La Scala Butchery

[Jim E]

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On 12/24/2004 12:28:08 PM ooteedee wrote:

According to the factory design blueprints: Part #3 is called a "splitter".

If you don't want to call it a "splitter", what would you prefer it be called?

An acoustic diverter?

Long wave re-director?

A tri-sided chamber support?

And if you don't want to call it a "wedge", what would you prefer it be called?

Triangular shaped beam?

An extended half pyramid?

A bisected square rod?

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It has been refered to as the "Prizm".

Question on the "factory blueprints" you mentioned. I don't recall ever seeing a factory blueprint on the LaScalas. Would you post the drawing here?

Jim

[ZAKO]

Where did you get factory blue prints?

[lynnm]

And if you don't want to call it a "wedge", what would you prefer it be called?

A wedgie ??

[lipinski]

you guys give ol' ooteedee a break. he'll probably learn more from this little experiment than about 90% of us. yeah, it'll costs a few bucks, but half the fun is in the building, right.

[ZAKO]

I hope you dont build your house that way.

[djk]

" he'll probably learn more from this little experiment than about 90% of us."

I prefer to learn from other peoples' mistakes, rather than make my own.

Hope he doesn't cut his fingers off feeding the boards vertically into the rip fence to cut the 'V' for the doghouse.

[ooteedee]

Wedgie... I like that.

From here on out........it shall be called "The Wedgie."

RE: My House

My house and the barn was built by a farmer in 1887. Using trees he found and cut into lumber on the property. I don't buy the finest wood, fixtures, mouldings, carpet, etc...to repair the house. But I repair it well.

RE: Cutting my fingers off on the rip saw.

I am very skilled with most power tools. My Father taught me well. My fingers are safe. IF I have to make a jig to cut the 60 degree ...so be it. And...no...I would not try and rip the board vertically. Give me a little credit.

RE: Factory Plans.

I'm sure you've seen them before. I found them easily enough online. The title on the picture says 1977 LaScala Factory Dimensions. Whether or not that is correct, I don't know. They appear to be accurate (See attached and the following two posts)

But I will put forth the following question on one of the drawings. The one named LaScala22.bmp.

What are the pairings of numbers?

[ooteedee]

And this one............see attached

[ooteedee]

And this one too.

My question is: What are the pairings of numbers on this drawing?

Metric?

PS: I also have the metric versions of the other drawings. In German I believe.

[ooteedee]

Thanks lipinski.

[ooteedee]

TO: djk - No Life

Thank God every single person who ever made a difference in this world....did not think like you.

Good luck to you.

[djk]

"I would not try and rip the board vertically. Give me a little credit."

How do you think you are going to cut it then? If you have ever used a table saw you would know the blade does not tilt to 60*

"TO: djk - No Life

Thank God every single person who ever made a difference in this world....did not think like you."

Just for you I am going to enlarge on my statememnt "I prefer to learn from other peoples' mistakes, rather than make my own." and add: even though I can learn from people making mistakes it can be very depressing to see how stupid people can be. In the future I think I will choose to stand on the shoulders of giants (like Paul Wilber Klipsch) so my vision will gain from their stature and I will be able to see even farther.

[edwinr]

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On 12/25/2004 10:44:44 PM ooteedee wrote:

TO: djk - No Life

Thank God every single person who ever made a difference in this world....did not think like you.

Good luck to you.

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Hey, ooteedee. You're a bit sassy aren't you?

If you're not careful we'll set thebe's twins on you!

Good luck with your cabinets...

[colterphoto1]

Nice set of drawings, don't believe I've ever seen those before so thanks for posting. I must agree with others that you might be building an enclosure for a driver that are ill-matched.

ALthough it is not a bass reflex cabinet, so port size is not critical, so this will help you. Any experiment like this is worthwhile, at least you're having fun with acoustics. Possible outcomes, great cabinet, you love it or pos, you buy a real LS. I say go for it, but keep all 10 digits in the process. This is not an easy cabinet to construct as each joint must be completely rattle-free.

Have fun! Keep us posted.

Michael

[ooteedee]

To djk:

Ok sorry. A bit harsh perhaps. Forgive me.

RE: The 60 degree cut:

You're right. Saw don't go to 60 degrees.

So........I plan to extend the height of my fence on the table saw about 5 or 6 inches, set the blade at 30 degrees and carefully make my cuts.

If that fails. I'll just use a hammer and chisel.

Just kidding.

As a last resort, there's a mill nearby that does a ton of custom mouldings, interior woodworks, etc.

But most likely I'll get it done at home.

[Marvel]

Attached is a zip file with the two plans sheets for the LS, and a txt file with notes from Andy (HDBRBuilder) a former Klipsch employee. He made corrections, an as far as I know, these are about as close as they will get.

He tells you how many pieces of a given size you need, etc., and the order of assembly. It might help you out.

Marvel

[D-MAN]

Build 'em and put ANYTHING that you want in them. It's called experimentation, and it's perfectly ALL RIGHT.

