In the patents they list example frequencies which have been measured that are within the audio spectrum. Inductance is Inductance. There's no reason that I know of why it wouldn't affect all frequencies, depending on the degree and Q of the cables being tested.
it *seems* like it would be extremely difficult to control it in very fine regions like MIT is claiming.
Exactly, but there is more... Imagine the ideal dynamic driver that needs no crossover; the amp "sees" a single inductor with back-EMF; then throw a capacitor or any RLC network in parallel, and all of a sudden the load changes; oops; is this a good thing or not. Then consider real-life speakers with complex crossovers, and imagine how putting anything in parallel or in series might adversely affect things. At the end of the day, they are filters, and any filter in series or in parallel that affects the sound is in the signal path - do you want that? A lot of people do and they see benefits, and that's fine. Then consider how widely different the crossovers are amongst all speakers out there... would one then begin to wonder how said cable networks widely and wildly might interact with said speakers and amps? I would. Notice, patent http://www.freepatentsonline.com/7242780.html talks about carefully selecting RLC values so as to not have too large of such an impact:
Each of the RC or RLC circuits is selected to have a phase angle of ?45° at a frequency equal to or different from the frequency at which the positive conductor has a phase angle of 45° depending upon the audio effect desired. In addition, the component values of the circuits are selected such that the measured impedance of the network at all frequencies in a predetermined frequency range is equal to or greater than 0.20 M?, and the overall combined capacitance of the cable and the capacitance and/or inductance of the network does not cause the effect of audible “roll-off” in the system.
But is it possible not to have an impact at all? I would be very hard pressed to believe that, and I didn't see any such claim in the patents.
So you believe that these patents are not based in reality?
Depends how "reality" is defined. 'Reality' as in signal transmission in an extremely wide frequency bandwidth where 45 degree phase shifts do occur, embedded in a super noisy environment? Sure, I am willing to believe there is merit to their claims. But in the audio band, as I mentioned earlier, I question any basis for the claims and the value the proposed solutions add. But I am willing to be convinced otherwise, and it has to start with a technical analysis.
At the end of the day, what really matters is that: a) people like and enjoy their MIT cables (nironda, Myles and so many others); b) I do too of mine, but only because they solve a completely different problem that Spectral designed for its own needs to complete the *amplifier* design.
BTW, I took the liberty to post these opinions only because of the thread's subject and really after someone else (you) started making some technical references wrt MIT, and I really don't care to turn this into an MIT thread.