Thanks, but I can take the knocks upside the head; I feel it but it's nothing that I haven't had from others here and at other forums. What matters is how much I've learned from Art, Camplo, Docali, Marco, Ro808, Robh3606, Lynn Olson, Gary Dahl, et al. As long as I learn enough to return to ask intelligent questions I invariably learn more from their replies.
But IF the horn you describe is a "circular" horn-and if it's geometries are identical with this horn https://josephcrowe.com/blogs/news/circular-horn-no-1689 , then how might you account for Troy Crowe's very favorable conclusions?
Referring to the sketch of my below or my room, is my room too small to use with CD horns because those horns-unlike the JMLC AH425-would create too many reflections which could mask details and deform the timbre of sound, even if it could deliver some kind of appreciated "spaciousness"?,
By constant directivity horn system, you mean like Robh36306 prefers, or horns like these?
https://audiohorn.net/x-shape-horn/
https://audiohorn.net/next-gen-bi-radial-horn/
https://www.bcspeakers.com/en/products/horn/1-4/0/ME464
https://www.limmerhorns.de/292/
Everything does, and it's not a reflection on quality. Specifically, it's unlikely everything will be where it should since so many factors are involved in a system, even when using perfect and expensive devices.
There's the chance people will reject a good system because they can't find the right EQ. It becomes very difficult (impossible, actually) when there are unresolved acoustic issues in a room/speaker combination.
Furthermore there are some that may not see the need to EQ or reject the idea because they feel EQing is a sign of unresolvable problems.
This is a significant reason to be wary of online reviews. (This post is not aimed at anyone in particular.)
The -6dB downward sloping response of the AH425/Radian745Be is easily corrected to flat with a single capacitor and resistor.
Later, Gary switched to the JA6681B drivers, but finding them soft in the high end, added RAAL ribbon tweeters.
Then in 2018, he indicated he hadn't yet found a supertweeter implementation that extends the top end without other penalties:
I'd guess he preferred the "soft highs" to the convincing string sound.
IIRC, his listening position was ~2 feet from a back wall, 12 feet from the horns, too far a distance, but dictated by a very large screen.
I find the hard wall reflections from a horn at that distance from a wall that close to sound terrible.
30 iterations may be a "drop in the bucket" for some DIyers.
Trying to tweak a response so someone else would describe it as "smooth and relaxed" could take more attempts.
Assuming both sets of horns are equalized to meet your preferred on axis response, if you choose a listening position that offers symmetrical reflections, the only change required might be the toe-in angle, to give you different amounts of "spaciousness" the reflections impart.
Wall positions that are obvious to you in the two sketchs are not to me, and your written explanations don't substitute for a floor plan that visually depicts them.
Your room walls will react to high frequency sound waves similar to a shining a light at a mirror, the angle of the reflected waves are equal to the incident ray:
Non-symmetrical reflections will distort the sense of space present in the recording and make localization cues amorphous.
Have fun listening,
Good luck!
Art
Attachments
That was a much earlier issue which Gary had obviously corrected when he designed the crossover. [/QUOTE].
Gary-and Martin Seddon, who also used the Yamahas for some time https://www.azurahorn.com/JA6681B on 425 Horn (2).pdf admitted that they roll off quickly after 10kHz. But as they found tweeter compatibility and placement of a tweeter impossible with the Yamaha/AH425 combo, Gary obviously chose not to discard the Yamahas, given their ability to do everything else superbly, and so Gary settled on their less than extended HF range in a two-way system.
Aren't you taking things just a bit out of context? What Gary ultimately found intolerable some years later about the Radians were other HF response irregularities-and, according to Gary, other design features about that driver, which perhaps even you couldn't fix? Here's the missing text you omitted from that same post of Gary's.
"Beryllium certainly has advantages as a diaphragm material, but other factors seem to come into play as well - surround, phase plug, etc. The Radian 745Neo becomes less flat when equipped with a beryllium diaphragm. I did as much as I could to tame its response in the crossover. Strings ended up sounding quite good, but there was still an element of hardness that had been present in every implementation of a compression driver that I had ever heard up to that point." https://www.diyaudio.com/community/threads/compression-driver-impedance-question.318749/post-5352494
In which case Troy might decline to use my 745Bes to build any horn/driver combo.
Could a much more easily achievable but equally satisfying EQ target be be at least one reason why Marco prefers the JBL2450J +Be over the Radian745 Bes?
And yet Gary's present day AH425/Yamaha combo system https://galibierdesign.com/wp-content/uploads/wa-trip_gary-d.jpg appears to be in the same location as it was with the Radians, though apparently very pleased with the changed sound, which he fully attributes to the Yamahas. These were his first pair of 425s which he used with the Radians and which he had painted black. http://i190.photobucket.com/albums/z179/paukenspieler/IMG_3087_zpse3b0ffd5.jpg
If I place the speaker diagonally-with the left side of left speaker opposite the east wall and right side right speaker opposite the absent west wall but some distance from the left side of the fridge and/or from the front of the kitchen counter peninsula, without a visually complete floor plan, can you usefully speculate at all on likelihood of satisfying results from such placement?
🤦♂️Of course, and along with aural observations, I would hope to learn how to use the right software and test signals to measure how effectively that would work.
Okay, I had my listening session the 2095 speakers yesterday afternoon, which despite a software driver glitch went as planned. Took notes on the experience, of course.