When I was in high school, I built a pair of cornerhorns and I started off with CTS 15" woofers and eventually moved up to EVM-15B's and Radio Shack midranges, and yes, compared to what I have today, they sounded like crap, but THAT WAS THEN, and it was fun, and a learning experience.

For some technical advice now, I would recommend that you:

1) cut a 78" throat cavity opening. This is 13x6". This allows for you to use 8 Ohm woofers. The 13x3" opening is exclusive to use by the Klipsch K33E and variants.

2) the back chamber is sized based on the horn total cross-sectional area, not the woofer; the woofer HAS NOTHING TO DO WITH IT. Ignore the nay-sayers; they know not what they do.

Choose your upper frequency drivers for a 104db sensitivity. The woofer should be approx. 96.5db eff to match that. Basically, the woofer should be capable of horn loading (that is, it has to be able to overcome a high amount of resistance). Look specifically for drivers that are designed for horn loading or come out of horn cabinets (PA-types). Fc 35 Hz or lower, with as much as 9mm Xmax. Remember 8 Ohm drivers will require the 13x6" throat opening or you will literally muffle the dickens out of them.

3) use a separate motor board to mount the driver. This will allow you to use a smaller (narrower) throat cavity opening, so you can go back and forth between a K33 or an 8 Ohm driver (high wattage handling, etc).

4) see the throat splitter thread in the UPDATES and MODIFICATIONS section.

5) the crossover is going to be a perpetual draw-back to you until you actually make or buy a good one. Cheap ones sound grainy and irritating. Save your pennies, and build you own using high quality parts.

6) have fun and enjoy. Upgrade when money allows as desired. It's a great platform to tweak incessantly.

DM

[ooteedee]

Marvel, D-Man

You guys rule.

Thanks for the plans, tips and the encouragment.

I appreciate it.

D-man

I may have some questions for you after I digest your message a bit.

Thanks

[ooteedee]

TO: D-Man

Regarding your instructions:

I'm hip to all your suggestion but I have a few questions.

I've always wondered about the opening on the motorboard. Seems counterintuitive to have such a small opening. However, I can see why it would be designed that way ....with the right woofer. Since mine is not, I will do as you suggest.

I have studied the forum thread about the splitter mod. Exactly what should I learn from that? (Besides the comments on the size of the opening to the horn.) Can you be specific?

And lastly, where can I find the schematic for the La Scala crossover?

I found some Klipsch crossover schematics online but they were special interest mods.

[D-MAN]

ooteedee, the throat (the smallest portion of the horn) is 3" deep by 13" tall BUT it is bifurcated or split in two, so if both channels were put side-by-side, it would form a rectangular horn channel 6" deep by 13" tall. This forms a cross-sectional area at the horn throat of 78 square inches. This is the same size throat as the Klipschorn, LS and Belle! It is specific to a 15" woofer.

The "slot" opening (also called the throat cavity opening) was originally designed for and used the full throat area 78 sq. in. (or 6x13" slot) up until 1963 when Klipsch went to the K33E from the previous CTS woofer. There apparently is a pronounced peak in the frequency response of the K33E at 400Hz, so the slot was altered and narrowed to 39 sq. inches or 1/2 of the throat size.

When the slot is smaller than the throat, it acts as a physical capacitance and limits the upper frequencies from traveling through the opening. This is also referred to as a physical band-pass limiter. It causes a higher resistance to cone excursion, and the first to go are higher frequencies because they are a shorter wavelength and are basically modulations riding on a larger (low frequency) excursion, and they get reduced to virtually no modulation at all. The size of the slot also effects overall efficiency, and the full size 1:1 ratio with the throat area cross-section would provide the highest efficiency, of course.

The resistance at the throat, compounded by the reduced slot size naturally suppresses cone excursion on the driver. This results in less modulation distortion(s), as IM and FM. The back chamber is sized to allow for the same compressable volume as presented to the front of the cone by the volume of air in the horn and the resistance of the horn throat to the movement of air.

The resistance (actually called reactance) appears to the amplifier as an increase in electrical resistance. Hence the K33E is a 4 Ohm voice coil, which appears to be a 16 Ohm voice coil to the amplifier. By the same token, putting an 8 Ohm driver into the horn will appear to be 32 Ohms to the amp, unless the resistance at the throat is reduced. This can be done with a wider slot opening such as the original 6x13" 1:1 slot, dropping the impedance down to a more efficient level.

Since there are many, many more 8 Ohm drivers available than the lone K33E 4 Ohm driver it is a rather good idea to set up your horns to be able to use both, IMO. One caveat here, though, I have found the the K33E to not only sound the best IMO, but it is also the cheapest driver for the level of performance. But hey, experiment around and see what you think. All of the comparable 8 Ohm drivers cost at least twice as much.

But if you want to go with higher wattage capability (say 1000 watts) you are definately talking an 8 Ohm driver.

Hope that clears it up a little. Also for crossovers, check out Al Klappenberger's website at www.alkengineering.com

One more thing, the splitter thread had some pics of a back chamber showing the easiest (and best) way to mount a convertable motor board (i.e., with different size slot) to the horn enclosure using wing-nuts on carraige bolts.

DM