Effects of magnetic fields

Yes it's possible to hear the effect.

The proximity of my HT sub woofers effect the sonics of my Soundlab Ultimates by disrupting the back-plate (power supply). The sound is improved proportionately by increasing distance between the large woofer and the Soundlab as well as removing the power cord of the sub from the wall outlet.

Guess the Soundlab doesn't like the field from the amp either.

Darrylhifi,

The effect I heard was from moving the sub woofer SIDEWAYS, away from the Soundlab Ultimates.

Since the Soundlab is a dipole, the sub at it's side has very little effect acoustically. Anyway, I'm discussing the sound with the sub woofer (un- shielded box) in an inoperative state, merely it's presence both magnetically and electrically.

The magnetic field in the sub is strong due to the 15" woofer and even worse, the built in plate amp (200 watt) effected the power supply of the Soundlab. I assume the step up transformer or bias circuit was being effected but cannot say for certain.

Herman is correct that moving speakers have great effect sonically but in this instance the sub was definitely effecting the Soundlab, other than acoustically.

Since magnetic fields are so easily seen on televisions when speaker fields are near I don't see much stretch in imagining it could effect some circuits during music playback.

Wish I could answer your question as to how to measure the magnetic field, but I don't know.

Jim Aud of Purist brought a device to my home some years ago and could read all the fields in my room, including the location of wire in the walls.

He built a isolation platform that contained a shield, I assume similar to TI shield and it could be placed in between my sub and the Soundlab and get identical improvement as moving the sub. I think they were built for Japan and never marketed here.

The TI shield was at one time sold by Mike Percy. I have not tried it but assume it performs similar function.