A K-402-Based Full-Range Multiple-Entry Horn

[Chris A]

On 1/24/2016 at 2:31 PM, Khornukopia said:

...as I re-read the explanation about collapsing polars I wondered if there is a link to an illustration showing the differences of this effect between something like the K-400 and the K-402.

 

Here is a collapsing vertical axis polars cartoon of a midrange horn of the K-400 type:

 

 

Here is a polar plot of the K-402 (non-collapsing polars) horn in the vertical axis.  Note the frequencies above 1 kHz especially:

 

[ClaudeJ1]

Wondering if these loudspeakers may be better a bit higher off the floor.

 

Mine are, but they also sound good ON the floor. Just depends on personal preference. 

[Khornukopia]

Obviously, the patterns for the K-402 look good, allowing it to operate as a full range, multiple entry horn. Just for clarification, when you write about collapsing polars of the K-400 type horn, does that refer to the narrowing dispersion pattern as the frequencies get higher?

[Chris A]

Yes...the polar pattern "collapses" as the frequency increases, thus compensating for the natural fall-off in on-axis SPL that is inherent with controlled coverage horns, like the K-402 and K-510.  PWK always was mindful of costs, reliability, complexity, and robustness of his loudspeakers.  Having to provide boosting EQ to his midrange drivers/horns was something that I believe he was trying to avoid because of the his focus on those factors. 

 

Nowadays it's fairly trivial to have EQ compensation in the crossovers, or even to sub-out the parts.  Fifty years ago. that wasn't something that was prudent due to the QA costs and probably the lack of sufficient suppliers that had good quality programs (ISO 9001, etc.).  His troubles with woofers and compression driver suppliers are well known. 

 

Chris

[DrWho]

Keep in mind the K403 came after the K402.....PWK wanted to narrow the vertical polars and I think it was more than just simplifying the xover networks.

 

I could be wrong though. I'd love to hear Roy's thoughts on it.

[Bill W.]

Mike, I recall the K-403 as being an R&D piece that was older than the K-510. The K-402 was developed after the K-510.

[Khornukopia]

I appreciate all of you smart guys explaining things in ways that are easy for me to understand. I am not an engineer, but I listen to a lot of music in many different environments just for fun, and I find the subject of loudspeakers very fascinating. 

 

Most of you are long time forum friends and I'm sort of a freshman around here, so I think a fairly recent picture of me standing next to one of my favorite singers might be a favorable way to present myself to the forum, because it is said that standing next to a pretty girl makes a guy look good.

 

[ClaudeJ1]

She was a total doll in Grease. She still has the babe factor going on. I photographed a lady engineer who looked like her.

[DrWho]

Mike, I recall the K-403 as being an R&D piece that was older than the K-510. The K-402 was developed after the K-510.

 

Ya, I remember Roy mentioning the K402 was a larger version of the K510.

 

If the K403 came first, then why did they skip a number? The K400 became the K401 - then K403 and back to K402? I'm pretty sure I heard Roy telling stories about PWK hearing the Jub LF with K402 combo - and I would have thought that would have happened before the CES showing where they had the wooden K403?

 

My memory is horrible, but I think it'd be interesting to know if PWK preferred the K403 over the K402. I vaguely recall Roy mentioning something about PWK preferring the efficiency benefits of collapsed vertical polars. Efficiency is probably a misnomer (since it should be nearly the same total energy output), but for a given on-axis SPL target it's going to have less distortion.

 

And maybe he actually wanted less off-axis high frequency energy. If the surface you're reflecting off attenuates some frequencies more than others, then technically you want the inverse of that attenuation in the sound coming off the speaker so that the on-axis and off-axis have the same tonal balance. The objects in our rooms that cause reflections certainly do not reflect all frequencies equally...

 

Anyways, not trying to put words in PWK's mouth. I just know the ideal solution is more complicated than only looking at the speaker itself.

[Bill W.]

Mike,

IIRC, Roy said Paul never got to hear the K-402 but he did hear the K-510. He wanted a larger horn than the K-510 for the Jubilee (home version) and liked horns with collapsing polars. Roy was working with constant- coverage horn designs (K-510). The K-403 was already developed and was a hybrid design which collapses the vertical polars but maintains the horizontal polars. I believe the K-403 was to be the template for the pretty wooden horn in the pictures of the home Jubilee. I can't speak to the question of nomenclature, perhaps the numbering system is based on assignment for production not development. Hopefully, Roy will let us know.

[mikebse2a3]

Keep in mind the K403 came after the K402.....PWK wanted to narrow the vertical polars and I think it was more than just simplifying the xover networks.

 

I could be wrong though. I'd love to hear Roy's thoughts on it.

 

Roy demonstrated the Jub LF for the first time with a K510 for PWK.  (See page 2 of the KPT-KHJ-LF Fact Sheet)

Roy's thoughts on Constant Directivity and Constant Coverage.  (See page 2 of the KPT-402 Fact Sheet)

https://community.klipsch.com/index.php?/topic/147255-jubilee-kpt-khj-lf-k402-kpt-k402-fact-sheets/

 

My understanding is the K403 design never went into production.

