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La Scala AL crossover


Masca72
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14 hours ago, Marvel said:

 

 

 

You mean it's not now?

When I bought my LaScala's way back when  there were a lot of rags testing audio gear. K-horns and Klipsch speakers in general, Heritage line, did poorly in their testing for frequency response. If memory is correct the factory specs were something like + - 5 db where speakers like the AR-3a's were almost flat. I previously had a pair of AR-3A's. To put it mildly the AR's sucked. PWK said it best, music is dynamics and his speakers shined in that department. Too much emphasis was put on specs that fooled many into purchasing the best number products and were disappointed with the sound afterwards. Klipsch speakers back then depended on the drivers and horn for it's frequency response graph using the best ones available at the time. With time and improvements the drivers and horns have improved and expect have a better frequency response.  

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15 hours ago, Deang said:


Dennis (DJK) was the first to talk about its issues - and only after people started showing up here complaining about them.  Some of this was going on before Bob was even selling networks.

Are you the same Dean that makes, made crossovers for a profit on this forum? If so his opinion would be biased for financial gain. I lurked back when that Dean and Bob had serious conflict of opinions on whose networks sound best trying to sell their products on this forum. I will say one thing, Bob was always a gentleman and I respected him for that and he did not try and improve on what the engineers at Klipsch produced not having an audio engineering degree. Only selling the original design with new parts. 

 

The bottom line is if you like the sound you have now with the AL crossover, or for that matter any of the Klipsch crossovers, why try to fix what is not broken.

 

I do not ever remember replacing an inductor in any piece of audio gear due to failure or for that matter a film cap as well. But I do understand that some of the equipment in the 30's and 40's had film caps that did give a problem. I do not work on gear that old. Just finished restoring an Onkyo receiver, which is by the way a tank, replacing all the electrolytic caps testing both the old and new ones for specs and ESR and about half were still in spec. Replaced them anyway due to the way an electrolytic is made with a liquid that leaks and dries out over time. Still half being 40 to 50 years old still being in spec. is really good considering how old they are. Many restorers do not replace all the electrolytic caps leaving the good ones alone.  

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@Deang, I can't speak for anyone else on here but I ALWAYS appreciate your willingness to share what you have learned and your perspective as a result of what you have learned.

 

If I remember correctly, you were the first forum member to assist me in my very first post years ago.

 

And speaking from personal experience, a cottage industry is more a labour of love than a for profit industry at the end of the 12 hour day. No overtime pay and 24/7 accountability. 
 

No thanks! LOL

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On 12/2/2021 at 11:59 AM, jason str said:

Al is considered the least desirable crossover in the La Scala though it's all individual preference.

 

I personally run the type A 4500

 

 

 

I agree with Jason ^^^ on all counts.

 

I owned Khorns and La Scala both with Type AA crossovers.  I added the A/4500 crossover (XO) to the Khorns along with a more robust tweeter section.  That was the best sound to my ears.

 

When we say "A/4500" that means the Type AA and the Type AL have a crossover point of 6000 Hz.  The A/4500 drops the XO point of the tweeter to 4500 Hz.  There was a known hole in the frequency response in that 4500-6000 range, technically.  From a human listening point of view you could not hear a "hole" but it was there.

 

If the A/4500 XO is used a more robust tweeter needs to replace the delicate K-77 compression driver which could not handle the lower XO point.

+++

 

To our new Italian friend:  Welcome to the Klipsch forums!

 

 

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On 12/2/2021 at 3:28 PM, henry4841 said:

I think it foolish to think the engineers at Klipsch ever made what you would call a bad crossover,

They did make a bad one, in fact, two.  Both the AL and the AL-2 were considered the worst sounding Klipsch ever produced for the LS.  There are numerous threads on this and more details on the backstory as to how that happened.

 

The AL came out in 1983 and was so bad it was immediately replaced in 1984 with the AL-2.  The AL-3 came out in 1989 and was universally acclaimed as a good one.  I believe this had the 4500 XO point.

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42 minutes ago, wvu80 said:

 

When we say "A/4500" that means the Type AA and the Type AL have a crossover point of 6000 Hz.  The A/4500 drops the XO point of the tweeter to 4500 Hz.  There was a known hole in the frequency response in that 4500-6000 range, technically.  From a human listening point of view you could not hear a "hole" but it was there.

