Klipsch Horn Woofer designs....

[moray james]

There have been a couple of interesting threads here of late pertaining to conventional front loaded horns. I have been reading up on Klipsch speakers as I recently purchased a set of Klipsch speakers at a price which was too good to pass up. I was of the impression that the Klipsch horn woofers such as used in the Belle and the La Scalla were too small to really be taken seriously as modern high efficiency designs. However after reading I think that I was mistaken. While these cabinets do not extend much below 50 Hz. with out room gain though they are very compact and very efficient and would seem to have reasonable response.
I am curious to to know if any here have ever run either the Belle or the La Scalla cabinet design through Horn Response to see if Paul got it right the first time all those years ago? From what I can see they both represent a good compromise as a commercial product which has consistently stood the test of time in the market place. Both design are very similar with the Belle being a shallower cabinet with a wider mouth. Many owners consider the two versions to be pretty much the same in terms of performance. I have included a link to the AES paper which Paul Klipsch wrote many decades ago for reference. Thanks for any comments or thoughts. Best regards Moray James.

http://forums.klipsch.com/forums/storage/3/898769/LaScala AES Pre-print.pdf

 

[TerryO]

Moray,
You probably already know about the LaScala modification where the bass horn's back chamber is opened into the subsequently enclosed (sealed) top hat. Another variation is to add a sealed plinth under the horn which uses an opening from the bottom of the woofer's back chamber and is sometimes also ported.
Either modification seems to allow a fair amount of extension to the bass frequency range.

Best Regards,
TerryO

 

[bentoronto]

It is great fun to experiment and explore the bass. But ultimately, hard to fill a gallon jug from a quart pitcher (or some old cliche like that). Even the Klipschorn has big compromises.

There's a lot of excessive hoopla about bass below, say 40 Hz. Sure not audible on music. Just feelable on rare recordings... and movies. And, without going all mystical here, there are qualities to woofing not fully accounted for by freq response, that your speakers may exemplify.

Are the drivers the same as in the Klipschorn?

In the AES paper, I think he is sniping at the Altec Voice of the Theater. Great guy. Love my "true" bass horn.

 

[WithTarragon]

I also agree with the above about going down to 40 Hz. If you can do that honestly, then you are probably covered for most music.

The drivers are not the problem. They can still be purchased, and at a reasonable price. Of course you can always spend more if you want.

An alternative to using the single 15inch driver is to use a pair of 12 inch drivers. Such a bass bin was outlined in a JAES article by Delgado & Klipsch (2000). This is the "Jubilee" bass bin and when compared to the Klipschorn it has 1) better efficiency (lower distortion) and greater bandwidth (so it could be used in a two-way configuration).

It is an easier build for a DIYer and it can also be purchased from their commercial division (go to the Klispch forum and ask how to do this - it is not a simple matter of calling up a dealer).

Good luck

 

[moray james]

Hey Terry: yes I am familiar with that mod (but it had fallen of my radar) so thank you for reminding me. Just for clarity I did not purchase one of the Klipsch horn designs rather a set of Forte ll.

The KHorn and the Belle and the La Scalla all use the K33 woofer I believe. I have T/S data in a file. I am not looking so much to get deeper bass from these designs as they pretty much are maxed out in the bandwidth department. I was more interested to know how modern day simulation programs compare to PW with a slide rule pencil and a pad of paper.. I realize that these designs have compromises but that is to be expected. I am interested to find out how reasonable those compromises are.
The Jubilee is a nice horn but like the Khorn requires two solid corners while the Belle and La Scalla will get by with a wall behind them. JBell's two foot cube is a nice bass tapped horn but is limited in bandwidth (upper). I wonder how much bulk could be shaved off of a Belle or La Scalla if its bottom end response was limited to 100 Hz or so?

 

[bentoronto]

moray james - I'd appreciate getting a copy of the T/S K33 parameters. Also, if anybody can help me with the SpeakerLab clone driver parameters* too.

PWK was a practical guy with a good ear.

WithTarragon - my Klipschorn bass box is a built-in, unfinished, "industrial" model from the early '50s, I believe. (But I've had it only since 1968.) Piece of cake to finish the flat front panel in a nice hardwood veneer. But also needs a top, stretching from wall to wall. Also a piece of cake to make a heavy, sealed top piece and to glue veneer on its flat surface too.

Little question: It is correct to call the whole 3-driver speaker "a Klipschorn" but then what is the proper name for the bass horn alone? I usually just call it "a Klipschorn" too. Well, like "cannon" and "cannon."

*one experiment too many with motional feedback.... which, by the way, seems suitable for true horns within their passband, esp. with sealed boxes behind the driver.

 

[WithTarragon]

A few comments to the above.

1. The Jubilee does not require a corner, although the very deep bass will benefit from a corner (as will all cabinets).

2. The Speaker lab plans are not the best - there is more then one version, and some have errors.

3. The bandwidth with a K-33 is not maximized in the designs mentioned. The upper range is a function of the cabinet folding. IOW, the K-33 in a straight horn has greater bandwidth.

4. The Jubilee is an easier build then the K-Horn, since there are no double bevels. For folks like me, there are a surprising number of ways to mess up.

5. Have look at the graphs in the JAES article, before you build the Klipschorn. You will get a notion of the performance differences between it and the Jubilee. I have owned both, the Jubilee has several advantages. Incidentally, you can buy a factory version of the Jubilee and there might be someone in your locale that would let you listen to theirs ahead of time.

 

[moray james]

Thank you With Tarragon for the info and correction regarding the Jubilee
room loading. I had made the assumption as a result of pictures on line I have seen, that's good to know. Regards Moray James.

