gpa 604 8H II crossovers again, sorry

[Seadweller]

Indeed, Stephaen has gone to a 4th order crossover that he said measures incredibly flat in his room...I'm on the verge of going with his 4th order design, because I'm facing the same "hot midrange" issue...I've already ruled out source components, and have gone so far as to move from a solid state amp to a tube amp, thinking the higher output impedance of the tube amp might balance things out...On my system, vocals, brass, and any other "sound" in that particular range will drive you right out of the room...

I will say one thing though, I'm hooked on this driver...The dynamics and liveliness truly help to recreate that "you are there" presence...I just need to tame the midrange before my eyeballs shatter...

[selmerdave]

Have you tried adjusting the "toe in" of the speakers, perhaps more outward or straight so the drivers aren't pointing directly at your ears?

Dave

[Salectric]

Seadweller, I have the same GPA drivers and xovers, and my experience is so different from yours that I am quite perplexed by your comments. Here are a couple ideas or possible explanations for what you're hearing:

1. The GPA drivers and/or xover take a very long time to break in. I am estimating 500 hours before things really settled in. You say you have over 500 hours so I am going to assume this is not the explanation in your case.

2. Internal wiring. I have tried half a dozen different wires between the GPA xover board and the drivers, and they all sound radically different. Some of these were some pretty expensive types. This has given me some perspective on the sound of the wires that came attached to the GPA board, and which you are probably using. First of all, they sound pretty good overall. The stock wires don't have any serious flaws, but they do add some edge or grain and they don't allow all of the high frequency detail and nuances that the drivers are capable of. The wire that I am now using, and which hopefully will be my final wire, is the silver braid sold by Homegrown Audio. It's called SC-16 and it consists of 8 solid silver 22g wires for each conductor. The effective AWG is 13. It's pretty expensive at $32 per foot (but the braid has 16 conductors which you separate out for each leg, so it's really $16 per foot). It is well worth it in my opinion. The silver braid is very smooth, detailed, coherent, dynamic, full range, and with no added grit or grain that I can hear.

3. The binding posts that you use are also critical to the sound quality. I have been experimenting with this lately, and fortunately have come up with a solution that is cheap. After trying several expensive types and being quite disappointed with the change in sound, I have gone to a simple arrangement of having the speaker cable lugs and the short wire coming from the xover board crimped together on the same end of the binding post. In other words, the binding post isn't used as a conductor but rather just a means to hold the wire and the s/c lug together. Try this, and I suspect you will be amazed by the improvement in detail, coherency and smoothness.

4. Your other equipment may not be up to the standard of the GPA gear. It does reveal what is happening upstream, the bad as well as the good.

5. Perhaps the drivers or the xover is defective.

6. Finally, just like no one shoe fits all people, maybe the GPA 604 just isn't your type of sound.

Dave

[dr.joe]

Mondonitro,

Are you interested in a pair of Iconic Supercrossovers v2? I ordered them with my Iconic 704-8A--which are OEM GPA 604-H-II--and I prefer the stock 604-8K crossovers. They're also in-phase at the crossover point which, apparently, other versions are not. I'm told a lot of people really like them compared to other versons.

In any case, they're way too recessed for me. I'll take forward any day.

Just a thought.

[GM]

Originally posted by Seadweller:
I have the same issue with my system using the stock GPA crossover...The midrange is way too hot...The range where vocals exist is so forward that it's actually "shouty," and it overwhelms the rest of the spectrum to the point that everything else is out of balance, from bass to highs...

Interestingly, I was listening to a CD and was floored by the detail; the impact of the percussion, and the "almost there" presence these drivers provide...When the vocals began, I had to stop listening to the song, they are that forward...

I'd be very interested to know how that resistor swap works out...I'm toying with building either a 3rd or 4th order design that Stephaen kindly provided the schematics on...I feel like I'm just a step away from nirvana, but I'm still not sure which direction to go...

<font size="2" face="Verdana, Helvetica, sans-serif">All CD horns need CD EQ and combined with the fact that vocals are normally 'presented' in front of the music to a greater or lesser extent and also combined with the usual need for some baffle step compensation (BSC) if not up against a wall or in a corner to tonally balance the system down into our voice fundamentals, an adjustable (shelving) CD EQ is required.

Factor in the horn/woofer's need to be phase aligned (TD) at least through the XO, then if you're not either using a high resolution 20-20 kHz digital EQ with adjustable TD or at least an adjustable passive with CD EQ and TD, then you will get a lot of voice 'presence' ('shout') along with unnaturally boosted LF thru mids instrument harmonics.

WRT using higher order XOs, they have their virtues/vices, but if passive, then strictly from a technical 'diminishing point of returns' POV, JM's adj. phase corrected XO seems the best choice overall, though it may need BSC depending on the cab's alignment, etc. and some fine tuning for other than the 604-8H it's designed for: http://home.earthlink.net/~jmarkwart..._8Hpcwmfeq.pdf

GM

[imported_tom_h]

Could this be a problem with speaker placement? I saw a similar problem where sound bouncing off a nearby flat surface increased the loudness of vocals. Moving the speaker a little fixed my problem. I learned there is a range of effects, increasing and decreasing loudness at different frequencies, when you move speakers. Finding the right spot makes an amazing improvement if you started in a bad location. Moving heavy boxes is a pain, but worth it.

[GM]

Originally posted by Seadweller:

I moved to a new Cary tube amplifier (I tried both Triode and Ultralinear modes), experimented with BSC filtering (this killed the dynamics)........

<font size="2" face="Verdana, Helvetica, sans-serif">Hmm, BSC doesn't 'kill' dynamics since it shelves the speaker down in the 100-400 Hz BW depending on a number of variables, which is well below the BW where what we perceive as 'dynamics' come into play.

Now if you instead erroneously applied it to the HF horn, then this makes sense.

Regardless, with a high output impedance amp (which I assume the Cary is), its 'smiley face' EQ would probably be all the BSC needed and maybe too much depending on baffle width, room acoustics and speaker placement.

GM

[Seadweller]

Greetings,

Just a quick update on my situation....I've got a pair of 4th order crossovers on the way, as I exhausted every other option using the stock GPA crossovers....The designer of the crossover reported measuring incredibly flat in-room response with a system nearly identical to mine, so I figured I'd give it a shot....A contributor here kindly offered to build them for me....

I moved to a new Cary tube amplifier (I tried both Triode and Ultralinear modes), experimented with BSC filtering (this killed the dynamics), speaker placement, changes in the listening position, cabling, etc., and was still unable to tame the midrange energy....

I hope to have the 4th order crossovers this week, so I'll report back with my results....

[Seadweller]

By the way, I highly considered the Jeff Markwart crossovers, but when I compared the schematic to my stock GPA crossovers, they looked nearly identical, so I decided to take a different course....Good thing I didn't go with a flea powered amp, as I would imagine the 4th order design might be a tad power hungry!

[Seadweller]

Thanks for the input GM....The new tube amplifier did actually improve the bass somewhat, but the hot midrange remained....I'll report back when I get the new 4th order crossovers installed...