Design a better Khorn bass bin

[Colin]

OK smart guys, the Khorn takes a lot of work right? Klipsch knows what they are doing, right? But what if they don't....

How can they make a bass bin with as little parts as possible, still retain the same size or smaller and still get the same depth or lower?

can the folds be made more efficiently?

[boom3]

I think the answer is the home version of the Jubilee. However, there are no home version Jubilees, official or otherwise, in the wild to compare with Klipschorns, yet. All we can do is deduce what the Jubilee was 'meant to be' and try various approaches. From the threads recently I think a few folks are going to build them soon. I know I'd like to, but I will hang back a bit and let other brave souls take the point.

[Colin]

funny you mention that, I always thought a double 15 in a vented box like Cornwall could come awfully close, easier to construct, but the driver might be more than the wood and assembly...

[boom3]

I've fancied about building an MTM Cornwall with two K-34s, two K600/601s and one K-79. Ah well, I will be content for the moment with four CW IIs.

[Daddy Dee]

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On 2/25/2005 2:35:14 PM Colin wrote:

funny you mention that, I always thought a double 15 in a vented box like Cornwall could come awfully close, easier to construct, but the driver might be more than the wood and assembly...

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That would be interesting. The Jubilee bass bin looks to be considerably simplified compared to the folded horn in the Khorn. I think that would be the best bet. However, people I've heard describe the sound of the Jubilee sure didn't say that it kicks the Khorn in the butt or anything like that. My take on the marvel of the Jubilee is doing all that in a two way speaker. (the two woofs in the bass bin counting as one.) That speaks well for PWK's Khorn bass bin.

[greg928gts]

I was on a website recently where someone claimed that the Khorn bass bin was compromised in some way, done on purpose for space savings and cost savings. We seem to have some people on this forum who are proficient in figuring the proper angles of bass horns, I wonder if anyone has taken a close look at the dimensions and angles of the Khorn bass bin to see if it is compromised somehow and if improvements could be made. Us audiophiles don't care if it costs more money or takes more space!

Greg

[Colin]

for example, what if another fold/wall was put around the current bass bin, wouldn't that deepen the response?

[ZAKO]

The Khorn was compromized in that it had to pass through the front door. Larger Khorns have been made but it didnt lower the bottom octive that mutch. Interesting the Jubilee horn is similar to the JBL Hartsfield. The Jubilee cinema is available.. If any one has the deep pockets to purchess both for comparison? Why not trade in the Hummer for a good cause.

[boom3]

Some perspective: When PWK designed and fielded the Klipschorn in the late 40s, the last two octaves (20-40 Hz, 40-80 Hz) were rarely found on phonograph records. As LPs matured in the 50s, the second octave improved, but very few LPs, until the boutique pressings of the 70s, had anything below 40Hz. Now, with digital media and rock-em sock-em sound effects, some folks are worried that the basic design is set for 'only' 40 Hz. In reality, there is very little music down there and most of what we perceive in sound FX are the high-frequency leading edges of explosions, gunshots, etc. The significant compromises in the Klipschorn are not really in the bass horn, they are in the midrange (too small) and the tweeter (antiquainted design). In a bass horn, if you get a 10:1 ratio beteween the lowest usuable frequency and the highest, you are doing very, very good. PWK got 40-400 Hz out of the bass horn through years of refinement. If one wishes the bass horn to grow larger & longer to go to 30 Hz, that means the midrange horn now has to go down to at least 300Hz. That drives one to a larger midrange horn and beefier driver, which may also lead to a lower crossover to the tweeter. This is why we see so many folks using big Altec mids, JBL babycheek tweeters, etc on the basic Klipsch basshorn.

[JohnA]

Greg,

The Klipschorn bass horn IS compromised in many ways in order to make it small enough and cheap enough people will buy it and put it in their homes. Mr. Paul was a consummate engineer. Engineers work to make things smaller, lighter, and cheaper while meeting their design loads or other requirements.

Do you think compromises to make the K-horn smaller and more affordable are bad?

[greg928gts]

John - if one's goal is to design a bass horn that fits through doorways and meets a certain cost point, then no, the compromises are not bad. But you know how us audiophiles are, always looking for more! I would like to know what the size and shape of the Khorn bass bin would be without compromise. Or, to put it a better way, built with the optimum angles, length of each individual part of the horn, and mouth size.

It's not that the compromises might be limiting frequency response so much, but what about output? I agree that 32hz is as low as a speaker really needs to go for all practicality, but what about total output? What would the output of a non-compromised Khorn bass bin be like?

Greg

[ZAKO]

What do YOU mean by total output?

