Here are a few key points on how the number of exciters affects the power handling capability of a DML speaker:
- More exciters allow spreading the acoustic output across multiple voice coils and motors rather than overdriving a single exciter[1].
- Using multiple lower powered exciters can sum to equal or exceed the output of a single large exciter, with the benefit of redundancy[2].
- Power handling scales approximately linearly with number of identical exciters, assuming adequate amplifier power is available[3].
- The panel itself can ultimately limit max power handling regardless of exciter quantity if driven past its sustainable vibration amplitude[2].
- Impedances can be wired in series/parallel to optimize amplifier loading with multiple exciters[4].
- DSP can be used to actively limit and balance output levels across exciters to prevent overdriving[5].
- Too many exciters packed close together can couple and cause phase issues, so spacing and location optimization is critical[1].
- Costs, wiring complexity, and amplifier requirements scale up with additional exciters, so balance performance goals with practicality[4].
In summary, using multiple exciters in a properly designed DML panel allows increasing power handling capabilities while reducing strain on individual components. But more exciters add cost and complexity that may not always be justified.
Citations:
[1] https://www.diyaudio.com/community/threads/a-study-of-dmls-as-a-full-range-speaker.272576/page-254
[2] https://youtube.com/watch?v=MHCpcbOnZZw&t=1
[3] https://www.audiocircle.com/index.php?topic=138277.0
[4] https://techtalk.parts-express.com/forum/tech-talk-forum/64791-diy-flat-panel-speaker-love/page19
[5] https://techtalk.parts-express.com/forum/tech-talk-forum/64791-diy-flat-panel-speaker-love/page56
[6] https://www.instructables.com/Plywood-DML-Speakers/