Apologies! So I been thinking backwards all this time as I thought the 605 is the 515/802 combo. Thanks for the clarification!

Abe

**bowtie427ss** · November 11th, 2011, 08:59 AM

Positively no apology necessary Abe.

I'm certainly no expert, but in general consider the main difference between 604's and 605's is that the 605 trades a few db of sensitivity for a bit tighter coherence/phasing between the HF and LF sections. The shorter magnet/motor structures of the 605 naturally put the acoustic centers of the moving assemblies closer together.

I've read that 604 production was stopped while 605's were in production. I doubt this is true for the entire production span of the 605 as i've seen catalog pages advertising 605B and 604E simultaneously.

Some points to ponder:

Is there a significant audible difference between 604 and 605?

Is this(phase coherence) why the Beatles preferred it over the 604?

or

Was the cost/price difference truly the most decisive factor for users of a 605 vs. 604?

**cradeldorf** · November 10th, 2011, 02:49 AM

Originally Posted by juniper

Cradeldorf, What type of crossover are you using?

GPA N-1600 16A crossovers. Like this
http://www.ebay.com/itm/Altec-Lansin...-/230631710252

**juniper** · November 10th, 2011, 10:12 AM

Originally Posted by cradeldorf

GPA N-1600 16A crossovers. Like this
Altec Lansing GPA N1600-16 Crossover NEW | eBay

I was afraid of this, a few months ago I purchased some GPA X-overs but for 604 8-g's. I haven't installed them yet. I have always heard that Altecs can have a shout or a bite to them up top, but with my 604's and X-overs, I have yet to have this type of problem. I can't wait too hear the new x-overs for comparison. GPA does some amazing things!!! Bill is the best!!!!

**cradeldorf** · November 10th, 2011, 04:41 PM

Originally Posted by juniper

I was afraid of this, a few months ago I purchased some GPA X-overs but for 604 8-g's. I haven't installed them yet. I have always heard that Altecs can have a shout or a bite to them up top, but with my 604's and X-overs, I have yet to have this type of problem. I can't wait too hear the new x-overs for comparison. GPA does some amazing things!!! Bill is the best!!!!

Well like I said I hit the lo cut buttons on my EQ and they smoothed right out. Very enjoyable now.