[D-MAN]

As an excercise in 1/8th space, the Khorn is THE smallest footprint true-40Hz corner horn in the world. It cannot be made smaller in any dimension and still function the way we have come to expect. It is 1/8 the size of a full sized straight 40Hz horn with a 16 sq. ft mouth area when placed in a corner.

Here's what I consider the drawbacks of the design, rather than things that I disagree with PWK's decisions about, like the fixed 45 degree top cabinet, choice of drivers, etc.

The drawback of the design is two-fold, IMO.

1) after the first fold, the waveform is twisted from horizontal expansion and proportion to vertical expansion and proportion. This limits mid and upper bass.

2) the access to the throat is from the side, limiting the design to 1 topology of use, that is a 3-way due to the low (400Hz) "high-pass" limit on the bass horn, using a single 15" woofer.

The Jubilee design attempts to "correct" the 2 drawbacks.

However, it has a couple of drawbacks to it. It has a high part count, about the same as a Khorn. It does NOT save any space (larger footprint). It's drivers are more costly.

DM

[Colin]

what about dual 12s in the same Khorn bass bin, would that improve depth or punch without requiring a larger cabinet?

[D-MAN]

It would be louder and more efficient. PWK's Khorn patent shows 2 15" drivers in a single cabinet for extreme SPL capability.

DM

[greg928gts]

What I meant by total output was how much bass comes out of the cabinet, not necessarily how deep the bass goes. I assume that it is limited by something, probably the cabinet itself. But I don't know. I love the sound of my Khorn bass bins, but if they could be better, I'd like to know how. If the Khorn bass bin is compromised, I'm asking what would one look and sound like not compromised? How would it be built differently?

Greg

[D-MAN]

The SPL at a given frequency within the band pass of the horn is determined by the excursion and efficiency of the driver itself.

I suppose at a certain point, you could theoretically force the Khorn into throat overload distortion, i.e., where the soundwaves literally cannot "fit" through the throat, but it would seem to be theoretical, I would think. Maybe an 18" driver could do it, if it could installed. It would be dang loud, that's for sure. IM distortion from over-excursion would be very nasty way before throat overload occurred. The cone would slap against the motor board, as an added bonus. So the overload distortion remains a theoretical circumstance, IMO.

As to what constitutes "better" bass? Here's something to think about. The bass still has to seemlessly blend with the lower midrange output. To increase bass output, you have to also increase the upper frequencies output to "keep up". This will be an expensive proposition.

I agree that a well setup pair of Khorns is pretty much as good as it gets on the bass end of things. Anymore bass than that and there's a rough road to go down to keep an cohesive soundwave front coming at you.

DM

[djk]

"As an excercise in 1/8th space, the Khorn is THE smallest footprint true-40Hz corner horn in the world. It cannot be made smaller in any dimension and still function the way we have come to expect. It is 1/8 the size of a full sized straight 40Hz horn with a 16 sq. ft mouth area when placed in a corner."

Except for its a 50hz horn.

The original Klipschorn with the 12" woofer was about 5" longer in total air path length and was stated to be a 47hz taper rate.

It got shorter when the 15" was installed, hence the 50hz.

The Jubilee is 38hz taper.

With about the same mouth area the Jubilee has a little less bass than the Klipschorn (no such thing as a free lunch), but with a little EQ it can dig deeper.

"The bass still has to seemlessly blend with the lower midrange output. To increase bass output, you have to also increase the upper frequencies output to "keep up". This will be an expensive proposition."

The K55 is only receiving 1/8th the power that the woofer does (because of its impedance and being attenuated 3dB in the network).

Sound quality is another thing.

[D-MAN]

Dennis, I'm suprized, you're usually right on!

{edit} I presume that you are talking about the production Khorn, not the patent version with the 12" driver, which I am not referring to...

The production Klipschorn with the 15" driver is 40 Hz. - work it out, the cross-sectional horn area doubles every 21.7 inches which = 40 Hz.

For example, the back opening (toward the tail board) is 7x37.5" which gives a sq. in. area of 262".

The throat is 78 sq. in. in cross-sectional area (6x13"), and the length to the first fold is approx. 18" (1/2 of the 37.5 in. height) from the apex of the throat splitting wedge. The length of the rearward channel after the first fold (horizontal proportion to vertical) is about 23". 18+23=41 so the throat area (1/2 of 78) is 39 and that doubles at 43.5 linear inches which puts us at 1/2 of the 262 value or 7x18.75 sq. inches (131 sq inches). I estimated the 23 value, it is approximate, but very close, I recon.

That is a 40Hz expansion rate, no two ways about it.

DM

[khorn58]

EV made a scaled up 18" drivern khorn bass bin.

very pricy when the come up for sale, but there are plans around for them.