Improvements to the Khorn design

[DrWho]

Could you expand a bit on the "double-slit"
diffraction? Are you worried about distortion, or some abberation in
the response resulting from the bifurcation?

...

If the distance between the mouths is much larger than half the wavelength, then multiple lobes form.

It's not distortion. It's exactly the kind of "clover-leafing" polar pattern that you mention later in your post. See here.

Oops, for some reason I read "mouth" from your original comment and interpreted it as the throat. Sounds like we're on the same page. The only thing I would add is that to push the lobing higher in frequency requires the mouth exits to be closer together. I guess I'm not convinced that the two wavefronts couldn't be brought back together into one coherant one with the right folding technique.

I'm not convinced that pattern control is a big issue when radiating into half-PI space.

Why do you say that?

[Invidiosulus]

I've thought it would be interesting to make it so the mouth was more like a Frazier Dixielander.

I'm sure that presents a billion other problems though.

-Josh

[Edgar]

I guess I'm not convinced that the two wavefronts couldn't be brought back together into one coherant one with the right folding technique.

http://forums.klipsch.com/forums/p/98253/992045.aspx#992045

I'm not convinced that pattern control is a big issue when radiating into half-PI space.

Why do you say that?

Because at low frequencies, the walls, floor, and ceiling provide the pattern control. By the time you get high enough in frequency to where you need the horn to provide pattern control, you're usually in the midrange horn anyway.

Greg

[DrWho]

Anyone who believes Klipsch/Roy/PWK used a
particular driver because it was cheap or what was in stock, IMO is
seriously under estimating them and their reasons for the choices they
have made.

I disagree completely. Good engineers stop
when the performance is good enough, which is defined by the design
goals before the project is started. Klipsch is not a research
institution, but a business that needs to make money. Reuse of a driver
is an incredibly huge cost savings and is a great example of good
engineering.

Heck, just look at the K-33....another great example
of PWK forcing reuse. If the Cornwall was to have an optimized driver,
then they would have come out with the K-48 much sooner. It didn't make
sense from a business perspective to have another driver so they lived
with it until it made sense to change things. Of course they brought
the cornwall back with the K33, but that was more for nostalgia than
anything else really.

To suggest that Klipsch embraces reuse of
drivers is by no means a slight on their engineering prowess. If
anything, it's a compliment.

Mike,
I know Roy has mentioned that it "might be possible" to gain a little
performance with a correctly chosen (4" voice coil) driver but until it
is tried/tested and proven it's just a thought on what else we might
can do to squeeze a little extra performance from it.

Just
because theory and reality don't always correlate isn't justification
to throw out all theory. Heck, even when the theory doesn't line up,
it's still not useless knowledge. In fact, I would suggest that it is
extremely important to understand why they don't correlate. That, in my
mind, is true understanding. Tossing out ideas "because it's not proven
in reality" demonstrates a gross misunderstanding of the theory and its
correlation to reality.

In a horn, there is plenty of research
showing that the bulk of distortion is still dominated by the driver.
The K-31 is an old driver and isn't using any of the modern driver
technology in it. I can't fathom how someone could even suggest that
there might not be an improvement. That'd be like arguing that the K69
is the best driver for the K402...

To be honest, I see alot of modeling being used and theory being talked of (I
have no doubt that Klipsch and Roy have their own modeling and design
formulas reached after decades of research and actual prototypes being
built and measured/listened to and finally made into successfull
finished products) but something I believe is very important to remember is what Klipsch does "that
as far as I'm aware of no one here in this do-it-yourself area of the
forum has shown the real capability to do on their own" is verify by measurements in an anechoic chamber and other advance measurement methods
that they have reached their design goals! That they have actually
reduced distortions and met their other performance goals and thus made
a real improvement and not just a different and maybe even nice
sounding loudspeaker.

Doing outdoor ground planes with
the mic on the ground actually yields better results than the anechoic
chamber at Klipsch provided the noise floor of the surroundings is low
enough (which isn't hard to achieve if you're patient). This is
something that everyone is capable of at their own home.

I've
also had the opportunity to directly compare my measurement rig against
the system used in the Klipsch chamber and consider my own results to
be valid to within less than 1dB over the range from 100Hz to 10kHz.
Michael Hurd is running a very similar system and has done a lot of
testing as well. Both of our measurement rigs correlate well to each
other, and a lot of our measurements correlate extremely well to the
predictions too.

Actually, the thing that I've always found the
most reassuring is just how closely the models correlate to real life
when the assumptions behind the models are held valid. I have a lot of
faith in the hornresp plots that Greg (Edgar) has posted and would have
no problem building something that came within a dB or two of the
model. The actual implementation that Edgar is suggesting will
certainly be a bit further off, but the point is that the models can correlate very well to reality.

