Khorn Clones

[KLIPSCHORN LOVER]

I asked these questions before but no one really gave me an answer to the original questions. So here goes again, I'm relatively new to this forum, so hopefully all of you can bear with me.

I am going to build a set of Speakerlab K's and I know the best driver (or so i read) is the K33. Are there any other drivers that can be used that offer the same or better performance sonically? With a higher power rating?

As I search the net I see the parameters for the K33's on Volvotreter's website. I know he said that he would use the K33 if he did it all over again, but I want to get as many options as possible before I buy, as I am not independently wealthy. [] While searching, I have found alot of18" drivers matching and far surpassing the "at least" parameters posted on his site. Could a driver this size be used?

Has anyone ever tried an 18" in a Khorn cab? Will it even fit? If the driver parameters better match with 18's why are they not used? Would an 18 make the cabinet sound terrible?

Hopefully I haven't typed anyones eyes off. Have a great week.

[BS Button]

BEC, on this forum has a woofer that met the original PWK spec.

[Guest " "]

I did 18's in a k-horn, but the cabs were bigger by 15% across the board. every part was increased in size by 15%. the thing wieghted as much as a refrigerator...but the sound was aewsome...I had 500 watts per channel to drive them.

would recommend stock size, and the traditional drivers.

[3dzapper]

EV did an upsized Klipsch licensed bass horn in the '60s with an 18" woofer the Patrician IV. They "only" weighed 350#. Small for a Sumo werstler.

[SilverSport]

EV did an upsized Klipsch licensed bass horn in the '60s with an 18" woofer the Patrician IV. They "only" weighed 350#. Small for a Sumo werstler.

"...Oh Flash...what does Ming the Merciless have planned for us with those???..."...[]...Bill

[ajsons]

I am going to build a set of Speakerlab K's and I know the best driver (or so i read) is the K33. Are there any other drivers that can be used that offer the same or better performance sonically? With a higher power rating?

The K-33 is the best driver for the 3 x 13 slot on the motorboard. The actual throat size of the Khorn under the motorboard is 78 sq inches. I will not try to explain why it works with a slot half of the throat size it should have. Dr. Edgar wrote an article in Speaker Builder to explain it, then wrote a second one because the first article is in error. If you're going to use another driver, you may have to enlarge the slot to 6 x 13.

Most 15" drivers can use the 6 x 13 throat. An 18" driver will require a larger throat size and a redesign of the enclosure. A 12" can be used if you build a horn extension inside the doghouse to reduce the throat area for a 12". I doubt that you'll do that. Dr.Edgar's article "The Show Horn" which is also on the Volveter's website gives you guidelines on driver selection using T/S parameters. Also read Keele's "Low Frequency Horn Design Using Thiele-Small Driver Parameters". Basically, what these articles are saying is that you need a driver with a high Fs and low Qts. Most musical instrument speaker drivers meet the requirement.

A prominent member of this forum recommends a cast frame woofer, and says that the K-33, structurally is "not good" (These are not the exact words he said, I'm being nice.)

[ajsons]

I'm using Electrovoice EVM-15L's in my SK's (200w, Fs=43hz, Qes=.2 something. I'll post the spec sheets shortly, but the picture attached shows a 15-B which is almost identical to the 15L. Both are great musical instrument drivers. Cast frame woofers.

I use them interchangibly, for the last 25 years or so, they sound great. The 15L, EV says has a bright sound, and the 15B a more traditional bass sound. I need my ears checked because I can't tell the difference.

The University C15W, also shown, might work. It would not fit thru the SK's access cover. It might fit if I remove the magnet cover.

Another prominent member of this forum used an Eminence CB15 for a horn he designed and has a patent pending on it. He says you get great results if you use a driver that meets Keele's figure of merit for bass horns.

[ajsons]

First page of EVM 15L spec sheet.

[ajsons]

sheet 2.

[Guest " "]

if you use a PA bass driver...take a look at the frequency response...the 15L has a bottom end of only 60hz. Also take a look at the ohms....15L is 8, k-33 is 4 ohms, which means some xover re-work will be in order. woofer mounting slot is another issue if you use a PA Bass driver 6X13 will be needed as opposed to 3X13.

[ajsons]

Third.

[ajsons]

Fourth.

