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

[ClaudeJ1]

 

Those polars are indeed impressive. The differences in the ~15kHz region are kinda interesting.

It's pretty good out to 80 degrees (included angle), or 40 degrees off-angle.

 

I remember Roy mentioning that anything above ~8kHz is really controlled by the driver itself.  My own calculations have shown that to be a true statement--it's related to the phase plug geometry. I'm sure that the last few notes above 10 kHz that are audible will be different with a TAD driving the horn.

 

Chris

 

The JBL 2360A I used to own and measured clued me in on this very thing at 8 Khz. The 402 is no different in this regard based on the plots I've seen. This would be why some people prefer 1" drivers and tweeters in a 3-way.....greater dispersion up at the very top..........more "air" in the room, so to speak. This is what I had in Indy with Quarter pies on the bottom. That was a very good stack.

 

I suspect that TAD 4002's, with their 1.5 to 2" adapters built in, have a pretty narrow beam above about 6 K, but I have yet to install and measure to confirm this. Although I'm not as concerned, since I only care about the sweet spot and not getting the last octave spread all over the room. We shall see.

Edited January 23, 2016 by ClaudeJ1

[ClaudeJ1]

This is my mathematical equation asking you if the noise in your background was from your wife... 

 

One has to have a wife first and foremost. Second, one has to have a wife who cares about such things. This is why man caves exist. They are free of wife noise. 

 

However, wives come in handy for their superior hearing at high frequencies and to provide some extremely objective viewpoints since they typically don't care or have any vested interest, other than aesthetics.

 

Dtel's wife and daughter would be the rare exception.

Edited January 23, 2016 by ClaudeJ1

[Don Richard]

 

Think all you want, but a proper understanding of something includes measurements and/or equations to describe that behavior. Are you able to quantify how much of a load the front chamber and port entry is providing at low frequencies?

 

Of course I can, but I choose not to since I prefer listening to those adequately loaded woofers rather than calculate or measure them........for the moment. 

 

 

I recently read an article on fusion reactors and the recent progress of this technology. It seems that businessmen are driving the advances in development rather than the academics these days. The reason is that when something is tried and works, the businessmen simply accept that it is working and move on to something else. When the academics try something and it works, they stop and try to figure exactly what's going on before continuing. That's how they keep their grants coming.

[Chris A]

This is why man caves exist. They are free of wife noise.

 

Clearly I understand this.  The comment that I remember when that subject came up here was..."I'd never see you again.  You'd just disappear into it."

 

She knows me better than I do.   

 

But we share mornings and evenings together regardless with the system playing music: lots of Vivaldi, Corelli, Bach, Boyce, and Handel in the morning and movies/streaming Netflix in the early evening.  That's even easier to look forward to...with the new center.    

 

Chris

[Axz Hout]

c

[Chris A]

Yes, It looks like he's crossing to his woofers below 300 Hz by the looks of the distances from the throat to the woofer ports. He also has forgone the bass reflex ports in the horn and perhaps in the boxes.  I'd say he's gone 60 x 60 degrees. 

 

I bet the K-402 profile sounds even better, however: its 100 x 60 polars are spectacular relative to dual flare conical horns.  YMMV.

 

Thanks for sharing that.

 

Chris

Edited January 23, 2016 by Chris A

[juniper]

Even on youtube these things don't sound like regular speakers, they seem very focused over a fairly large area, like a mega point source studio monitor, with microdynamics that are insane.... I need a pair!

[Marvel]

I believe those are using 8 inch woofers. They think 10s are too big, since they also use even smaller mids and the panels get crowded.

[Axz Hout]

x

[Chris A]

My wife still has hopes to recover her fireplace.  "xt-ne" on that apparently great idea. 

 

Chris

[kg4guy]

Here is a link to the build with all the info you need to build a pair of these.

http://techtalk.parts-express.com/showthread.php?239910-Synergy-Horns-Dayton-and-PRV

Edited January 23, 2016 by kg4guy

[tromprof]

Here is a link to the build with all the info you need to build a pair of these.

http://techtalk.parts-express.com/showthread.php?239910-Synergy-Horns-Dayton-and-PRV

 

Many thanks!!  I will enjoy carefully reading this.

