DIY La Scala mid upgrade options

[Marvel]

It's okay, Dave. I'm not getting bothered by it. I agree with you.

Bruce

[Bubo]

I have the remaining pages of the brochure, if you want them.  They bounced around the Forum a few years ago. 

 

 

If you can scan the paper copies and post them as a high res PDF that would be best, if it's just the Gif files, post them.

[JohnA]

The rest of the story!

[JohnA]

There are 2 diaphragm types (well, maybe 3 with the early 16 Ohm) in the T-35.  One has a filament connection to the terminals and the other has a ribbon connection to the terminals.  As indicated in the attached brochure for the T-350, the newer T-35A with a 5 watt rating (and the same ribbon connector diaphragm) should follow the T-350s 5 watt RMS/50 watts Program/100 watts Peak ratings.  Caution is advised with that 100 watts; I have no idea how short duration the pop must be to hit 100 watts and not melt the ribbon or voice coil. 

 

It is logical that the K-77, that had the filament connection would carry a 2/20/40 rating and that the K-77-M carries a 5/50/100 rating.  That makes the K-77-M a tough enough tweeter sans clipping. 

Edited November 8, 2015 by John Albright

[No.4]

I am curious because I am no expert. Both the EV paper and the University paper state the crossover frequency for these drivers is 3500hz. Assuming this is the absolute minimum wouldn't most program material at the printed power level damage the driver? Another thing I was curious about was universities statement that these could be used in two and three way applications. where these employed in any full range two way systems?

[Chris A]

Both the EV paper and the University paper state the crossover frequency for these drivers is 3500hz. Assuming this is the absolute minimum wouldn't most program material at the printed power level damage the driver?

 

There are tradeoffs to crossing at 3.5 kHz: what are you crossing over to?  I've found that the Klipisch Heritage midrange horns and K-55 drivers like to be crossed at 2.5 Khz or 5 kHz using steeper slope--at least 24 dB/octave Linkwitz-Riley filters:

 

https://community.klipsch.com/index.php?/topic/123370-settings-for-tri-amping-an-82-belle-with-an-active-digital-crossover/

 

I played with many different crossover points and found that 4.9 kHz seemed to work best in terms of amplitude, phase, harmonics, and coverage angle mismatches.  I tried 2.5 kHz and 3.5 kHz, but it didn't sound as integrated, and there were FR issues, as well as phase and coverage angle mismatch issues.  I had to add boosting PEQs to compensate for the drooping FR on the K-77, for instance.  Klipsch typically uses very gentle slope crossovers on the K-77 and no crossover filter on the high end of the K-55 midrange, so the crossover region using the Heritage passive crossovers is extremely wide in terms of crossover bandwidth, and not very pretty in terms of phase/time delay mismatches in the crossover region (stock versions).

 

Chris

Edited November 8, 2015 by Chris A

[No.4]

I am using the Crites a/4500 network. I was just curious. At 2500hz the response dropped, was there audible distortion or just lower output? Again just curious.

[Chris A]

At 2500hz the response dropped, was there audible distortion or just lower output?

 

It just didn't sound as "solid" or smooth, even with compensating PEQ boost filters.  It could have been the different coverage angles or harmonic distortion.  It also could have been the phase issues, or a combination of the above.  I didn't like what I heard and what I saw on my REW sweeps, and the boosting PEQ filters were getting hard to handle in the 2-5 kHz region, with filters fighting each other, or the FR had peaks and dips that weren't very nice to look at on the plots, or to hear.

 

Chris