I'm
all for proof of performance, but there are some things you just know
after a little bit of experience. I'm not saying we shouldn't measure
the final results, but the models are far more valid than you're trying
to imply. I also fail to see how the fact that the results "might" be
different than the predicted outcome is going to have any impact on the
design.

[DrWho]

Because at low frequencies, the walls, floor,
and ceiling provide the pattern control. By the time you get high
enough in frequency to where you need the horn to provide pattern
control, you're usually in the midrange horn anyway.

My
concern would be ensuring a smooth transition from the lower
frequencies to the higher frequencies on the same horn. Designs that
give you a nominal 90x60 at the high end of the passband are gonna be
hard to achieve without bifurcating the horn unless you don't use the
side walls to control the polars...

It's kinda hard to describe
in writing though, but if you back pedal from the mouth towards the
throat the solution kinda forces itself...

The concern I'd have
on your design from page 1 would be the interaction between the mouth
exit and the front wall...at low frequencies it wouldn't matter, but as
you moved up there'd be a region of comb-filtering from the delayed
reflection until you got high enough that the mouth width was
controlling the polars again. I'm not suggesting it'd be a show stopper
or couldn't be addressed, but that is the kinda thing my approach of
working from the mouth back is trying to avoid (if possible).

I'm
also interested in maintaining a consistent vertical expansion through
the horn....no unexpanding portions in any dimension.

[Edgar]

My

concern would be ensuring a smooth transition from the lower

frequencies to the higher frequencies on the same horn. Designs that

give you a nominal 90x60 at the high end of the passband are gonna be

hard to achieve without bifurcating the horn unless you don't use the

side walls to control the polars...

Understood. It's a valid design criterion. Each designer has to decide for him/herself which criteria to maximize and what compromises to make in the process.

The concern I'd have

on your design from page 1 would be the interaction between the mouth

exit and the front wall...at low frequencies it wouldn't matter, but as

you moved up there'd be a region of comb-filtering from the delayed

reflection until you got high enough that the mouth width was

controlling the polars again.

Again, it's all in the compromises that one is willing to make. The asymmetry in the design is only about nine inches, i.e., the opening is only displaced about nine inches from the center of the face of the enclosure. That means that it can't possibly have significant effect until the wavelength is about eighteen inches -- about 750 Hz. By that point the audio should be crossed over to the midrange horn anyway.

I'm

also interested in maintaining a consistent vertical expansion through

the horn....no unexpanding portions in any dimension.

It's a worthwhile goal. Unfortunately it makes the horn very difficult to build.

Again, understand that I'm not disagreeing with any of your comments. We just seek to optimize different things.

I should also add that I haven't built any prototypes, yet. So there's always the possibility of some unforeseen problem(s) ...

Greg

On edit:

Correction: The asymmetry could have effect at 375 Hz -- half what I originally said. The path length is 9" longer in one direction, but 9" shorter in the other, for a total of 18".

[greg928gts]

Greg.

Here are my thoughts.

First of all, I am excited to see what you are doing. I wish I had the time to do the type of thing you do.......but I don't have a shred of time for customer service of something I were to make. This is why I stop building computers for sale.

This forum has all kinds of respect for the khorn. I'm sure we would love to see it get better and to see it grow after the passing of PWK. However, I'm thinking that the man did everything he could to make the Khorn:

1) sell

2) make a profit

3) improve the peformance in that FOOTPRINT.

I put in that order for a reason. There were a lot of speaker maker gurus in his time but he was able to land the speaker into your living room and make profit. So there was a mix of all the above mentioned to make PWK as great as he was...and still is to us.

If you read the AES on the Jube....you can see he was trying to improve performance but keep the same footprint. That is the key in my mind. I don't think anyone here on this forum is better than PWK to get more of what you want in that footprint for a single 15" K33.

You can take ideas and try them...but you might do a lot of building and testing. He was selling to the masses in his day....Unnfortunatley (sp)....with the Ipod GEN....small sells are made on some of his concepts.

I do think the jubilee bests the Khorn....easily in my mind. Having said that, I'm not afraid to say that I think the Jamboree is right in there...easily better than the khorn and a match for the jube.

So with the above....my vote is to attempt a dual driver design....consider what footprint you want to accept...and go with that..then build the rest upon. The foot print is the key....

24' depth only allows so much you can do...."physics" as Dana would say. He built the jamboree on this footprint. Yes....he could draw up a longer horn to trounce the jubilee....Heck...the geektard/rookie I am...I can do way more with 30" depth....but that usual won't sell (I don't have a problem with it).

