Tri-amped LaScalas

[pat_in_dfw]

I bought a paid of LaScalas recently from the original owner who purchased them in the mid 70s.  The cabinets were in good shape but even causal listening told me that something was off with the tweeters.  I am going to need to get new diaphragms, rebuild parts of the crossover or both.  I have a pro AV company and I have a QSC CX168 laying around and a Biamp Nexia DSP.  Rather than rebuilding the crossovers I was thinking about bypassing the stock crossover and using the Nexia as a crossover. I could bridge a few of the channels on the QSC amp so I could drive the woofer with a bridged channel (260w @ 8 ohm) and the mid and high each get 90w @ 8 ohm.  The 8 channel amp would give me 2 channels at 260w and 4 channels at 90w.

 

Using the Nexia would allow me to pick any value as the crossover point, any slope and have full phase control as well.  What are the group's thoughts about doing this?  Has anyone does this before?  What are the potential drawbacks that I might not be thinking about?

 

Patrick

[derrickdj1]

The LaScala does not go that low: you could you a lot less for the bass driver.

[Chris A]

Here is a thread on tri-amping a Belle (which is very similar in performance to the La Scala that replaced it in the Klipsch Heritage line-up):

 

The delays of the La Scala midrange are about 0.5 millisecond less than the Belle due to the slightly longer midrange horn: ~0.5 ms for the midrange (relative to the bass bin), and I'd guess about 2.1 ms for the tweeter (i.e., the same delay as used in the Belle). 

 

The midrange-bass bin crossover frequency can be lower than the Belle: you can go as low as 400 Hz using a relatively steep slope (24 dB/octave). I recommend Linkwitz-Riley if using IIR crossover filters.

 

If you've got something like Rephase, you can build the FIR filter taps for EQ and phase correction based on an on-axis measurement if you have a FIR filter active crossover.

 

Chris

[The Dude]

5 hours ago, pat_in_dfw said:

Has anyone does this before

Pat welcome to the Lascala club.  I see you all ready have some good answers.  To build on what derrick said, I have had only 60 watts going to my Belle and Lascala bass bin with no problems.  

[Coytee]

Tweeter problems?  Here's a sledge hammer to kill that fly....(though it sounds fantastic!)

 

 

[Schu]

Ive often wondered if one could use a passive XO if bi-amping (tube hf section, solid state lf section)?

[jwgorman]

1 hour ago, Schu said:

Ive often wondered if one could use a passive XO if bi-amping (tube hf section, solid state lf section)?

 

I heard a pair of biamped belles this past weekend. The guy who sold me the lascalas had a pair. They were highly customized. So long as you separate the woofer section in your passive crossover, why not? This guy's system used some room correction and a solid state amp for 500Hz down and the high horns were passive and powered by an Audio Research tube amp, so he essentially had a hybrid of what you're describing. Sounded unbelievable! 

[Schu]

I think that is what I am going to do... wish I could direct couple.