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Chris A

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

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You know where the PM button is...I'd guess... ;)

 

I'm around a lot...nothing on the calendar to speak of. 

 

Chris

Edited by Chris A

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Okay, I feel that it's time to post the Hornresp inputs and predicted outputs.  First the Crites Woofer input (T/S) parameter screen:

 

post-26262-0-59980000-1452633840_thumb.g

 

Then the horn configuration and approximate TAD 4002 driver input (T/S) parameters:

 

post-26262-0-57140000-1452633926_thumb.g

 

Then the output power plot.  This configuration reflects mid-wall performance (1.0 x pi steradians):

 

post-26262-0-02900000-1452633992_thumb.g

 

And finally the woofer cone displacement plot:

 

post-26262-0-12900000-1452634027_thumb.g

 

I made some on-the-fly updates to the ports, etc., but the above inputs and response plots largely reflect what I built.

 

The corner performance reflects the additional LF performance.  Note that the power output predicted is about 3-5 dB higher output than the Jubilee bass bin:

 

post-26262-0-96660000-1452634420_thumb.g

 

Chris

Edited by Chris A
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You know where the PM button is...I'd guess... ;)

 

I'm around a lot...nothing on the calendar to speak of. 

 

Chris

 

Noted.  We were in Plano in August.  If we have to go back up I may holler.  I hope you have a high tolerance for stupid questions.

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I hope you have a high tolerance for stupid questions.

 

No problem there. 

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Just be mindful with running a full-range horn (like the OP's perforated K402, Synergy, Unity, etc..) 1/4 wave interference from the floor will be a major factor below Fc.

 

The 2 & 3 way designs (K-horn, Jub, La Scala, Belle) fare much better in that regard.

 

IOW, for the uninitiated, don't fuss too much (or get overly excited) about how much low freq performance is gained going full range, unless the plan is to set them on the floor. At ear level, they'll need to be high passed according to their nearest boundary distance regardless of capability.

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IOW, for the uninitiated, don't fuss too much (or get overly excited) about how much low freq performance is gained going full range, unless the plan is to set them on the floor. At ear level, they'll need to be high passed according to their nearest boundary distance regardless of capability.

 

Tom,

 

That shows up only as a extremely narrow "floor bounce" notch [EDIT: ...where they are located along a wall]. Thanks for pointing that out.  If you can hear it, put up a baffle to the floor.  I can't even hear it in the REW upsweeps due to the fact that it's so narrow (about 2 Hz effective notch width in my room).

 

It's significantly narrower than the time misalignment notches the you'll see--twice--in any La Scala or Belle using passive crossovers-once around 400 Hz and once in a very wide region centered on 4500 Hz and extending almost 2 kHz on each side of the center crossover frequency. 

 

Do you hear those?  I've also got the data for Cornwalls - it's almost as severe. 

 

One reason why I haven't brought that up is that most do not hear those very narrow disturbances (except the tweeter-midrange crossover region, which isn't pretty or particularly nice to hear- but that can be cured merely by moving the tweeter to the top of the loudspeaker and aligned with the midrange driver). 

 

That's why I post psychoacoustic octave band data--so that you can see the stuff that you can hear.

 

Chris

Edited by Chris A
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By the way, the SH-50s that you were playing with have half the woofer area of the current K-402-based design.  While you might say that is only 3 dB of difference, my experience is that that difference turns out to be bigger when you consider modulation distortion and other nonlinear distortion effects in the drivers due to moving mass effects.

 

Chris

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By the way, the SH-50s that you were playing with have half the woofer area of the current K-402-based design.  While you might say that is only 3 dB of difference, my experience is that that difference turns out to be bigger when you consider modulation distortion and other nonlinear distortion effects in the drivers due to moving mass effects.

 

Chris

In my case, the only Playing I do with them is music. Although I found that they have too much bass in corner, so I prefer them out of corners, since they image as well as direct radiator speakers that way in the right room, like Artto's.

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As I was talking about earlier on this subject, it appears that Danley sets up its EQ and internal ports (like a Cornwall as but ported through the horn closest to the mouth) so that the speaker is balanced in frequency response in half space or even full space.  That means if you use them in 1/8th space (a corner), you will have 9 to 12 dB too much bass shelving.  That's a reason why the SH50s might sound too bass heavy in a corner unless they are EQed down to flat FR again.

