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Chris A

Nearly Full-Range Multiple Entry Horns (MEHs)

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Because of the inability of getting K-402 horns internationally (outside of North America), and the interest in MEHs seems to be continuing to expand, this thread is focused on those MEHs that are planned to be crossed to separate bass bins above 100 Hz. 

 

There are several threads that can be used as resources here:

 

1) the original "full range" MEH thread based on the K-402 horn

2) the "small syns" thread over at diyAudio, based mainly on Bill Waslo's spreadsheet and other, smaller existing horns

3) other MEH threads at diyAudio that are focused on specific horns (with links found on the thread linked just above)

 

This thread is initially set up to discuss the use of the largest SEOS horn--the SEOS-30.  A comparison shot of the K-402 and the SEOS-30 is shown, below:

 

1501564368_Seos30ogK402003(Large).jpg.52fa7124a2a2eb8dd265c924da3f396b.jpg

 

In general, the SEOS-30 horn seems to be available in the EU (+the UK), but is rarely found in North America.  This horn provides the necessary "real estate" to construct a nearly full-range multiple entry horn, but one that requires crossing to a bass bin at ~300 Hz ± 100 Hz.

 

Chris

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Here is the genesis of this thread from the original K-402-MEH thread:

 

On 4/28/2021 at 5:00 AM, Vathek said:

First post and not even Klipsch related, but I think reasonably on-topic in this thread: Since over here in Europe K402 are special order through pro install dealers and prohibitively expensive, has anyone here thought about MEH-ing a SEOS-30 or even done so? That's the biggest easily obtainable ready-made horn suited for the job and relatively cheap. The flat conical surfaces should make it easy to work with regarding woofer mounting / porting too.

  

14 hours ago, Vathek said:

Thanks everyone. The reason I’m looking at the SEOS-30 is mostly build simplicity. I’m in a big city with no back yard, garage or anything like that to use for wood work. So for something based on Bill’s spreadsheet I would have to hire a carpenter and then things get expensive quickly. Whereas a rectangular CLD box can be built at home with pre-cut wood from one of the various home depot like stores here. What intrigued me about the K-402 MEH in this thread was the omission of the midrange cone drivers by using a large compression driver, which makes it so much easier for this ready make approach. Most threads / projects go the 1-inch plus 4-inch cone midrange route, this is why I posted here.

 

I’m fully aware a SEOS-30 will not control directivity down to Schroeder frequency unless I put it in my shower, but if that was a sine qua non criterium there would only be a handful of speakers in the world in the first place. It’s a compromise I would be willing to live with. Since autotech don’t put their prices on the website, I’m not going to make them public here, but you could easily get a surround system for the price of a single K-402 and they’re extremely well built from about 10mm thick fibreglass (which might be just about perfect for the woofer taps). And in Europe they’re readily available, I’ve bought several of their smaller waveguides from them. I realise that the situation might be pretty much the opposite in the US.

 

Also I would aim for a x-over point around 400 or 450 Hz or so, which allows for more (and cheaper) options than the Axi2050. I’m not trying to make the argument that any of this is better than the Axi2050 on a K-402 (not at all!), but three pieces (LCR) of that combo would set one back around 10k over here, and that’s just for the horn and the compression driver. Whereas a couple of 12-inch woofers and a BMS 4590 on a SEOS-30 would cost somewhere around a grand per channel. And the 400 - 450Hz crossover has been proven to work in many MEH’s with the 1-inch plus (one or several) 4-inch midranges.

 

If I had (access to) a proper wood work shop, I would absolutely pursue the plywood version based on Bill’s spreadsheet. The whole idea behind this is to find a solution that is as ready made as possible and here the SEOS-30 seems to be the second best option after the K-402 at a much lower price point and at least in EU it’s easily available. The BMS 4590 is more expensive than a 1-inch and a couple of 4-inchers, but it’s “bolt on and done”. The key to the whole thing is the choice of woofers and the location, shape and size of the woofer taps and maybe some sort of ‘mounting construction’ for the woofers. And that’s really what my question was aimed at. I realise that was way too implicit in my initial post. And if nobody has done this with a SEOS-30, I guess I’ll have tackle it myself. But I haven’t even been able to wrap my head around Hornresp, so this might prove to be a challenge.


Chris

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53 minutes ago, Chris A said:

Also I would aim for a x-over point around 400 or 450 Hz or so, which allows for more (and cheaper) options than the Axi2050.

