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Adding extension bass bin cab to La Scala


Don McPhee

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Has anyone who posted so far actually tried the djk mod?  I have, and I recommend it wholeheartedly to anyone who has neither the space, finances, or desire to add a sub or subs.  Personally, I would add multiple subs (horn or tapped horn) to domesticated La Scalas, which would make the mod unnecessary.

 

I performed the mod on the La Scalas I refurbished for the local high school band.  That application was never going to add a sub, so any bass enhancement was a welcomed improvement.  

 

The following are my thoughts and observations:

  • La Scalas, without the mod, are NOT horn-loaded below ~ 100Hz;
  • Without the mod, below ~ 100Hz, La Scalas are direct radiators;
  • With the mod, La Scalas are still horn-loaded above ~ 100Hz;
  • With the mod, La Scalas are bass reflex below ~ 100Hz;
  • The mod reduces the efficiency ever so slightly;
  • With the mod, a tiny chip amp can power the La Scalas to loud and clear levels so that Back In The USSR can be heard throughout the two-story school from the basement band room;
  • The mod is easily and completely reversible;
  • TTBOMK, no one who has done the mod, without sub(s), has reversed it;
  • djk, Dennis (RIP), the author of the mod, knew what he was doing;
  • Follow Dennis’s recipe, including crossover modifications, for best results;
  • The perceptible and useful bass extension provided by the mod in a residential environment is into the mid 30Hz range;
  • If you want useable bass below ~ 35Hz, sub(s) are required;
  • IMO, the “tight” low distortion dynamic bass that I love about La Scalas is not diminished a bit by the mod; and
  • YMMV.

The details of the mod are searchable.  IMO, an unwillingness or inability to search old threads and posts to follow Dennis’s excellent modification exactly act as a filter.  It’s a hobby.  If you need, or prefer, to snap your fingers to get lower bass from La Scalas, add subs.

 

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You have received some great advice. Leave that LaScala alone and ad a horn sub and keep ythe system fuylly horn loaded for cleaner and tighter bass. As for the K-43, the only thing I would add is the K-33 is more efficient and as such is better for filling in at low listening background levels like a loudness button is, but if adding a sub this will not be an issue.

 

Roger

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On 11/27/2019 at 10:26 AM, Deang said:

Detractors and skeptics are almost universally people who have never tried said modification.

 

It doesn't take first hand knowledge to realize that you are trying to turn a LaScala into a Cornwall with this mod and I have lots of experience with horns being less distortion than a direct radiator. I also have a pair of Pro Split LaScalas with K-43s in them and at one time had forty some Klipsch 15 inch drivers. I tried 8 different Klipsch 15 inch drivers that I tried all of them in a LaScala Bass Bin on the same day; those drivers included K-33 Round magnet, K-33 Square Magnet, K-43, K-44, Crites 15, K-46, and K-48, and Electrovoice EV 15W-K. Woiithout a sub, both my brother in law (also a Klipschorn owner) and I prefered the Electrovoice Klipschorn driver.

 

 

Roger

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2 hours ago, twistedcrankcammer said:

 

It doesn't take first hand knowledge to realize that you are trying to turn a LaScala into a Cornwall with this mod and I have lots of experience with horns being less distortion than a direct radiator.

 

 

Roger

But have you ever actually heard a Lascala with the mod?

 

You realize that the Lascala is only horn loaded down to 100 Hz right?  You're already hearing direct radiator bass below 100 Hz with the Lascala in stock form.

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On 9/18/2019 at 8:24 AM, Frzninvt said:

This will turn your horn loaded speaker into a bass reflex type speaker just to gain LF extension.  Far better to leave them alone and add a competent subwoofer or two and keep the horn loaded accurate bass intact.

I second the motion. The "bass reflex extension" is a half assed solution. You need an F-20, THT, or THTLP to do the job from 100 Hz. down to 20 Hz. The (Tuba Home Theater Low Profile sub by Bill Fizmaurice) THTLP is like two Cornwalls stacked up to the ceiling, so it takes very little floor space. Get 2 of those built for two corners or front/rear center of the room  and you are set for life. The K43's are better than a K33 in a LaScala that uses THT subs, so leave those alone. Make you recap your networks. Now you are really set for life.

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41 minutes ago, CECAA850 said:

But have you ever actually heard a Lascala with the mod?

