jmlc horn measurement

Jean Michel LeCleach's 340 Hz Azura Horn in the main room at 7' distance, with equalization added.

DSCN2847

1/5

The horn performed well at the listening position.

With the dual Fane 15XS and the Beyma CP22 tweeter:

The subjective evaluation seemed to point at 550 Hz and 6500 Hz as the optimal crossover for the 340 Hz Azura Horn @ 24 dB/oct LR filter on both ends.

The CP22 isn't very happy below 6500Hz.

The Radian 760PB resonates strongly at ~400 Hz so I used a -16 dB notch to keep this down. You can clearly see this on measured response. (ran full range for the purpose of the measurement)

The 3rd harmonic peak at 700 Hz seemed like it was a resonance of some sort. I don’t recall this from the last measured 12" away response. Perhaps it was room effect. Not sure what happened here.

I ran this measurement "full range" and at a realistic SPL. Not trying to embellish anything, I did not move the microphone until I got the best result. Measured once and that was it.

The room acoustics accounts for maybe 40% of the measurement, as it's 7 foot away. Take this with a grain of salt.

Since the 340 Hz JMLC beams and becomes quite directional above 6 kHz. the CP22 blends in very well and complements the sound quite nicely.

I could had the measured response above 7 kHz flat, until about 14 kHz where the 760PB start to be raggy, but with a super tweeter kicking in at 6.5 kHz what’s the point of correcting this? I just let the 760PB frequency fall naturally at 7 kHz, as you can see on the measurement.

Obvious during my listening tests, is that the Beyma CP22 super tweeter really does treble better than a big 3" voice coil CD with heavy equalization ever can.

I feel the pain of people trying to use a 2 ways system and using strong equalization on their compression driver trying to reach 18kHz

I use the CP22 as low as I can to maximize it's sonic advantage over the 760PB.

With the top extension not being of uttermost importance, the beryllium diaphragm upgrade for the 760PB becomes now unnecessary in my quest, as the CP22 takes care of the high treble.

The 3" VC of the Radian 760PB could be replaced by a 4" VC compression driver that could play lower and have much reduced distortion.

I have the B&C DMC50 in mind here or perhaps another heavyweight from FaitalPRO, the HF200.

Update: I bought the Radian 950PB