You know....as I'm posting this...can we make a shout out to get Dana and Ajsons back on here. This forum was so much more interesting when the both of them were here. I know they have there "issues", ......but hey...I loved both of their posts...

jc

I agree with everything you have to say here.

However, this is not the time for me to attempt to build and sell a $10K speaker that is of a completely new design. I'm sticking with the Khorn design because it is a known result. Known, from a marketing perspective. The other designs will come in due time. I need to build my business in the proper order.

I hope nobody here thinks that because I'm asking about how to improve the Khorn design, that I lack respect for the original design and/or PWK. I have the utmost respect for what PWK did. Every single product that comes out of my shop has a "K" stamped in it. My way of saying thank you to Paul; for I would not be able to do the little that I do without his work.

But I live in a different world that PWK did. I have the internet, and an enormous free flow of information at my fingertips. I know my strengths and my weaknesses, and as I move forward in this business venture, I have to stick to my guns on what it is I can sell, and work hard to get the information needed to help me get there.

I know I can sell upgraded Khorns. I don't know that I can sell a new speaker based on an unknown horn design - right now.

Greg

[greg928gts]

The Jubilee is superior to the Klipschorn, no question about it. It curves better, has lower distortion, and allows some flexibility with placement. It sounds better too.

If we pretend that there is no Jubilee, I would have to say that the one that brings the most improvement to the Klipschorn bass bin is to close off the back like the 60th Anniversary Edition. I don't see much point in pursuing further improvement, it's unlikely you're going to do anything that hasn't been tried before -- you can make it curve/sound different, but that's not the same as making it better. I mean, even PK threw in the towel.

Like you said, the Jubilee, patent or not -- belongs to Klipsch. I think the same can be applied to the Klipschorn. If Dana is willing to let you build the Jamboree, that's probably the best direction to go.I would call it something different though -- "Jamboree" doesn't work for me.

I believe that building the Khorn bass bin with denser/thicker materials, will provide very good results. I noticed this with the Jamboree bass bin build. I had a very rigid. well-glued cabinet, and the results are well worth the extra time and materials cost. So I would agree that enclosing the backs is a big improvement, I think that building with thicker material will provide a noticeable improvement, I guess I'm just fishing here, to see if there's another idea that someone comes up with that might offer yet another improvement. Who knows?

I don't really like the name "Jamboree" either.

Greg

[mikebse2a3]

Anyone who believes Klipsch/Roy/PWK used a particular driver because it was cheap or what was in stock, IMO is seriously under estimating them and their reasons for the choices they have made.

I disagree completely. Good engineers stop when the performance is good enough, which is defined by the design goals before the project is started. Klipsch is not a research institution, but a business that needs to make money. Reuse of a driver is an incredibly huge cost savings and is a great example of good engineering.

Heck, just look at the K-33....another great example of PWK forcing reuse. If the Cornwall was to have an optimized driver, then they would have come out with the K-48 much sooner. It didn't make sense from a business perspective to have another driver so they lived with it until it made sense to change things. Of course they brought the cornwall back with the K33, but that was more for nostalgia than anything else really.

To suggest that Klipsch embraces reuse of drivers is by no means a slight on their engineering prowess. If anything, it's a compliment.

Heck Mike somebody needs to let Roy know that what he does and others at Klipsch isn't Research..!!!!

Reuse of a driver only makes since if it allows one to reach their design goals and any savings that intails is great but you are saying exactly what I'm talking about in that you assume that saving money was higher in priority than acheiving the performance!

As far as the K-48 versus the K-33 as used in a cornwall well since I don't have actual performance data to support which driver actually would perform best nor I suspect do you we both would just be guessing wouldn't we and thats my point when you make these kinds of assumptions and spout them as fact it's really just guessing on your part. Since maintaing the voicing of the Heritage Line appeared to be an important goal at Klipsch then keeping that woofer makes sense,fair enough, but was that the only reason for going with the K-33 versus your suggested K-48? Do you have actual performance data of the two options to back up your statement?

Mike, I know Roy has mentioned that it "might be possible" to gain a little performance with a correctly chosen (4" voice coil) driver but until it is tried/tested and proven it's just a thought on what else we might can do to squeeze a little extra performance from it.

DrWho said:

Just because theory and reality don't always correlate isn't justification to throw out all theory. Heck, even when the theory doesn't line up, it's still not useless knowledge. In fact, I would suggest that it is extremely important to understand why they don't correlate. That, in my mind, is true understanding. Tossing out ideas "because it's not proven in reality" demonstrates a gross misunderstanding of the theory and its correlation to reality.

