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On 3 Jan 2004 04:39:58 -0800, (Bob-Stanton)
wrote:

"Rusty Boudreaux" wrote in message

So how do you enter into the computer the load impedance being it
is a complex fuction of frequency?

There a two ways one could do it.

1) One could use a general lumped constant model of a speaker as the
termination of the line.

2) The better way is: measure the input impedance of a given speaker
at many frequencies (at 100 frequencies would be good). Mathemetically
convert the input impedance into S11 (input reflection cofficient).
One can then put in dummy values for S22 (output reflection
cofficient), S12 (reverse transmission cofficient) and S21 (forward
transmission cofficient). Create a two-port (data file) device from
the data. Terminate the cable (in the computer) with the two-port
(data) device.

The two-port device will present exactly the impedance you measured,
at the frequencies you measured. The computer will interpolate values
in between the frequencies you measured, to give the correct complex
impedance, at all frequencies.

Simple, no? :-)

Indeed yes. Now tell us how you optimise a transmission line between
the sub-ohm source impedance of the amplifier, and the wildly varying
multi-ohm load impedance of the speaker. Sheesh, whatta maroon!
--

Stewart Pinkerton | Music is Art - Audio is Engineering