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DIY La Scala Idea


Tizman

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Hi All.

I picked up a pair 1976 La Scalas about a month ago and really, really  like them.  I got to thinking that I would like to build a diy set in two parts, separating the bottoms from the tops, and build them out of one inch Baltic birch plywood.  My question is in regard to the ramps that create the horn shape from the hole in the woofer's motor board to the left and right back corners of the cabinet.  Could these ramps end at the front of the flat parts of the doghouse that are parallel to the cabinet side instead?  Would this result in a better horn that has a progressively  increasing mouth size as opposed to a horn that has an increasing mouth size in the back where the ramps create it and in the front where the sloped doghouse and the cabinet sides create it, but a section in the middle that is not increasing at all?  Please see the attached drawing, a very rough one, as it helps explain what I am talking about a bit better. 

image2.JPG

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Welcome.

 

I would not do that.  It will be a different horn, but, IMO, not a better horn.  I would make certain the doghouse joints are sealed tight, brace the side walls (either by adding another layer of Baltic Birch or by fashioning internal braces) and refresh the capacitors.  You could exercise your DIY skills separating the top from the doghouse and/or by doing the bass bin modification.

 

A search of this forum will confirm that I am all about DIY and tweaking Klipsch designs.  While I don't always subscribe to the belief that there is no room for improvement, I do feel that way about what you are suggesting.  It seems to me like a lot of work to end up with something that is not an improvement.  Others will disagree.  It's your decision.  Whatever you decide, please post photos and progress updates.

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what you are looking for is called a Peavey FH-1 the Klipsch Belle is a shorter length smaller mouth version of the FH-1. Hope this helps and is of interest.

 

PS: while the Belle and the FH-1 are better horns in terms of constant expansion (no dead spots as in the LaScala) both are still short and both have small mouths thought the Belle and the LaScala are both smaller than the Peavey FH-1 there is not really a lot of difference in the overall performance between the three. The brace work of the FH-1 is a significant upgrade and the constant expansion is nice but even with that the horn is too short and the mouth too small as most are, it is a simple fact of life that horns get too big for home use very quickly. The other problem with these horns besides not playing very low is that they also don't play very high either which means that you have to have a mid horn which can play lower and that of course means it has to be larger. The Khorn is already getting into the soup at about 325Hz and the LaScala is getting messy by 400Hz. So you have a big horn that does not play low or go high and a mid horn that only just mates with the bass section. The very best horn I have ever found in terms of wide bandwidth is a horn called the California designed by the late Ernst Georg Beck and it still manages to be a very reasonable size but still bigger than most This is an impressive design which is equaled by none that I am aware of. I have included a copy of the design, it is the smoothest and widest I have ever seen and builders have confirmed it does indeed perform this well. fh1_002.pdf

 

 

 

Ernst georg Beck bec1fr.jpg

 

 

 

5a029e22105b8_ErnstBeckCaliforniahorn.gif.ff77607346513abdfd7a3163bbd0482c.gif

 

 

fh1_002.pdf

 

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I might add the bracket between doghouse and side panels, but my preference would be to leave my LS as original as possible.  I would like to DIY an all horn speaker.  I asked about the ramp because I like the look of the bass horn in a La Scala.  The FH1 has the same look as an LS.  The wider the range of the bass bin, the better, and the California has that.  I would like to DIY the horn for the higher frequencies as well.  I'll probably make it out of wood and shoot for a crossover frequency of around 400 HZ.  The diy paper horn project at Inlow Sound looks interesting as well.  Thanks for the links Moray.  Are there photos of the California?     

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with an already small horn losing any energy (output) is an extra insult you don't want. Horn mouth flexing is a problem often overlooked. The braces in the Peavey FH1 have been used to very good affect in the LaScala along with thicker side walls (not the dog house sides but the main cabinet  sides) they are worth your time and effort. I think I have some pictures of built up California horns will look tomorrow. Take a look at Tom Danley's Unity or Synergy horns for current sota wide band horn designs. Danley's tapped bass horn is also the smallest way to make a lot of low frequency energy happen in your room. 

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I think Andy already posted about this . But if you use 1 inch on the dog house it will throw everything out of spec. 

On my 1980 Scalas when I added cherry veneer to the out side they got considerably stiffer than they were. If someone could make video of them flexing a stock side wall I can make a video of mine so we could compare them. I wished I had documented this before I veneered them. I do remember it did not take much effort to make the side wall flex. But now if flexes very little with great effort so it is better.

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Peavey FH-1

 

mocksys1sm.jpg.e29bec4be93fe14020c2a2f032e7c84b.jpg

 

It is a good bit bigger that a La Scala, but doesn't go noticeably deeper.  It does go higher, partly due to the corner reflectors in the rear corners of the last fold.  The Peavey woofer may also be to blame.  It has very high distortion, more distortion than fundamental below ~100 Hz, but can absorb 400 watts.  The FH-1 might be awesome with a K-43. 

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if you turn the Peavey FH1 on end it is then only 21.25 inches wide frontal which is about three inched less than a LaScala and it is taller which is a good thing because it will get your horn up at your seated ear level, depth is about the same as a LaScala. The FH1 is a solid design has better upward extension than a LaScala so it will be easier to cross to a mid horn or to a Karlson K-Tube. 

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mouth braces in your LS clone would help a lot.   I would not mess with it nor the Belle (although for fun I'll sometime have a 0.83 scale Belle).

 

the old University Classic seems a good horn, but huge.  Old school low qts drivers would fare better in the Classic than LS.  (I'd like to hear Beck's horn)

 

I have nice condition FH-1 but don't use them as prefer a K12 with pym1298 (like Kappa12a)  the little K, is only about 100dB sensitive

but has better dynamics.

