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


Chris A

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Yep, cheers for lower pattern control.

Ime, lower pattern control is what allows the quality of indoor listening  to approach that of outdoor listening.

 

Another yep, it's been clear from the start that the Hyperion picts looked like the SM-60f horn, and that the speaker is a morph off existing products rather than a clean sheet design.

And I saw in the other thread mentioned, that Tom said someday he might like to redesign a SH-50 for home use.

 

Big question in my mind though ......Do you think the home market can really accept the size it takes to get  lower pattern control?

There doesn't seem to be any way to get around Keele's pattern control formula......making large size mandatory

I'd be surprised to see DSL make a clean sheet home-use Synergy for 200Hz pattern control.....unless maybe it was a 90 deg design for use in corners, like you've been using.

(That would kinda go against the narrow SH-50/60 pattern preference seen to date, though.)

 

I'm very interested in the AXI2050 for a MEH too. My only concern with it, is how deep a horn will it take to use it down to 200Hz.

Well, that and its weight. 

The dcx464 loads to 300Hz fine...with the me464 horn .....which adds depth with a diffraction slot.

My guess is the Axi will need depth too, like with Celestion's Big Red Horn prototype..https://celestion.com/our-news/see-the-celestion-big-red-horn-on-display-at-pro-light-sound-with-the-axi2050-axiperiodic-driver/

 

It will be late summer before i can get back to speaker building/testing.  I hope by then to have seen some Axi  builds to learn from ....

 

 

 

 

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@ Steffen, good stuff.  I'm pondering the same compromises.

 

@parlaphone1, the thing about Amir's phase video that doesn't any make sense to me....

 

.....is that his key point appears to be, that by the time direct sound and all the room reflections reach the ear, phase has become a jumbled mess and can't matter..

Seems to me, by that logic, the same should be said about frequency response....as we all know how jumbled up it gets too.

 

Plus, how about outdoors... where there are considerably fewer and weaker reflections to mess things up.

Does phase matter then? My ears say a resounding yes.

 

So no, i don't buy it.  

 

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27 minutes ago, gnarly said:

 

Big question in my mind though ......Do you think the home market can really accept the size it takes to get  lower pattern control?

There doesn't seem to be any way to get around Keele's pattern control formula......making large size mandatory

 

 

Well, I was going to mention the Mill's Cross beamforming technique as a way to reduce the required size, but a Google search found a few examples of its application, but nothing about the theory behind it. I'll have to see if I can find my old SONAR books.

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See: https://www3.mbari.org/data/mbsystem/sonarfunction/SeaBeamMultibeamTheoryOperation.pdf, page 43 of 107

 

To be honest, I'm not really interested in making the horn smaller for this thread's discussion--quite the opposite.  I would recommend the following thread for further discussions of smaller horn sizes, use of midrange drivers in MEHs, or across-the-center off-axis MEH ports:

 

Chris

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6 minutes ago, Chris A said:

 

Thanks, Chris, I actually found that very reference in my search. But it doesn't delve very deeply into the theory. I have an old SONAR book somewhere that does a much better job. I am really surprised at the lack of information on the subject.

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Thanks guys.  I appreciating this discussion of a scaled up k402 MEH to shift the crossover of the Celestion Axi2050 closer to 200-250Hz, and better accommodate the location of the dual woofers and their port locations.  I've started a mold inspired by the K402, and plan to fiberglass it to make a few ~k402 inspired MEH's, with the Celestion Axi2050's and likely using dual 18" woofers.  I saw mention of an overall length of 21" as opposed to the k402's 17" length.  Given that dimension of 21", the scaling would be (21"/17"=~1.24).  Would the path forward be to simply scale all dimensions (except the 2" apex of the horn) of the k402 up by ~1.24? Or, would there be benefit of equalizing the length/width of the horn mouth, to make it more square than rectangular?  Given that weight and size are trade-offs in increasing size of the horn, what about scaling the k402 up 1.5x, 2x, 3x?  Where is the point of diminishing returns?

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In my Hornresp simulations, about 1.5x scale is about where you run into diminishing returns.  Here is the input record from Hornresp (an "ME1" record) for a 1.5x K-402 horn --the woofer section (two woofers are used).

 

image.png.eb8edfa3b17036224e4cf0d8d5708ac8.png

 

This should reduce the roll-off frequency from about 170 Hz to about 113 Hz, which is about the point where the present Jubilee bass bin (KPT-KHJ-LF) loses pattern control, both horizontally and vertically:

 

KPT-KHJ-LF (Jub Bass Bin) Directivity plot.jpg

 

KPT-KHJ-LF (Jub Bass Bin) Directivity plot - Vertical.jpg

 

Here is what I used for the TAD high frequency section of the Multiple Entry Horn wizard--the so-called "Nd record":

 

image.png.94050e33893571cb082c432952603633.png

 

I was so impressed with the K-402-sized horn performance within Hornresp at that time (December 2015) that I decided that horn would be "good enough".  The 1.5x-sized horn is pretty big, and you have to be careful to be able to get it through doorways.

 

Chris

 

 

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That is very interesting! I have been thinking in the same direction. Please keep us updated.

 

I have been wondering for some time, whether it would be OK to create a thread here on Klipsch Community Forum to share a big-MEH build? although it is not a Klipsch product it is heavily inspired by one, the K402 horn. And I regard this forum to be an excellent and natural place to share and gain knowledge about horns. I have learned a lot here.

