Hmmm that’s quite interesting, is it the radio broadcast or the speaker magnet that is causing the problem? I have an ARVA 9000 that uses a magnet and hall or reed switch to actuate the beacon. Obviously a stronger magnet, such as in a speaker, could cause problems. I think the DSP has a reed switch so it seems like the speaker magnet is causing the problem. I guess if you are buried this could be a factor as you have little control where your radio might end up. Something to think about.
Reed switches seem like a flakey design to me, but beacons must be waterproof and this is one way to do it, switch is actuated remotely through the case by a small magnet in the clip.