FH1 are 10 cubic foot external bulk vs ~8 for LS and Belle bass sections.

 

here's one of my FH-1 with stock Peavey woofer outdoors

- the mic on the ground trace goes pretty high -

HpooFTV.jpg

 

WRaHX31.jpg
7UkTOGF.jpg

 

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Thanks for all the responses and all the excellent information contained within them.  I am leaning towards the California at the moment.  I'll probably get someone to build the bass bins for me rather than do it myself.  Thanks Moray for the plans of the design.  I am hoping that the person that makes them for me, who is a great carpenter, will be able to decipher the plans, as they seem fairly straight forward.  Moray, if there are any additional plans, or if you have found any photos, that would be much appreciated.  Also, would you happen to know what frequency the California can be crossed over at, and how low it goes?  . 

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  • 1 month later...

It looks like I have managed to source a pair of FH-1s locally before my plan to build the California's got started.  I await their arrival on Sunday.  I have a pair of 511Bs and a pair of 811Bs, and I have a pair of Renkus-Heinz SSD 1800-16 also due to be delivered shortly.  I am going to borrow a friends' BEHRINGER SUPER-X PRO CX3400 to play around with as soon as I get everything together.  I would appreciate any comments that you all might have on these choices, and especially on the Behringer, as my friend really likes it, but it seems to get some bad press. 

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On 11/13/2017 at 1:41 AM, Tizman said:

Thanks for all the responses and all the excellent information contained within them.  I am leaning towards the California at the moment.  I'll probably get someone to build the bass bins for me rather than do it myself.  Thanks Moray for the plans of the design.  I am hoping that the person that makes them for me, who is a great carpenter, will be able to decipher the plans, as they seem fairly straight forward.  Moray, if there are any additional plans, or if you have found any photos, that would be much appreciated.  Also, would you happen to know what frequency the California can be crossed over at, and how low it goes?  . 

This is all I could find on line you can contact the member at Lansing Heritage site He may have more info.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Beck California exterior view.jpg

Beck California interior view 2.jpg

California Response.jpg

Ernst Beck California horn.gif

Sato12.jpg

Sato11.jpg

Beck California interior view.jpg

Modified California Bass Horn.gif

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On ‎11‎/‎8‎/‎2017 at 5:01 AM, ricktate said:

I think Andy already posted about this . But if you use 1 inch on the dog house it will throw everything out of spec. 

On my 1980 Scalas when I added cherry veneer to the out side they got considerably stiffer than they were. If someone could make video of them flexing a stock side wall I can make a video of mine so we could compare them. I wished I had documented this before I veneered them. I do remember it did not take much effort to make the side wall flex. But now if flexes very little with great effort so it is better.

The flexing "problem" on LaScalas pertains the cabinet side panels and can be solved by using heavier stock FOR those panels, as what was was done on the CURRENT LaScala bass bins, by going to one-inch-thick side panels.  There is really no need to use thicker stock for the top and bottom panels, because the thicker side panels will solve the issue.  As for the doghouse, it is not a part of the problem so you can run with 3/4" thick panels for it, since its construction is more than stiff/stable enough once the doghouse itself is attached within the bass bin "box"..  You can also use rabbet joints instead of butt joints in the construction...with rabbet joints used for attaching the side panels to the rear panels and the side panels to the the top and bottom panels of the bass bin.  Rabbet joints in lieu of butt joints will stiffen those particular joints AND, stiffen the cabinet itself...the rabbet joints will provide up to 50% more glue joint area at those locations, and that will create a stronger box and reduce any tendency for flexing except at the sides at the mouth of that bass horn lens, and the thicker stock used there will solve that problem.

 

Thicker stock on the side panels eliminates the need for any frontal bracing between the doghouse "roof" section and the side panels at the mouth area. 

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12 hours ago, moray james said:

Bruce that's true re digital compensation however the adjustment will only work in the sweet spot. You have to physically adjust the components for the effect to be realized around the room.

 

What I mean is that crossover can only delay the bass, which is opposite what you need with these cabinets.  You need to delay the mid/tweeter to match the length of the bass horn.

 

And you are wrong., having the proper delay works, not just in the sweet spot. Where would you get that idea?

 

Bruce

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I didn't realize that the Behringer only delayed the bass section.  I will be using 511Bs with the FH-1s.  Assuming that I adjust for the delay by physically aligning the drivers, what does that look like?  With respect to the delay, the 511Bs are about 1.5" shorter than the LS midrange horns.  The Behringer is a loaner and, at around $200 CAD, is a reasonable solution if workable, but the delay only working on the bass makes them less attractive.  If adjusting the 511Bs physically allows them to sit on the bins in an aesthetically acceptable manner, I may still pick up the Behringer for myself.  This is obviously going to be a personal call, but an idea of where they would need to sit would be helpful.    Are there any other crossover choices that might be reasonably priced and more acceptable choices than the Behringer?  Also, would a regular passive crossover be an acceptable choice if physical alignment is acceptable?  I have been looking at doing a DIY version of the ALK  AP12 crossover in 500 or 600HZ, or another simple 12 DB/octave crossover instead of going active.  Do you have any recommendations with respect to going passive?   There is also a passive Jean Hiraga version of a Altec crossover that helps compensate for dropping HF response in a two way, that I have looked at.  I use DIY tube amps that put out 2 to 8 Watts, and would use two stereo amps with an active crossover.  Thanks in advance to any advice and information!

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