Gpa 288h

[robertbartsch]

..The bass horns are very nice!

Did you make them?

The 288s are very large; they remind me of a set of 2" - 2445s at 30 lbs that I have running in my basement....


Have you looked at the frams in these drivers; are they similar to other Altec large format drivers?

[Panomaniac]

It was intensely frustrating. I have trueRTA running on my computer and after taking 100s of measurements and playing with EQ...

I know what you mean! I have found any RTA to be hard to use for speaker tuning. trueRTA is OK, but still tricky.

Earl and I are both using HOLM Acoustics freeware now. Much easier to use and the results are worth it. Free, too. You do need to play with the impulse window a bit, the automatic didn't do well for me. And 1/6th octave smoothing helps.

But let your ears be the final judge. The software just makes it quicker and easier.

[Earl K]

Okay, I'll try to keep you guys up to date on the latest pain.
This new driver is like riding a bronc'ing buc.

Fact 1: The 1" drivers I had were in retrospect easy to play with and it was not too hard to get a decent sound easily.

Fact 2: The sonic quality of the 288 is an order of magnitude higher than the 1" drivers I used.
I doubt I go back ever...it's a HUGE step up...not even close to incremental.

Fact 3: This "quality" comes at a price that I'm unsure yet how to come to grips with.

Steve, my apologies for dragging this back up / but / did you ever resolve the issues that you spoke about in that post ?

- I do believe I know where you were coming from ( when you gave us your initial impressions ) since I've used 288-8Ks at home for @ 5 years now .

I spent 3 full days trying to dial in the 288h drivers this past weekend. It was intensely frustrating. I have trueRTA running on my computer and after taking 100s of measurements and playing with EQ...I realized strictly speaking this was not a good way to dial in the speakers.
- There's no substitute for good ears.
- But then I also realized I have to make a decision.
- Do I want a laboratory system or do I want it to sound good?
- For some reason I have shielded myself from thinking in those direct terms, somehow thinking I could get both. I can get something that's technically decent, but there's so much more than measurements...and that wasn't a BOSE conversation starter.
- Anyway, after a brief pause and not precluding that technical approaches were invalid I concluded I wanted something that sounds good.

So, for the last two days I have been going through literally hundreds of recordings making tweaks and becoming accustomed to as many edges as I could ride. By that I mean what does changing the slope of a crossover point sound like? What do different crossover frequency settings do to the sound? What does no adjustment sound like? What do different EQ shelves do to the sound? How about a bandpass and the playing with Q change things? And then because of all of these variables what is the systemic effect of all of these things WRT the sound? This last one takes the most time because there are iterations of tweaking and listening to overcome.
- In effect this last week has been a crash course in acoustic reality. Without this cheap behringer unit none of this would have been possible. And sonically it is holding up with very high calibre transducers to boot! ...can't say enough good things about it.

Now that I've circled the wagons with the system, I am approaching it from a minimalist perspective. How do I continue to keep things as simple as possible?

- But with all this I am still having problems getting what I want.
- When I had the small formats in I now realize they sound like the upper midrange was more pronounced... for example the percussives of strumming guitars are very convincing. - WRT this issue I have to first realize that I am hearing much more information and the lower mid range is simply to die for with the 288h, which I was not getting with the small drivers.
- Matter of fact I have never heard such a sweet sounding mid range ever, before these drivers...
- But out of the box and into the horn it doesn't do everything automagically.
- So I am experimenting with shelving some lower mid range out and shelving some high end in. For some reason these dam Junior Brown recordings are good for analyzing this issue.

Another issue is what I am used to hearing with the past system and what either should be carried forward or what was never good to begin with. Additionally these drivers are even more dynamic which affects relative levels in recordings. THAT is interesting and a whole nuther subject.

,,,,,,, happy with the overall sweetness of the presentation...but my ears tell me these drivers with this horn needs EQ and tweaking...I just didn't suspect I would still have so much more to work on.

- Yes , you've nicely articulated the challenge of working with the 288 very, very well .
- I agree that the 288s midrange is to die for ( low cutoff till the "lower presence" range ) .
- Conversely, to get the response above ( say 4K ) to match up in subjective quality / takes quite a lot of finess work ( and I'd say it's not just about flattening the FR curve ) .

- Do you feel like talking further about this ( voicing ) challenge ?

>< cheers

ps ; Obviously, I've taken the liberty of highlighting certain lines for emphasis .

edit : I'm travelling & offline till the 24th or so / will try to pick this up then .

[Leland]

Beautiful looking set-up, very nice. Congrats. Keep up the posts.

[Altec Best]

I forgot about this thread.Thanks Earl for bringing it back.Steve You out there somewhere ? This was 2 years ago and am very interested at your final tweaks for this setup.As I'm in the middle now of setting up a pair of 288's with the 511E's on my project.Any tips,adjustments,etc.... Would be most appreciated ! Thanks !