Ummm... how would you generate the anti-phase audio?

Using a DSP and a lot of math. I suspect that the SA1100 would not really be up to it, to tell you the truth.

If you are using your stereo to generate it, I suspect there would be considerable impact on the sound quality when the stereo was trying to do "double duty".

It does depend somewhat on the power output of your amp (you wouldn't want to use a 2x 20W RMS amp, for example ), but Lotus showed it did not require too much to do it.

Getting the anti-phase sound pickup to differentiate between extraneous noise generated from outside the vehicle, and the in-cabin noise generated by the stereo system might prove difficult

Well, all cars have a definite accoustic "Fingerprint". At different engine and road speeds, the fingerprint varies somewhat, but not a significant amount. It is mainly in the amplitude that the fingerprint varies across the range. Before you attempt cancellation, you have to characterise the vehicle's signature, then after that you simply subtract it from the cabin noise by inverting it and playing it out. The extent of the cancellation depends on the amplitude of the antiphase, which is (as you can guess) dependent on your amp.

However, you don't need to totally noise cancel, as only a relatively small level reduction of particularly intrusive fingerprint components can produce a subjectively large improvement in listening environment quality. Hence, no really big special amp necessary.

It would be truly excellent if the Empeg had the processor capability and the signal path needed for the injection of antiphase. This would really make it an absolute killer app for the road.

If the Mk3 included a DSP in the signal path (not the output processor that exists now) for signal matching and injection (plus other unusual effects ) then my cash would hit their coffers so fast they wouldn't know what hit them....




One of the few remaining Mk1 owners... #00015