Here are a few key points on how panel size affects the sound quality of DML (distributed mode loudspeaker) speakers:
- Larger panels can reproduce lower frequencies, down to around 100Hz before needing a subwoofer. Smaller panels have more limited bass extension[1][2].
- With larger panels, the distribution of vibration modes is increased, resulting in a smoother frequency response. Smaller panels can have more peaks and nulls in response[2][3].
- The low frequency roll-off is dependent on panel size. Doubling the area provides about an octave lower extension. Bigger equals better bass[1][4].
- Efficiency is also related to size, with larger panels capable of greater output. Small panels need more amplifier power for the same output level[2].
- Directivity and dispersion pattern is affected by size. Larger panels act more like a line array with more consistent coverage across a wider listening area[3].
- The open, spacious soundstage produced by DML panels is more pronounced with larger sizes. Small panels sound more directional[4].
- Edge diffraction and beaming effects are reduced with larger panels. Small panels suffer more from these issues[3].
- Construction is easier with smaller panels, but bracing may be needed to prevent flexing on large, thin panels[4].
In summary, increased size benefits the bass extension, efficiency, directivity and soundstage of DML speakers. But there are practical limits for home use. A balanced approach is best.
Citations:
[1] https://dmlspeakers.com/articles/Does%20Size%20Really%20Matter
[2] https://www.diyaudio.com/community/threads/a-study-of-dmls-as-a-full-range-speaker.272576/page-38
[3] https://www.reddit.com/r/diyaudio/comments/lhgv7w/optimum_length_width_ratio_for_dml_speaker/
[4] https://hackaday.com/2019/10/26/building-the-worlds-best-dml-speakers-for-under-115/
[5] https://projectgallery.parts-express.com/speaker-projects/dml-flat-pannel/
[6] https://youtube.com/watch?v=Lk95g2lIB7A