la scala project

[Islander]

There's another thing I should mention about the JubScala conversion: it's not just a tweeter upgrade. The electronic crossover smooths some lumps out of the frequency response of the LS bass bin and increases the woofer output. In my case, I was able to reduce the subwoofer output by 2.5dB. Since I have the sub crossed over at 150Hz (sounds high, but it's what works well with La Scalas), that's a few octaves that are now coming out of the LS bass bins in stereo, instead of mono from the sub connected to the LFE/sub out from the receiver.

The JubScala conversion improves the LS sound from the top all the way to the bottom. The speakers now sound fairly good without the sub, something I would not have said about them in stock form.

As for power handling, the K-69A tweeter is rated at 50 watts. The 510 and 402 horns are made of non-resonant composite material.

If you really like the look of standard La Scalas, you'll be happy to know the 510 horns will fit inside the standard LS cabinet, to replace the 400/401 squawker and K-77 tweeter horns. When you're making the front panel, you just make a single cutout to receive the single horn instead of two cutouts for the two stock horns. If you have a router, you could make a 1/4 inch relief to accept the flange of the 510 horn, so it would be flush with the front panel, for a very tidy job. You could even add a grille to make the modification invisible.

Finally, JubScalas are all Klipsch and the crossover is programmed using settings provided by Klipsch and arrived at after tests in their lab. There's no guessing around, since the project follows a proven Klipsch recipe.

[Islander]

510 JubScala rear 3/4 view (K-55V in cabinet is no longer connected):

[Islander]

510 JubScala front view (the 510 horn is 9 inches tall and 15 inches wide, measured edge-to-edge):

[Arky]

Pat, I know you must be enjoying those.

Dean

If you read this don't you have a pic or drawing with the 402 you can post for comparison? I really liked these in Hope.

[bluesboy]

One more............

That's got to be a nice sounding setup bluesboy. Have you tried turning the bass bins into the corner? I did, and WOW. It depends on the room though.

http://forums.klipsch.com/forums/t/104054.aspx

Greg

Actually this is a set up I built for a friend of mine (Tarheel). I saw your thread on reversing the bass bins. That's an interesting idea but I doubt if Tarheel would go for it as it would expose the unfinished backside of the speakers.

[Islander]

Here's a picture showing, in the left corner, the La Scala bass bin with a 402 horn on top of it. In the right corner is a Jubilee, also with a 402 horn.

[Islander]

Here's a drawing showing, from left to right, a 402 on a Jubilee bass bin, on an MCM bass bin and on a La Scala bass bin, followed by a 510 horn on a La Scala bass bin:

[Arky]

Those are them. The 402 on top might be a tough aesthetic sell but it damn sure sounds wonderful.

[JohnA]

john,

you say the 902 is a bit low on power. Do you know what the 908 is like power handling wise?

some bloke on ebay said in a product description for a 902 that he was selling, actually, was a 908, and this was much better because it(908) had double the power handling. is that true? is it sonically interchangeable?? or just spin. The 902 i'm considering is the Great Plains if that is important.

ALL other 902's i have ever seen advertised S/H on ebay have been at least 1.5-2 ohms lower than spec. I don't exactly know what this means soundwise except to say "they aint gettin' my money".

nice pics. i really love the look of la scalas.

again, i have to reiterate the roughness i was referring to earlier was about the harshness of the top end. i quite like the utilitarian look of la scalas and i want to recreate the retro look of these speaker without all of their anachronistic faults.

P

Paul,

908s DO handle about twice the power of 902s. They have a different diaphragm, called Symbiotik. It reduces the HF limit to about 10k and would require a tweeter. For home and light commercial use the 902 is enough.

All drivers with a nominal rating of x will show a DCResistance of less than x. Typically, an 8 ohm driver will have a DCR of 6 to 6.5 ohms. If that is what you are seeing on eBay, the drivers are normal and undamaged. No reason not to buy them. The 4 ohm K-33-E has a DCR od 3.2 to 3.4 ohms. Placed in a bass horn the *impedance* rised to 6 ohms, thus the 8 ohm nominal rating.

