Looks like a complex tree of options oltos. I can't be of much help except to say I've been running the SB Audience Rosso 65CDN-T CDs with Troys 3d printed rear covers, and they hit 600 hz with no problem in my Azura 425s and have excellent treble extension. More importantly, they sound really good, beautiful, natural tone. Wouldn't hesitate to use them again, they're a bargain.
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Wish I could find someone who's used them in the TH4001 horn, but probably won't if a throat adapter is needed.
This looks like one of those statements that a competent DIYer would avoid using because it exceeds it's own authority.
What does it mean.. Can you simply EQ anything and call it uncoloured? Is a person trying to imply certain spatial characteristics? ..certain timing characteristics?
Again, I'm only the messenger:
"ES Biradial technology has virtually zero acoustical resonances which makes it devoid of any horn coloration. This unlocks the true sound quality potential of your compression driver, providing audiophile sound quality that is free from honkiness, shout, and harshness. "
Source: https://josephcrowe.com/products/3d...3-es450-biradial-for-sb-audience-65cdn-t-1-40
"...........What is left is an clean and transparent sound that is free from any horn colorations......"
Source: https://josephcrowe.com/products/es-290-biradial-wood-horn
In theory, if I make a recording of myself banging on a frying pan with a serving spoon, then equalise it completely flat, don't I also remove all resonance?
Again, I’m hardly the one to expect a sufficiently technical and useful answer to ask that theoretical question, or a practical one, though I’m quite certain that equalizing the Radian Be driver/TH4001 horn combo to yield a smooth response within some band is how Pierre was obviously able to achieve a very sizable amount of “discoloration”. But what procedures he undertook to do so I know nothing of.
As for why Troy’s ES horns have virtually zero acoustical resonances, and thereby making them devoid of any horn coloration, you’d have to ask him.
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Any horn could have a number of unique properties a person might want to question, features that might, or perhaps under certain circumstances produce audible consequences.
Oltos, regarding the decisions about horns to go with the Altec 416 Woofer, I don't really understand the options as you've presented them or how they are framed as different expressions of trade-off in horn and driver selection.
First, Lynn, Pierre, and yourself have expressed attraction to the SB Audience CDN-65T. Lynn says this 1.4" driver has remarkable extension to 17k. I would think that this choice would reflect a fundamental decision to move Xover point higher to take advantage of the HF extension of 1.4" drivers. But then you mention you want to use a 2" driver B&E DCM50 and a Fostex 900A supertweeter on Troy's 450.
This really looks like a comparison of apples to oranges to bananas to find the best orange.
If you stick with the SB Audience CDN-65T, you could use Troy's 600 and you'd get good HF extension and a smaller horn will give you better HF directivity or wider dispersion than a larger horn, all things considered. Notice Troy reviewed the 18Sound1480Be on his ES600. Both the SB and 18Sound 1.4" drivers give up the ghost at 500hz and the ES600 does not cut these off prematurely. If HF directivity and extension is your primary concern, this might be a good way to go.
Or, you could take a different tack and try to pull the Xover down lower than 700 hz using a larger horn a 450 or a 290, also mentioned by Lynn. This might allow you to use a simple first order Xover low enough to avoid the 426 peak at 1.5k. No notch required. The DCM50 could do this, although a lot of the drivers in this series give up around 400 hz. This is really the key decision and there's no free lunch. Ultimately, you either get LF extension or HF extension, except in the rare case of some 1.4" that seam to do both. And, the size of the horn will determine directivity much more than brand X or Y of biradial horn design.
You can also decide that you just don't care about HF above 13k or so, as we can't hear it, then you can compare response and directivity just in the audible range and save yourself a whole bucket load of trouble. The DCM50 is very flat in this range.
But first I think you really need to decide your Xover strategy and then make decisions from that instead of trying to let brand X or brand Y biradial horn decide things for you.