 

What would be involved if one wanted to modify an AA to drop the crossover point to 4500 Hz?

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14 hours ago, wvu80 said:

 

The AL came out in 1983 and was so bad it was immediately replaced in 1984 with the AL-2.

 

the reason the AL-2 was brought in , was because klipsch switched to  the K55M  , and moved away from the  K55V

 

@JEM Performance through klipsch USA currently offer an upgrade kit for the klipsch AL-AL2-AL3  for anyone who owns these networks -

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47 minutes ago, mboxler said:
2 hours ago, wvu80 said:

I believe this had the 4500 XO point.

 

Pretty sure the high pass filter to the K-77 was identical on the AL, AL-2, and AL-3 crossovers...around 6000Hz.

 

Thanks for the clarification on the low pass filter, I just couldn't remember.  At some point Klipsch, Inc went with the 4500 Hz XO point.  I didn't take notes as I should have to document exactly which version that was.

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1 hour ago, Dave MacKay said:

What would be involved if one wanted to modify an AA to drop the crossover point to 4500 Hz?

 

I don't know, not an electronics guy.

 

I've never heard of anyone converting a Type AA to one with a 4500 Hz XO so there must be a reason.  Good question though.

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3 minutes ago, wvu80 said:

 

Thanks for the clarification on the low pass filter, I just couldn't remember.  At some point Klipsch, Inc went with the 4500 Hz XO point.  I didn't take notes as I should have to document exactly which version that was.

 

I believe the AL-4 is 4500hz, due to the K-77F(?).

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4 hours ago, Dave MacKay said:

What would be involved if one wanted to modify an AA to drop the crossover point to 4500 Hz?

 

You can't just drop the tweeter crossover point to 4500Hz. You have to change BOTH the midrange lowpass and tweeter highpass crossover points. The below image contains the changes you need to make;

Crites A4500 Crossover.jpg

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3 hours ago, mboxler said:

 

I believe the AL-4 is 4500hz, due to the K-77F(?).

 

Mostly due to the steep slope employed by Roy. A lot of attenuation is applied to that part of the filter in the newer networks. None of the K-77's should be crossed over that early in a first order filter. You could probably get by with it if you listen at relatively low volumes. 

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On 12/3/2021 at 7:22 AM, henry4841 said:

Are you the same Dean that makes, made crossovers for a profit on this forum? If so his opinion would be biased for financial gain.

 

lol! Mostly funny because the more parts in a network, the more money I make. Time = money. I should be promoting the AL! With that said, my opinion, like everyone else's here, is based on my subjective preference.

 

Where is the Klipschorn equivalent of this filter? Oh, yeah, it doesn't exist.

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34 minutes ago, Curious_George said:

 

You can't just drop the tweeter crossover point to 4500Hz. You have to change BOTH the midrange lowpass and tweeter highpass crossover points. The below image contains the changes you need to make;

Crites A4500 Crossover.jpg

However, that is an "A" network, not "AA", which is what the OP questioned.

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27 minutes ago, Deang said:

 

Mostly due to the steep slope employed by Roy. A lot of attenuation is applied to that part of the filter in the newer networks. None of the K-77's should be crossed over that early in a first order filter. You could probably get by with it if you listen at relatively low volumes. 

Thanks for the clarification.  I always thought that the K-77M could run lower with a steeper filter (voltage wise), but it's SPL was too low below 6000hz to

sound right.  Or I could be misremembering 🙄

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Here you go Mike.

 

 

K77M_K77F.jpg

 

Bob's post with the plot, dated December 7, 2006.

 

"I think the one I tested was from 2004.  I don't think there is a way to make that design go higher than the K-77M really. And Klipsch only claims the new Khorn's frequency response up to 17 khz. The K-77F is simply a clone of the K-77M and there would be no reason to expect it to be better than the K-77M.  The different K-77Ms I have tested vary quite a bit in frequency response and sensitivity.  I think that would be true also of the K-77F.  I think from the ones I have seen the inside of, the K-77F might be improved a bit by installing a new EV diaprhagm.  The EV diaphragm looks to be a lot better constructed than the clone of the EV diaphragm that the K-77F uses.  

 

I do have a bunch of brand new in the box T-35As (K-77M) made toward the end of EV manufacture of those.  I probably should test one of those to see how a brand new never used fresh from the factory one tests."

 

Bob Crites

 

 

 

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