This is essentially the same crossover frequency as the original Klipsch Jubilee and the Klipsch KPT-942 (using the K-402 horn), as well as other KPT bass bins.

 

The idea of using an MEH is to get a single horn aperture to house multiple acoustic drivers that are arrayed by their pass bands (lower frequency drivers toward the horn mouth on "off axis" ports that are not on the horn's centerline, and higher frequency drivers at or very near the horn throat).  It is noted that the K-402 horn itself is capable of supporting a single full-range driver (the relatively new Celestion Axi2050) down to ~225 Hz, easily, thus eliminating the need for an MEH. 

 

So the use of a smaller MEH that may or may not use separate midbass or midrange drivers is actually borne out of the need to reduce the costs of the horn/driver combination.  Secondary considerations include reducing the size of the horn mouth, but at a cost of requiring a separate (and usually direct radiating) woofer/bass bin. 

 

So the smaller MEH should be focused on cost savings and the appearance of a smaller horn (which is actually not smaller than a full-range MEH).  Examples of these sort of hybrid MEHs are found at diyAudio.  Curiously, the source for the original "Synergy" and "Unity" horns (Danley) seems to avoid making MEHs that require crossing above ~100 Hz, with the possible exception of the newly announced "Hyperion", which will actually cross at 260 Hz to dual "subwoofers" (actually direct radiating woofers tuned to 14-260 Hz passband).

 

I do think that it's fair to also discuss at length on what the "small syn" means in terms of midbass and bass performance.  In general, unless crossing to a folded horn bass bin like the Khorn, La Scala, Belle, or Peavey FH-1, etc., the smaller MEH will lose directivity below the crossover frequency to the woofers, thus requiring careful in-room placement to generate flat SPL response in the bass and midbass (midbass here is defined as being above 100-200 Hz--the typical home hi-fi room's transition or Schroeder frequency), but will create an unbalanced power response in-room unless placed in full room corners.  This design trade has significant consequences, in my experience, that puts the small MEH into a different class than the full-range MEH that can cross to subwoofers below 100 Hz. 

 

One possible alternative approach on the bass bin: use a "Dutch & Dutch" style array of woofers to approximate a line array for a narrower range of listening angles.  Perhaps more discussion of that approach has merit, but note that this drives the cost (and size) of the resulting loudspeakers up to be in competition with a single K-402/Axi2050 combination with 15" off-axis woofers, than also can support a 17-500 Hz passband in quarter space loading.

 

Chris

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37 minutes ago, Chris A said:

One possible alternative approach on the bass bin: use a "Dutch & Dutch" style array of woofers to approximate a line array

 

I had to look this up, but after reading some things, still need to ask if you could describe this. 

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Basically, the Dutch & Dutch 8C uses diffraction (two woofers + ports --sort of like a line array, but in this case arranged differently) to control horizontal and vertical directivity into a cardioid-like pattern.

See: https://www.audiosciencereview.com/forum/index.php?threads/dutch-dutch-8c-quasi-anechoic-spinorama-and-measurements.12111/

 

8c.jpg?format=2500w

 

The patent: https://patents.google.com/patent/EP3018915A1/en

 

Horizontal directivity sonogram:

 

8c-horizontal-contour-png.54828

 

Vertical directivity sonogram:

 

8c-vertical-contour-png.54829

 

Chris

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7 hours ago, Chris A said:

Whereas a couple of 12-inch woofers and a BMS 4590 on a SEOS-30 would cost somewhere around a grand per channel.

This is a valid design constraint--cost--and it comes up everywhere in sound reproduction as either the most limiting factor or second-most limiting factor in loudspeaker design.   Probably the most limiting factor in loudspeaker acoustics performance is the rather arbitrary and extreme limitations on the visual size/shape of loudspeakers. 

 

7 hours ago, Chris A said:

The whole idea behind this is to find a solution that is as ready made as possible and here the SEOS-30 seems to be the second best option after the K-402 at a much lower price point and at least in EU it’s easily available.

Actually, I believe the best option is a plywood dual-flare horn.  This is the solution provided by Bill Waslo's Synergy Calc spreadsheet. 

 

But if you believe that you cannot do it yourself and that reasonable carpentry services are not available, then I suppose that the SEOS-30 is the best available "bought" horn, but note the limitations of its horizontal (i.e., major dimension) mouth size to control the loss of horizontal directivity to below 300 Hz (or lower) is a significant factor. 