 

One of the great advantages of the K-402 over the dual-flare conical horn is its bass performance at or near fc (the frequencies corresponding a horn length of a quarter wavelength) is much more smooth and free of notches or "mouth bounce" issues.  I would guess that the SH50 has two FR disturbances at frequencies at and below fc: one corresponding to the initial horn flare bounce, and a second, lower frequency disturbance corresponding to the final horn flare mouth bounce.  

 

Additionally, because the SH50 is covering only 50 degrees of width and height, once the frequencies fall to close to those of the horn's length at a quarter wavelength, there will be a more dramatic fall-off in SPL vs. frequency because the coverage angle is moving from 50 to 180+ degrees, while the K-402 will be moving smoothly from 100 degrees to 180+ degrees (horizontally).  Both horns will fare better in a corner due to the reduced 90 degree coverage angle of the room's corner, which reduces the drop in on-axis SPL.

 

Chris

Edited by Chris A
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Do you hear those?
I hear everything, and my post was targeting those reading the thread that might develop the impression that these large format horns can bend the principals of acoustics in that regard....because they don't.

 

I disagree with you on the floor bounce issue, and set my high pass filters accordingly.

 

Wasn't implying the other designs were any better...just pointing out the compromise for doing so. We both know it's a give and take situation.

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(Lots of hyphens in that title...I like it... ;) I bet this topic has your full and undivided attention if you're here reading this.)

 

So let's get into the basic idea: crossing the ideas of Mr. Roy Delgado and Mr. Tom Danley on horn design, namely using a K-402 as the basis of a multiple-entry horn design--like the Unity Horn design of Sound Physics Labs.

 

[The Synergy Horn of Mr. Danley is still patented, but it reuses the exact physical design of the Unity horn 100% (which is an apparent violation of patent practice in the second patent).  So I won't be talking about Synergy Horns in this thread very much, but rest assured, the basic physics involved with the Unity and the Synergy horn designs are exactly the same.  I like Unity horns, so I'll talk about those.]

 

Specifically, what I'm discussing is a cross between the K-402 horn used on Roy's Jubilee (the real secret of the Jubilee, IMO) and the multiple-entry horn design of Tom Danley--whose original Unity Horn patent has now expired.  So neither of these topics are controlled by legalities except of course the names that may be copyrighted by Klipsch and Danley Sound Labs, so I'll just refer to this new design as my "New Center" design, since I'm currently using it between two 2-way Jubilees as a center loudspeaker.

 

What am I really talking about?  Perhaps a picture will help:

 

attachicon.gifNew Center - small.jpg

 

So the first question is: why?

 

That's pretty easy: I needed a better center loudspeaker between my Jubilees, but the size of another Jubilee is not possible to accommodate in my room.  So I reused the horn profile of the most important horn--the high frequency K-402 horn used in the Jubilee--in a full range loudspeaker design. 

 

How can you do that?  Isn't the K-402 just a HF horn?

 

Well, the answer is: no, it isn't only a high frequency horn.  We'll get to that in more detail as time goes by.  Suffice it to say that the K-402 is used, unchanged, in the KPT-305 mid-bass module used by the 4-way behind-the-screen cinema systems.  This module goes down to about 200 Hz using only a puny 8" driver that Klipsch provides.  So the K-402 horn is good from at least 200 Hz to 20 kHz.  I was needing more low end than just 200 Hz, so I decided to try my hand at a multiple entry design that reuses the aperture of the K-402 for both the bass woofers and the apex-mounted 2" compression driver.

 

How does that work?

 

Basically, you take two or more woofers and mount them on the sides of the back of a K-402 horn and provide through holes through the side of the horn at the right places to provide a secondary entry point for the bass frequencies, while the rest of the horn behaves like a K-402 horn with 2" compression driver.  Two for one, basically.  No Jubilee bass bin is used. 

 

Besides the fact that the Jubilee bass bin is exceptionally large, by itself, as a center loudspeaker, it just isn't possible to use the Jubilee bass bin in my case.  But I still wanted everything else that I get from my Jubilees on either side, and I want this center loudspeaker to seamlessly integrate in terms of its timbre, coverage angles, and in all other sonic performance areas.  In addition I get a few things that I don't get with the Jubilees:

 

1) point source loudspeaker performance (more on this topic later).  [This is a big deal that Danley has been capitalizing on of late.  Using separate horns for each way of loudspeaker has interesting issues that few people typically think about.]

 

2) I avoid the issue of dual-mouth bass bin polars at the crossover frequency that the Jubilee bass bin has.  In fact I get the same polars all the way through the crossover region--something that is an issue for the Jubilee (refer to the EASE data for the Jubilee).  I get full polar coverage up to and through 600 Hz and above.  The Jubilee bass bin has issues starting at 200-300 Hz in this area due to its two bass bin mouths.

