The last couple of days there was a few people saying I should go sealed when I'm going active. And when I think of it, pretty much every manufacturer I know that makes active loudspeakers like Paradigm, Meridian, Kii, Xanadu, all make them sealed. And Magico as well. And they do produce some pretty deep bass and obviously also very tight. I think my ported design is very good but I know sealed is basically the best. But how do you optimize the system so that it will produce that low bass from a sealed enclosure?
Unibox suggests a volume of 63,2 L for a Qtc of 0,707. But then it has a F3 just 47 Hz and the woofers already reach Xmax at 35 watts. I would like to go sealed because I know it offers the best sound quality when done right but how do I optimize it so it will still produce very low bass as well?
Unibox suggests a volume of 63,2 L for a Qtc of 0,707. But then it has a F3 just 47 Hz and the woofers already reach Xmax at 35 watts. I would like to go sealed because I know it offers the best sound quality when done right but how do I optimize it so it will still produce very low bass as well?
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Ulrik from SB-Acoustics says sealed is a good way to go and he would do it himself as well. He explained to me how to correctly tune a sealed enclosure for use in a active DSP driven system. He said I don't necessarily need the Qtc at 0,707 but actually will want it higher for this application. He said is should make the box volume smaller (Qtc higher) and look for the volume at which the F3 and excursion are at a optimal ratio. I found 58 L has the lowest F3 at 46,56 Hz and slightly lower excursion. Smaller than that made the F3 rise quickly as expected but then approaching 52 L it got slightly lower again to 47 Hz but with obviously even less excursion. What is the reason for this suddenly lower F3 in a way smaller box? And does it have any negative side effects like weird resonances or is it usable and will just offer great control over excursion?
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I've calculated the volume with the optimal balans between excursion and F3 by multiplying the F3 by the excursion in mm at 20 Hz. The lowest product will be the optimal. The optimal is at 51 L but there is that raising F3 at 56 L. Is that because the tuning frequency of the enclosure is one octave above the Fs of the driver? Because the tuning frequency at 56 L is about 49 Hz. Can I make the box 51 L without any problems? because it will be the best.
Ulrik Schmidt from SB-Acoustics said it's weird/incorrect that the F3 is at lowest with a Qtc higher than 0,707 or a smaller volume. Which seems logical. Maybe I'm stupid that I only know this by now but I thought a Qtc of 0,707 will only give the flattest response. I asked him what he thinks is going wrong and what I should do. I can't really imagine Unibox being wrong but maybe it is doing something weird.
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