Actually I don't think that is possible at really low frequency, as you would have only the lowest flexing mode of the panel (so maybe it's just a semantic distinction, but to me Distributed Mode means multiple parts of the panel should be resonating and not all in phase).īy the way, I once was doing R & D at a big speaker company, playing with different honeycombs. I question if attaching an exciter to a panel is really yielding a true DML. Those panels were made of various Styrofoam-ish product, by the way). I say supposedly because while the guys were very smart and the speakers had a lovely sound and great dispersion, I never saw any kind of laser interferometry analysis or similar that showed what was actually going on. Well, are you making a DML really? OR something more like the old Bertagni/Sound Advance/Sonance panels? (Those are driven by a "hammer" but supposedly operate more like a drumhead than a Distributed Mode speaker. And you get bass with area and the driving force, not the mass of panel. In summary, I feel it's still better to use light & stiff material, no matter the frequency range. Fun experiments but not for long term music listening. There're various LF resonance problems and low efficiency as expected. I've also tried MDF table and large piece of glass in the office. But eventually I dropped it because it can't go deep enough and there're other problems. However, I've tried very light PS foam board with a bass shaker, and that was one of the most realistic drum playing in my room. I've read someone use wood panel - the same material and similar size of the sound board of a piano - and the guy is happy. If the panel is for bass only, then it's freer to experiment with any material without concerns of the mid and high frequency. Honeycomb board should be very good, but no 1st hand experience here. Heavy materials would be hard to control (damp) if you encounter problems of resonances. It may come to that, but not as much fun. I realise someone may say 'just buy a cone speaker and stick it in a box with the amp if you want bass'. 3mm or thicker? Or would thicker & stiffer honeycomb panel be better for bass? Or should I just use something cheap and dense like MDF board? Questions: To those of you who have experimented, any suggestions about optimum thickness for an aluminium composite panel? E.g. If bass is OK, I might try including extra exciters and mid-high frequencies later, just to see how it sounds. The audio signal to the plate amp can come from the subwoofer audio output of my Yamaha amp, and crossover frequency can be set on either amp. full range Dayton Audio MCA2250E 2.1 Channel Class D Plate Amplifier, or a subwoofer plate amp). DAEX25SHF-4 Steered High Flux 25mm Exciter 20W) and powered by a plate amplifier (e.g. Idea: large panel about 2m x 1m, driven by 1-2 Dayton exciters (e.g. But, would aluminium honeycomb panel say 10mm or 20mm thick do so? Or would panel density be too low? Question: Some say 'heavier' panels produce lower bass. I expect the answers may be 'try it and see', but maybe you can give me some starters. So, I'm thinking of experimenting with a largish DIY panel that can produce bass somewhat below 100Hz. Maybe better than panel like Gatorboard which has soft foam core?Īlso, for CLS, in Oz you can buy these panels custom roll-curved to your specs, no kinks, for a nominal extra cost. There are now some composite aluminium-polyethylene panels available cheaply (eg 2400x1200 Alupanel = AU$40), with thicknesses from 3-10mm, and even some composite aluminium honeycomb panels, commonly used in signage (6 to 25mm thick). I've read nearly all the 'Piezo NXT-type panel' thread pages starting with Ziggy's about a decade ago.
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