 

You realize that the Lascala is only horn loaded down to 100 Hz right?  You're already hearing direct radiator bass below 100 Hz with the Lascala in stock form.

 

Maybe, but what Carl said is the truth. Yes, it's a compromise.

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On 11/27/2019 at 10:26 AM, Deang said:

Detractors and skeptics are almost universally people who have never tried said modification.

The "never tried that particular thing comment" is by those who have never built or bought ALL of the subwoofers mentioned, and even designed built some better ones. There are those of us who can be CORRECT without it. It's SCIENCE, and quite predictable when all the parameters and budget are stated.

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3 hours ago, twistedcrankcammer said:

You have received some great advice. Leave that LaScala alone and ad a horn sub and keep ythe system fuylly horn loaded for cleaner and tighter bass. As for the K-43, the only thing I would add is the K-33 is more efficient and as such is better for filling in at low listening background levels like a loudness button is, but if adding a sub this will not be an issue.

 

Roger

Sorry to rain on your parade, but the K-33 is not more "efficient" than the K-43. The higher BL product of the K-43 in concert with the cone suspension tips the response towards the midrange more than the bass.

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8 minutes ago, ClaudeJ1 said:

The "never tried that particular thing comment" is by those who have never built or bought ALL of the subwoofers mentioned, and even designed built some better ones. There are those of us who can be CORRECT without it. It's SCIENCE, and quite predictable when all the parameters and budget are stated.

I don't believe the discussion was if a Lascala with the mod was better than a Lascala plus sub.

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17 minutes ago, ClaudeJ1 said:

The "never tried that particular thing comment" is by those who have never built or bought ALL of the subwoofers mentioned, and even designed built some better ones. There are those of us who can be CORRECT without it. It's SCIENCE, and quite predictable when all the parameters and budget are stated.

That's fair.

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7 minutes ago, CECAA850 said:

I don't believe the discussion was if a Lascala with the mod was better than a Lascala plus sub.

Discussions do evolve, usually tangentially! I think the majority opinion was still in favor of subs, and trying to prevent someone from making a mistake if it's their goal to go for the best.

 

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53 minutes ago, ClaudeJ1 said:

The "bass reflex extension" is a half assed solution. You need an F-20, THT, or THTLP to do the job from 100 Hz. down to 20 Hz. The (Tuba Home Theater Low Profile sub by Bill Fizmaurice) THTLP is like two Cornwalls stacked up to the ceiling, so it takes very little floor space. Get 2 of those built for two corners or front/rear center of the room  and you are set for life. The K43's are better than a K33 in a LaScala that uses THT subs, so leave those alone. Make you recap your networks. Now you are really set for life.

IMO, this is the correct answer.

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34 minutes ago, Deang said:

 

Maybe, but what Carl said is the truth. Yes, it's a compromise.

A LaScala is, however, a good compromise, as long as you address it's weak areas. After over 4 decades of being a Klipschead and DIY guy, I would rather have LaScalas and THT subs rather than a pair of Khorns only. And I'd rather have Jubilees with active Xover and TADs over Khorns any day of the week. That being said, all the above are in the top 1% of Audio Perfomance, so you can never truly go wrong.

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5 hours ago, ClaudeJ1 said:

Sorry to rain on your parade, but the K-33 is not more "efficient" than the K-43. The higher BL product of the K-43 in concert with the cone suspension tips the response towards the midrange more than the bass.

 

 

Please explain then why I have heard it personally, many have said similar about swapping the 43 for the 33 in MWM bins, AND Klipsch  rates the home LaScala as more sensitive than the LSI ??

 

Rog

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1 hour ago, twistedcrankcammer said:

 

 

Please explain then why I have heard it personally, many have said similar about swapping the 43 for the 33 in MWM bins, AND Klipsch  rates the home LaScala as more sensitive than the LSI ??

 

Rog

In a LaScala, the lower bass is "thinner" sounding  below 100 Hz. with the K43 because the K33 resonates with the air volume as a direct radiator in a tight environment. The LaScala is not a horn below about 104 Hz. Sensitivity ratings of a woofer enclosure interaction has much to do with what frequency you are doing a conversion to spl, looking at impedance, etc., and assigning "efficiency" rating. The K43 has a much bigger magnet and voice coil, and besides, which K33 are you speaking of? CTS, Jensen, EV, Square Magnet Eminence, Round Magnet Eminence? Same goes with the K43. They vary by date.

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