There are 4 reasons the La Scala will sound harsh. One, the Type AA network had a pair of zener diodes, in series and paralleled across the tweeter. Above about 2 watts, they shorted and limited the power to the tweeter, by sending it something like a square wave. Two, the tweeter is recessed in a hole. Klipsch designed a pair of "Z" brackets to push the tweeter through a larger hole and make it flush with the front of the motorboard. Three, the K-400 horn rings. You can feel it with your hands. I put Dynamat on mine to stop it. Rope caulk works, too and is cheaper. K-55 squawkers have a "bounce" in the response curve. K-55-Vs with spring terminals have it at 9k and some were pretty bad. K-55-Ms have it at 7500 Hz. If the crossover doesn't reduce the "bounce", you will hear it as treble harshness. The diodes in the Type AA crossover are, by far, the worst.

I bought my electronics from a local electronics boutique. The owner was a bit of a snob, if a likable snob. He was really into his Apogee Diva ribbon speakers. He refused to listen to my system for about 2 years, complaining as you do. Finally, he had to during an upgrade he did. He becake a convert when he heard it. The harshness he said they had to have was not there and he liked them.

I need to get a good pic, but here is one of the Paevey FH-1 and Altec system I built for amusement and to use at church functions.

[paulV12]

WELL EVERYBODY I have looked at all your threads pics and ideas. This is why i posted here. I'm constantly blown away by the smartness of people round here!

I'm pretty smart, but not so much in the ways of woodworking, or speaker inception and design, i have to admit. Some of the things people think of, are incredible.

So, John you reckon "the rectangular slot beside the doghouse could be a bit wider". I need to know more! are you referring to:

A)the distance between the woofer mounting board and the rear?

B)or, the 71/2"doghouse side(4 in the plans) to speaker side(8) slot?

if B(above), then this has to be adjusted going to 1" from 3/4 anyhow to keep critical horn dimensions(ratios perhaps) so widening it in the planning stage is easy. How much do i widen it?, and what effect will it have?

i don't think i will(won't) brace the doghouse roof externally as i think it looks repugnant. Though i suppose I could do it like that if I put grille cloth over the "W" bin. Might be fun to see it puff in and out like a heart during surgery while listening to the Thunderstorm in Beethovens 6th really LOUD. I understand the reasons for this mod but the 60's theme in this case, is more important than looks(hence inch ply). I might be able to brace internally the dog box roof somehow(steel might be good here and not take up too much space) but i'm not at the cutting stage till I've thrashed the issues with you guys.

John are the "corner reflectors" the doghouse brace? I'm not sure! If not, what are they, and what is their principle of operation?

So, if i undestand you correctly you reckon stock lascala woofer, mid(damped), Bobs tweeter(flush) and modded klipsch Xover. iT'S all starting to get a bit confusing now.

On the one hand I want the La Scala look (and you have given me that), on the other hand the 511/902 Marvel(bruce i think) has pointed out the projected radius of the 511b horn being recessed inorder to flush fit is an unknown. I suppose the only the edge parts of the horn will be effected if i do that, but the reflections may stuff the sound.

Does anyone know what will happen if, one(me), were to put a ct125 tweeter in a horn 171/2"Wx3"H? I know this tweeter sounds FINE as is but............(you know the looks thing again).

ALK"s es500 crossover for 511b/902 in belle and lascala?.....thoughts anyone.......!!?

Better go to bed know its 5.00am here......speak soon guys, Paul.

[Islander]

WELL EVERYBODY I have looked at all your threads pics and ideas. This is why i posted here. I'm constantly blown away by the smartness of people round here!

Just speaking for myself, most of what I know of hi-fi has been learned on this forum, although I thought I knew a fair bit before. Stick around and see how much more you can soak up. [8-|][H][Y][]

[JohnA]

Paul,

The braces between the sidewalls and doghouse in the FH-1, above, are what I was recommending. There is a photo of PWK in his lab and a La Scala so braced in the background. The company never did it because of the difficulty in consistently centering the doghouse, supposedly.

The corner reflectors are shown in the sketch below. The dimension I think should ve a bit wider is the 3 1/8" in the sketch below. Horns should expand more or less smoothly. If you do the math, the horn behind the doghouse is 3" x 22 1/4". In the corner it is 4 1/3" x 22 1/4". Then, beside the doghouse it is 3 1/8" x 22 1/4". Corner reflectors can help that, but there is little expansion from the back of the doghouse around to the "roof". FH-1s have the corner reflectors and respond adequately to 1k Hz.

The 902/511B responds quite well to 20k Hz and needs no tweeter. I would use Al's ES600 crossover, or something similar, instead of the ES500.

