On December 14, 2002 I responded back to the ex-Bohlender-Graebener employee's comments above as follows, including the plots displayed to the left of the text in my e-mail (message text in blue):

RD-75 3m free air suspended impulse at a Screen Gain of x1, and 2.6mS duration.

Not to argue, but to share, I've reprocessed one measurement's data for this email an am attaching the GIF files for your entertainment. As to any virtues that the RD-75s may or may not possess, Oscar Wilde's comments about the talking dog apply I think, to wit, "Its not so much what he says, but that he says anything at all."

In the measurement the bare driver is in free air, the bottom at 61" off the floor and the mic at mid-point 99" above the floor and at 3m distance (1m and 2m measurements also exist). There's photos at my website of the suspended drivers. What I'm sending you is a look at the impulse and the the waterfall for the first ~2.5mS - since s damn mic stand reflection occurs at ~2.59mS. A half-Blackman FFT window, and 1/12 octave smoothing massages the data a whole lot - but this maybe the most "anechoic" look at the raw driver that you or I will ever see? I'm more that willing to do the same with the 1m and 2m data given what you've written.

Note that the IMP/MLS cursor marker obscures the mic reflection, and that the full-length time sample in the lower trace exaggerates the amplitude of the reflections. The second set of reflections at ~6.5mS are much lower in amplitude when seen in the upper trace window, and are secondary driver-to-mic stand reflections. The reflections at ~32mS are from the room. In any event, I think we can agreed that the first 2.5mS are nominally 'clean'?

RD-75 3m free air suspended CSD plot, at 2.6mS duration.

The CSD plot at left is in ERROR!