 

Even buying dual-flare plywood horns from abroad would be an option if carpentry rates are perceived to be too high where you live. Note that Danley uses mainly plywood dual-flare horns, in addition to its "molded Synergy" (SM) series of loudspeakers.  This is an area that is clearly ripe for third parties to provide assembled or even flat-pack MEH kits. One might ask where the bass bin box that is required for use of the SEOS-30 in-room--but not in room corners--comes from.  Does that also require carpentry skills to produce?

 

Chris

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1 hour ago, tom1066 said:

Chris -

 

I wonder how a JBL 2384 would work?  https://reconingspeakers.com/product/jbl-365359-001-2384-hornwaveguide-3732/

It looks like the 2384 is slightly smaller than the SEOS 30 horn, or at least, about the same mouth size:

 

image.png.799e29ad55279dc78c50291fdeecf949.png

 

I would think that this horn would behave much like a SEOS 30, and it's available in North America.  If you're going to "bite the bullet" and do what I call a "hybrid horn/direct radiator", you could use the 2384 on top of your favorite direct radiating bass bin, and have performance that's very similar to the JBL 4722:

 

4722_front_z_vert_medium.jpg

 

My next question would be: "why go to the trouble of doing an MEH on top--why not just use a 4722"?

 

Perhaps by now you might see why I want to break these types of MEHs into a separate thread. There is a lot more head scratching going on when the horizontal horn dimension is less than 35-40 inches (the actual mouth size--not the horn flange size).  You begin to question why you're going to all that trouble to avoid spending a few hundred bucks.  

 

If you're right on the edge of not being able to afford good horn-loaded loudspeakers of the full-range MEH design (i.e., the K-402-MEH), you'd be doing bottom dollar on the compression driver, woofer(s), and DSP crossover, and having to live with the system noise floor to do that (or playing with resistor attenuation networks to drop the noise floor from the DSP crossover). 

 

I think that working an extra couple of weekends for overtime pay (if an hourly wage employee), not going out to eat for a while (i.e., bringing your lunch to work, etc., or doing dinner at home instead of fast food runs, etc.), or cutting down on your cellphone bills by cutting back the "bells and whistles" extras tacked onto your bill would be a key  enabler to get a setup that avoids all these issues.

 

Chris

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3 hours ago, Chris A said:

 

 

My next question would be: "why go to the trouble of doing an MEH on top--why not just use a 4722"?

 

Perhaps by now you might see why I want to break these types of MEHs into a separate thread. There is a lot more head scratching going on when the horizontal horn dimension is less than 35-40 inches (the actual mouth size--not the horn flange size).  You begin to question why you're going to all that trouble to avoid spending a few hundred bucks.  

 

If you're right on the edge of not being able to afford good horn-loaded loudspeakers of the full-range MEH design (i.e., the K-402-MEH), you'd be doing bottom dollar on the compression driver, woofer(s), and DSP crossover, and having to live with the system noise floor to do that (or playing with resistor attenuation networks to drop the noise floor from the DSP crossover). 

 

I think that working an extra couple of weekends for overtime pay (if an hourly wage employee), not going out to eat for a while (i.e., bringing your lunch to work, etc., or doing dinner at home instead of fast food runs, etc.), or cutting down on your cellphone bills by cutting back the "bells and whistles" extras tacked onto your bill would be a key  enabler to get a setup that avoids all these issues.

 

Chris

 

Must admit, your reasoning does not make sense to me....if i understand it correctly.

You seem to be saying, unless you go all the way to a very large Synergy/MEH, there's no point going at all.   ????

If that were true, there would be no point in the SH-50, or any of the small-syn DIY builds people have been pleased with.

 

To directly answer the question "why go to the trouble of doing an MEH on top--why not just use a 4722"?

I would say to gain the coherence of moving closer to a point source, regardless of where it looses pattern control. 

I would try to mount some big mids on the 2384 horn just to gain coherence down as low in frequency as possible, again regardless of where it looses control.

 

Tightening up c-2-c's  of any and all drivers simply works ime. And that's what MEHs do best, big or little, imo.

 

Right now I'm running listening tests on the same Syn7 horns, where one has only 1.125" quarter round for mouth termination, and the other has tractrix like mouth flares.

Tuning/processing  is identical for both. 

The larger Syn7 does have a fuller richer mid bass sound.  But the smaller one can be EQ'ed pretty dang close...

and the real point is, the smaller one is still one of the best speakers I've heard. (maybe the second best Lol)

 

So my advice is, heck yeah, build small syns too !

