Adjusting Tri-Amp Levels

[ClaudeJ1]

So when you place the mike a certain distance from a horn to measure Pink Noise with RTA.

Do you put mike at horn mouth?

1 foot from horn mouth?

1 Meter from horn mouth?

Or, if you have a 5 foot bass horn, a 2 foot midrange, and a 6 inch tweeter, do you use a distance EQUAL to all of them from the VOICE COIL location?

[Chris A]

I used one meter for the center Belle triamp, and used starting channel gain values derived from suggestions found on this forum for passive crossovers: I found that these starting channel gain values weren't quite right after all was said and done. The microphone was centered a bit high - close to the centerline of the midrange horn. I did try to get equidistant from each horn mouth for the midrange and tweeter.

I also found that setting the delays correctly within 1/10th of a wavelength at the midrange-tweeter crossover region was critical to getting the center Belle's timbre to match the Jubs on each side. I was ready to sell the Belle(s) until I finally got these values worked out.

The wife was my best test asset as it turns out, when I finally got the speaker dialed in. I was amazed how sensitive the speaker's timbre was to getting the time delays right. I figure that most folks here haven't heard this effect for themselves. I can demonstrate very easily just by slightly changing either the midrange or tweeter delay by as little as 0.05 ms...

Chris

Edited March 6, 2014 by Chris A

[Chris A]

Here is a link the the thread on the tri-amped Belle settings.

Here is a link to Greg Oshiro's thread on tri-amping Khorns.

Chris

[djk]

"I can demonstrate very easily just by slightly changing either the midrange or tweeter delay by as little as 0.05 ms..."

And/Or the level by as little as 0.1dB, 0.25dB is hugely audible.