On 2011-07-27, Jörn Nettingsmeier wrote:
power transmission impedance matching.
That I've understood for the longest time. But then, when you learn it from a power electronics book -- which only talks about power transmission efficiency at a single frequency -- and then somebody tells you that's all bunk with audio circuits since there the ideal is to have total input-output control by always going from minimum output impedance to maximum input impedance... You can sort of lose track.
When I reread Robert's idiot-guide, I literally blushed.
if you look at the spec sheet of a commercial p.a. amplifier, 9 times out of 10 you will see twice the power rating for 4 ohm loads than for 8 ohms.
How is this possible, given that the intrinsic ohmic load of the source ought to stay the same? Yielding more current, and as such not just more (linear) distortion from the reactive components, but also more power lost within the amp instead of within the wiring and/or the speaker?
Then the real question is, why can't this sort of a problem be corrected across the board with adaptive feedback? Even in the endstage? I mean, it shouldn't be too difficult to measure both the current and the voltage going out, and to feed them back via some mock-reactances over to the input side of the final amp. Over a narrow band that should be doable even in analog hardware. And over the whole audio band, why not just go with adaptive zero latency convolution and be done with the speaker impedance matching problem, once and for all? I.e. even if you don't have real variable reactances on the amp side which could be brought to bear, you could always go with the smallest common denominator you *can* handle by brute force, achieving a flat matching to an arbitrary speaker.
Or is it that this is patent protected already? Somehow I seem to remember reading a research paper or somesuch from Meridian, which could have suggested they did something like this at least for their flag-line DSP speakers' bass section, in order to get optimum power transfer, and as such high SPL's. Do we perchance have Bob Stuart online to verify or dispute my hunch?
-- Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front +358-50-5756111, 025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