 

syn7 size compare.jpg

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1 hour ago, gnarly said:

You seem to be saying, unless you go all the way to a very large Synergy/MEH, there's no point going at all.   ???? If that were true, there would be no point in the SH-50...

Well, I think that the SH-50 is most definitely a "full range MEH"...

 

SH-50 PEQs in center.JPG

 

What I'm referring to, above, is MEHs whose on-axis SPL can't make it down to 100 Hz in half space (or perhaps even quarter space).  The SH-50 has a -3 dB (f3) point of ~50 Hz.  If you look at all the other larger Synergy horns (of which the SH-50 is one), their f3 frequencies are generally at or below 100 Hz. 

 

When the MEH has a -3dB roll off at 300 or 400 Hz, then all of what I said above applies.

 

1 hour ago, gnarly said:

...or any of the small-syn DIY builds...

This is where the waters part in our assessments.  I don't see a lot of reason for those type of MEHs, to be honest.

 

1 hour ago, gnarly said:

...To directly answer the question "why go to the trouble of doing an MEH on top--why not just use a 4722"?

I would say to gain the coherence of moving closer to a point source, regardless of where it looses pattern control...

Are you aware that you have to cross over to a separate (and usually direct radiating) bass bin at ~400-600 Hz?  That's why I said that the 4722 is a better deal, and much simpler to implement.  Doing an MEH that only goes down to 400-600 Hz is instead much easier and better done (from many different points of view) in a single 2" compression driver on the same horn--without extra drivers.  The reason for the extra drivers--like the midrange drivers in the Danley--is the added power handling of the midranges to alleviate the load on the high frequency compression driver (a 1" BMS compression driver).  Danley also uses the midrange as a "phase link" driver with very narrow bandpass in order to facilitate its use of passive crossover filters for fixed PA duty.  That's not really a home hi-fi requirement.

 

1 hour ago, gnarly said:

...I would try to mount some big mids on the 2384 horn just to gain coherence down as low in frequency as possible, again regardless of where it looses control...

I'm not sure what you are saying here.  Could you be a little clearer in what you're saying?

 

1 hour ago, gnarly said:

...So my advice is, heck yeah, build small syns too !...

Well, if you just like to tinker, that's certainly okay.  But I wouldn't waste much time on that sort of thing, to be honest.

 

Chris

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Chris,

I agree that an MEH with a low end cut off only extending to 300 or 400hz makes little sense.

Your K402 based MEH look to be astounding, but the 402 is really wide for a lot of rooms, especially if used LCR.  And,  it exactly cheap either.😊

 

The sweet spot for me would be an MEH using a 2” driver crossed around 400 to dual 12” (or 8”?) woofers mounted on the sides firing through the horn.  Low end cut off of around 80-100hz.  Preferably 24-30” wide.  
 

 Perhaps this is pie in the sky. 
 

Maybe the better solution is the Peavey FH-1 + 2 Large Heils from your other thread.  
 

Bruce

 

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Posted (edited)
3 hours ago, Chris A said:

Well, I think that the SH-50 is most definitely a "full range MEH"...

 

SH-50 PEQs in center.JPG

 

What I'm referring to, above, is MEHs whose on-axis SPL can't make it down to 100 Hz in half space (or perhaps even quarter space).  The SH-50 has a -3 dB (f3) point of ~50 Hz.  If you look at all the other larger Synergy horns (of which the SH-50 is one), their f3 frequencies are generally at or below 100 Hz. 

 

When the MEH has a -3dB roll off at 300 or 400 Hz, then all of what I said above applies.

 

This is where the waters part in our assessments.  I don't see a lot of reason for those type of MEHs, to be honest.

 

Are you aware that you have to cross over to a separate (and usually direct radiating) bass bin at ~400-600 Hz?  That's why I said that the 4722 is a better deal, and much simpler to implement.  Doing an MEH that only goes down to 400-600 Hz is instead much easier and better done (from many different points of view) in a single 2" compression driver on the same horn--without extra drivers.  The reason for the extra drivers--like the midrange drivers in the Danley--is the added power handling of the midranges to alleviate the load on the high frequency compression driver (a 1" BMS compression driver).  Danley also uses the midrange as a "phase link" driver with very narrow bandpass in order to facilitate its use of passive crossover filters for fixed PA duty.  That's not really a home hi-fi requirement.

 

I'm not sure what you are saying here.  Could you be a little clearer in what you're saying?