[DrWho]

 

Those polars are indeed impressive. The differences in the ~15kHz region are kinda interesting.

It's pretty good out to 80 degrees (included angle), or 40 degrees off-angle.

 

I remember Roy mentioning that anything above ~8kHz is really controlled by the driver itself.  My own calculations have shown that to be a true statement--it's related to the phase plug geometry. I'm sure that the last few notes above 10 kHz that are audible will be different with a TAD driving the horn.

 

The part that I find interesting is that the notch only exists in one plane - not the other. Is the driver not axisymmetric?

[kg4guy]

 

Here is a link to the build with all the info you need to build a pair of these.

http://techtalk.parts-express.com/showthread.php?239910-Synergy-Horns-Dayton-and-PRV

 

Many thanks!!  I will enjoy carefully reading this.

 

Yes this guy is an engineer and builds and designs speakers professionally and has Tom Danley permission to post the build .

[Chris A]

Tom Danley permission to post the build

 

Danley doesn't own the patent, now expired--Sound Physics Labs did.  He's a very nice guy, but I believe that's a bit over the top in being nice back.

 

Chris

Edited January 23, 2016 by Chris A

[Chris A]

Well, the design parameters include crossing at ~300 Hz to the woofer, and it's a 60 x 60 degree dual-conical flare horn, so those guesses were good.

 

At $298 (US) for a K-402 horn, it seems to me...

 

...But what do I know...?

 

Chris

Edited January 23, 2016 by Chris A

[DrWho]

I wish that he'd open the source, or at least publish an analyst's manual for each modeled capability.  He's steadfastly refused to document such things, it seems.    While his freeware application is certainly useful for DIY, it doesn't engender a lot of confidence in its validation/limits to its methodology.  It also doesn't tell you much about coverage angles and SPL, at least for multiple-entry horns.  It doesn't presently model tractrix mouth flares, either.

I totally agree - I don't understand why the tool is offered free of charge without publishing the source code, or at the very least documenting his assumptions and the equations he's using. Not even a reference to the papers he's basing it on. Totally invalid for engineering work, but the results from it are interesting nonetheless if we can trust that he's some kind of sane assumptions.

 

Btw, Hornresp will model tractrix flares....just not with a multiple entry horn. I'm not sure one could combine a conical and tractrix flare using lumped element modelling anyway - I think that would necessitate a boundary solver of some kind.

[Chris A]

Is the driver not axisymmetric?

 

The K-69-A may be slightly off center.  I'll check it when I get it apart again. 

 

I know that centering up the TADs resulted in measurable improvement in FR and phase at the 1/4 wave frequency of the driver's "snout" (adapter tube).  That got my attention. 

 

Chris

[Chris A]

I think that I see what you're referring to: a dip around 300-400 Hz.  That's the ground plane microphone null when I was measuring the unit in its horizontal plane. 

 

When I measured in vertical plane, I had to raise the microphone to about double its original height to be on-axis because of the angled side of the cabinet.  The unit weighs about 190 pounds, and I wasn't sure that I could brace it securely while it was laying on its side on the stool's base to bring the horn's axis back down to horizontal.  As it was, I think the higher microphone position while measuring the vertical axis actually yielded significantly less microphone dip. 

 

I forgot to mention that...my apologies.

 

Chris

[DrWho]

At $298 (US) for a K-402 horn, it seems to me...

 

 

Seriously? That's all it costs? Who's the vendor? I may pick one up next week. If the walls are as flat as you say, then I have some ideas on how to cut one set of "holes" in the horn and experiment with multiple driver / port entry configurations. For some reason I thought they'd be $1500 each.

 

I'm with you Chris - the K402 horn is the major differentiator here.

 

I only want to get down to 80Hz in my application since I have a subwoofer for the bottom two octaves. I have a pair of 12" NDL76 drivers laying around that I'll probably start with. Attached is a simulation with ported versus sealed rear chamber.