newbie la scala/k-horn project

[Tony Reed]

For more info on the "Little Bastard" check page 180 of PWK's book. It was built for MIss Valerie.

Tony

[WMcD]

Attached is a sheet from the 4138594 patent. The woofer is listed as a K-33. You can see the midrange horn is about 15 inches long. No model number is given but that is too long for a K-400 (used in LaScala and K-Horn).

I don't have the book so can not offer info on whether this is the little darling mentioned above.

Gil

This message has been edited by William F. Gil McDermott on 04-15-2002 at 05:37 PM

[bigdnfay]

Here is a scan from an early to mid 70's La scala brochure. Sold these for many years when I worked at my local klipsch dealer. Part of my job was replacing defective or burnt drivers. Never did I see a la scala that opened from the top of the bass bin..always from the bottom.hope this helps.

I have a k-400 horn (no driver) if anyones interested. It came out of a la scala. just sold one to j-malotky for a center channel project.

[WMcD]

The spec sheet recommends amps rated for a 4 ohm output.

I selected the little Sony RB-5 receiver/CD to drive the Forte II because the supplied speakers are 4 ohms, so presumably it was designed for such a load.

I use a 1975 vintage JVC receiver for the Quartets. These are also 4 ohms in the bass area and I've confirmed there is no sag in output of the amp.

I sometimes wonder if complaints about good versus bad amps is because of this issue. On the other hand I have no actual data that a given amp sags at 4 ohms. But it is something to think about.

Gil

[HDBRbuilder]

Gil,

Yep, those drawings are of the LB-76...some of those built were textured black finish, and some were fiberglass with metal edge and corner trim...I am sure that we were testing them prior to 78, but not quite sure when they first became available to the employees for loan on weekends...likely around 79...they sounded great too....a mere 10 watt car tape deck would punch out some serious dbs from em. If I recollect correctly, none of those we had available to us had the wings attached, but I DO remember seeing a pair or two with the wings. Also...I think they were punched by heresy parts...not sure on the crossover. One pair was even a split design like the split lascalas...with separate high end and woofer sections for ease of transport. As for Gillum designing the lascala with heavy input from PWK...that was what i was always told when i worked there...but that could be wrong...(between you and me, i believe it is right tho...gillum was still just a "wet behind the ears ex-science teacher at the time working as an 'engineer's apprentice' under PWK...and with all the input PWK had into the design, I am sure he got the credit for it).

John,

The LB-76 was narrower and not as deep a cabinet as the lascala...depth was close to BK depth...height was maybe a couple or so inches shorter than lascala. Again...not sure on which midrange horn was utilized, could be either heresy, cornwall, or BK...but i dont think it was a specially built horn. As for patent date...I am sure we were testing these a year or so before the patent date. And they would make a great rear speaker for k-horns or whatever.

Tom,

Why not just build the "scalawags" using parts from sale online or the company, and save the "hearsays" for rear channel speakers? Another point is those little midrange horn suports are pretty easy to make from a common angled shelf bracket found at home supply stores...a helluva lot easier to make than scalawag cabinets..HA HA! One more point here...ACOUSTICALLY speaking, MDF would be a better medium for scalawag construction due to its consistent density(ie, no voids in interior plys, etc)...BUT standard BIRCH CORE (NOT poplar core) 3/4" cabinet plywood is alot easier to build with...and alot more resistent to moisture...not to mention that it isnt as loaded with volatile chemicals that could weep out in gaseous form and separate the veneer skin from the substrate mdf...go with the plywood!!!!

[Tom Mobley]

HDBRbuilder,

Somebody named MS built my 78 HDBR's. Who was that?

On the wood deal, I worked in plywood mills in Oregon for many years, in fact I was making solid core Douglas Fir 9-ply birch faced stuff when I bought my Heresy's at the Music Shop in Grants Pass, Or. That stuff is a real PITA to lay up, the plugs in the core are always popping out as the core feeds through the glue rollers, it's like chasing around after wet bars of soap to get them back in right. I'm having trouble locating what I would call decent plywood here in Phoenix, Az now. I don't think anybody makes good plywood anymore. Particle board is a lower form of life to plywood guys, wouldn't touch it with the proverbial ten foot pole. Yuo know, that is some really nice plywood my HDBR are made from, but it's a funny thickness, not exactly 5/8". Nobody seems to have it, I'm going to end up using 7 ply 3/4" for the LS's, not nearly as nice. I can't find marine grade solid core either. Guys at the specialty wood places here told me to drive over to San Diego to look for it. Like there's time for that.