 

Well, if you just like to tinker, that's certainly okay.  But I wouldn't waste much time on that sort of thing, to be honest.

 

Chris

 

I guess i don't see the SH-50 as a larger Synergy, as the entire frontal box size is 28"x28".

And I know it doesn't take a big Synergy/MEH to reach below 100Hz, other than for how loud do we want.

 

Can't say i've ever seen anyone build a MEH that didn't get to down to at least 300Hz...in fact i'd say it's almost impossible not to. 

Even the little 3"s and 4"s tied to a CD will do that.

And it's very rare to see a DIY MEH that doesn't also have a woofer(s) to go with smaller mids, taking response to at least 100Hz or below.

 

I totally get and agree with what you're saying about the mids being the added power handling to the CD, but i'm not sure what you mean by the mids being a phase link.

I think too much has been made of the Danley passive xovers...they seem pretty normal to me, especially when you look at the SH-50's phase trace scale...not quite so flat then. Lol.

 

I guess what I'm trying to say, is we need to separate the size of a MEH and its subsequent pattern control , from the response of a MEH and its sonic benefits from close coupling  drivers.

I think the sonic benefits are great enough to pursue any MEH that gets within reach of a sub, no matter how small the MEH.

 

But at the same time, i also acknowledge that sonic benefits get amplified with lower pattern control from a larger MEH...which i take is your viewpoint.

 

Edited by gnarly

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On 5/3/2021 at 7:51 PM, gnarly said:

I guess i don't see the SH-50 as a larger Synergy, as the entire frontal box size is 28"x28".

That's because is only has 50 degrees of coverage horizontally (or vertically).  You need two stacked together side-by-side to have the same coverage as a K-402-MEH.  But there seems to be some folks that have such small (or terrible acoustics) listening rooms, that they prefer that extremely narrow coverage. 

 

As a matter of course, Klipsch designs horns have 90-degree horizontal coverage horns--basically all of them.  There is a reason for this.  I should add that the default coverage requirement (above) is 90 x 60 degrees.  If you decide you need narrower coverage--that's certainly up to you, but my experiences are that it doesn't have "apparent source width" (ASW) that fills the front of the room, and without loss of directivity control.

 

On 5/3/2021 at 7:51 PM, gnarly said:

And I know it doesn't take a big Synergy/MEH to reach below 100Hz, other than for how loud do we want.

It does if you want to call it horn-loaded, i.e., that it has directivity down to at least 200 Hz (or below the transition frequency of the room).  Otherwise, it's a "hybrid horn--direct radiator" arrangement of drivers that gives the impression of a point source, but in reality is illuminating everything in the near field below the point of loss of directivity control.  You can call it an "MEH", but at some point, it's just another direct radiator loudspeaker with a horn-loaded top end.

 

On 5/3/2021 at 7:51 PM, gnarly said:

Can't say i've ever seen anyone build a MEH that didn't get to down to at least 300Hz...in fact i'd say it's almost impossible not to. 

With directivity control?  They're not really "horns"...but more like a D'Appolito arrangement of drivers below the point of loss of horizontal directivity control (after loss of directivity in the vertical axis).  Some folks might be satisfied with that.  I wouldn't call it a "horn", however.

 

On 5/3/2021 at 7:51 PM, gnarly said:

I totally get and agree with what you're saying about the mids being the added power handling to the CD, but i'm not sure what you mean by the mids being a phase link.

This: http://www.tonmeister.ca/wordpress/2015/10/29/bo-tech-uni-phase-loudspeakers/

 

On 5/3/2021 at 7:51 PM, gnarly said:

I think too much has been made of the Danley passive xovers...they seem pretty normal to me, especially when you look at the SH-50's phase trace scale...not quite so flat then. Lol.

Then I think that you've not experienced a lot of linear phase loudspeakers having passive crossovers and full-range directivity (horn loaded).  That's what Tom D. achieved with a fully horn-loaded loudspeaker, but almost no one has picked up that it's the cause of them sounding so special.  Tom apparently hasn't been able to break through the tough hide of "audiophiles" that full range directivity combined with linear phase transfer function response (in a loudspeaker having passive crossovers only) yields the "Synergy horn" sound quality that captivates so many listeners.

 

On 5/3/2021 at 7:51 PM, gnarly said:

I guess what I'm trying to say, is we need to separate the size of a MEH and its subsequent pattern control , from the response of a MEH and its sonic benefits from close coupling  drivers.

Go ahead...separate them...if you feel it's necessary. 

