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GFelber

La Scala I updates

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Greetings all,

 

New member and long time Klipsch enthusiast/owner (Heresy's, Corwalls, La Scala and Cornscala) new residing in Montana. 

 

In December I picked up a pair of 1985 birch LS1s for a bargain and they're in pretty decent condition. They have a few nicks and scuffs and some odd holes drilled into the bottom of the bass bin that looks like they were mounted on stands, so I plan on re-veneering with something like walnut or perhaps a more exotic species.  Last month I ordered the AL-4 upgrades from Klipsch and I also picked up a pair of the MAHL tweeter lenses and DE-120s to try.  Too bad I pulled the trigger before the walnut varieties came out!  

 

At any rate, my question is regarding the cabinets.  In order to get these from the garage to the house (and please the Mrs), I am considering three options and would like feedback:

 

  1.  Simple (still a challenge) re-veneer perhaps grills as these do not have any and prefer the look.
  2. Adding 1/4" birch ply just to the sides of the cabinets and re-veneer, + grills.  I would also veneer the front of the horn motor boards and then add 3/4" trim to frame the grills so it would be difficult to tell these were any different from stock other than the ticker walls on the bass bin.
  3. Separating the tops from the bottom bins, building the top hats, and adding 1/4" ply and veneer to closely match the LS IIs.  This would obviously be a lot more work with little gain compared to #2 above, but I really like the looks of the IIs.

 

Seems like #2 would be the best bang for the buck and would stiffen the bass bin a bit, but once I start adding wood and veenering, should I go all out and do #3 or just do #1 and call it a day...or week?


Thanks much,

 

Gene

 

 

 

  

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IMAG0518.thumb.jpg.3f32a2f8fe854ccfd03f0ba9611e9cc6.jpgIMAG0326.thumb.jpg.378b4f01182745aa65692cb92cab1556.jpgI veneered my original ones with cherry on the out sides and just stained the dog house. Then I made lambs wool grills.

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  I like option 2. Adding a 1/4” to the cabinet will stiffen a lot. Even the veneer helps.

  If it was not so heavy I would prefer one piece cabinet. My LS ii weigh 182 pounds. If one piece it would still weigh over 160 lbs. 

  The AL-5 is 200 lbs, the top hat is now 1” wall MDF to match the bass bin. If you add a 1/4” all the way around it is almost the same wall thickness on the outside.

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It seems to me that if you do #2 and then decide you want #3 you will be ruining a lot of your earlier work.  So why not go for #3.

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1/4" ply over the 3/4 will not stiffen the cabinet much at all, its just not the same as 1" material though you would think so.

 

Bracing is really the way to make it right, might be a bit more work but worth the time and be sure to brace the inside of the cabinet ( where the woofer is) as well so you have bracing all the way from one side to the other.

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1 hour ago, jason str said:

1/4" ply over the 3/4 will not stiffen the cabinet much at all, its just not the same as 1" material though you would think so.

 

Bracing is really the way to make it right, might be a bit more work but worth the time and be sure to brace the inside of the cabinet ( where the woofer is) as well so you have bracing all the way from one side to the other.

That's a good point, but is it stiffness that's key here or absorbing resonant frequencies? That is, isn't it the case that birch plywood is stiffer than MDF for given thickness but likely resonates more at is has less mass?  Would adding MDF to plywood work or would braces suffice?

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Ask yourself firstly... "how loud do I really listen"?

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6 minutes ago, Schu said:

Ask yourself firstly... "how loud do I really listen"?

 

Loud occasionally, but that's the exception.  My motivations for this project are: 1. to update the LS1s in the best and most reasonable manner possible and 2; aesthetics so they can be "accepted" in the house :)

 

I should have added that I'll be incorporating a sub or two as well, most likely THT or Table Tuba(s), so the low end will be covered by these.  Hmm... maybe I just answered my question.

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21 minutes ago, GFelber said:

 

Loud occasionally, but that's the exception.  My motivations for this project are: 1. to update the LS1s in the best and most reasonable manner possible and 2; aesthetics so they can be "accepted" in the house :)

 

I should have added that I'll be incorporating a sub or two as well, most likely THT or Table Tuba(s), so the low end will be covered by these.  Hmm... maybe I just answered my question.

 

No need to add material to the side of the cabinet.

 

Table Tuba or THT is a great choice to solidify the bottom end.

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  I have seen comments that just adding veneer takes some ring out. I used to build horn cabinets a long time ago. 

  Used to only use highly ply birch and in many places double thickness.Used a 3/4” roundover bit for front corners on router table and wrapped the fronts with veneer. Got good at right angle corners too. Looked professionally done sometimes. 

  One trick I learned was to press an ear against a speaker panel at moderate playback level to hear how the cabinet was singing along. The output is way down and is offset by the difference in radiating area between the mouth of the horn and the cabinet. 

  Sometimes the panels seemed full range. These were the cabinets I thought sounded the best. But using MDF the highs were attenuated. 

  Try listening to your cabinets first. I still like option 2. But it is not my speakers.

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Adding mass like veneer may change the frequency of the resonance a bit but its not going to help with the problem.

 

Bracing will fix the issue, panel flex is proportional to the square of the unbraced span.

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lascala1a.jpg.67c48ad0a88548e15f346bcc597700f7.jpg

 

Though it exists, under extreme loudness, the rumour of the La Scala's bass horn resonance is mostly imaginary.  The correct solution is bracing, but they don't need that at sane listening levels. 

