DrBurrito Posted October 17, 2017 Report Share Posted October 17, 2017 Hi, I’m planning to build a tapped horn subwoofer around the BC iPal 18, which models very well in hornresp due to its extremely low q (0.14!) and high motor strength. There’s something magical about this driver; nothing else I’ve modeled manage to get as low with as reasonable a response curve in a not-too-absurdly-huge box. VERY low: I’m planning on scraping 10 Hz if I can! One problem I’ve run into, though, is that the horn compression ratio wants to be quite high, for both response curve smoothness and to keep the box size reasonable. Something in the range of 1:6 all the way up to 1:10 works best. Now this is far outside what is typically quoted for subwoofers, which are supposedly recommended to be held around 1:2, with 1:4 a typically quoted maximum. I’ve read two reasons for this maximum: avoiding excessive horn air velocity and thus distortion, and avoiding simply overstressing and blowing the woofer cone itself. However, I haven’t heard a good *quantitative* reason why the recommended ratios are chosen. If there are any. Since this is databass, I hoped I could get a data-driven discussion on the real limits of horn compression ratios for subwoofers. Is the old 1:2 ratio just based on wimpy older drivers, and is outmoded by the new generation of crazy motor force neodymium magnet woofers, or are there some very good reasons to avoid going too high? How high, exactly, could you go, before you run into problems? Is 1:6 ok? What about 1:10? I’m thinking of something like Ricci’s dual opposed 21 iPal build, which clearly ignored the typical rules of sealed box design and overwhelmed the limits of the tiny air volume with the iPals’ high motor force. If this can be done for sealed boxes, maybe something similar can be done to create mini-horn subs. Link to comment Share on other sites More sharing options...
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