Center to Center of Drivers 29" apart in proposed config - Problems??

[Ken L]

Originally posted by slowmotion

Since you have the Behringer why not use digital delay on the dds waveguides?

Could work if I was tri-amping - however, the amp is to be a GM70 "boat anchor" that is massive. I have now collected almost all of he parts. Not practical to add another amp. I am bi-amping with a Crown amp on the bass bins now.

I have thought a number of times about centering the waveguide in the horn - but what holds me back on that is the time alignment part - using the digital delay to time align the bass and the horns has me thoroughly convinced of the benefits of time aligning - Analog passive delay looks like it would be putting too many parts into the signal path.

Were this last year I would just buy the drivers, etc. and give it a shot. However, this year things are down considerably financially, hence the need to make my mistakes in theoretical discussion instead of with my pocketbook.

Which is why I am most appreciative of everyone's input to this thread.

regards

Ken L

PS, Slowmotion, is that your setup in the pics ? Ihave seen that before and thought it was pretty slick

[slowmotion]

Originally posted by Ken L


Could work if I was tri-amping - however, the amp is to be a GM70 "boat anchor" that is massive. I have now collected almost all of he parts. Not practical to add another amp. I am bi-amping with a Crown amp on the bass bins now.


regards

Ken L

Hi Ken

Yes, I know what you mean, these amps tend to get pretty big, you run out of room in a hurry. Please tell us how your GM70 amp turns out, will you?

PS, Slowmotion, is that your setup in the pics ? Ihave seen that before and thought it was pretty slick

Ken, I wish I had something like that.
As far as I know that's a full Goto setup.
I think those horns belongs to someone in Japan,
but I'm not sure. Great inspiration, tho

cheers

[Ken L]

Originally posted by slowmotion

Please tell us how your GM70 amp turns out, will you?

Will do. I have heard a very similar one that others have described as a "sonic masterpiece"

I have seriously got to get some stuff completed - one reason I've been looking at drivers.

the Dowdy LLama is debugging hum from my long-humming 12b4 transformer volume control preamp - a proprietary Dowdy design - I have almost all of the parts for the GM70 amp except power transformer for the power supply and filament tranformers, will do initial build on scrap mdf

Finally picked up 75th driver tubes and spares just a few weeks ago -

And need to do updates to the Behringer DCX 2496

I plan to make appropriate interim reports/reviews, but I'm looking forward to that far-off day when it's all completed -

Now if I can keep from getting off on any other tangents - hopefully I can get over the hump and start getting some stuff completed.

Best regards to all who have participated in this thread

Ken L

[John Sheerin]

Ken,
I've had decent results with big messes of horns, just moving them forward or backward to get the alignment as close as I could. You always end up with the tweeter way behind the mids and spaced some distance away so you can see the thing around the midrange horn's mouth, but if you get it all aimed at one spot, it can work. I wouldn't want to be trying to do the aligning by ear, though...

For example:
http://ldsg.snippets.org/HORNS/images/4way/stack.jpg
http://ldsg.snippets.org/HORNS/5way.html
This second one should have the midbass horn (on the far right) a few feet forward of where it is, and the sub is something like 15 feet behind the midbass (acoustically), but it still manages to sound good. Hopefully I'll add some digital processing to my arsenal at some point and see what a truly 'aligned' system sound like.

John

[Ken L]

Originally posted by John Sheerin
Hopefully I'll add some digital processing to my arsenal at some point and see what a truly 'aligned' system sound like.

Thanks for your comments John

For now, I think I'll go with Lowther PM5A's and be done with it. Partly because I don't have time, money and the mental clarity to tinker with it.

As to "truly aligned", I don't know about other frequency ranges, but when I set the delay on my current subs, the results were truly notable.

The Azurahorns sit on top of 14' by 18" by 14" sealed subs - the center to center of the drivers is about 29" apart - I'm crossing to the subs at 145hz 4th order L-R

I put on some tracks with a lot of bass parts and played them while I had my wife spin the knob setting the delay - Initially, you could locate the bass comming from the 12" drivers, as being a physically lower source

However, as more and more delay was gradually implemented - the woofers seemed to be moving upward physically - when the sound from the woofers seemed to be coming from the center of the Azura's, I stopped.

Presumably, this effect is due to the overtones being produced by the 8" in the Azura.

Had I not done it, I doubt that I would have believed how much effect there was.

Actually, I think that doing it by ear was better than measuing and calculating - FWIW, what sounded best was about 15% off from my original calculations and after correcting my calculations for actual distance to my ear, still about 7%

This effort was enough to convince me big time of the benefits of correct time alignment.

regards

Ken L