 

I think that I'll elect to have full-range directivity control down to the room's transition frequency (i.e., at least down to 200 Hz), and 90 x 60 degree coverage.  BTW: vertical coverage can be less than 60 degrees, but typically not without incurring pattern flip at some higher frequency that's too far from the room's transition frequency.  Vertical coverage can be too narrow, too.

 

I think that D'Appolito arrangements are useful, but not really "horn-loaded".  Acoustic coupling of drivers without using horn loading is still direct radiating drivers. 

 

On 5/3/2021 at 7:51 PM, gnarly said:

I think the sonic benefits are great enough to pursue any MEH that gets within reach of a sub, no matter how small the MEH.

Then you will be a fan of the type of loudspeakers described in this thread. 

 

For me, there is too much that's lost with this approach--that otherwise significantly adds to the listening experience...when listening to full-range MEHs...(i.e., also having 90 x ~60 degree coverage as a constraining requirement).

 

Chris

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7 hours ago, Drumdoctor said:

but the 402 is really wide for a lot of rooms, especially if used LCR.  And,  it exactly cheap either.😊

Yes, I'm aware of the limitations of some listening room sizes to handle them.  "Cheap" is another issue, not related to acoustic performance.  That's a barrier to entry for some DIYers that are severely budget constrained.  But when you look at the cost of a new pair of Cornwall IVs, I think the cost of the K-402s isn't quite so bad.

 

7 hours ago, Drumdoctor said:

 ...Preferably 24-30” wide...

If that's all you can handle, then that's it.  The listening room itself is the limitation.  However, I would also point out that I've seen many people state that they can't handle the width when what they are really saying is that they don't like the visual width in their room.   I try to go with the acoustic performance first.

 

7 hours ago, Drumdoctor said:

...Maybe the better solution is the Peavey FH-1 + 2 Large Heils from your other thread...

This actually works quite well (I use AMT-1s on top of Belle bass bins currently as my surrounds in my 5.2 array, and they are outstanding).  Using K-402-MEHs and/or Jubilees, doesn't really constrain where the listener is located, however--anywhere from sidewall-to-sidewall in multichannel music mode (LCR). 

 

Welcome to the forum!

 

Chris

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6 hours ago, Chris A said:

That's because is only has 50 degrees of coverage horizontally (or vertically).  You need two stacked together side-by-side to have the same coverage as a K-402-MEH.  But there seems to be some folks that have such small (or terrible acoustics) listening rooms, that they prefer that extremely narrow coverage. 

 

As a matter of course, Klipsch designs horns to have 90-degree horizontal coverage horns--basically all of them.  There is a reason for this.  I should add that the default coverage requirement (above) is 90 x 60 degrees.  If you decide you need narrower coverage--that's certainly up to you, but my experiences are that it doesn't have "apparent source width" (ASW) that fills the front of the room, and without loss of directivity control.

 

It does if you want to call it horn-loaded, i.e., that it has directivity down to at least 200 Hz (or below the transition frequency of the room).  Otherwise, it's a "hybrid horn--direct radiator" arrangement of drivers that gives the impression of a point source, but in reality is illuminating everything in the near field below the point of loss of directivity control.  You can can it an "MEH", but at some point, it's just another direct radiator loudspeaker with a horn-loaded top end.

 

With directivity control?  They're not really "horns"...but more like a D'Appolito arrangement of drivers below the point of loss of horizontal directivity control (after loss of directivity in the vertical axis).  Some folks might be satisfied with that.  I wouldn't call it a "horn", however.

 

This: http://www.tonmeister.ca/wordpress/2015/10/29/bo-tech-uni-phase-loudspeakers/

 

Then I think that you've not experienced a lot of linear phase loudspeakers having passive crossovers and full-range directivity (horn loaded).  That's what Tom D. achieved with a fully horn-loaded loudspeaker, but almost no one has picked up that it's the cause of them sounding so special.  Tom apparently hasn't been able to break through the tough hide of "audiophiles" that full range directivity combined with linear phase transfer function response (in a loudspeaker having passive crossovers only) yields the "Synergy horn" sound quality that captivates so many listeners.

 

Go ahead...separate them...if you feel it's necessary. 

 

I think that I'll elect to have full-range directivity control down to the room's transition frequency (i.e., at least down to 200 Hz), and 90 x 60 degree coverage.  BTW: vertical coverage can be less than 60 degrees, but typically not without incurring pattern flip at some higher frequency that's too far from the room's transition frequency.  Vertical coverage can be too narrow, too.