 

miketn

Edited January 26, 2016 by mikebse2a3

[mikebse2a3]

Very Interesting thread Chris.. and sure makes one think..!!!!

 

miketn

[ClaudeJ1]

If the K403 came first, then why did they skip a number? The K400 became the K401 - then K403 and back to K402? I'm pretty sure I heard Roy telling stories about PWK hearing the Jub LF with K402 combo - and I would have thought that would have happened before the CES showing where they had the wooden K403?   My memory is horrible, but I think it'd be interesting to know if PWK preferred the K403 over the K402. I vaguely recall Roy mentioning something about PWK preferring the efficiency benefits of collapsed vertical polars. Efficiency is probably a misnomer (since it should be nearly the same total energy output), but for a given on-axis SPL target it's going to have less distortion.

 

I think my first pair of 402's were from about 2000 or so. I was attending a different conference in Ceasar's Palace and stumbled upon the Klipsch room at the tail end of the CES show. I missed PWK by about 5 minutes, but I do remember seeing Roy there. as they were starting to put things away. The picture of them together next to the wooden K-403 was taken there, I'm 90% sure, as it's the only time I ever saw Roy wearing a suit.

 

I'm guessing PWK, had he lived long enouth, would have thought the K-402 as too big for consumers and that it requires some EQ to work right. But that has never stopped us fanatics, now has it?

Edited January 26, 2016 by ClaudeJ1

[juniper]

Interesting read on the Diyaudio forum under "Another Unity Horn" . Tom Danley has some fascinating things he talks about. On page 9 he discusses levitating things with high spls.

[Chris A]

Thanks for that.  Here's an interesting excerpt from Mr. Danley at that diyAudio thread:

 

"I ended up working on that stuff in a weird way, I have no college at all, no math background, in fact math is my worst subject but I guess I have gotten a feel for some things.

 

I worked in electronics repair and loudspeakers my whole life however and got a job doing electronics first.  After a few years I was in charge of electro-acoustic research [and] had a couple inventions that were important to the company and flown on the shuttle. Speakers were my first love though, and had an idea for the Servodrive woofer that my boss let me pursue.
 

As a DIY’r and an inventor, I observed what happened, got ideas, tried them and revised my understanding of “how it works” based on what I already knew and could observe in experiments.  I don’t claim to have “the book” of facts, most of the time it seems like you have to find out for yourself in that particular set of conditions...

 

...Anyway, the thing is Earl [Geddes] and I disagree some what about what conditions permit significant levels of higher order modes in a conical horn and I am in no position to argue the math.

 

Clearly, it's his weight of experience that's been the source of his inspiration, not theory.  My hat's off. 

 

Chris

Edited January 26, 2016 by Chris A

[jason str]

 

Wondering if these loudspeakers may be better a bit higher off the floor.

 

Mine are, but they also sound good ON the floor. Just depends on personal preference. 

 

 

I never understood why some angle their risers either, seems like it makes the sweet spot even smaller.

 

Normally i like the horn least ear height when sitting down, in fact i plan on using a small riser between the bass bin and top section on my La Scala type build to add just a bit more height so its perfect.

[ClaudeJ1]

Funny that Don Keele told me that he and Earl Geddes disagree on things also. Roy says he loves to listen to people argue with Geddes.

 

I drive within 5 miles of Geddes house 5 days a week, but I have never been there to hear his Summa speakers.

 

After I was out of college, I jointed the AES and heard him speak about Thiele/Small parameters and his computer program to simulate Bass Boxes. I simply aked him which alignement sounded best and he admitted he had never built one (he was at ford Motor at the time). I simply wrote him off as a theorist and not a builder at that time. Although I admit, he is a brilliant man. My experience in engineering tells me that Ph.D's are often that way and not very practical.

 

Danley is just as briliant, IMHO, but just the opposite he's a prolific loudspeaker designer rather than a theorist. Care to guess as to whose designs (numbering over 50 now) everyone wants to copy or buy?

Edited January 26, 2016 by ClaudeJ1

[ClaudeJ1]

 

 

Wondering if these loudspeakers may be better a bit higher off the floor.

 

Mine are, but they also sound good ON the floor. Just depends on personal preference. 

 

 

I never understood why some angle their risers either, seems like it makes the sweet spot even smaller.

 

Normally i like the horn least ear height when sitting down, in fact i plan on using a small riser between the bass bin and top section on my La Scala type build to add just a bit more height so its perfect.

 

I drove over 800 miles to get my first pair of SPL TD-1's about 1 1/2 years ago. First thing I did was to throw those small, but massive, triangular cabs on the floor in a warehouse, with the mouth pointing up. The imaging and tonality just blew me away upon first listen, and those do not have the sophisticated Xover of the Synergy Horns, but in principle they are the same. Unless you have experienced Danley's horns first hand, it's difficult for any Klipschead to understand.

Edited January 26, 2016 by ClaudeJ1

[ClaudeJ1]

Very Interesting thread Chris.. and sure makes one think..!!!!

 

miketn

and more and more of us to act.

[jason str]

Claude i admit most of my home audio experience has been Altec Lansing and Klipsch because i love horns.

 

These would fall in to the the category of something i would love to hear and if i like maybe build someday.

Edited January 26, 2016 by jason str