 

Mine have a 3/4 x 3/4 solid cherry strip on the front edge to frame the upper grilles an cover the ply edges. 

 

I vote #1 for WAF.

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2 hours ago, JohnA said:

lascala1a.jpg.67c48ad0a88548e15f346bcc597700f7.jpg

 

Though it exists, under extreme loudness, the rumour of the La Scala's bass horn resonance is mostly imaginary.  The correct solution is bracing, but they don't need that at sane listening levels. 

 

Mine have a 3/4 x 3/4 solid cherry strip on the front edge to frame the upper grilles an cover the ply edges. 

 

I vote #1 for WAF.

 

Without bracing, the La Scalas I refurbished for the local high school band room had an annoying resonance.  The playback volume was not insanely loud, but louder than would be typical in a home environment, due to the relatively large space.

 

When the band leader first brought the problem to my attention, I thought it was caused by poor recordings.  The proof that was not the case was wedging short pieces of 3/4” dowel between the side walls and the deepest part of the doghouse, the eaves, if you will.  That immediately eliminated the resonance.  The long term solution was the braces visible in the outdoor photo.

 

post-6832-0-60120000-1423623361_thumb.jpgpost-6832-0-93440000-1423926401_thumb.jpg

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43 minutes ago, DizRotus said:

 

Without bracing, the La Scalas I refurbished for the local high school band room had an annoying resonance.  The playback volume was not insanely loud, but louder than would be typical in a home environment, due to the relatively large space.

 

When the band leader first brought the problem to my attention, I thought it was caused by poor recordings.  The proof that was not the case was wedging short pieces of 3/4” dowel between the side walls and the deepest part of the doghouse, the eaves, if you will.  That immediately eliminated the resonance.  The long term solution was the braces visible in the outdoor photo.

 

post-6832-0-60120000-1423623361_thumb.jpgpost-6832-0-93440000-1423926401_thumb.jpg

 

I have had 2 sets, the old set from late 80's and newer to me late 70's.

 

Both had bass bin resonance, luckily spent time on the refurbish on my newer to me set and added bracing to remove any signs of the irritating noise.

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There was a kit at one time for those braces and it would be what I would do too even if I had to make them myself. If I ever own another set of La Scalas they will be ones I build out of 1" Baltic Birch. My experience has been they will resonate at higher volumes and everyone I know who has these will play them that loud on occasion. 

 

  Best set I ever had was one piece LSI with Al edge trim and fiberglass. They did not resonate even when played loud enough to physically thump your body 12 feet away.

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1 hour ago, Dave A said:

There was a kit at one time for those braces and it would be what I would do too even if I had to make them myself. If I ever own another set of La Scalas they will be ones I build out of 1" Baltic Birch. My experience has been they will resonate at higher volumes and everyone I know who has these will play them that loud on occasion. 

 

  Best set I ever had was one piece LSI with Al edge trim and fiberglass. They did not resonate even when played loud enough to physically thump your body 12 feet away.

 

Thanks for the input and welcome all!  I think I've found one song, quite by accident, that will resonate these cabs at an appreciable volume (> 50 w).  

 

I'm sort of noodling the Al edge, or even Al channel on the bins per one of the other threads.  I could go with something I've not seen done such as steel angle and channel to frame the front of the cabinets with a medium to dark veneer, but not sure how that would look.  I'm pretty the metal would add sufficient stiffness to the edges of the cabinets, but they may still resonate. Adding fiberglass would dampen the sides further. I'm still a little unclear on the effect of adding braces for stiffness vs. material resonance. The former will very likely mitigate the pesky LF resonance and shift to perhaps a higher resonant frequency that has less energy and cannot be heard.  However, I'm favoring the look of the LS II-like clone (cant' fix the doghouse though) with the 1/4" birch ply wrap (glued and fastened very well), high-end veneer, and add the braces if necessary. 

 

I've been reading some publications on exciters used to measure cabinet resonance and may choose to do an experiment of sorts with different materials and thickness clamped to the sides of the bin.  It seems that the best way to measure this is with accelerators and/or lasers, but I'm not going to invest in that for one pair of loudspeakers.  I think I may be able to use an exciter and SPL measurements only as a guide to find the resonance and may be a fun little project. 

 

 

Edited by GFelber
edited for clarity

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The trim won't do much at all except protect corners and look cool. The fiberglass was the big dampener on my LSI's I am certain.

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  As I get older the looks of the speakers gets to be more important. 

  If adding the 1/4” plywood is not a project you are willing to tackle, those braces should be easy and effective. Then veneer the outside. Add trim and the speakers will be very presentable. I prefer the looks of the one piece to the current design. 

  When I had a pair of B&W 801 S2 in walnut sitting in exactly the same spot as the La Scala’s my wife commented repeatedly how ugly the 801 were. The top and mid/tweeter were black.

  Her only comment on seeing the La Scala was how much were these? I told her expensive, which she sets at around 500.00. The 70th Anniversary models shipping may have been close.

  At least to my wife the La Scala’s are not ugly. She may think she can flip them over on the back and put dirty laundry in the them down the road. Dual purpose. 

  The jacuzzi tub in our master bath was dual purposed when we moved in 17 years ago. Holds a lot of dirty clothes. 

  I do not have a lot of say around the house. Even in my listening area upstairs.  Ugly speakers would be gone.

  BTW, nice find. Hope they bring at lot of satisfaction and happy listening.

  

  

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