Remember, it was about 50dB at my ears. Might've been 80dB at the mic. Easy enough to make a mic preamp clip with a high output mic and the input gain cranked.
I could get you a measurement that's perfectly flat, but it'd involve clipping the input across the board.
I couldn't hear the final sweep, and only heard the second-to-last sweep when it passed through the sensitive range in the kHz region. Hard to say what the acoustic background noise was, but it was quiet enough that I could hear water convecting in the radiator in the room while the heating was off (ie, no flow in/out of said radiator).
Thinking about it, the mic has a known voltage sensitivity, 30mV/Pa, the USB interface will have a fixed maximum gain, and also a fixed maximum input level before clipping. With that knowledge, we can calculate the actual SPL at the mic, rather than using my estimate. I've got a busy day today, but will try to get around to this later.
Chris
It would be interesting to see this experiment being done on a pro midrange driver with stiff suspension like the 5MDN38. If a driver like this performs the same as a good hifi driver at low volumes, then why would one ever use anything but pro drivers?
Remember, a conductive voice-coil former causes more "drag" (manifested as mechanical resistance aka Rms, but the starting point is electrical) than a non-conductive voice-coil former.
So a driver with a very stiff suspension (low Cms, low Vas) with a non-conductive voice-coil former can easily have less mechanical resistance than a driver with loose, high-compliance suspension (high Cms,high Vas) with a conductive (e.g. aluminium) voice-coil former.
If Rms is not indicated for a driver then check the Qms, which is not exactly the same as Rms but a good indication of it.
And pro sound drivers usually have a non-conductive voice-coil former, the opposite as e.g. SEAS where most of the drivers have conductive VC former. Compare their Rms or Qms!
So a driver with a very stiff suspension (low Cms, low Vas) with a non-conductive voice-coil former can easily have less mechanical resistance than a driver with loose, high-compliance suspension (high Cms,high Vas) with a conductive (e.g. aluminium) voice-coil former.
If Rms is not indicated for a driver then check the Qms, which is not exactly the same as Rms but a good indication of it.
And pro sound drivers usually have a non-conductive voice-coil former, the opposite as e.g. SEAS where most of the drivers have conductive VC former. Compare their Rms or Qms!
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It sounds as though you are talking about electrical damping. Do you think they should create conductive formers with a gap in them?
This conjecture doesn't help make your point.
Drivers with electrically conductive VC formers have lower Qms. But Qms is a mechanical indicator, isn't? We cannot separate totally the electrical and mechanical properties of an electro-mechanical device like a dynamic loudspeaker. One will always have something to do with the other.
Check the T/S parameters (mainly the Rms) of the following two drivers. One with an extreme stiff suspension and one with a very soft, high compliance suspension but with an electrically conductive VC former. The home hifi driver have almost twice the mechanical resistance of the pro diver despite the very loose suspension:
BEYMA 605ND (mid-range 6.5", 8 Ohm, 250 W)
SEAS W18EX001 (Mid-woofer 6.5", 8 Ohm, 250 Wmax)
BEYMA 605ND (mid-range 6.5", 8 Ohm, 250 W)
SEAS W18EX001 (Mid-woofer 6.5", 8 Ohm, 250 Wmax)