Raising the While Flag on 604 Project

[oface1]

Seadweller,

have looked at your speaker connections? Sounds maybe there "might " be a phase issue.

I had a similar problem with another set of speakers....

sorry if you have all ready went through the trouble.

I have 604-8k's and at very low volume the bass is a little anemic, but when I crank it up , I get bass. Plus it looks like I will have to do some acoustic panels to help tune the room. I have a bass nodes when I walk around. DO you notice an increase/decrease in the BW when you walk around while listening?

-chris

[Seadweller]

Seadweller,

have looked at your speaker connections? Sounds maybe there "might " be a phase issue.

Hi Chris,

Yep, I've gone through the connections 100 times at least! I do notice that the bass improves in the very back of the room, but I'm sure that's normal. Some CD's have more bass than others, but in general, the bass output is much weaker than my previous pair of speakers.

It seems that the low bass output, and excessive midrange output have combined to create one heck of an issue to overcome..

[oface1]

Hmm...

Well, I can tell you that my 604's (in 620 A cabs, using the older GPA XO), do not have the slam/impact in the bass region that I was used too, but it is there....

And just like you, I got to the back of my room and there is the bass, just rattling the walls (music depending),

But when I go to my listening position, it is not as pronounced.....

when you say the bass is weaker, can you give a factor maybe?I know that he 604 isn't suppose the be the last thing in BW dynamics, & and there is a significant drop below ~40 Hz.....Have you tried using a Active XO or any other Eq to adjust to taste?


-chris

[aeyb701]

Good day:
You mentioned insulation-too much can hinder bass extension in my experience-typical thing is to line one opposing side of each pair of sides from what I've gleaned on this site over the years.
I didn't read if you were using new GPA drivers or 604-8K's, when I glanced back briefly. New drivers may have very stiff suspension, as I know from a 604C re-cone from GPA versus the springiness of the original cone. This may or may not affect LF response, and if so does it need time and use to improve? I don't know and have not been able to tell from a forum search. I have not used mine long enough to tell.
What about trying original Altec 604-8K crossovers, without the tweaks? I have -8K's in Stonehenge-style aftermarket enclosures, about 8 cu. ft., with orig. Xovers and they sound great- strong bass is there when the program calls for it, but no bass hints or boom ("undertones"?) when there is no bass info.
-Jon Archibald

[vuki]

Hi,
few months ago friend of mine bought GPA604-8hII. He built 10cu ft. boxes and decided to use Jeff Markwart's crossover design. To make a long story short - it was disaster.
Very bright (no bass), extremely colorated midrange - unlistenable. He asked me for a help.
Measurements revealed the situation I just described. So, after a bit of measureing, soldering and listening here is what I came up with. It measures pretty linear and sounds excellent. Anyway - I think it's worth a try if not satisfied with stock (GPA) or any other crossover.

[Panomaniac]

Hey, maybe we've got you back on the horse! :2thumbsup:

If you really want to tweak, you should get a Behringer DCX2496 and an extra amp. You may already have the amp. You can always sell the DCX2496 after if you don't want to keep it.

I got a pretty nice sounding rig going with the 604-8K and the DCX crossover. No lack of bass, not shouty. Good imaging. Those drivers should be close enough to your 604-8H to be no problem. My crossover points were 1160Hz on the woofer, 1530Hz on the horn. 3rd order butterworth. Some shelving EQ on the woofer and the horn. 28mm delay on the woofer.

With the DCX2496 you can tweak to your heart's content and we could even help. Once you get what you like, a passive crossover could be built. I feel for your crossover guy. Doing it long distance like that is super hard.

[Todd W. White]

The 604K's, almost without exception, have the wrong magnet on them - after EV bought Altec, they forced them to consolidate on some standard magnets EV was already using, and they made Altec use the DH-1A HF driver magnet, if memory serves, for the 604 and the 515.

The result in the 604-8K was the midband got too much energy. It wasn't that the bass was suffering - it was still there, just like always - but the midband was getting too much magnetic energy. Jerry Hubbard figured this out and fixed it - the GPA 604's don't have this problem.

I believe you're using GPA-built 604's, so this isn't an issue, but I thought I would mention it anyway.

Here's a really stupid question - have you tried taking them outside, weather permitting, and listening to them using the GPA crossovers, no eq, and a live recording? You might find they sound completely different, maybe actually really good!

[Seadweller]

Here's a really stupid question - have you tried taking them outside, weather permitting, and listening to them using the GPA crossovers, no eq, and a live recording?

Hi Todd,

Yes, GPA 604's is what I'm using...Actually, I haven't thought of taking them outside...The neighbors might think I'm nuts, but hey, who cares?

I've got to find an amplifier now...

[SD-50]

The 604K's, almost without exception, have the wrong magnet on them - after EV bought Altec, they forced them to consolidate on some standard magnets EV was already using, and they made Altec use the DH-1A HF driver magnet, if memory serves, for the 604 and the 515.

The result in the 604-8K was the midband got too much energy. It wasn't that the bass was suffering - it was still there, just like always - but the midband was getting too much magnetic energy. Jerry Hubbard figured this out and fixed it - the GPA 604's don't have this problem.

I have a pair of 604-8ks waiting for cabs and this is the first I've heard of this problem. Is there a solution to correcting the midband by replacing, or modifying the stock XO?
Cheers

[aeyb701]

The 604K's, almost without exception, have the wrong magnet on them - after EV bought Altec, they forced them to consolidate on some standard magnets EV was already using, and they made Altec use the DH-1A HF driver magnet, if memory serves, for the 604 and the 515.

Hi Todd:

In 2005 you said on this forum, "You see, during the years EV owned Altec Lansing (after the move to OKC), they forced Altec to standardize on a few magents, rather than the large number Altec was using. The early, Anaheim K's were actually quite good - almost as good as the "H"....but the change to a different magent hurt it a lot."

How do you tell an early vs late (Anaheim vs OKC) K? Serial number, but I recall no one kept a serial number list in all the reorganisation. I have K's and am quite satisfied with their overall balance, using K-xovers and Stonehenge encl's. S/N's are in the low 1000's.

-Jon Archibald