First, Lynn, Pierre, and yourself have expressed attraction to the SB Audience CDN-65T. Lynn says this 1.4" driver has remarkable extension to 17k. I would think that this choice would reflect a fundamental decision to move Xover point higher to take advantage of the HF extension of 1.4" drivers. But then you mention you want to use a 2" driver B&E DCM50 and a Fostex 900A supertweeter on Troy's 450.
This really looks like a comparison of apples to oranges to bananas to find the best orange.
If you stick with the SB Audience CDN-65T, you could use Troy's 600 and you'd get good HF extension and a smaller horn will give you better HF directivity or wider dispersion than a larger horn, all things considered. Notice Troy reviewed the 18Sound1480Be on his ES600. Both the SB and 18Sound 1.4" drivers give up the ghost at 500hz and the ES600 does not cut these off prematurely. If HF directivity and extension is your primary concern, this might be a good way to go.
Or, you could take a different tack and try to pull the Xover down lower than 700 hz using a larger horn a 450 or a 290, also mentioned by Lynn. This might allow you to use a simple first order Xover low enough to avoid the 426 peak at 1.5k. No notch required. The DCM50 could do this, although a lot of the drivers in this series give up around 400 hz. This is really the key decision and there's no free lunch. Ultimately, you either get LF extension or HF extension, except in the rare case of some 1.4" that seam to do both. And, the size of the horn will determine directivity much more than brand X or Y of biradial horn design.
You can also decide that you just don't care about HF above 13k or so, as we can't hear it, then you can compare response and directivity just in the audible range and save yourself a whole bucket load of trouble. The DCM50 is very flat in this range.
But first I think you really need to decide your Xover strategy and then make decisions from that instead of trying to let brand X or brand Y biradial horn decide things for you.
A lot to think aou
of uneasy about doing this but it’s the right time to add that there’s one more driver option in the mix. https://www.usspeaker.com/radian 745neoBepb-1.htm I have a NOS pair. But the only way I would know how to proceed is
to either sell them at whatever loss-which I'm also reluctant to do as beryllium drivers, if precisely implemented, can yield
extremely detailed yet smooth, non-fatiguing performance-or use them in a two or three way. So, I knew that I ought to put this out here for your feedback on that as well.
Meanwhile, lots to ponder among these options, and then weighing them against pursuit of what Pierre and Camplo
would call direct sound presentation, though which Camplo recently explained that I can get much closer to by sufficiently dampening the room.
A lot I need to think about here but am deeply grateful for this invaluable advice and description of options. I’m sort
of uneasy about doing this but it’s the right time to add that there’s one more driver option in the mix. https://www.usspeaker.com/radian 745neoBepb-1.htm I have a NOS pair. But the only way I would know how to proceed is
to either sell them at whatever loss-which I'm also reluctant to do as beryllium drivers, if precisely implemented, can yield
extremely detailed yet smooth, non-fatiguing performance-or use them in a two or three way. So, I knew that I ought to put this out here for your feedback on that as well.
Meanwhile, lots to ponder among these options, and then weighing them against pursuit of what Pierre and Camplo
would call direct sound presentation, though which Camplo recently explained that I can get much closer to by sufficiently dampening the room.
All horn and driver combo's are not created equal. You need a measurement on your chosen horn. If you are going to use JC ES horns and he has your cabinets send him the drivers and ask f he can test them for you to see what you get.
Rob 🙂
During some of the intense evaluations of drivers and horns, I think several people were really impressed by the Radian Be and I think this is one of the key ingredients for legendary reputation of the TAD drivers. I’ve never been able to even see the Radian Be as available for sale. I have no real direct experience, but boy, I think I’d start with that. I’m not even sure you can put a price on it unless production of Be is back up. Troy can certainly recommend his best horn for it.
Regarding imaging, soundstage, etc. I don’t think you’ll ever find a way to differentiate your choices that way. You’ll end up with some options that only have 2nd hand subjective reports and most likely you won’t find a single person who’s compared your final options side by side and instead you’ll be trying to make an intuitive leap between two different observers. It’s not the subjectivity that’s the problem, it’s the lack of credible observations side by side with the same driver, Xover, etc.
