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LaScala Sonic Detail Improvement for only $220.98


ClaudeJ1

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I am glad I read this. A La Scal user here. I rotated the LS by 90 degree so it sits on one of its otherwise resonating panel, then put crossover, mid horn (a Le Cleac'h flare) and tweeter on top that damps the other side panel by their weight. This kills much of the annoying infamous resonance but still some are left there and I suspect its the doghouse. Will putting in 15c cure this?

 

With some music, the La Scala side panels may seem to resonate, but it is not audible.  The speakers have a peak at 148 Hz, but that is a consequence of the shape of the horn, and has nothing to do with "resonating" side panels.

 

The proof of this is that the La Scala II has the very same peak at 148 Hz, although its much stiffer 1" thick sidewalls do not move at all.

 

Most people don't find the actual sound objectionable, but stiffening the side panels seems like an easy fix and a cool thing to do, although it doesn't address the issue of the sound peak at all.

 

If the peak really is an issue, the best, and maybe most expensive, way to fix it is to convert the speakers to JubScala spec, which adds an active electronic crossover that can EQ out the peak.

 

This is correct. Just drop the peak by -7db with a fairly low Q and you are there.

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I am glad I read this. A La Scal user here. I rotated the LS by 90 degree so it sits on one of its otherwise resonating panel, then put crossover, mid horn (a Le Cleac'h flare) and tweeter on top that damps the other side panel by their weight. This kills much of the annoying infamous resonance but still some are left there and I suspect its the doghouse. Will putting in 15c cure this?

The 15C will greatly improve the midrange. The peak is enherent in the horn. About 4-5 db at 400 Hz. which is clearly audible.

Edited by ClaudeJ1
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I thought the 148Hz peak was from the parallel walls (doghouse and outside walls).

I would then assume the Peavey FH1 doesn't have this prak.

Bruce

They both do. But the Peavey is smoother.

 

 

Do you have the Peavey response curve, can you post it??

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The proof of this is that the La Scala II has the very same peak at 148 Hz....
Where did you get that from? Got a link? 

 

Real data for the La Scala II is awfully scarce.  :mellow2:

 

 

Roy tested the La Scala and the La Scala II when he was dialing in the settings for the JubScala.  The EQ settings for both speakers are the same, so the peak exists with both speakers.  If it didn't, it would make no sense to have a 7 db cut at 148 Hz with both speakers.

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Roy tested the La Scala and the La Scala II when he was dialing in the settings for the JubScala.  The EQ settings for both speakers are the same, so the peak exists with both speakers.  If it didn't, it would make no sense to have a 7 db cut at 148 Hz with both speakers.

 

Islander is correct about this peak. It's inherent in the horn. The Peavey has it too. Go to my Quarter Pie thread and I have a curve for a Peavey vs. a Quarter Pie, which, with a 15C driver will trounce them all. 

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Do the Kappa 15c need burn in much to perform as expected?

Not really since horn loading makes their excursion less than 0.060" at normal volumes. I call horns, "air squeezers" and direct radiators "air pushers" like trying to clap for a performance with one hand instead of two. Which has the better transient response to move the air?

 

Direct radiators need break in because they DEMAND high excursion and the associated IM distortion for their output. It takes about 6-8X the number of direct radiators to do what a horn can do with just 1, and even then, the horn has less distortion.

Edited by ClaudeJ1
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Another dumb question.

 

For forward facing horns like the Altec A-7, and other similar designs, are these considered Direct Radiators (which I think of as the woofer on the Heresy) or do they share the same minimal driver-cone movement-excursion as the Folded-Horn Klipsch speakers like the LaScala etc..or something in the middle?

 

On some of the JBL literature, I noticed they were cautioning about the woofers slapping on the bezels of the cabinets, not sure which cabinets they were worried about.

 

Altec-A7s-Restored-510x382.jpg

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Do the Kappa 15c need burn in much to perform as expected?

Not really since horn loading makes their excursion less than 0.060" at normal volumes. I call horns, "air squeezers" and direct radiators "air pushers" like trying to clap for a performance with one hand instead of two. Which has the better transient response to move the air?

Direct radiators need break in because they DEMAND high excursion and the associated IM distortion for their output. It takes about 6-8X the number of direct radiators to do what a horn can do with just 1, and even then, the horn has less distortion.

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Do the Kappa 15c need burn in much to perform as expected?

Not really since horn loading makes their excursion less than 0.060" at normal volumes. I call horns, "air squeezers" and direct radiators "air pushers" like trying to clap for a performance with one hand instead of two. Which has the better transient response to move the air?

Direct radiators need break in because they DEMAND high excursion and the associated IM distortion for their output. It takes about 6-8X the number of direct radiators to do what a horn can do with just 1, and even then, the horn has less distortion.

I think smilarly.

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Another dumb question.

 

For forward facing horns like the Altec A-7, and other similar designs, are these considered Direct Radiators (which I think of as the woofer on the Heresy) or do they share the same minimal driver-cone movement-excursion as the Folded-Horn Klipsch speakers like the LaScala etc..or something in the middle?

 

On some of the JBL literature, I noticed they were cautioning about the woofers slapping on the bezels of the cabinets, not sure which cabinets they were worried about.

 

Altec-A7s-Restored-510x382.jpg

Don't take this the wrong way, but you might want to start a thread on the Altec/JBL site about this. This is the reason why I try to only discuss Klipsch stuff here.

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Claude, my understanding of a K-horn or LaScala horn bass with the board with the slot in front is making a compression driver out of the 15 inch woofer much as the mid and tweeter driver. This board with the slot is what limits the movement of the cone and the horn magnifies the sound where a lot of movement is unnecessary, so less movement, less distortion. So the result is a 15 inch compression driver. I know PWK was invasive about how the bass horn worked. Just a short response on the Altec no slot no compression of the cone so more movement, more distortion and bass reflex to boot. 

On a "gut feel" level, you have a pretty good understanding of how these work. Altec voice of the Theater speakers are a primitive compromise that sound like crap compared to a Khorn or LaScala. The below the horn cutoff is weak bass, just like a LaScala. Good subwoofers have been around to give us TRUE 20 Hz. performance for 30-40 year, so there is no excuse about bass below 80-100 Hz. As to the 148 Hz. peak, raising the sound below it with a sub and above it with a 15C will help smooth out it's presence to the ear or measurement microphone. As to the performance below 200 Hz., the ROOM has the greatest influence as to what you hear in the sweet spot.

Edited by ClaudeJ1
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