One thing is funny about my HDBR's, they're not veneered on the front edges like all the others I've seen, rather, there's a piece of molding that's sort of like 1/4 round but a little flatter on the front. Is this normal? I haven't seen this on others, but I guess there's no veneering an unfinished speaker. They had to put something on there to surround the grilles.

Thanks for chipping in here.

Tom

[HDBRbuilder]

Tom,

While I was there I must have trained up 30 or so employees to build Heresys and/or Cornwalls. I can't remember the names of all of em, as you can imagine. We tended to have alot of turnover with our new employees during that time frame. When building HDBRs, I was most often doing it solo, but at times I had a helper installing the glue blocks in the back and the fronts to the glue blocks i had installed in the front edges (on drop-in front models). Later I would put them doing my part so that they had experience building them in case i took off for a day or so. This helper was also my partner in building cornwalls, normally a two-man operation, although it COULD be done by one person. As for the MS, it was probably one of our "transient" employees...most of whom i cant remember the names of...for obvious reasons.

I will say one thing though, if the stamped in initials on Heresy D models or cornwalls are my "A" or "AB", Ronnie Barham's "RB", or Charlie Horn's "C" or "CH", then they were well-built cabinets. As for LaScalas, Ronnie and Charlie built alot of em, but the best ones were built by Jay Wheeling "J" or "JW". Lynn Stevenson built some of everything, including Belle Klipsch models until he became foreman over the cabinet shop...for awhile before him, Charlie Horn was foreman, then Ronnie, then Lynn. Their predecessor as foreman had been there for years and stepped down to become the BK builder...and he was a damned good builder...his name escapes me now, but i will remember it in a day or two...sorry.

As for Inspectors on the label, if it says Gwin Cox, then they were well-inspected while she did the final assembly. She later began to test them in the testing booth, then moved up to become first assistant in final assembly/shipping dept. Judy also did a helluva job in final assembly and inspection.

Bradford tested the finished speakers for most of the time i was there...but he wasnt the only one.

As for the plywood used, we used Georgia Pacific cabinet grade 3/4" birch plywood(5 interior plys of BIRCH, with outer plys being thinner birch veneer...for a total of 7 plys) for the cabinet bodies...not 5/8". The drop in fronts started out as 3/4" birch, but soon became Baltic birch...a bit thinner than 3/4", but thicker than 5/8" due to its being a metric measurement(i think it had 11 equal thickness plys), and even then it was inconsistent from pallet to pallet load in its thickness...it was hell on the saw blades and router bits due to all the glue in it for each ply...dulled the hell outta the cutting edges real fast...LOL!...BUT made really smooth routed openings!!! The speaker backs were sometimes Georgia Pacific Birch "half-inch" and sometimes baltic birch "approximately half-inch". NOTE: We tried using poplar core plywood for awhile in the cabinet bodies, since it was somewhat cheaper than the birch core, but ran into problems with it "holding the glue" as well on the edges...also...there was a problem in the sanding department with it, since the poplar plys were more "pithy" than the outer birch veneers, it made getting a good clean FLAT edge on the open edges very difficult with the humidity of southwest arkansas involved in swelling up the inner plys of it. It also sucked up paint like a sponge, causing the painted ones to look funny...I am sure with your woodworking experience you know what I am talking about...LOL!

Go with the birch core 3/4" plywood for the Lascalas, since that is what the originals used. You may have to go to a specialty lumber shop to get good stuff tho... from what i have seen most of our new-fangled home depot and lowe's type places either offer only the poplar core, or a lower grade of birch core than what i like to use. Consider this though...for just a few more bucks a sheet, you can get some mighty fine oak veneered birch core plywood from these specialty suppliers...in either a rotary cut veneer or a strip veneer with book-matched strips in it...if you go with this instead of the birch and can pick through the sheets to get some "consecutively veneered" ones that match each other...it would look really fine. just run a perimeter of oak "screen molding" around the front perimeter and tops to hide the visible open plys of it...OR you can holler at me sometime and i will tell you how some VERY custom versions were built utilizing alot more labor time, but totally eliminating any visible joinery and edge plys showing anywhered on the lascalas except the back of them. And consider cutting the side panels with the grain running vertically instead of horizontally...it looks alot better that way...have the top grain run left to right instead of front to rear...same for the folded woofer bottom....and leave the upper front (tweeter/Squawker motorboard) with left to right grain.