I think, but can’t validate, that in general for imaging you need a coherent and clean pattern of dispersion or directivity AND a smooth and artifact free response. I think all of the horns you are considering have a fairly similar polar pattern that is known to provide good results. I think the differences are going to come from the drivers, throat designs and diffraction effects. Jean Michelle Le Cleach inspired a focus on mouth termination and it’s impact on mouth diffraction and impedance ripple effects. Geddes has emphasized driver exit geometry and throat transitions as possible sources of HOM distortion. He also said the actual driver didn’t matter so much, so there that.
I’m not saying it’s a way to make a decision, but it’s a school of thought. The more modern horn designs and Troys designs in particular fully embrace all of the research done by Jean Michelle and Geddes. You won’t find any sharp geometry, inside or out. You can see the response measurements, distortion and directivity. I don’t know if the benefits of the dip Geddes throats and Le Cleach mouth flare can be seen in the measurements, so you might have to embrace or disregard the philosophy of that.
Anyway, that’s all to suggest that if things like resonances, distortion or HOMs appear in the response and cause problems with imaging or special queues (leaving open the question of whether a firm grip on stereo image is a good thing) then you might try to select drivers and horns that have the least of those artifacts, assuming the best spatial reproduction will result. You can nail most of those artifacts down in measurement.
And, all of that is probably entirely useless. Thanks for letting me think out loud.
I will just say, I am currently most interested in multi-cells which may have a lot of problems, but I am currently not very enthusiastic about conventional stereo imaging. I want to see what it would be like to have 4 to 9k truly done 90 degrees or more horizontal. My listening room just isn’t big enough I think to let typical horns breathe.
Regarding imaging, soundstage, etc. I don’t think you’ll ever find a way to differentiate your choices that way. You’ll end up with some options that only have 2nd hand subjective reports and most likely you won’t find a single person who’s compared your final options side by side and instead you’ll be trying to make an intuitive leap between two different observers. It’s not the subjectivity that’s the problem, it’s the lack of credible observations side by side with the same driver, Xover, etc.
I think, but can’t validate, that in general for imaging you need a coherent and clean pattern of dispersion or directivity AND a smooth and artifact free response. I think all of the horns you are considering have a fairly similar polar pattern that is known to provide good results. I think the differences are going to come from the drivers, throat designs and diffraction effects. Jean Michelle Le Cleach inspired a focus on mouth termination and it’s impact on mouth diffraction and impedance ripple effects. Geddes has emphasized driver exit geometry and throat transitions as possible sources of HOM distortion. He also said the actual driver didn’t matter so much, so there that.
I’m not saying it’s a way to make a decision, but it’s a school of thought. The more modern horn designs and Troys designs in particular fully embrace all of the research done by Jean Michelle and Geddes. You won’t find any sharp geometry, inside or out. You can see the response measurements, distortion and directivity. I don’t know if the benefits of the dip Geddes throats and Le Cleach mouth flare can be seen in the measurements, so you might have to embrace or disregard the philosophy of that.
Anyway, that’s all to suggest that if things like resonances, distortion or HOMs appear in the response and cause problems with imaging or special queues (leaving open the question of whether a firm grip on stereo image is a good thing) then you might try to select drivers and horns that have the least of those artifacts, assuming the best spatial reproduction will result. You can nail most of those artifacts down in measurement.
And, all of that is probably entirely useless. Thanks for letting me think out loud.
I will just say, I am currently most interested in multi-cells which may have a lot of problems, but I am currently not very enthusiastic about conventional stereo imaging. I want to see what it would be like to have 4 to 9k truly done 90 degrees or more horizontal. My listening room just isn’t big enough I think to let typical horns breathe.
