Here are some guidelines on the ideal size for a DML speaker panel to achieve good sound quality:
- For full-range reproduction without a subwoofer, panels around 3 ft x 4 ft (0.9 m x 1.2 m) or larger are recommended. This allows extension down to around 100-120 Hz before roll-off[1][2].
- Panels smaller than 2 ft x 2 ft (0.6 m x 0.6 m) will have very limited bass extension and need a subwoofer to fill in the low end[2][3].
- A good compromise size for many home setups is around 2 ft x 3 ft (0.6 m x 0.9 m). This provides decent bass to 150-200 Hz while still being practical in size[1][4].
- For a multi-panel array, smaller panels around 1-2 ft (0.3-0.6 m) on a side can work well. The combined surface area matters more than individual panel size[1][5].
- Aim for a width-to-height ratio between 0.6 and 0.8 for a rectangular panel. Closer to a square shape can cause issues with modal distribution[1][3].
- Panel thickness around 0.5-1 in (10-25 mm) is recommended. Thinner panels may flex or tear over time. Thicker panels are heavy and less efficient[2][4].
- Consider the room size and desired bass extension. Larger rooms and full-range reproduction demand bigger panels[2][5].
In summary, around 2-3 ft on a side offers a good balance of size, bass extension and practicality for most DML speaker designs targeting home use. Follow a proper aspect ratio and thickness as well.
Citations:
[1] https://www.reddit.com/r/diyaudio/comments/lhgv7w/optimum_length_width_ratio_for_dml_speaker/
[2] https://dmlspeakers.com/articles/Does%20Size%20Really%20Matter
[3] https://www.diyaudio.com/community/threads/a-study-of-dmls-as-a-full-range-speaker.272576/page-38
[4] https://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/
[5] https://techtalk.parts-express.com/forum/tech-talk-forum/64791-diy-flat-panel-speaker-love/page89
[6] https://hackaday.com/2019/10/26/building-the-worlds-best-dml-speakers-for-under-115/