From: Isaac, [111.a.004.syd.iprimus.net.au]
Subject: Re: 8th Order BP question
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Hi, > I know 6th-order bandpass subwoofers are much louder than 4th-order bandpass subwoofers Not necessarily, it depends on the given systems. > but what is the advantage of an 8th-order bandpass subwoofer over a 6th order bandpass subwoofer? The first obstacle that you might run into is finding suitable drivers that require practical enclosure and port sizes. I have found the following drivers to be a bit suitable for this type of enclosure. 5" vifa C13WG-19-08 - I've only simulated these two boxes: (Flat FR / positive-slope FR) Vab1 = 15L / 14L Fb1 = 30Hz / 29Hz Vab2 = 5L / 4L Fb2 = 92Hz / 104Hz Vab3 = 15L / 9.6L Fb3 = 65Hz / 55Hz phased-out 8" Kicker F8a (4-ohm version) - this one is almost the size of the BOSE 701 - box1 = 30.85 - 28Hz - box2 = 8.45L - 102.22Hz - box3 = 19.28L - 53.5Hz 6.5" Kicker F65c - box1 = 18.43L - 32Hz - box2 = 6.10L - 96Hz - box3 = 17.68L - 55.63Hz Jaycar 5" Polycone woofer (Qts = 0.39, Fs = 58.5Hz, Vas = 6.85L version) - requires small box, but port lengths might be a little difficult requires BIG boxes: vifa P17WJ-00-08 vifa PL18WO vifa M18WO even BIGGER box: vifa M21WO From what I've seen in simulations, and given only one woofer make and model, the only advantage that I see is the fun factor and the steeper upper frequency roll-off rate. Again, given the same woofer, the major disadvantage of the 8th-Order type is the (usual) need for a bigger enclosure to get a smooth passband and acceptable low-bass response. If size is not an issue, (usually) the next hurdle is the port length required for the lower-tuned chamber of the system. Rather than go through all that trouble, it is usually better to go with an ordinary vented-box type enclosure using a larger woofer. BUT, if fun factor is important, I guess an 8th-Order box is worth the extra effort. > I know the series III Bose Acoustimass subs are 6th-order The AM-5 series III bass module was also an 8th-Order BP box. > What I want to know, though, is whether or not the extra effort to design an 8th-order BP is worth it. For the fun of it? Yeah! =) Good luck! Isaac PS: The vifa C13WG-19-08 drivers are currently on special here in Australia. If I have some extra $$ to spare, I might build the above-mentioned box, I'll know in two weeks =) |
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Follow Ups:
- Re: 8th Order BP question Rory 21-Aug-2001 16:59:37 (2)
- Re: 8th Order BP question Jason U. 22-Aug-2001 19:56:29 (1)
- Re: 8th Order BP question Rory 22-Aug-2001 23:00:07 (0)