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In the Forum: Horn-Loaded Speakers
In the Thread: Open cell foam in horns and MF drivers
Post Subject: Do not forget the damping the cones with amplifierPosted by Romy the Cat on: 1/31/2008

 be wrote:
The best driver I have heard is the TAD 4003.

It does not use the secondary resonance of the suspension, as described by Duke LeJeune above for the TAD 4001-4002, to extend the response towards 20 kHz, but has a natural roll off from app. 15 kHz.

Interestingly the sound of the 4003 is much better than the 4001-4002, the density of information and ability to articulate, also in the treble, is on a different level.

The sound of the TAD 4001-4002 might impress for a few notes until you realise that everything they do in the high frequencies have the same monotonous character and is not able to express the "smell" of the instruments very well.

If one looks at the AES paper for the 4001 it can be seen that their response over 8-10 kHz is due to deliberately placed resonances.

The JBL 375 was also made with the same trick, it is generally more coloured than the TAD 4001, but in a pleasing way.

All these drivers where designed by Bart Locanthi, the 4003 was, if I am not mistaken, his last completed driver before he died, apparently he realised his mistake with the others.

Very interesting comments about TAD 4003, thanks, Be. I had in past the 2001 and 4001, did not like them for their “over oily salad sound” and I dismissed TADs all together. 

The concept of the deliberately placed resonances is complicated and I would never feel that any driver might not suffer from it. They are all hugely resonating, some of them do it in “right way” and some of them now, go figure…  From what I remember when I was trying the 2440 and 375 (had them both) I god a feeling that they probably were the most neutral but at the same time the most capable in term of “discrimination” among the common drivers.

There is another aspect that I did not research in 2000-2001 what I was doing over many compression drivers – the control the drivers by amplification. In 2001 I used Lamm SET that cared everything above 100Hz. I did try to use different taps on the compression drivers that I used. It changed the harmonic envelop of the MF drivers but it also changed a lot my upperbass channel.  The upperbass channel is a bone of a compression MF driver so, it was not realty intuitive what was doing on. Also, at that time I had less evolved listing assessment skills then I have now and I presume that I did not give to some of the tried drivers the chance that they might needed.

What I feel the MF horn drivers need is to be driven by a dedicated SET where the effect of variable loading of the SET might be observed at the MF driver only. I know that MF compression driver have very little reactance back to amp but still, their sound very much might be moderated by SET’s plate loading. Particularly the drivers that use the “deliberately placed resonances” mish be very much comforted by loading the out stage of SET slightly heavier. Under other circumstances I would try some better drivers again, with my progressed understanding how to deal with compression drivers but I am not on the MF drivers market. If I begin to lose satisfaction and would detect some specific annoyances with the MF driver that I am using then it might open opportunities for further try. I would then try your TAD 4003…

The caT

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