If you want to preserve the look and 3-way design, Skip the 902/511B and get a pair of Klipsch K-400s from eBay or buy a pair of K-401s from Klipsch, $US50 each. Get a pair of K-55-Vs or Atlas PD-5VHs. Then, run Al's Universal A replacement crossover or a Klipsch Type AA, or Type AL-3 with Bob Crite's tweeter, unmodified.

Not knowing the horn, it's impossible to say what Bob's driver will sound like on the wide horn you described. In general, larger horns can play lower frequencies. A large horn might let you cross to the tweeter at a lower frequency, as long as you stay an octave or more above the driver's resonance.

[JohnA]

More data on the la Scala/902/511B:

http://forums.klipsch.com/forums/p/103727/1049084.aspx#1049084

[paulV12]

thanks john and pat!

ummm where was I........yes

Actually, last Sunday week ago, just for fun, i decided to draw up(only roughly) an "unfolded" LaScala design using all the critical measurements from the plans here, and believe it or not you need to add these "corner reflectors(only now there not corner reflectors)" to make the horn transition smooth. It kind of takes on the appearence of the mortar part of a mortar and pestle in cross section if you know what i mean. So you must be right, and i must congratulate myself for attention to detail and correct measurement. All this research and i must have learnt something! the unfolded design for this horn is not that much deeper than the folded design, but i didn`t however do the rear cone volume calcs i have to admit. Just the horn but the rear horn volume shouldn't be too difficult as there is quite a bit of space to play with. I only really did it to ensure i have my head around the folded design by looking at it in a different way. There might even be enough space to increase the volume some. I might try it someday but i don't want to loose sight of main goal at the moment.

It's really good to here your opinion on how the "more stock" la Scala sounds too. It almost seems to be unbeatable esp. if i do the reversable bass mod. I have not heard these speakers at all really and your opinion is like gold. I really mean that!

What are your thoughts on the 811? I was also thinking the Atlas mid on the 811 and CT125 and corresponding crossover. And what is the deal all those folks at Lansing forums go on and on about the 288-16g? They all reckon those units are a bargin for what you're getting. Do we use them???? I checked the specs. and they apparently go 20k also.

With regards to db readings, i have a question. I understand that some enclosures, by their nature, are intrinsically efficient and others are not. Good transistor amps can generally handle the less efficient(sensitive) pretty well and vice versa for tubes(valves in my part of the world). In a frequency response vs db graph, the part where the roll off in db's occurs, say in this example: the flat part of the graph is between 102-106db on average, then i look at the roll off of the low frequency part of the graph, what denotes the actual bass specification of a given speaker? Is it 62, 73, 75db? (i just pulled these out of me head as they seem to be in the ball park) or even 90db if the main sensitivity is flat at an average of 106db for example? Is it the same for the high frequency and the mid for that matter? Or, is THIS question off the mark because anyone can play around with specifications to get the answer they want(esp manufacturers)? Is there an excepted convention that the layman(me) can casually glance at and see the real specs. as opposed to the sales pitch? I'm pretty sure a few people may be interested in this question, and other just afraid(yeah, me again) to ask. (John, this question took quite a bit of time to compose. I hope i got it right).

i suppose i had my quota of questions for the day, again!??!!@#$%@@$%**&^%

its 5.23am better go.

seeya you soon,

paul

x

ps. in case anyone was wondering i do have a thing for Jag V12's. I think Australia and the US are the last 2 industrialized countries to have cheap fuel. not for much longer though.

[JohnA]

Unless the Altec 811B is really cheap, its cut-off frequency is a touch too high for a La Scala bass horn. It is intended to run from 800-up, though it will go down to 500 Hz, or so. You should typically run a horn at least an octave above cut-off. Above cut-off the air column in the horn loads the diaphragm well and prevents over travel. At least one former forum member used 811Bs in a Belle Klipsch crossed around 600 Hz (I think). With the corner reflectors, the bass horn may well respond high enough to use them.

The 288 is a large format driver. Its throat is much larger (2"?) than the 902 or K-55, so its distortion levels are lower. If you run a 3-way system using typical phenolic squawkers, like a K-55, the system's power capacity will be higher.

As to frequency response, speakers are spec'd at xxx dB/w/m +/- y dB, say +/-3 dB. So the system might be 104 dB +/- 3 dB. There is a Spec called f3 that is the low frequency that is 3 dB below the nominal rating and f10 that is 10 dB below nominal. F10 is the practical low limit of response. Is that what you're asking? Using the graph in this thread, http://forums.klipsch.com/forums/p/103727/1049084.aspx#1049084, f3 is 90 Hz and f10 is about 65 Hz (the 20 Hz line is not visible).