In a horn, there is plenty of research showing that the bulk of distortion is still dominated by the driver. The K-31 is an old driver and isn't using any of the modern driver technology in it. I can't fathom how someone could even suggest that there might not be an improvement. That'd be like arguing that the K69 is the best driver for the K402...

Your rambling here is just ridiculous..! I made no such suggestions...!

What I will say is until you actually build, measure and verify the performance you can theorize and model all day but you really don't know fully what you have!

To be honest, I see alot of modeling being used and theory being talked of (I have no doubt that Klipsch and Roy have their own modeling and design formulas reached after decades of research and actual prototypes being built and measured/listened to and finally made into successfull finished products) but something I believe is very important to remember is what Klipsch does "that as far as I'm aware of no one here in this do-it-yourself area of the forum has shown the real capability to do on their own" is verify by measurements in an anechoic chamber and other advance measurement methods that they have reached their design goals! That they have actually reduced distortions and met their other performance goals and thus made a real improvement and not just a different and maybe even nice sounding loudspeaker.

DrWho said:

Doing outdoor ground planes with the mic on the ground actually yields better results than the anechoic chamber at Klipsch provided the noise floor of the surroundings is low enough (which isn't hard to achieve if you're patient). This is something that everyone is capable of at their own home.

I've also had the opportunity to directly compare my measurement rig against the system used in the Klipsch chamber and consider my own results to be valid to within less than 1dB over the range from 100Hz to 10kHz. Michael Hurd is running a very similar system and has done a lot of testing as well. Both of our measurement rigs correlate well to each other, and a lot of our measurements correlate extremely well to the predictions too.

Actually, the thing that I've always found the most reassuring is just how closely the models correlate to real life when the assumptions behind the models are held valid. I have a lot of faith in the hornresp plots that Greg (Edgar) has posted and would have no problem building something that came within a dB or two of the model. The actual implementation that Edgar is suggesting will certainly be a bit further off, but the point is that the models can correlate very well to reality.

I'm all for proof of performance, but there are some things you just know after a little bit of experience. I'm not saying we shouldn't measure the final results, but the models are far more valid than you're trying to imply. I also fail to see how the fact that the results "might" be different than the predicted outcome is going to have any impact on the design.

Again I didn't imply anything about the validity of the models or measurements and would appreciate it if you would stick to what I actually said..!

If you fail to see how the fact that the results "might" be different than the predicted outcome is going to have any impact on the design. Then why would you even bother to measure..? Just build on Theory and Models and be done with it..!!!! That's definitly more Logical than what I'm suggesting..!

mike tn

[Edgar]

I know I can sell upgraded Khorns. I don't know that I can sell a new speaker based on an unknown horn design - right now.

I'm sorry, Greg; I misunderstood your objective. If you want to keep the basic KHorn design and just make performance improvements, then I suggest that you make internal modifications to eliminate the discontinuities in the contour shown here. As I mentioned further-on in that thread, if you eliminate the "bumps" at between about 80 cm and 115 cm (that's the part where the path goes from the front of the enclosure to the back), and install a woofer with better high frequency response, Hornresp says that things will smooth out very nicely. See, for example, here.

[Oblio]

Make them lighter []

[greg928gts]

Make them lighter

LOL. Unfortunately they're going to get heavier.

Greg

[Invidiosulus]

It's amusing to me how the Jubilee fan's get all riled up when people start talking about building/improving Khorns.

[DTLongo]

Far be it from me to contest the more engineer-philes among you. All I have is my 67 y.o. ears. But to those ears my 2003 Klipschorns always sounded voiced too strong in the midrange. Yet the stock crossover is fixed, no user adjustments. IMHO THE big improvement Klipsch should make, and that ought to be commercially relatively economically doable to boot, is to have the midrange (especially) and tweeter Xovers user-adjustable.

My '03's are now upgraded with ALK Trachorns and exteme-slope crossovers and they are a definite improvement, not least because AL K's default setting holds back the midrange several db's. His Xovers allow for further adjustment but it's awkward, you have to pull the heavy speakers out from the wall and get in there and move jumpers in ways that are not crystal-clear from the written information Al provides. Much better to have the crossvers dial- or multiposition switch-adjustable.

When properly set up and with the midrange (and treble) held back to one's taste, the Klipschorn bass is AWEEESOME. So pure and enveloping. But with the hot stock midrange it's hard to get there.

[jcmusic]

I am a little late here but, I like my k-horns with the V-tracs and BMS drivers just fine. I think that the drivers and Greg's horns are a very nice improvement on the original design.