FWIW. I use the Radian 745 Neo Alum version on my 425 hz. Azurahorn. See the response below. This curve looks very much like the factory curve in the LF. I'm seeing it about 3 to 4 db down at about 600 hz. The factory shows 500 hz is about 10 db down, but I'm only about 6 db. down. This is where my knowledge also ends abruptly. I don't really know what this means for the Xover. If we say 500 hz is the cutoff, conventional wisdom might say we'd Xover at 1.5 or 2 times that or 750 to 1,000.
There's no problem with the horn hear, but the Altec 416 is still quite energetic at 1,500 hz. with a 700 hz. 1st Order Xover. I think this is why Lynn asked Troy for a notch filter. See enclosed, Altec 416 in green with 700hz first order.
So, really, at first blush from this, and in my current incompetent building, I think the woofer is doing a lot more damage to imaging, etc. than anything from the horn. Not from beaming, but breakup, etc. I'm using a Hypex FA123, so I can use steeper slopes easily, but I'd rather not, although damn if I can construct an A B test where I can hear the difference.
I think you'll find some of the old guys, the one's who've tried everything, really like to get the Xover down to 300 hz. ish, if they can for this reason. Coaxials anyone?
There's no problem with the horn hear, but the Altec 416 is still quite energetic at 1,500 hz. with a 700 hz. 1st Order Xover. I think this is why Lynn asked Troy for a notch filter. See enclosed, Altec 416 in green with 700hz first order.
So, really, at first blush from this, and in my current incompetent building, I think the woofer is doing a lot more damage to imaging, etc. than anything from the horn. Not from beaming, but breakup, etc. I'm using a Hypex FA123, so I can use steeper slopes easily, but I'd rather not, although damn if I can construct an A B test where I can hear the difference.
I think you'll find some of the old guys, the one's who've tried everything, really like to get the Xover down to 300 hz. ish, if they can for this reason. Coaxials anyone?
Attachments
About the SBAudience CDNT, in his review of this driver Troy Crowe said it would be suitable for a two-way system. But if you added the 6” Azurahorn and the Faital HF10AK how did things change? More smoothness, detail, tonality, airiness (?), larger sound stage and/or other benefits?
Still struggling to amass knowledge boosts to better aide in horn selection, spending time here towards that end.
https://www.diyaudio.com/community/...001-clones-makers.375215/page-10#post-7799142
Those criticisms, design schemes and performance goals, often hotly debated, are largely unintelligible to me are likely due equally to my numerous knowledge gaps and their language proficiency.
But among the most knowledgeable and DIY experienced there, even dummies can conclude that there remains a strong love/hate thing with the A290 horn; likewise regarding with the Crowe ES290 and ES450. AND now there’s NicoB’s forthcoming 2nd version of what seems a truly conceived version of the TH-4001 horn. https://audiohorn.net/next-gen-bi-radial-horn/
Indeed, some hackles remained raised for pages since I introduced it here.
https://www.diyaudio.com/community/...0-or-tad-th-4001-clones-makers.375215/page-15
I’m so hoping that if Nicolas’ NYC customer, now spending hearing this horn, really loves what he hears he may buy a pair and invite me for an audition before year’s end. How might it work (properly adapted for the Radian745Be?) atop my Altec 416 woofers?
https://josephcrowe.com/blogs/news/altec-416-8b-in-100l-sealed
Likewise, a chance to hear a system with the ES450/B&C DCM50 combo + Fostex T900A in Troy’s waveguide.
If only the A425s too! Hearing all three should clinch it for me!
There must certainly be ample measurements of the 425 on this and other threads.
https://www.diyaudio.com/community/threads/geddes-on-waveguides.103872/page-113
But while the proof is largely in the hearing, we await the series of critical plots from Nicolas and Troy.
How much I may have to trade one set of performance goals for another I wouldn’t know. Certainly, performance goals like smoothness, detail, vocal authority, tonality, HF airiness will be driver specific. But not all drivers will work well with all horns, and as the works of Marco-gea, Docali, Kevin-kr and Pierre Qui Roule show matching horns and drivers go well beyond just throat adaptation.