 

3) I don't have any folds in the horn.  The advantages of this are many, and have been discussed in detail in the forum threads many times. 

 

4) The cost of the center loudspeaker is about 1/3 of a full-up Jubilee.  This isn't a trivial point to consider.  It's also much less cost than Danley Synergies.

 

5) I don't need a corner of the room in the center of my setup to get good bass response, like the corner-located Jubilees need. Danley Synergies also have an issue in this regard (except the SH-96). 

 

attachicon.gifNew Center Mid-wall On-Axis.png

 

6) All of these advantages will also work even better for those that might want to use this design instead of Jubilees in the corners--except in a package that is about 1/3 the size of a Jubilee--essentially the same volume and form factor as a La Scala II, and about the same weight (190-200 lbs). 

 

7) You can use this loudspeaker in a vertical orientation--like the difference between a regular and vertical Cornwall--without having to change out the internal baffle.  The horizontal coverage can then be 60 degrees instead of 100 degrees.  Ceiling bounce issues can be controlled at the loudspeaker in this orientation. 

 

Etc.

 

Why doesn't Klipsch do that already?

 

Probably because the Jubilee is aimed at the Cinema marketplace, which requires much higher average SPL.  Secondary to this have been the patent issues that have more recently been resolved by the expiration of the controlling patent.

 

Why not use a Danley Synergy Horn instead?

 

Well, price for one.  And all the Danley products are designed for PA use - even higher SPL than Cinema.  This means that the requirements that they have been designed to don't match the needs of the home hi-fi enthusiast, like myself.  Additionally, the K-402 horn is a better horn than the Danley dual-flare conical horns, in terms of polar control and coverage angles.  The Danley Synergies used at home have been the SH-50 or SH-60 designs, which have about half the horizontal coverage angle that I need in my listening room, and they have insufficient low frequency headroom that the modified K-402 with two 15" woofers has.  You would have to buy two Danley SH-96s to have two stereo loudspeakers, and those units apparently go for about $11K each (they have 11 drivers in each cabinet--which is neither necessary nor useful for the home hi-fi enthusiast, and those drivers cost real money).  This K-402 design is much more "fit for purpose" than any of the current Danley designs.

 

Chris

One day......maybe.....I will show you guys things I have in the vault........
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On 1/12/2016 at 6:39 PM, 'Quiet_Hollow said:

IOW, for the uninitiated, don't fuss too much (or get overly excited) about how much low freq performance is gained going full range, unless the plan is to set them on the floor.

 

 

I agree that any loudspeaker, put on a riser out away from the walls which induces a gap between the loudspeaker and the floor will have severe in-room LF issues.  PWK's paper on that subject still holds, regardless of it being horn-loaded or not.  If you do move them out on the floor, I believe that it is understood that they must at least be located on the floor or with full baffle--like a tower loudspeaker or like the ca. 1953 Klangfilm Bionor:

 

bionor6.JPG

 

Chris

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I also believe that I now understand the context in which you make that comment: it's a valid comment. 

 

There's no substitute for actually understanding the physics of the situation in-room.  Some want to ignore that and substitute their own ideas about acoustics: I don't recommend that course of action.  It doesn't work very well.

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On 1/12/2016 at 11:14 PM, Chief bonehead said:
One day......maybe.....I will show you guys things I have in the vault...

 

:emotion-21:🖖 :emotion-21::cool:

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By the way, the SH-50s that you were playing with have half the woofer area of the current K-402-based design.  While you might say that is only 3 dB of difference, my experience is that that difference turns out to be bigger when you consider modulation distortion and other nonlinear distortion effects in the drivers due to moving mass effects.

 

Chris

I'm not sure if you were referring to me about SH-50's, but living with them, as you do with Jubes, makes one appreciate the superior intelligibility you speak of, and it IS all done with passives. Even with a 28x28" mouth (still bigger than a LaScala or Belle I have too much bass down to 40 Hz. which mus be EQ'd down in my room. No the speakers are NOT in the corners. I get a deeper sound stage that way and there is never any need for a center channel except for movies. Everyone that has heard them, upon hearing smack dab center vocals in the "wall of sound" has to be convinced that the center is not on so I hand them the Neutrik connector for it. LOL.

