Quote Originally Posted by RonSSS View Post

... I've never heard the GPA 604's.
But I wonder.......
Are they really that good?
Are the crossovers really that good?
Altec got the dual shelved crossovers for these reasonably right, and they flat work.

Your test of removing the horn tells a lot in my opinion......the schematic for the stock crossovers for the woof is a simple 12dB/oct setup.

Maybe the woof of the GPA drivers just sucks?
Ever tried one of the vintage versions?

Ron
@ron,
before I decided to purchase the GPA 604H series II I had the opportunity to audit 604E in 602 EMI enclosures and 604H in 612B enclosres side by side. finding a serious pair of vintage 604H (last with alnico and first with tangerine phase plug) is a jackpot. only reason why I would shift from GPAs to vintage Hs when ever I get the chance to buy a pair of those vintage Hs is pure PSYCHOLOGY! and I'm quite sure that if I swap them I already miss the GPAs because I fell in love with this in-between vintage and modern sonic that might distinguish the series II from the original Hs I've audited ...

@seadweller,
I use the 604H series II in 'gutted' 612B enclosures. they are lifted from the ground via spikes, bent and sloped. also my room is quite huge (>40sqm) the distance while auditing is 2.5 to 3 meter. the bass is lovely delicate and subtle I've never heard before with my former audiophile systems that contained all tube gear and speakers for more than 15k. however in my experience cables and amplification are quite important next to the crossover. in my case triode in single ended is an outperforming match ...
good luck