But beginning with the horn (either for midrange or a two-way design), and in my 2660 cu ft room with a high ceiling and sitting 11 ft from the speakers, ideally nothing that might resemble coloration, a wide and deep sound stage, superb off axis response and blends wonderfully with my woofers.
What am I forgetting? At least this: There’s a recognized, though perhaps somewhat more subjective characteristic, but chiefly determined I believe by a horn’s directivity index. That is, given a room which was reasonably well corrected acoustically, a high DI horn will produce a direct “You are There” sound. The presentation for the listener would be as if the walls and room size collapsed and/or radically changed because he's now transported to the recording venue. Conversely, with a low DI horn, producing an indirect “They are Here” sound, it's as if the musicians and vocalists were transported to the listener's room.
Camplo, here, is certainly better qualified than me to state this, but he also makes the same distinction; see post 190.
https://www.diyaudio.com/community/...001-clones-makers.375215/page-10#post-7799142
Would agree with Camplo on this?
Therefore, in which category the AH425?
People talk about this like it's a choice, and don't consider the real efforts put towards improving imaging. This suggests that much of it is repeated information. It is possible that you can hear both in a way that they are distinct, and not mixed up if it's done right.
Sure, loudspeaker directivity and the imaging produced by it is a choice. You can choose to build a low directivity design or a high directivity design (or anywhere in between). In the same room / same speaker enclosure with the same drivers / same in-room response, the difference between low and high directivity levels is pretty obvious.
A horn with consistent DI over it's usable range could fit into either "category", but you are forgetting that a horn like the AH425 increases from a DI under 3dB to over 10dB at high frequency so does not fit into a single category. It does have a smooth continuum of directivity change :
It's -6dB response is around 180 degrees wide at 500Hz, dropping to under 40 degrees at 10kHz, neither "here" nor "there", but it's "beaming" response on axis does nicely compensate for the falling upper response of the compression drivers typically used with it.
Radial horns are often designed for fairly uniform horizontal dispersion, with vertical response beaming, both "here" and "there".
If you want to choose between “You are There" or "They are Here" or something in between, chose a horn with a consistent DI over the range it's used, and EQ it's response as desired.
Art
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I've had the little horn on line for about 2 weeks, crossed at 5k, and I'm still dialing it in, but here are my impressions so far:
The two way with the Rosso CDN-T made beautiful sound, but with the AH-435 horn carrying the whole range from 600Hz through the treble and driven by tubes, it felt like the high end could use a little boost, since both of my tube amps roll off the high end a bit and I like more air and I'm a sixty year old carpenter. I can still hear to 12-13k by some miracle. I hooked the little horn with the HF10AK up to a very nice class D module that I put in the same box as the one driving the 15" Faital 15PR400, and rejigged the rear panel with the extra sets of XLRs and binding posts.
I think I've suffered a bit in imaging, but the extension and air are very exciting! I listen to a lot of jazz and love to hear everything the drummer is doing with cymbal taps, brushes, and very subtle stuff, and this setup has delivered exactly as I'd hoped. I haven't taken any measurements yet but when I tested the horns/CD's several weeks ago they were dead flat beyond 20k, that's an amazing driver. I mean ruler flat from 3-4k and up, crazy.
I think crossing at 5k might be taking away some of the imaging I had before, so I've just swapped in a 7k module to my Sublime active xover, and I'm hoping that handing more of the treble back to the Rossos will be more coherent and give me a bit more separation, we'll see. They're both very capable CDs in my opinion.
Yes nudging the cross between the two horns to 7k did the trick. With such relatively large baffles my system isn't an imaging monster in the HiFi sense, things are clearly separated but a bit more diffuse than my standmounts, but it sounds very natural. It's seems like a shame to have these wonderful drivers (HF10AK) and only be employing them from 7k, but they're giving me a LOT of air and beautiful clarity.