 

I'm very glad to see you did have the guts to try it on a 402, big Kudos to you for that one. In my case, I will wait until I have the wooden ones, as I don't want to mess with the original.

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IOW, for the uninitiated, don't fuss too much (or get overly excited) about how much low freq performance is gained going full range, unless the plan is to set them on the floor.

 

 

I agree that any loudspeaker, put on a riser out away from the walls which induces a gap underneath the loudspeaker and the floor will have severe in-room LF issues.  PWK's paper on that subject still holds, regardless of it being horn-loaded or not.  If you do move them out on the floor, I believe that it is understood that they must at least be located on the floor or with full baffle--like a tower loudspeaker or like the ca. 1959 Klangfilm Bionor:

 

attachicon.gifsiemens_1.jpg

 

Chris

 

I no longer practice this. The SH-50 is flat to 50 Hz. outdoors and is designed to be floating in space. Most of the direct radiator Audiophile community that are technically not as savvy, but spend 20 times the money that most Klipsch people do, set up their speakers OUT OF CORNERS. They image better that way. Paul Klipsch's own system had the Khorns NOT IN CORNERS of his living room, but in false corners. His 2PH3 array with his twin spaced omni mike recordings of symphonies were simply splendid with great depth. Heard it for myself for a several hours. He never talked about that in his papers, but even though I had the same setup as PWK for 30 years in different homes, mine never sounded as good as his, and I believe that was the reason. His room was bigger too.

 

TH-50's can will not have thermal compression until they reach an input of 758 Watts, which is over 130 db of output in a home environment. This is with twin Faital Pro Woofers that are 12" each.

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I no longer practice this...Paul Klipsch's own system had the Khorns NOT IN CORNERS of his living room, but in false corners [on the floor].

 

PWK did...you said it right there.

 

The SH-50 is flat to 50 Hz. outdoors and is designed to be floating in space. Most of the direct radiator Audiophile community that are technically not as savvy, but spend 20 times the money that most Klipsch people do, set up their speakers OUT OF CORNERS. They image better that way.

 

You pay a high price for that when you pull your loudspeakers out away from the walls and them raise off the floor. DR loudspeakers have their own issues that horn-loaded loudspeakers don't have.  And instead of treating the walls of the room for the DR radiators (especially above 200-500 Hz), most apparently take the cheap inexpensive way out and pull them out on the floor to help control the early reflections.  That's why they sound like DR loudspeakers.

 

You don't have to pay that price but still get equal imaging performance with your horn-loaded loudspeakers. Look at the above PWK article on corner loading...that applies to your loudspeakers and your room, too.

 

Chris

Edited by Chris A
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One day......maybe.....I will show you guys things I have in the vault........

 

 

 

Maybe a day in the 3'rd week in May??????

Edited by CECAA850
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One other thing that I've not discussed that I've learned as a result of listening for these few days:  the performance of the mid-bass and crossover regions relative to the prior tri-amped JuBelle, and the Jubilees on either side.

 

One thing that I should point out is that this New Center is injecting a fair amount of LF energy into the room at a point and a level that the JuBelle just couldn't inject, so some of my listening impressions my be due to the effect of "distributed bass" into the room-like using multiple subwoofers scattered in the room. 

 

My current impressions are that the midbass just below A440 tuning fork frequencies down to perhaps 100 Hz are much more coherent and realistic with acoustic instrumentation, like pianos, baritone/bass vocals, clarinet/oboe, bassoon, cello, etc.  This was something that was expected when I made the change of center but once it arrived, it still caught me a bit off guard.  It's a fairly large difference--but audible only when the source material is hi-fi enough to hear it.  Typical movie soundtracks and amplified music usually doesn't show up this aspect, but hi-fi surround music discs and higher sound quality movie soundtracks with acoustic music really bring out this aspect in a startling way.  It's a very realistic and palpable effect, increasing the feel of realism by a significant measure.

 

I currently attribute this difference not only to the better controlled polars in this frequency band, but also to the point source effect, perhaps without the folded horn of the JuBelle introducing some amount of fidelity issues (probably lower modulation distortion and higher order horn modes).  It's a bit more difficult to put into words, but the whole presentation seems to come together much more realistically, even though the physical difference lies only in the center channel change, with the Jubilees on either side unchanged. 

 

If one loudspeaker in the center makes this amount of difference, I'm now wondering what would happen if all three front loudspeakers were of the same configuration (i.e., multiple-entry K-402-based).  I suppose that I'll have to wait until I can fabricate two more units to get that answer.

 

Chris

Edited by Chris A
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