I'm trying to think how, and I'm not coming up with any ideas. Speakers are electromagnets, so the presence of a static magnet would interfere with their operation. The rest of a saber, I believe, is just a simple circuit, so having a (relatively non-moving) magnet nearby wouldn't affect it.
But! I haven't looked at a circuit diagram and I went into software not electrical engineering, so don't quote me on this.
If your Apprentice has neither Obsidian not Emerald, I think you should be good to go. The definitive answer would be to email
info@ultrasabers.com though.