Jay

[DrWho]

Reuse of a driver only makes since if it allows one to reach their design goals and any savings that intails is great but you are saying exactly what I'm talking about in that you assume that saving money was higher in priority than acheiving the performance!

So why doesn't Klipsch sell the K402 with a TAD driver instead of the K69? Performance? []

As far as the K48 / K33...I have more than enough data to verify my conclusions.

The smaller squawker horn in the new Cornwall III shared with the Heresy III is yet another example of reuse where they didn't want to spend the money on another tool.

What I will say is until you actually build, measure and verify the performance you can theorize and model all day but you really don't know fully what you have!

Well let's just take it to the Nth level and conclude that we really don't fully know anything. What purpose does pointing that out serve?

I think there is a lot of knowledge contained in the theory that is being overlooked / criticized for the sake of promoting a non-causal universe.

If you fail to see how the fact that the results "might" be different than the predicted outcome is going to have any impact on the design. Then why would you even bother to measure..? Just build on Theory and Models and be done with it..!!!! That's definitly more Logical than what I'm suggesting..!

Knowing that the results will be different doesn't provide any practical insight when choosing design parameters. You can only design to the extent that you can predict behavior. How elso does one know what to adjust ahead of time? If you need to re-enter the design cycle, then you still need a way to predict behavior so that you can fix whatever it was that cropped up.

[greg928gts]

Far be it from me to contest the more engineer-philes among you. All I have is my 67 y.o. ears. But to those ears my 2003 Klipschorns always sounded voiced too strong in the midrange. Yet the stock crossover is fixed, no user adjustments. IMHO THE big improvement Klipsch should make, and that ought to be commercially relatively economically doable to boot, is to have the midrange (especially) and tweeter Xovers user-adjustable.

My '03's are now upgraded with ALK Trachorns and exteme-slope crossovers and they are a definite improvement, not least because AL K's default setting holds back the midrange several db's. His Xovers allow for further adjustment but it's awkward, you have to pull the heavy speakers out from the wall and get in there and move jumpers in ways that are not crystal-clear from the written information Al provides. Much better to have the crossvers dial- or multiposition switch-adjustable.

When properly set up and with the midrange (and treble) held back to one's taste, the Klipschorn bass is AWEEESOME. So pure and enveloping. But with the hot stock midrange it's hard to get there.

In my re-design, the crossovers, midrange drivers, and tweeters will all be easily accesible without moving the speakers out from the wall. The midrange horn and tweeter will be independently adjustable for toe in/out, and up/down. The crossovers will be easy to adjust by simply removing the top horn section screen.

Thank you for your input.

Greg

[dkalsi]

Invidiosulus, Edgar, and Dr. Who,

I don't understand 1/100th of the stuff you guys talk about, but please don't stop commenting despite criticisim from others.

I am trying to learn here and your input/contributions are priceless.

Thanks,

Dhar

[Invidiosulus]

I would think that part of the problem with having a larger throat in the Khorn design is that you don't have room for a large enough 45 degree splitter directly opposite the throat since the front panel is only about 3 inches away.

Since the splitter indicates a height of the St of 3 inches I would think you would want to maintain a St of less than about 42sq inches.

-Josh

What was I thinking, That should have been height of the St being 6 inches which would get you up to around 84sq inches.

-Josh

[Wrinkles]

Greg, I think you should graciously bow out of this thread and threads like this.

When a hobby becomes a competing business to produce a better product whether the patent has run out or not, then it is just not right to be mining the great minds of this forum so blatantly that could cause in effect harm to any Klipsch products or their selling potential.

Your comments and your desire about your building a better Klipschorn may be true. But you are in essence advertising on the Forum about your business. And right now it appears one of your business avenues is to better the Klipschorn. By your comments on this forum, you may be helping to reduce sale of the Klipschorns while guiding prospective buyers to your website.

I am not suggesting you cease your designing, building and selling a better mousetrap, I am only suggesting you take this thread to a non-competitors website (Audio Asylum as an example, there are others or have your own website).

Being very facetious, maybe Klipsch can start a new category called "Competitors Corner" where competitors can expound on their opinions of their perceived Klipsch weaknesses and why they think their products sound better and are cheaper, etc.. (I know, what a smart a$$)

Is what you are doing legal, sure it is.

Forum rule under Advertising
2. Advertising
All manufacturer's representatives and competing brand personnel must identify themselves as an employee of said company in each post on the forum.

Only listing a website probably does not qualify.

Greg, you may not fall into this category yet since your business presently is for upgrades and enhancements, many of which I have admired. Apparently you are within the forum guidelines until you produce your first "CUSTOM HORN LOADED SPEAKER". Then you'll have to make some changes.

Good Luck with your company.
This is my opinion.