 

Regards

 

Steffen

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On 7/3/2021 at 12:21 PM, Supersteff said:

I have been wondering for some time, whether it would be OK to create a thread here on Klipsch Community Forum to share a big-MEH build? although it is not a Klipsch product it is heavily inspired by one, the K402 horn.

I don't see why not. After all, there have been more than a few home-brew loudspeakers and subwoofers on the K-forum over the years.  Staying within the terms of use seems pretty easy to do.

 

Chris

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On 6/23/2021 at 2:53 PM, gnarly said:

Big question in my mind though ......Do you think the home market can really accept the size it takes to get  lower pattern control?

There doesn't seem to be any way to get around Keele's pattern control formula......making large size mandatory

 

Majority of home market probably not.

But there are always exceptions 🙂, which of course do not make money for the speaker companies.

As for me, I have decided to put a pair of SMWMs with K402 horns in my smallish living room, even my darling agreed to that. Bought the tools, Xilica is waiting in the closet for year and a half. Unfortunately it has been two years since I have been trying to get my hands on K402s through official dealership and otherwise, with no success.

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  • 2 weeks later...

I hope this hasn’t been covered.  I’m wondering how cabinet volume affects bass response in a 402 MEH. Has anyone explored this, either in prototypes of simulations.  I’ve never really understood the relationship between cabinet volume and bass response in bass reflex, let alone MEH.

thanks, Ted 

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On 7/7/2021 at 12:56 AM, parlophone1 said:

 

Majority of home market probably not.

But there are always exceptions 🙂, which of course do not make money for the speaker companies.

As for me, I have decided to put a pair of SMWMs with K402 horns in my smallish living room, even my darling agreed to that. Bought the tools, Xilica is waiting in the closet for year and a half. Unfortunately it has been two years since I have been trying to get my hands on K402s through official dealership and otherwise, with no success.

Where are you that getting K-402 sets are a problem? My understanding is Klipsch will sell you sets all day long. Replacement parts are an issue though if you are not an owner with serial numbers.

 

OK S-MWM #2 go for it! Mine has the 402 + 1132 driver and when you get done I can send you the Xilica file I use for mine.

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10 hours ago, VDS said:

I’m wondering how cabinet volume affects bass response in a 402 MEH. Has anyone explored this, either in prototypes of simulations.  I’ve never really understood the relationship between cabinet volume and bass response in bass reflex, let alone MEH.

"Not much"...is the answer.  Throat reactance annulling isn't really an issue with the K-402-MEH design using DSP crossovers, I've found.  I have done half volume and double volume back chamber trades within Hornresp and found so little difference in power response at low frequencies that I've ignored the effects of the acoustic reactance at the lowest frequencies. 

 

Chris

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7 hours ago, Dave A said:

Where are you that getting K-402 sets are a problem?

Outside of North America there apparently is a problem with availability of K-402 horns, as has been reported by all that have tried to obtain them. 

 

For those that have found a way to get them to their country, the import duties tend to be ferocious (like doubling the cost, etc.).  It's very unfortunate.

 

Chris

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1 hour ago, Chris A said:

Outside of North America there apparently is a problem with availability of K-402 horns, as has been reported by all that have tried to obtain them. 

 

For those that have found a way to get them to their country, the import duties tend to be ferocious (like doubling the cost, etc.).  It's very unfortunate.

 

Chris

Well there is an alternative though I have yet to hook my set up and see how they will do. The B&C DCX464 and ME464 can be bought and in the EU beats a lot of fees for EU customers. You live on a big island you have problems no matter what.

 

That's true for design and machining software too and EU customers pay far more then we do here for the same thing.

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3 hours ago, Chris A said:

"Not much"...is the answer.  Throat reactance annulling isn't really an issue with the K-402-MEH design using DSP crossovers, I've found.  I have done half volume and double volume back chamber trades within Hornresp and found so little difference in power response at low frequencies that I've ignored the effects of the acoustic reactance at the lowest frequencies. 

 

Chris

The only thing too small of a back chamber does is provided a slight peak (like 1-3 db) right before horn cutoff at the low end of it's band. No biggie, since you can PEQ it out.

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25 minutes ago, ClaudeJ1 said:

The only thing too small of a back chamber does is provided a slight peak (like 1-3 db) right before horn cutoff at the low end of it's band. No biggie, since you can PEQ it out.

 

My experiments with Hornresp (assuming that it is a pretty good model of what happens in the real world) show that altering the back chamber volume mostly affects cone excursion below the cutoff frequency. The effect in the passband of the horn is minimal unless the back chamber volume changes are extreme.

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53 minutes ago, Edgar said:

 

My experiments with Hornresp (assuming that it is a pretty good model of what happens in the real world) show that altering the back chamber volume mostly affects cone excursion below the cutoff frequency. The effect in the passband of the horn is minimal unless the back chamber volume changes are extreme.

Yes indeed. Some designs (very few) that I have seen don't even use a back chamber. Perhaps they want to create a weak DiPole effect of the horn vs. direct radiator going backwards and out of phase, bouncing off the back wall. Dipoles do have a characteristic "3D exaggeration" in the sound field at the listener's ear, which is a preferred illusion by some audiophiles. This makes me wonder what would happen if ChrisA didn't use an enclosure around the MEH, and used it about 1 Meter out off both walls?

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