As for your question about the front edge molding...you havent made it clear whether your heresys are "drop-in front" models or flush front models...anyway, here is the deal from what i can remember: the old style flush front models only had edge veneers showing on the front vertical edges, whereas the drop-in front models had edge veneers showing all around them at the front. Whenever we built flush front models that were requested with grill cloth, it was installed in final assembly using the raw grill cloth stapled to the front edges, and 3/4" wide "screen door" molding bradded over it along the front edges...this meant the grill cloth was permanently attached. I have seen some of the drop-in front models built at customers' requests with this same screen door molding mitered and installed on the front edges to hide the plys...and of course it would be no real hassle for a customer to do this mod himself, but that would still leave the veneer edges showing on top of the speaker cabinet...by the way...this molding over grill cloth was also installed on some lascalas at customer requests....i personally thought it was ugly as hell tho...LOL!

I hope this answered yer questions...like i said...if you are a pretty accomplished woodworker, holler at me and we can discuss how to make a pair of "to die for" cabinets that have blind joinery with no edge plys showing anywhere except the rear of the lascala cabinets.

[CaptnBob]

Wow!

This has been fun to follow.

I do want to add this. In my earlier years I ran tech. for an auditorium at small liberal arts college in downstate Illinois. We bought several pairs of LaScalas, eventually winding up with 3 pairs plus one odd, extremely old one. I can say - with out a doubt-early LaScalas came with the access port for the woofer on the top, beneath the midrange horn. I had, on more occasions than I'd like to remember, had to unscrew the top (I think there were 16 or 18 screws) then unscrew the squawker horn (the two screws on the bottom were the hardest) then disconnect everything on the crossover and then finally take out the screws holding the board over the hatch. You may have to pry this off as I seem to recall some sort of sealant on there, but I could be misremembering that. These LaScalas were about an inch shorter than the newer ones which had the hatch on the bottom.

I believe the change was made at the start of the "Disco" era, when LaScalas started being used in clubs as an alternative to the venerable VOTT, and blown woofers became an issue.

Capt'n Bob

p.s. If you ever have some time with nothing to occupy "the devil's workshop" and have a burly friend to help you, try stacking your LaScalas, with a towel between them and the top one upside down. You'll be impressed.

[mungkiman]

Capt'n Bob,

Thanks for your help. The tops of these La Scalas are held on by 12 screws; 2 in the back, 4 in the front, and 3 on each side. Your description of replacing the woofers (removing the TOP) will help me tremendously. I have to remove the squawker and tweeter anyways to "mock-up" my Speakerlab cabinets with the Klipsch components.

Can anyone help with my crossover question? I have the La Scalas with crossover type "AA". Will I have to modify anything for the crossovers to be suitable in the K-horns?

Many thanks to all. I'm pleased this thread was of interest to so many people. I have learned fantastic history, found clarification, and have been impressed with the way you all work together to help newbie's like me.

I will still post pictures of these cabinets as soon as I am able.

[HDBRbuilder]

Capt'n Bob,

I can imagine what a bear it is to remove the woofer from the top of a lascala...geez....and i intend to agree with you about that change to a bottom entry coming about due to the disco days...back then alot of these clowns at these clubs believed that if the speaker was big, then it absolutely HAD to have 1000 watts pushed thru it...and there were alot of fried woofers, etc. resulting from this insanity...which of course would require more user friendly opening into the doghouse to change out a woofer...by the way, am i just crazy or does it still seem that today's purported audiophiles(they call themselves speakerfreaks) havent realized that ya dont need a kazillion watts to blow the windows out of a room?...it seems that they dont understand effficiency in speakers any more than they understand that equalizers are to shape the speakers to the listening environment, NOT just a separate VOLUME CONTROL!!!some things never change...LOL!

As for inverting a speaker on top of another one(in your case you talked about lascala), i mentioned in this forum on another thread that a pair of heresys inverted on top of cornwalls is pretty darned impressive too...LOL!...or even heresys on top of each other inverted...that is how i worked parties while in college...two heresys on each side, one inverted on the other....pushed by 90 watts rms...can sure "pump ya up" for rock'n'roll....LOL!

[hetmann]

The AA crossovers will work. I would try them first and only upgrade if there is a reason to. I have a pair of AA that I will be using for my khorn project.

------------------

Klipschorns and Moondogs

[CaptnBob]

Hi, all,

Now that you mention it, the one odd LaScala we had was a K-447 instead of a KS-BB, was made of pine plywood instead of birch, had a larger hole in the back, and a top held on by fewer screws. (I should also mention this La Scala got dropped down a ladder when the screws ripped out of the plywood sides. A student was trying to lift it through a trap door at time, using the tweeter and top as handles. So be warned.)

I also wanted to mention I found it easier to remove and replace La Scala woofers by putting the cabinet on its back after all the hatches were taken off. That way, the woofer wouldn't "get away from me" when the last few screws were taken out.

Capt'n Bob