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La Scala side modification


Dave A

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Just getting around to working on a set of LS's I picked up some time ago. I will be replacing the sides on these with 25MM Baltic birch. My intent is not to do a total step by step as most who will be interested in doing this are already versed in basic wood working. Just a few comments here. I take a rubber mallet and beat the side off. The best way is to start at the bottom front and give it some healthy whacks. Once it starts breaking loose I go to the top of the bass bin and work the top loose. Careful work with a slender flat prybar from there gets it off.

 

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 Notice the black back side. These were painted with a black topcoat and white primer and then on top of that Varnish. Chipped and no way to repair well I know of and since I like wood grain off this mess goes. I used GoofOff paint stripper and I am sure any brand will do. This stuff is hard on skin so wear goggles and rubber gloves. It works quickly and it took two applications and scraping to remove all the paint. Varnish is another story and with a good fan blowing the fumes away I remove Varnish with Acetone and a rag. 

 

  However doing this never gets you back to nice raw wood appearance and your only recourse is to stain. Of all the stains I have tried Golden Oak by Minwax has been the very best at matching new BB surfaces to the old cleaned surfaces. The above picture  shows the interior of the bass bin scrapped cleaned and stained. If you were wondering when the paint stripper dries and after you have scrapped a bit of light sanding is in order with some scotchbrite pads used by hand for getting into corners the sander can't. This leaves a ready to stain or paint surface.

 

  On all the remaining edges make sure to remove all that old crusty wood glue and get back to a nice smooth surface for best fitup and gluing.

 

  I am going to modify the horn section motorboard to allow for using a set of LMAHL V2's.  This requires the motorboard to grow from 11" appx to 12" height top to bottom. Since I am going to use 25mm BB for this too I have to make an adjustment to allow for this and keep the sides at their original front to back dimension.

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 The extra thickness of the 25mm is coped to the .7" or so thickness of the OEM plywood. Measure the thickness and set your saw accordingly for setback and depth. I ended up with 35.125" tall for the sides from the top of the access panel to the top of the new motorboard.

 

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 These dimensions should never vary except for the cutout at the bottom back side to maintain front to back OEM dimensions.  What a new motorboard looks like. Yes before you sharp eyed carpenters comment that is a boo-boo at the lower left bottom corner. Since that is well hidden it gets wood putty and not a whole new piece. Just a reminder here BB has patches in it at times. I stick those towards the inside of the cabinet and they blend in well there or won't be seen at all.

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   More later today as I make progress.

 

 

 

 

 

 

 

 

  

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1 hour ago, Dave A said:

Just getting around to working on a set of LS's I picked up some time ago. I will be replacing the sides on these with 25MM Baltic birch. . I take a rubber mallet and beat the side off. The best way is to start at the bottom front and give it some healthy whacks.

 

you cut the tops off , 1st  -----and that leaves the bass bin , then you beat the sides off --perfect

in your opinion ,  would it be possible to not cut the tops off ,  and do the same  , one side at a time , then replace the 25mm BB , then do the other side -

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13 hours ago, Full Range said:

In my La Scalas the side panels are upgraded to 40mm or 1.6 inches plywood 

Along with the dog box braces - Makes a huge difference 

 

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Are those reflectors back in the rear corners, helping to cut the 90 degree angle?  Or is it just the way I'm looking at the picture?

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1 hour ago, CECAA850 said:

Seems like a lot of work when a single brace in the center of the doghouse would net you the same results.

 

The thicker side walls are way more aesthetically pleasing, though.

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2 hours ago, CECAA850 said:

Seems like a lot of work when a single brace in the center of the doghouse would net you the same results.

It's hard to tell but I think the top and bottom braces are just strips of wood and cosmetic.

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Got all the wood assembled last night and let it set up. A tip for when you glue is you want to avoid a mess. I use the bottom doghouse access panel as a guide for the bottom of the sides. I take it off since I need to check the screws on the woofer anyway and put blue masking tape down and the reassemble with just 4 screws. I also run a strip of tape along the inside to catch the squeezins on the inside. The outside is easy to wipe off.

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Here we are ready to fill in air nailer holes and go for final sanding and staining and listening.

 

 

 

 

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I like the look much more than the stock sides too.

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7 hours ago, Coytee said:

 

Are those reflectors back in the rear corners, helping to cut the 90 degree angle?  Or is it just the way I'm looking at the picture?


Yes all the way back 

 

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2 hours ago, RandyH000 said:

these must be 2x as heavy  ---------or close

 

Almost got a hernia once trying to move them 

 

8 hours ago, CECAA850 said:

Seems like a lot of work when a single brace in the center of the doghouse would net you the same results.


They double up as the fabric speaker cover contact point 

 

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Do you gentlemen hear this resonance at all volume levels? I am not sure I pick up on it even at high volume. My one pair are LSi splits with the fibreglass and aluminum trim so maybe they don't misbehave as much? My other pair are standard LS but have been duratexed and alum trim added which may help as well.

I may do the bracing to my regular pair to see if I hear the difference. I move both pair around often so dont want to add any more weight. It seems they get heavier every year without adding anything.

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I think the K-43 in the Industrials “alleviates” some of this (127hz?) hump.

 

Whether it be the higher efficiency or higher frequency response relative to the K-33, or the tighter bass. Or a combination of all three (likely...)

 

I just recently put the K-43s back in my LSIs after years of running them with K-33s (for alleged lower bass, pfffft) and REALLY like the change. Not unlike when I tried Kappa 15Cs in them.

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    Those are looking great. The thicker side walls an improvement both cosmetically. .

   The reflectors in the corners are sharp. When I used to build folded horn cabinets the evolution evolved to using these to try and keep the expansion rate consistent. Sadly never could tell if they helped by listening. Think the horns are forgiving of corners.

    The added mass get them up to LS II bass bin range. Mine weighed about 130 lbs. Glad they have top hats. The total was around 175. It was bad enough carrying the bass bins upstairs. I will get help when it is time to carry them down. 

   

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13 hours ago, CECAA850 said:

Seems like a lot of work when a single brace in the center of the doghouse would net you the same results.

I think @Full Range   build these LS bass bins from scratch  -----there used to be a build thread on these -----

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6 hours ago, Dave A said:

They will sound better than they look too. Mid braces are great but 25mm BB sides is the way to go.


Dave I’ve come to understand there are variances in the doghouse to side wall dimension but with your skills I imagine you could crank out sidewall braces and sell bunches of them. Dave of Fastlane once did this but has dropped that product long ago. Be a great addition to your lovely machined horns?

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On 7/26/2020 at 8:58 PM, Full Range said:

In my La Scalas the side panels are upgraded to 40mm or 1.6 inches plywood 

Along with the dog box braces - Makes a huge difference 

 

 

didn't you have  a build thread on the Forum for these  LSII Bass bins -----

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