XT18WO and W18EX tests in HobbyHifi 3/07

[capslock]

We had a discussion on the merits of the XG18 and XT18WH a while ago. Well, the XT18WO was just tested. The WO differs from the WH in that it has a larger magnet and a Kapton former.

Impedance has a little wiggle at 400 Hz and 1.4 kHz each. FR is very flat out to 3 kHz with no signs of the surround mode dip so common in paper cones. Actually, FR is +/- 4 dB flat out to almost 10 kHz!

CSD looks good for a paper cone but messy compared to good metal cones.

Distortion is really quite good! At 90 dB/1m, 2nd is around or below 0.3% 100 Hz - 10 kHz, 3rd is at or below 0.1% 120 Hz - 2.5 kHz with an occasional excursion to 0.2%. 5th is below 0.03% anywhere above 100 Hz. LF distortion, the Archilles' heel of the XG and XT18WH, is average for a decent 7 in driver: 3% 2nd and 3rd at 50 Hz.

[capslock]

Rather than recycling the same old measurement as they've done a few times, HH now have a new measurement of a fresh W18 with a rubber cap on the motor. The big FR peak is now at 5 kHz compared to 4.8 kHz in the data sheet and older published data. There is also a strange 3 dB step at 1 kHz that I have never seen before for this driver in either data sheets or other sources.

Distortion is quite comparable to the old HH review, 2nd and 3rd oscillating between 0.1 and 0.3% until they hit 0.5% at 1/2 resp. 1/3 of the first cone mode. 2nd and 3rd are well below 1% at 50 Hz, so here the W18 has an edge over the XT18WO.

[TacoD]

I also noticed the strange FR step at 1 kHz in the HH magazin. My own measurements of the old W18 had their peak at 4850 Hz and showed no peak at 1 kHz. The XT18WO could be interesting when one doesn't want to deal with all those difficult cone break-up modes associated with metal cones.