 

I think that D'Appolito arrangements are useful, but not really "horn-loaded".  Acoustic coupling of drivers without using horn loading is still direct radiating drivers. 

 

Then you will be a fan of the type of loudspeakers described in this thread. 

 

For me, there is too much that's lost with this approach--that otherwise significantly adds to the listening experience...when listening to full-range MEHs...(i.e., also having 90 x ~60 degree coverage as a constraining requirement).

 

Chris

i think maybe we are needing to agree to disagree.

 

You're definition of an acceptable MEH/Synergy, seems to require 90 deg horiz coverage and provide pattern control to at least 200 Hz. 

Using Keele's pattern control formula, that would require about a 46" wide horn, which i believe is about half a foot wider than even the k-402....which means the k-402 has to go in a corner to get the desired directivity.  So it appears your definition of an acceptable MEH is narrowed down to what you have and like, including an accommodating room.

 

My definition is simple......imho a Synergy  is a horn or a waveguide that has multiple drivers mounted to it, that cover different frequency ranges.

"Horn-loading" is an important aspect, but not essential throughout the design's frequency range, as all horns let go somewhere, even the larger than norm k-402 and my 49" wide conical DIY. (i do want to try 60" wide outdoors this summer, on top a bank of TD's Labhorns :)

 

I get what you mean by the mids on the SH-50 acting as a 'phase link now, thanks for the uni-phase paper.  I've seen that technique before for putting together 2 order Butterworths , and it could be a part of the SH-50 xover design...who knows. 

Tom D recommended LTspice to me for passive xover work, maybe that would be of value if you like to explore passives and what he might be doing, deeper.

I told  him I'm multichannel-active rephase/ FirDesigner all the way, and he smiled and said he used rephase to phase flatten his SH-50's at home.

 

Which btw,  the SH-50 is not even close to being a linear phase speaker.  I mean, look closely at the attached phase scale....look at all the phase rotation.

 

Yes, I do think I've heard  horn-loaded  linear phase speakers with directivity below 200Hz. My current Syn7's do that.

And I mean true linear phase, something that is pragmatically unobtainable with multi-way passives.

The sound is plain awesome for me, a magical clarity like really good electrostats, and with super transients and dynamics.

I attribute most of the magic to the acoustic co-location of drivers, that the MEH design allows.

 

T say again, i believe far too much emphasis and speculation about the great synergy sound has been put on their (to-date) passive xovers.  

I have the Danley SC-48 speaker processor that has DSP presets for their speakers.  There are correction EQs for every model including the SH-50.  Models that have bi-amp capability, in addition to passives, use standard xovers.. some even have a 4th order linear phase xover option.

The upcoming 4-way Hyperion is blurbed as 3-way FIR active, with a passive only between the CD and 5" mid.

Imho, xovers are simply a necessary component/problem to overcome..  with the least phase wrap possible.  

 

Anyway, i personally don't feel it's appropriate to narrowly define what a MEH is....or rather, define what it needs to be as acceptable for great listening.

I feel more comfortable just relaying what I've found to work, and what i like about it...

sh-50 phase snip.JPG

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1 minute ago, gnarly said:

Your definition of an acceptable MEH/Synergy, seems to require 90 deg horiz coverage and provide pattern control to at least 200 Hz.

Yes.  That's a good definition of a "full-range MEH".  The K-402 (...which isn't 46" wide...) does that, in spades:

 

K-402-MEH horizontal directivity sonogram, normalized to on-axis:

 

K-402-MEH horizonal normalized sonogram.jpg

 

Note where this 36" x 21" horn (without flanges) actually loses horizontal directivity (the -6 dB point is the light blue-green color corresponding to ~-9 dB on the right-hand scale).  This is a hybrid straight-sided/tractrix mouth flare horn that is sold by Klipsch (i.e., this forum's sponsors).

 

So the answer is that the horn needs to be perhaps 32-35 inches wide x 19-21 inches tall to fit my "full-range MEH" criterion.  That size horn will fit into a Cornwall cabinet (see the K-402-MEH thread for a layout from Waslo's Synergy Calc spreadsheet, dual flare).  More discussion on that here and here.  THere are a lot of people that own Cornwalls, and like them a lot.  Here is the loudspeaker type that I own (these are prettier than mine):

 

Z-Jub-Becky.jpg

 

Note the horns on top.  I needed a center channel between two of these, but my room will not permit a third Jubilee in the center (fireplace hearth gets in the way).  The K-402-MEH came from that need for a center channel between these two loudspeakers.  I found that the K-402-MEH works a lot better than planned.  More people are building these now, and we currently have four installations of these loudspeakers, seen to grow to a greater number.

