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In article <oduNdSC00UhB81Orc1@andrew.cmu.edu> "Raymond C. Chick" <rc4n+@andrew.cmu.edu> writes:
>I record classical music and have recently begun to investigate the
>affects of cable resistance on mic. level audio signals.  I used two
>cables, one about 20' and the other about 350'.  I passed identical
>signals through each cable and measured the  outputs levels for various
>frequencies.  I found no difference in output level between the two
>cables for frequencies from 100Hz. to 16Khz. Yet, the restistance of the
>short cable was .5 ohms and the long cable was 5.5 ohms.
>
>Shouldn't the long cable attenuate the signal or even roll of the high
>frequencies?
>
>How can I determin the maximum cable length before signal degradation begins?
>
>Raymond Chick

Simple cable problems become transmission line problems (attenuation, 
reflection of incident wave, length dependent impedance, etc.) when the
length of the cable is greater than 0.25 * wavelength of the incident wave.

This means (assuming the incident wave propigates through the cable at c):

	100Hz -> 2997km (wavelength)
	16kHz -> 18.7km (wavelength)

so, if your cable were at least 4.684km long, you would have to worry about
attenuation and the other fun transmission line stuff!

Also, a resistive element will not cause high frequency roll off...only a
a complex impedance will alter the signal at high frequencies.  The small
resistances you noted in your cable do not really effect the signal since
there are also output and input resistances of your source and amp in 
series/parallel with this.

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