DML Speakers Come In All Shapes And Sizes
Flat panel DML speakers can be made to any shape and size. As the audio frequency gets higher, the DML speaker will usually increase its frequency response as higher frequencies have a smaller wavelength, meaning the signal will resonate many times across the panel at the high end.
At the lower end, frequency wavelengths become very long. At sea level, the wavelength of a 20hz signal is over fifty feet long!
When the wavelength is longer than the DML panel, the speaker will be unable to fully express the entire wave form, causing a noticeable drop off in frequency response at the low end.
Larger Equals Lower
When choosing a DML speaker panel, the two most important considerations are the material the panel is made of, and the size of the resonating panel. There is a direct correlation between larger panel size and lower frequency response. If you want deep rich sound, you want a fairly large DML speaker panel.
Calculating Expected Frequency Response
Note: The following measurements are based on DML speaker panels made of 2 inch solid polystyrene panels. Panels made of a different material will have a much different low end drop off.
Based on our measurements, we notice 12 square foot panels (3' x 4') begin to decline in the frequency response around 155hz with the response falling off rapidly and becoming inaudible around 45hz.
The sweet spot you are trying to find when selecting a size for your DML panels is getting the best frequency response between the 100hz - 200hz range. Over 200hz even smaller DML panels will give a reasonably good response.
Under 100hz is definitely getting into the range of the subwoofer. But you can achieve a very rich lower end response by selecting for the best response in the 100-200hz range.
We put together this calculator to help explore the expected frequency response of different sized panels based on our test measurements. You can drag the corners of the panel below to resize it and view the calculated frequency response thresholds above.
Note: this calculator is intended to give a rough estimate of the lowest expected frequency responses of a DML panel based on our test measurements. This is not a scientific assessment of expected performance based on size. It's our best guess put together in a web widget.