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Waveguides and horns

Radian 950PB Truextent in JMLC-200T.

Would you say, by ear, that the Radian driver in JMLC-200T is suitable and "sufficient" sounding in its entire frequency span from ~300Hz and upwards, or does it feel notably restricted in its HF response? The curve indicates a rather rapid fall above 10kHz..

It would be an impressive feat to have one driver/diaphragm cover the entire and remaining frequency range from 300Hz and up in an audibly satisfying fashion, without any x-overs here..
 
Would you say, by ear, that the Radian driver in JMLC-200T is suitable and "sufficient" sounding in its entire frequency span from ~300Hz and upwards, or does it feel notably restricted in its HF response? The curve indicates a rather rapid fall above 10kHz

Radian Truextent does not have a sparkle of 4590 and need supertweeter. I would stick with 1.4" drivers and waveguide for highest HF energy, waiting for beryllium 18sound driver. Otherwise Radian Truextent alone will be very relaxing on EJMLC-300.

4590 directivity can be found here:
Horns
 
Would you say, by ear, that the Radian driver in JMLC-200T is suitable and "sufficient" sounding in its entire frequency span from ~300Hz and upwards, or does it feel notably restricted in its HF response? The curve indicates a rather rapid fall above 10kHz..

It would be an impressive feat to have one driver/diaphragm cover the entire and remaining frequency range from 300Hz and up in an audibly satisfying fashion, without any x-overs here..

Horns are a low pass filter.
Trying to find a compression driver and horn that will cover six octaves is like trying to find a unicorn.

This is the whole reason I've built a dozen Unity horns. It is the only practical solution to the problem you are trying to solve.

I don't mean this to sound harsh - believe me I wish there was a horn and compression driver that could do six octaves without breaking a sweat.

 
Hi John

Such a bandwidth is not theoretically impossible, I could do it, but what are the goals and what kinds of tradeoffs would be acceptable?

By the way, a nhorn is a high pass filter, not a low pass one.

To get good directivity control to 300 Hz would require a mouth size of about three feet or more. The driver would have to give up a lot of efficiency to go as low as 300 Hz and this would seriously degrade the MaxSPL such a system could achieve without overloading the device. But it could be done. A 1" throat with a heavy berylimum diaphram could do it - lots of magnet and limited turns (for low inductance). It would need a non-metal surrpound to get down to 300 Hz and the excursion down that low would limit its MaxSPL.
 


Horns are a low pass filter.
Trying to find a compression driver and horn that will cover six octaves is like trying to find a unicorn.

This is the whole reason I've built a dozen Unity horns. It is the only practical solution to the problem you are trying to solve.

I don't mean this to sound harsh - believe me I wish there was a horn and compression driver that could do six octaves without breaking a sweat.


Thanks for your respons, Mr. "Bateman" - which I didn't see in any way harsh. As mentioned earlier I'm a non-techie into this field, and my somehow naive questioning or replies may at times (subconsciously) be meant to "provoke" a corrective or otherwise illuminating remark from the ones in the know - now that I am not.

Within these limitations of mine there are still some markers I'd like to go by, such as trying not to stray too far from one point source per channel(which in effect means two per channel, if we rule out coaxials/full range units) as well as an overall goal to maintain simplicity, and from what I'm able to gather it's fully possible to have a horn/waveguide cover five octaves in an audibly satisfying manner - without, I presume, having to resort to huge mouth openings as suggested by Mr. Geddes.

Of course, what is "audibly satisfying"? What it is to some it mayn't be to others. I'm aware there are likely trade-off's wanting not to go beyond two point sources per channel, but to my mind the pro's in this case far outweigh the con's.

The question in my search right now seems to revolve around whether there are some clear benefits to be had from large-coil(3-4 inch.) diameter compression drivers covering the lower-lower central mids versus a 12-15 inch bass/mid driver covering this same area in "joint venture" upwards with a smaller coil-diameter(typically no more than 1 3/4 inch) compression driver. It seems, to my ears, the large coil comp. drivers provide a benefit in this very important area, as well as into the central mids, but then HF response is hampered. The BMS 4590/4592 then comes to mind as a possible solution, but that means having another cross-over to work around - albeit at a higher frequency, around 6-7kHz? Perhaps a x-over this high doesn't pose a serious issue? In any case, I'd rather try and maintain point source performance in the mids-highs and suffer ultimate HF response or another x-over(BMS 4590/4592) to deal with, instead of going with a third point source per side - apart from one or more subs perhaps.