Next up: Hoping for invites to hear constant directivity horn speakers and/or JMLC AH425 horn speakers compatible with a ~ 23 ft x 14 room. Can travel up to 175 miles from NYC. RSVP for a listening session set for no later than April 25th. Thank you.
Next up: Hoping for invites to hear constant directivity horn speakers and/or JMLC AH425 horn speakers compatible with a ~ 23 ft x 14 room. Can travel up to 175 miles from NYC. RSVP for a listening session set for no later than April 25th. Thank you.
Can't imagine an enclosed space with an "absent west wall", so can't usefully speculate at all about acoustic results.
Visual observations can be informative too.
For instance, in this photo you linked in post #667, there is a tweeter screwed to the crossover to the right of the AH425 horn.
At the position the photo was taken from, directly in line with the rug perpendicular to the video screen, half of the tweeter's direct output is blocked, and a significant portion of it's output is directed to the back of the AH425 horn.
The throat of the AH425 is clearly visible, it's high frequency response is unobsructed.
Can't tell from the photo whether the back of the AH425 is acoustically treated or reflective, which would make quite a difference in any sound heard from the tweeter over that of the horn.
If you were to measure from between the photographer's and the AH425 axis, you would find a series of peaks and dips in the response in the acoustical crossover region between the AH425 and tweeter as it goes in and out of phase due to the path length difference.
The choice of a laterally offset tweeter position insures that response can only match a target in one position in the room.
Anyway, every system design choice has acoustical consequence, individuals are free to choose which aspects they give most weight.
Art
It is less flat for two reasons. The Be diaphragm has a higher midband sensitivity so there will be a more pronounced 'hump' before the mass breakpoint.
The Be diaphragm is well damped, and the breakup is almost an octave higher.
While the AL diaphragm, judging by the impdeance curves found and physics, is having a secondaty resonance 10-12khz ish"extending" the respone further.
Look in the referenced old JBL sheet for explanation.
Easily achieveable ? no.
There is also a lot of 'dropoff' in the 2450's equipped with a Truextent diaphragm too.
The 2450s is distinguished by the 2450H and the 1,5" exit variants.
The 2450H internal thoat means it fits the same horns as the coveted TAD's 4001/" also, so if fits a lot of the wooden horn designs, diy and different mfgs.
the 1,5" exit 245x fits a multitude of JBL horns/wvaeguides, some diy options, and other throatless 1,5" exit horns like from DAS for the ND/K drivers etc.
Look here from 50mins on, it shows fairly well how a compression driver can be challenging to make a filter for, for many diyers depending on knowledge and equipment available. Because simple textbook crossover does not work well at all, also some info to suck up on how to fairly quickly make design iterations of different crossovers:
I think there is one big question that you have skipped straight past.
Which driver is the AH425 designed for?
The AH webpage shows it with a JA6681B, and if it is made to fit that driver.
The JA 6681B look very well behaved and easy to xo on that horn.
You will have hf irregularities with the 745 due to the difference in throat design.
It cannot physically fit both drivers.
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IIRC from other posts here, Gary said he only had partial to no consistent success integrating those RAAL Lazy ribbon tweeters with the Radians, before and/or after failing to improve the HF response. Nor do I recall him happily using them successfully with the Yamahas. Perhaps he only thereafter kept the tweeters there for show or to later motivate himself to sell or use them to build another speaker?
However, despite Gary’s failed attempts, would you be certain that those RAAL tweeters, or some kind of AMT-or perhaps as Lynn Olson, Duke Le Juene and James Romeyn once proposed, a rear firing tweeter array-could work with the AH425, if properly designed and placed? https://jamesromeyn.com/speakers/space-generators/bighorn-space-generator/
These are the only other photos I could find; https://www.diyaudio.com/community/threads/beyond-the-ariel.100392/page-678#post-4436268
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What these people have in common is they've tried these things. I don't blame you for thinking present company could know certain things if you, as you say are trying to find the answer without taking the intermediate steps.
If I've learned something it's that if you seek the ultimate answer, you shall receive it.. and it shall be known as "42".
QUOTE="weltersys, post: 7968266, member: 76639"] As you can (and should) see in the very similar polar charts of horns like your AH425, they are just as "completely free and devoid of any coloration or resonances that may harm sound quality."
The larger AH425 has control of it's coverage pattern to a lower frequency than Crowe's horn #1689.
[/QUOTE]
So, zero problems with the AH425 integrating with the Altec 416 midwoofers? Note here that compared to his prior use of the 425s, Pierre said of the TH4001 horn, “By virtue of its low profile, the sectoral horn allows positioning the two drivers closer together.”
The larger AH425 has control of it's coverage pattern to a lower frequency than Crowe's horn #1689.
[/QUOTE]
So, zero problems with the AH425 integrating with the Altec 416 midwoofers? Note here that compared to his prior use of the 425s, Pierre said of the TH4001 horn, “By virtue of its low profile, the sectoral horn allows positioning the two drivers closer together.”
So, zero problems with the AH425 integrating with the Altec 416 midwoofers? Note here that compared to his prior use of the 425s, Pierre said of the TH4001 horn, “By virtue of its low profile, the sectoral horn allows positioning the two drivers closer together.”
How can anyone answer these inane questions?
I would guess whatever you decide (if you can decide) there will be problems. You cannot outsource a diy project to a forum chat, gotta get your hands dirty.
It's all a giant compromise; You experiment so you learn what compromises you prefer.
Sorry, not sorry for the bluntness.