The Radian and the TD-4001 have comparably good distortion performance, the Radian driver geometry is just incompatible with the Yuichi horn.
Here is an on axis (7cm away) near field response measurement of the TD-4001 on a Yuichi A-290 with (red) and without (green) EQ. The EQ I settled on by ear when measured seemed quite reasonable. EQ: DIP 1.38kHz -1.9dB Q1, HF Shelf (6dB/oct) 4.02kHz +1.8dB. Measurement range 200Hz - 22kHz
In the application am crossing at 607Hz and 7..97kHz(not shown here)
THD at 80dBspl:
I think the Athos Yuichi A-290 is a very high quality clone and would recommend it with a compatible driver. The driver I would recommend not too surprisingly would be the TAD TD-4001.
I am not sure how representative my 2440 with 2441 diaphragms are, but the response and phase/impedance measurements indicate that these drivers are compatible. I find the distortion performance quite objectionable, but my JBL drivers may not be at all representative. (Perhaps they need to be remagnetized, or modern diaphragms from Radian fitted for better performance - for now I don't have an answer, and probably won't for a while.
The Radian NEO950PB is a good driver, it just is a complete mismatch to this horn. It easily outperformed the 2440 on a 2380A, and like the TD-4001 is a very low distortion driver. Probably ideal on a wave guide or something like the Eminence H2EA horn.
I understand that the Radian NEO745 and 18Sound ND3N are good matches with an adaptor. I have no experience with either of these drivers. If they work as well as claimed they are a cost effective alternative to the TD-4001. Once you start talking BE diaphragms acquiring TD-4001 makes more sense IMO.
Thank you to everyone who has helped me to figure out how to make these horns work in my system and meet my expectations.
I'm not done (When am I ever? 😈 ) but at least I seem to be on the right track finally.
I will post more data (phase/impedance measurements, etc.) in the coming days.
Here is an on axis (7cm away) near field response measurement of the TD-4001 on a Yuichi A-290 with (red) and without (green) EQ. The EQ I settled on by ear when measured seemed quite reasonable. EQ: DIP 1.38kHz -1.9dB Q1, HF Shelf (6dB/oct) 4.02kHz +1.8dB. Measurement range 200Hz - 22kHz
In the application am crossing at 607Hz and 7..97kHz(not shown here)
THD at 80dBspl:
I think the Athos Yuichi A-290 is a very high quality clone and would recommend it with a compatible driver. The driver I would recommend not too surprisingly would be the TAD TD-4001.
I am not sure how representative my 2440 with 2441 diaphragms are, but the response and phase/impedance measurements indicate that these drivers are compatible. I find the distortion performance quite objectionable, but my JBL drivers may not be at all representative. (Perhaps they need to be remagnetized, or modern diaphragms from Radian fitted for better performance - for now I don't have an answer, and probably won't for a while.
The Radian NEO950PB is a good driver, it just is a complete mismatch to this horn. It easily outperformed the 2440 on a 2380A, and like the TD-4001 is a very low distortion driver. Probably ideal on a wave guide or something like the Eminence H2EA horn.
I understand that the Radian NEO745 and 18Sound ND3N are good matches with an adaptor. I have no experience with either of these drivers. If they work as well as claimed they are a cost effective alternative to the TD-4001. Once you start talking BE diaphragms acquiring TD-4001 makes more sense IMO.
Thank you to everyone who has helped me to figure out how to make these horns work in my system and meet my expectations.
I'm not done (When am I ever? 😈 ) but at least I seem to be on the right track finally.
I will post more data (phase/impedance measurements, etc.) in the coming days.
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That is what you might expert but it is very gentle, I get a smooth throat at the expence of a slight discontinuity.
I sort of form the wavefront before entering the actual horn and the oswg curvature is not far off exponential area expansion in the beginning when the other plane is not expanding.
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Hi, do I understand correct that you use a super tweeter with the TD-4001? If so, why? What I have read about the TD-4001 it does not really need a ST and you could profit of the real advantage of a 2 way setup.
The system architecture is 3 way and wasn't designed for 2 way operation. The HF10AK/STH100 has better performance above 10kHz or so than the Yuichi, but this is largely irrelevant since my hearing does not extend very far into the top octave. It is also the case that having the tweeter significantly complicates acoustical integration.
This is probably something I will investigate further in the future.
For now I need to identify and fix some room and speaker placement issues. No question that there is too much stuff in here and I am looking again for highly reflective surfaces to treat or remove. My EE lab and machine shop share the same space unfortunately, acoustically speaking the space is an acoustical nightmare. Treatment has made a huge difference, but I believe some additional if painful improvement is possible. Is it necessary? I am not quite sure. Generally one knows these things in retrospect.