It's not that I'm oblivious to other very important aspects of the horns and waveguides themselves, but the horns from Auto-tech(as I'm sure others; also the ones that've been an inspiration to AT) seem to be able to "bridge" some of my concerns into actual solutions, which has then re-directed my focus to the drivers.

I'd very much like to hear of the experience from others in this regard!
 
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Crossover for SEOS-10 Flatpack ready for voicing. Time to make large Flatpack (JBL Everest style) for 1.4" drivers.
 

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In a nutshell (DE250+10CL51+SEOS-10 Flatpack) - reference mid and highs, perfect blend, high sensitivity, bright airy powerful but no sibilance, requires sub (Rythmik?). I want one :)

Wow, sounds great :) Sonic impressions compared to Mumia 2 and Universe coax.? What will cost relative to Mumia be?

Perhaps a stupid question, but what does "Flatpack" refer to? Are there serious plans to make the larger "Flatpack" version you mentioned above?
 
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SEOS-10 Flatpack:

http://www.diyaudio.com/forums/group-buys/166312-waveguides-horns-101.html#post2939927

made out of solid surface, as a kit for self assembly initiated by Erich (diysoundgroup). Cost unknown yet as it's prototype but for masses so keept low. Larger will come later.

Ok, thanks.

What drivers(size, etc.) are thought to be used in the larger version - twin 15" per side as in the Everest?! Unless of course you're referring to the JBL K2's, which comprises one 15" :)

But, a great concept/initiative! I'm definately very curious about info on the larger version as well...
 
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Depends how big the back you want :) a pair of Sonido SCW300 (10cuft), Beyma 12BR100 (5cuft) or any low power BC, 18 sound, Eminence etc.

Well, bring it on - 15 inches would be appreciated as well(EDIT: oh, you speak of pairs!!) :) The Beyma 12B100/R looks to be very appealing, speaking of 12" inch units, and then imagine two of them - my god, what a bliss...
 
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A little play with Acourate. SEOS-15+4538 equalized to 20deg (EQ filter not shown) versus ejmlc-600 + DE250 (EQ filter shown) equalized to 0 deg in a range 600-16800Hz.

Hello Jack,

http://www.diyaudio.com/forums/atta...d1332454599-waveguides-horns-ejmlc-600-eq.gif

ejmlc-600 + DE250 (EQ filter shown) equalized to 0 deg in a range 600-16800Hz.

to be compared with the optimum frequency responses curves for stereophony defined by Earl Geddes in his paper on directivity :

http://www.gedlee.com/downloads/directivity.pdf

see figure N° 11

Here attached figure 11 (from that paper, copyright Earl Geddes)


Best regards from Paris, France

Jean-Michel Le Cléac'h
 

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Jean-Michel

I think that you are taking my data a out of context. The lower figure in yours (the room/speaker layout) has nothing to do with the main figure, the two are describing different things, but you are linking them together. The curve that you show is not "optimal" in the sense of "desired" (I will admit to using the wrong words in my paper - I will correct that) but they are examples of what should be expected given some physical limitations of acoustics being described - namely that the lower frequyencies cannot have directivity but the higher frequencies always will. Hence, the purpose of figure 11 was not to show the "ideal" but to show what is likely to happen.

Thanks for pointing this out as rereading the paper this section could easily be misinterpreted as you have just shown. I will correct it shortly. To represent what you are trying to say they do represent, the curves should be much closer together and flat not curving downward.
 
Hello Earl,

I remember that several authors (Keele being on of them I think) admitted that in the case of conventional loudspeakers (not CD designs) such limited increase in directivity and such orientation of the loudspeaker axis is benefitial to a wider spread of the listening area and to a better sterophony.

Best regards,

Jean-Michel Le Cléac'h