 

I own an SH-50, and have used it between the two Jubilees (which is where I got that data).  It sounded good--just like the Jubilees, in fact--but its apparent source width (ASW) is far too narrow to match the Jubilees.  My room is 15.5 feet wide, 9 feet tall, and 40 feet long.  With the K-402-MEH, anywhere you choose to listen inside the room is good--outside of a 3-feet radius of the loudspeakers at the very front of the room.  I think others also see the advantages of that, and they are building their own K-402-MEHs.

 

52 minutes ago, gnarly said:

...the SH-50 is not even close to being a linear phase speaker.  I mean, look closely at the attached phase scale....look at all the phase rotation...

I think your definition of linear phase is more like "flat phase" instead of what I'd call linear phase.  If you look at the excess group delay plot, its really quite flat for a passive crossover horn-loaded loudspeaker (full range).

 

A couple of more plots of the SH-50 vs. the IIR-only Jubilees using a Xilica XP-8080 crossover:

 

TAD TD-4002 Jubilee vs. Danley SH-50 phase response.jpg

 

TAD TD-4002 Jubilee vs. Danley SH-50 group delay response.jpg

 

57 minutes ago, gnarly said:

Anyway, i personally don't feel it's appropriate to narrowly define what a MEH is....or rather, define what it needs to be as acceptable for great listening.

I feel more comfortable just relaying what I've found to work, and what i like about it...

That's clear. 

 

I don't define what an MEH is.  I've merely defined what I mean to be a "full-range MEH" instead.  (You can do what you like--as can anyone else.)

 

I'd like to retain my definition because it conveys what I need it to convey-especially to the members in this forum that own and prefer Klipsch products.  If you believe that your definition is more valid than mine--then you can certainly feel secure at the forum you post to.  I freely share my detail designs and data with others here, not to increase my own standing, but so that others can enjoy what I enjoy listening to.  There are very good reasons for defining a "full-range MEH" the way that I have.  It's a short hand way of saying that you most likely get the same level of performance as what I listen to each day (all day).  If that bothers you, I don't know what to say, except, "go listen to some K-402-MEHs" and/or Jubilees. 

 

Chris

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20 hours ago, gnarly said:

The larger Syn7...   has tractrix like mouth flares.

 

How is that constructed?

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That's some very nice directivity,, and a great looking audio room!

 

I guess what's been puzzling to me in this thread, is that i thought it's about finding a suitable substitute for a less than full-range K-402 based MEH ... like using the SEOS-30 in the thread starter.  Then later, i think your take on the JBL2384 kinda threw me.  It seems like it might be very similar to the SEOS-30 in terms of MEH suitability. So I was surprised and i probably pushed back a little in favor of encouraging smaller MEH explorations. 

 

Anyway, we are all of course entitled to profess our thoughts and preferences in any civil way we like....and i think it's nice to see someone like you so dedicated to a platform you enjoy so much. (and helpful to others)

 

Yes, my interpretation of linear phase is flat phase, flat as in a line.  Same interpretation as the rest of the world, wink :) 

Linear phase is a straight line against frequency when freq is on a linear scale, sloping when there is a constant delay in the measurement, and level flat at 0 degrees when the constant delay is removed.

 

Your group delay plots do look quite good for a passive. Nice !

Here's a typical example I get with FIR.  This is the group delay of a project i'm working on now, the B&C DCX464 on the ME464 horn....on top of a sealed 18" sub crossing to the CD at 300Hz. (still have something not quite right there below 300Hz). 

As you can see, group delay can really be taken way down...

 

 

 

Group  delay dcx on me464 and sealed sub.jpg

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16 minutes ago, Khornukopia said:

 

How is that constructed?

I made flares out of 2" thick XPS foamboard.

Here's a pict of one in progress, and the big hot wire knife used to form them.

Idea and how-to credit, goes to a member named Oohms....found the link to his project somewhere on these forums...

hotwire jig.jpg

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On 5/3/2021 at 6:11 AM, Chris A said:

Basically, the Dutch & Dutch 8C

 

That is what my google search led to, I just needed to verify that I was following you correctly. The directivity design seems to be similar in principle to the methods used during live sound to focus the low frequencies away from the stage and out into the audience.

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