BTW, where in Oz do you live? I wandered around the southeast about 20 years ago nd had a ball. I flew into Melbourne and out from Sidney.

[BS Button]

Go to www.jubilation.ws

It'll blow your mind

Fair dinkum

[PrestonTom]

Go to www.jubilation.ws

It'll blow your mind

Fair dinkum

Now, that is a project!

[paulV12]

JUBILATION alright!! It was great fun showing my 11yo son. I'm very jealous. The little dog is hilarious. I Love the way the grille looks and the complexity of the cabinetry was as awe inspiring. Its so good to see a project from beginning to end like this. the ideas i get!!!???? The rosewood although "not my cup of tea" was of particular interest. the way the huge size of these cabinets is "hidden" by the grille and the rosewood is very interesting. It reminds me of these Australian speakers built in Adelaide South Australia called Duntec Sovereign that cost about $30k that a friend of mine built from scratch. Each cabinet had 4 Dynaudio 12" drivers 4 mids and 2 tweeters. All time aligned. The bloody things were about 7' high and not very efficient. They were exact copies though, the crossover design gained by those who couldn't afford the silly price, industrial espionage. That was some time ago so i suppose it's OK to tell you guys now..... ooooh bugger. Anyway, i had nothing to do with that part of it, just the listening. What i can say is that you aint missing much. Terribly inefficient, only an amp that can drive a short circut can power the stupid things(3 phase welder could be OK) and they sounded sh*thouse at low volume level. I never heard these speakers at any stage sound good. For years he listened to the radio at nearly inaudible listening levels with these speakers, until he hooked up with this horrible woman who insisted proptlly i might add, it was her or the speakers. He sold them for $5000 and bought a pair of junkie bookshelf speakers!(dynaudio) What a d*ckhead. At a party one night he got a powerful PA amp and(attempted) to use them for their designed purpose.......listening to music, and the amp, after about 5-6 mins would overheat and shut down. Paul(me) just smirking in the background. these speakers required a special amp. they were marketed though, toward the high end of the market. If your paying the asking price then i guess you need a good(sh*t hot) amp and not a $80 reciever. Incidentally a Rotel 500+500 would not power these speakers but a Hafler DH-??(about 100wp/ch) would, if you kept the volume at around 11o'clock posi on the pre amp.(yay for the American product).

Obviously your speakers aren't going to suffer anything like this. I'd love to hear something like this. The thing that I really like about big speakers is they have the capacity to have amazing transient attack......you know the complex sound thunder makes when there's the initial bang and the rumble(subsonic) of the sonic boom decaying around mountains and valleys on a hot summers afternoon. You can't get that impressiveness from smaller speakers though horn designs seem to lend themselves in smaller sizes(lascala size and above) much better than most. The Sovereigns are(were?) apparently very good but notoriously difficult to power(apparently Krell make an amp that works well with them). John Dunlevey was in the employ of the US navy as an antenna designer i think, so he must be pretty smart and have done a reasonable job designing these speakers . Someone might be bothered looking up all of this on google, because everything i've written about these speakers and the man who designed might be full of factual innacuricies. (I couldn't care less though) i'm just here for the interesting anecdote.

paul

(tales from down under)

x

[paulV12]

Hi john,

Where i live is on a small isolated farm of 170 acres about 125KMS(75mi) NW of Melbourne in the state of Victoria. Australia only went metric in about 1973 so some of us are conversant in both forms of measurement.....a bit like a pilot really.

Closest town is Daylesford pop 5000 and I'm 6 miles to the north of daylesford. Closest large town is Ballarat pop about 65000 and Bendigo pop100 000. Check Google Earth, punch in Mount Franklin Victoria Australia and you'll see where. The map last time i looked went from a photo to "graphical representation(and a poor one at that) about where i live. Nonethless it'll get you to within a few miles of where i am.

P.

[paulV12]

hi all,
well its all becoming apparent how the project will pan out. I just won a pair of 511 horns on ebay so it looks like 902/511. It is kind or a relief really as all the confusion about what to do is evaporating and a direction becoming apparent!

here's one for ya. Can someone think of a way to have a split lascala with the the bass mod in the top enclosure? I liked the link posted about turning the bin around.

what we need is an airtight seal that will pivot. I don't know how big the hole would need to be....10-12"? to prevent restriction.

maybe something could be fabricated in wood. Also, i may have to increase the size of the cabinet to compensate for the volume of the 511 horn.

p