Spatialking - yes your FM antenna is miles away but the output LC filter of class D amp is set to about 60kHz and at, for instance, 60MHz has very very high rejection.
(and 60MHz harmonic of 60kHz is a very small fraction to start with).
Also FM transmitter, as you mentioned, has kilowatts and not watts.
Carrier frequency, or rather 1% of it that gets out, is not audible (unless one can hear 500kHz) and cannot even create intermodulation on nonlinearities on the tweeter since its membrane won't move at 500kHz at all.
Jeff Rowland made many preamps using batteries in power supply. One of his newest creations (with extremely fast op-amps) Capri - praised for great sweet airy sound has switching power supply. High frequency noise is easy to filter out. The noise I was talking about was not the output noise in class AB amp but power supply current spikes it creates (not so easy to filter out).
It is possible that your class D amp is simply faulty or poorly designed.
It is amazing to me that many people (not you) wouldn't consider class D even for subwoofer but never heard one.
If class D is not good enough even for subwoofer please read fragment of the review of the Cabasse La Sphere 5200W (fifty two hundred watts) Icepower class D system by John Atkinson (Stereophile):
"In terms of organizational skills, timing and phase coherence, and timbral and textural accuracy, Cabasse's La Sphère system sets new sonic standards. Its reproduction of the piano and the human voice is light-years ahead of anything else in my experience. Its ability to produce solid, three-dimensional images on a stable, remarkably well-organized soundstage also beats anything I have ever experienced anywhere, and by a considerable margin. And in terms of textural solidity, harmonic structure, overall control, and low-end extension, its bass performance is similarly unprecedented."
(and 60MHz harmonic of 60kHz is a very small fraction to start with).
Also FM transmitter, as you mentioned, has kilowatts and not watts.
Carrier frequency, or rather 1% of it that gets out, is not audible (unless one can hear 500kHz) and cannot even create intermodulation on nonlinearities on the tweeter since its membrane won't move at 500kHz at all.
Jeff Rowland made many preamps using batteries in power supply. One of his newest creations (with extremely fast op-amps) Capri - praised for great sweet airy sound has switching power supply. High frequency noise is easy to filter out. The noise I was talking about was not the output noise in class AB amp but power supply current spikes it creates (not so easy to filter out).
It is possible that your class D amp is simply faulty or poorly designed.
It is amazing to me that many people (not you) wouldn't consider class D even for subwoofer but never heard one.
If class D is not good enough even for subwoofer please read fragment of the review of the Cabasse La Sphere 5200W (fifty two hundred watts) Icepower class D system by John Atkinson (Stereophile):
"In terms of organizational skills, timing and phase coherence, and timbral and textural accuracy, Cabasse's La Sphère system sets new sonic standards. Its reproduction of the piano and the human voice is light-years ahead of anything else in my experience. Its ability to produce solid, three-dimensional images on a stable, remarkably well-organized soundstage also beats anything I have ever experienced anywhere, and by a considerable margin. And in terms of textural solidity, harmonic structure, overall control, and low-end extension, its bass performance is similarly unprecedented."