The TD-4001 has solved both my subjective and objective issues, it sounds and measures far better on the Yuichi than anything I have encountered in my admittedly limited travels.
This is probably something I will investigate further in the future.
For now I need to identify and fix some room and speaker placement issues. No question that there is too much stuff in here and I am looking again for highly reflective surfaces to treat or remove. My EE lab and machine shop share the same space unfortunately, acoustically speaking the space is an acoustical nightmare. Treatment has made a huge difference, but I believe some additional if painful improvement is possible. Is it necessary? I am not quite sure. Generally one knows these things in retrospect.
The TD-4001 has solved both my subjective and objective issues, it sounds and measures far better on the Yuichi than anything I have encountered in my admittedly limited travels.
@docali
Horn loading starts right around 300 - 320Hz as predicted by Yuichi. Impedance measurement below 200Hz is ~Re. Impedance varies between 10 - 20 ohms over the pass band. Recommended operating range is => 600Hz, I cross at 607Hz. Phase shift over the operating range is ~30°
Driver # 1 on Yuichi A-290
The other driver is very similar, what appears to be break up at around 18kHz occurs at about 20kHz in the other driver otherwise they are virtually identical.
Horn loading starts right around 300 - 320Hz as predicted by Yuichi. Impedance measurement below 200Hz is ~Re. Impedance varies between 10 - 20 ohms over the pass band. Recommended operating range is => 600Hz, I cross at 607Hz. Phase shift over the operating range is ~30°
Driver # 1 on Yuichi A-290
The other driver is very similar, what appears to be break up at around 18kHz occurs at about 20kHz in the other driver otherwise they are virtually identical.
Kevin, thanks for the measurements and the subjective report on the sonics. Makes me feel good I have both Athos Audio Yuichi A290 and Azurahorn AH425 horns ready to use. It's only a matter of selecting the appropriate compression driver, and it's good to know the TAD TD-4001 is still in production.
Lynn, to my knowledge The TD-4001 hasn't been in production for more than 30 years.
I find JBL 2441 & 2450 with Truextent Be to offer very similar performance for potentially alot less money. I sold my 4001's and kept the two aforementioned.
There are quite many different JBL designs. What is the difference between JBL 2441 and 2450? There is another model I found 2451 1.5" which looks similar to 2450. Is it possible that 2450 is a 2451 with adapter?
Hi @docali, JBL incorporated the coherent wave phase plug from 2446 and on. 2450 has this as well. Other than that they are very similar.
JBL 2451 is mostly the same as 2450SL, both neo, same phase plug, 1.5" exit but with a different/odd bolt pattern on the 2451.
2450SL is a 2450 (2" exit) with snout removed.
JBL 2451 is mostly the same as 2450SL, both neo, same phase plug, 1.5" exit but with a different/odd bolt pattern on the 2451.
2450SL is a 2450 (2" exit) with snout removed.
It’s still listed on their website In the professional section. And somewhere recently I’ve seen prices for new ones. They are $$$$$$
Listed doesn't mean it's in production. It isn't. New ones simply means NOS.
Their most recent driver, the TD-4003 was also discontinued a long time ago.
I might sell my TAD 4001 pair since i like the 2451Be better 🙂
I only have one Be diaphragm though since i had my most expensive drop on the floor when i was shifting phrams to test the Radian 1292. Otherwise they are in excellent condition and was re-charged about 6 years ago.
Were you in contact with TAD HQ in Japan or proaudiodesign (US distributor)?
I find it very hard to believe that TAD resumed production of a driver that has been discontinued for more than 30 years, and replaced by two newer and better designs. If they resumed production of TD-4003, that would make alot more sense..
I didn't disagree with you if you see my last comment on the matter.
Since I was not about to order a new set of drivers, I did not ask them directly. I made the assumption, perhaps mistakenly, based on their pages stating that they were still in production, and given that you can still order them directly on the proaudiodesign webpage.
My information came from this page: https://www.technicalaudiodevices.com/pro-hf-units/ Current copyright on the page is 2023
No problem @kevinkr, I have no real interest in the TAD drivers, just found it curious 🙂
But if there is a very high demand for these drivers, maybe they have resumed production.
I just sent an email to TAD Japan to see if they can clarify the situation, I will post my findings if they get back to me.
But if there is a very high demand for these drivers, maybe they have resumed production.
I just sent an email to TAD Japan to see if they can clarify the situation, I will post my findings if they get back to me.