Beyond the Ariel

ra7

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Joined 2009
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I did a comparison of four 1" drivers, B&C DE250, BMS 4554, Radian 475PB, and DNA350 on a SEOS-18 horn over at avs:
1 inch CD Comparison (SEOS18)

The BMS 4550 and B&C DE250 were pretty good. I measured Erich's DNA350 thinking it was the DNA360 (hey, they don't have a label and look the same :)). I have since bought a pair of the DNA360s and they are identical to the DE250s. Measurements of the DNA360 should be up soon.

Anyway, the point is the Radian was pretty ragged. The graphs on Radian's website are super-smoothed and don't give an idea of what the real response looks like. The raggedness might well have been a mismatch between exit angles, but for the SEOS-18 at least, it was not the right driver.
 
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marco_gea,
I'm in agreement that a TAD ET-703 is a great driver but at the same time the price has gotten crazy. I bought a pair at one time from TAD for less than $500.00 so the profit margin is astronomical now. This is my target device with the beryllium dome tweeter I am working on building.

well ,when was it, 30 years ago ? I don't recall times when diaphragms for jbl drivers were cheaper than $150 each and you got a pair of cobalt magnet berylium drivers for less than $500:confused:
Et 703 makes sense only in tandem with other tad driver like 4001 , 2001 .
tad 2001 high frequency is not very interesting , some say 4001 is breaking in more elegant fashion than 2001 but 4001 upper mid is unbearable thats why it's a better idea to cross 2001 over 4001 and than ad et 703 to keep the sound uniform. Fostex t500mkIII will be a better choice in different configurations. It does have distinct warm coloration which is extremely pleasant but not quite neutral. Lowther in 200hz Azura gives instant gratifications , kills 90% of high end available in stores at any price and its easy to implement . Of course you need competent low end which is a subject on it's own :D
 
Limono,
I happened to know the TAD sales rep at the time and I am sure I didn't even pay $500.00 for the pair, that was the wholesale price at the time and this was for brand new drivers. There is a huge profit margin on their devices, they actually tried at one time to discontinue the entire line. A threat of a lawsuit ensued due to the installed professional studio base that was pissed they wouldn't have any replacement diaphragms. This is when they decided to keep the line going and massively increase the prices. That is why they cost what they do today, real story.

ps. Sold a system back then about 1993? with a 10" down firing driver, 8" front firing driver, 6 1/2" horn loaded mid, Tad 2001 and TAD ET-703 in Rosewood cabinets for $5,000 and made money! Times have changed haven't they!
 
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Below is what I got with a Radian 745pb on the Azurahorn AH-425, which I posted three years ago (!) in this thread. Still using the same combo. I would love to try the 745neo with Truextent beryllium diaphragms when they become available, but I'm afraid I'd have to pick the correct Lotto numbers.

Pictures of the project were posted on p. 707 (post 7067 and surrounding neighborhood).

Radian4.jpg
 

ra7

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Joined 2009
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Thanks for that, Gary! Can you show that on a 50db scale? There are some ripples beginning near 4 kHz, but quite smooth overall.

Also, do you have measurements of the finished system? It may have been posted earlier, but I don't recall ever seeing measurements of the finished system.
 
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ra7,

Sorry, that's the only curve I have of that combination. My measurement setup was used on an old laptop that isn't particularly healthy right now. The only driver comparison I did was with several samples of GPA 288's, which were quite a bit more ragged than the 745's.

I didn't save any full-system curves; never did I really consider the project "finished." Eventually I got burnt out and stopped working on further optimization. Lynn had been a huge help to me along the way, but without the opportunity to hear the results for himself, there were limits to what he could do. I decided to wait for Lynn to get his own project built, and try to benefit from his experience. He has accomplished quite a bit in the meantime. When he has it up and running, I'm hoping to have a listen, which will help me decide how to proceed on my own project.
 
jzagaja, yes, I still use 50Hz horns, now cut down to 1.7m length and with Vitavox K15/40 drivers, open backed. I find these to be much more in tune with the mid / upper horns - I don't hear any difference or join. ..................They do double bass or piano low notes really well. Not sure anything so uncontrolled could be called accurate, but I have stopped worrying and just enjoy them.

martin

Hi Martin
I've been looking back at your bass solution again & discussing with a couple of the UK guys.
Is this the same 'lighthouse' and wooden L-horn as before, but chopped down to a smaller mouth, or did you change the expansion to suit the Vitavox ?
What does the Vitavox do, that the PM2A didn't - as you were quite keen on the PM2A a couple of years ago ?
I must say I'm struggling with the Fane 8M's on 120Hz wooden horns - there doesn't seem to be much snap & transient definiton, I noted your comments a few pages back, about lighter-coned drivers and low-level detail .
 
Where are we on a release date for Lynn's new system? I don't want to start a new project for myself if his will be ready by New Years of 2014.

Some time this year, I plan to build cabinets using a pair of side-by-side GPA 416's (16 ohm Alnico version) and the existing Azurahorn AH425's and Radian 745Neo's (16 ohm).

The prototypes in Dallas, with slant fronts, a resistive slot vent in a 4.5 cubic foot cabinet, a single GPA 416 (16 ohm Alnico version) worked well. A 4th-order 700 Hz LR highpass for AH425 & Radian 745Neo, combined with a 3rd-order 700 Hz LR/Bessel lowpass for the GPA 416, provided very flat response.

In principle, most 15" woofers need a broad notch filter tuned to 1.5 kHz, but in practice, it didn't seem to make much difference. I was very surprised the AH425 & Radian 745Neo did not need any equalization at all ... I was quite ready to use a notch filter combined with an overall HF tilt filter.

Switching the high-performance large-format RAAL supertweeter in and out of circuit was more subtle than I expected; then again, there isn't that much content above 10 kHz, and the main task of a supertweeter is to not add HF debris and draw attention to itself. This is where the cheaper Fostex models fall down and the more expensive ones work exactly as they should and sonically disappear. A correctly operating supertweeter should be very subtle as it is switched in and out of circuit.

The supertweeter sounded better as a side branch in the HF circuit, benefiting from the 700 Hz highpass of the compression driver as well as the additional 2nd or 3rd-order highpass at 7 kHz for the supertweeter. Moral of the story, unwanted LF energy does not sound good in either a compression driver or a ribbon tweeter.

Additional thoughts: the attenuation of the HF section was more tricky than I thought it would be. Fixed-resistor L-pads did the job, but I didn't like the subjective impression of dynamic compression and tonal flattening that I heard. The autoformer sounded much better, but less attenuation sounded better as well, even though the sound was out of balance. The setup in Dallas needed something like 13 to 14 dB of HF attenuation to match the single GPA 416. It measured and sounded flat (using pink-noise), but 12 dB of attenuation sounded better, even though it was fairly obviously out of balance.

A pair of 15" woofers provides 3 dB of efficiency gain, as well as 6 dB improvement in headroom (along with reduction of IM distortion), as well as decreasing the required attenuation of the compression driver to the 10 to 11 dB range. The dynamic match would also be better, with the LF drivers closer to the dynamic range of the compression driver.

For reasons that are not clear to me, it's pretty audible when there's a large mismatch in headroom between LF and HF drivers, which draws attention to the 2-way nature of the system.
 
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