Old K33E specs:

Name: 15162
Type: Standard one-way driver
Company: Eminence Speaker LLC
Comment: K33E
No. of Drivers = 1
Fs = 34.46 Hz
Qms = 7.39
Vas = 301.7 liters
Cms = 0.268 mm/N
Mms = 79.47 g
Rms = 2.328 kg/s
Xmax = 8.2 mm
Xmech = 12.3 mm
P-Dia = 336.6 mm
Sd = 889.6 sq.cm
P-Vd = 0.729 liters
Qes = 0.41
Re = 3.39 ohms
Le = 0.96 mH
Z = 4 ohms
BL = 11.93 Tm
Pe = 150 watts
Qts = 0.388
no = 2.903 %
1-W SPL = 96.78 dB
2.83-V SPL = 100.5 dB

 

[Frode]

I wonder how much bulk could be shaved off of a Belle or La Scalla if its bottom end response was limited to 100 Hz or so?

From what I understand, the LS basicly works as a sealed box below 100Hz. It's mouth supports down to 125Hz and the length supports down to 100Hz. So I guess you can't make it much smaller if you want it to act as a horn all the way down.

Frode

 

[tb46]

Jubilee v. LaScala

Hi Y'all,

I looked at these a while back, and entered then into Hornresp. For the LaScala I used the T/S parameters provided by moray james, and recalculated the values with Hornresp. From the literature I am under the impression that Paul Klipsch considered the Jubilees as his finest, sadly I never had a chance to hear them. Obviously, both designs could today be tweaked with Hornresp and AkAbak.

Regards,

 

[Frode]

Your LaScala sim looks just like the one I did a few years ago. Not very impressing on paper.

Frode

 

[djk]

LaScala with K43E (black) and K33E (gray):

Top graph: vented LaScala (black) with K43E (35hz tuning). Bottom graph: stock LaScala (black) vs vented LaScala (gray), K43E:

The vented LS is with 35hz tuning and no EQ. I designed the mod for 31hz tuning with the K43E and 6th order EQ (Q=2 at 31hz). With the longer ports and deeper tuning there is a gentler roll-off and less bass in the 40hz region, the EQ brings the 40hz back and leaves you with 31hz extension (in room).

With the K33E (15162) and no EQ, the 35hz tuning is to be preferred.

 

[WithTarragon]

"
... From the literature I am under the impression that Paul Klipsch considered the Jubilees as his finest, sadly I never had a chance to hear them. Obviously, both designs could today be tweaked with Hornresp and AkAbak."

==================
The Jubilee was designed in 1999-2000 or so. I am certain they had used the various professional modelling programs to tweak the design. They also had the advantage of actually cutting some plywood and building/testing them.

The are some comments about possible mods that were tried on the Jubilee (scaled down versions, larger versions etc), but you would have to scour many, many posts on that topic over at the Klipsch site.

 

[tb46]

Klipsch Jubilee

Type: "rigma jubilee build" into the Google. Plan on spending a few hours.

Regards,

 

[moray james]

Hi Y'all,

I looked at these a while back, and entered then into Hornresp. For the LaScala I used the T/S parameters provided by moray james, and recalculated the values with Hornresp. From the literature I am under the impression that Paul Klipsch considered the Jubilees as his finest, sadly I never had a chance to hear them. Obviously, both designs could today be tweaked with Hornresp and AkAbak.

Regards,

I would be interested to see what could be done to the response of the La Scalla horn as it is an interesting design especially considering it is a 2 Ft. cube. I have found a somewhat larger horn which does not go as low but which has very smooth response, have a look. Best regards Moray James.

 

[moray james]

Lets try that link again. sorry I can't get the picture to upload so here in the on line address.
http://www.egbeck.de/bec2.htm

 

[bentoronto]

Lets try that link again. sorry I can't get the picture to upload so here in the on line address.
BEC2Biex

Nice curve... the result of one-octave-wide smoothing? Not real-world, eh.

If you are going to shake a block of cardboard to produce sound, there's no substitute for impedance-matching to thin air using a horn. But when I look at some of the small horns, like in the link or the "tapped horns," I have trouble intuiting how much impact they could have on the radiation resistance on the cone... compared to say, the somewhat bigger and corner-loaded Klipschorn?

 

[moray james]

Regarding Beck...

I would suppose the graph was smoothed most are. I imagine that it is probably a good response as far as the design goes so it looks very promising. The attempt was for smooth extension to 500 Hz, not deep bass extension.
Unfortunately Ernst has just recently passed away. Audio was only a small interest of his. Regards Moray James.

Obituary: Ernst Georg Beck | Watts Up With That?

 

[bentoronto]

Not that I want to speak unkindly of the recently departed, but with curves, the devil surely is in the details. Particularly when the irregularity is likely to be quite dramatic and in the range right up to 100 Hz or more.

I think it is fair to say the curve in the link is too far smoothed to be a useful guide to the performance of that horn.

Nice obit. Sic gloria...

 

[moray james]

Ben you may be right but the horn layout looks to be more gradual than the La Scalla so it may well be a smoother horn. I am curious to know if HR can predict dispersion characteristics or polar response of a horn design.
I am considering a horn loaded bass/mid for use with a set of Nick Mckinney's Unity Horns. I have several options and one was to use a La Scalla bass section the other this Beck design and the third is a Lambda driver in a reflex box. From what I have found out so far the Lambda 15 is likely my best choice but the efficiency of a horn loaded bass/mid is tempting and is a reasonable size. So I am looking into these options before I make a decision.