[ajsons]

if you use a PA bass driver...take a look at the frequency response...the 15L has a bottom end of only 60hz. Also take a look at the ohms....15L is 8, k-33 is 4 ohms, which means some xover re-work will be in order. woofer mounting slot is another issue if you use a PA Bass driver 6X13 will be needed as opposed to 3X13.

The frequency response of the driver goes lower in a horn, read Edgar's article. I used ALK's universal A for crossover with no problem . Scaling a crossover to a different impedance is not a problem either, and I believe I mentioned the 6 x 13 slot above.

[WMcD]

I think you should take a look at Larry C.'s post in 2-Channel regarding his restoration of 1962 K-Horns. The most recent reply was 5-22, so it is down a few pages right now.

Essentially he modified back to the 6 x 13 throat size. I'm not sure of his driver specs. They might be the older K-33. Maybe BEC's units would therefore be a good choice.

It does seem that Bruce Edgar followed Don Keele and Prof. Small in the choice of drivers with a low Qts and high Fs. It was because the combination gives good high frequency output. The EVM15L is good by these specs.

But a close reading shows that both Small and Keele say that designing according to the formulas removes flexibility from the choices engineers can make. This means, you might want to fool around a bit.

These fellows don't talk about how to optimize low freq response.

On the other hand, PWK went to great efforts to get Fs down to 35 Hz. Essentially, there is not going to be much output below Fs. Hence the choice.

Ther is the issue of optimum throat size. PWK and Delgato used the Keele formula for that, and PWK used the version set out by Wente and Thuras, which is actually the same, but using electro-mechanical parameters.

As mentioned by others above, Edgar did some analysis of the small slot but eventually thought his analysis was incorrect. The factory in Hope sent him some comparisons of the K-Horn with and without the restriction. I can sent you that or post it if anyone is interested. I thought the 6 x 13 curve looked better. Larry C. seems to agree.

I suspect there is something going on with Qts. The suspicion is that if it is very low the peak at Fs is damped out.

Gil

[ajsons]

This is like W. McDermott's throat drawing in "The Cave" thread.

[ajsons]

As mentioned by others above, Edgar did some analysis of the small slot but eventually thought his analysis was incorrect. The factory in Hope sent him some comparisons of the K-Horn with and without the restriction. I can sent you that or post it if anyone is interested. I thought the 6 x 13 curve looked better. Larry C. seems to agree.

I suspect there is something going on with Qts. The suspicion is that if it is very low the peak at Fs is damped out.

Gil

Gil,

I'm interested, but I'll wait for the others to respond. Maybe it will be easier if you post it.

Armando

[Guest " "]

has it been determined what the slot size is in the speakerlab-k's ....can he go the PA bass driver route if the slot size is 3X13?

[D-MAN]

The K33E will require a smaller throat opening in a Klone. All other drivers will generally use a larger opening, with the maximum size being 78 sq inches, as Armando said previously.

Keele's T/S work indicates the optimum opening size for MAXIMUM EFFICIENCY for a specific driver. That is all that does! The general rule of thumb is 70% of the available diaphragm area (i.e., above a 2:1 ratio). The K33E in a wide throat opening is WAY TOO SLOPPY and FLABBY.

The LE/RE of the specific driver will certainly load the crossover, and you'll have to take that into consideration, also as stated before.

The "safe" way of insuring low frequency response, as with PWK, is to choose an FS BELOW the Fc of the horn (actually the F-3 of the horn to be exact).

The Vb (size of the back chamber) is paramount in getting the driver to resonate all the way down to its Fs.

Excursion is (believe it or not) over-rated. Most desireable : LOW QTS, High BL.

DM

[Guest " "]

I just checked my speakerlab-k construction documentation...it specifies a slot of 3X13. if that is the case...do we still want to recommend a PA Bass driver like the 15L?

I also checked my ACR Swiss EckHorn construction plans, it also has a 3X13 slot. The ACR Swiss EckHorn used a PA-38, which is a wide range full range driver (40hz - 4Khz) spl of 101 db at 1 watt.

Think that the driver considerations for a K-Horn should center around what type of slot your k-horns have. If you have a 3X13 slot, a k-33 type driver should be considered. if you have a 6X13 slot, and would not mind less low end, the PA Bass drivers are an option.

[ajsons]

Welcome back, Dana. I miss your posts!

I was going to send you an email tonight, and was reading your past emails about an hour ago.

I still will email you though.

Armando