Bigsub experts: I have a pair of the 299-716 Eminence 18s, and I have been checking them out in a 20cuft test box tuned to ~20hz with an 8in square port. Being driven by a 75watt NAD thru an 8mH laminate-core inductor. The good: low and loud; at half-volume on the NAD, great low-end musical grunt on big pipe-organs, and room-vibrating power on warble tones down to 20hz, with only ~3/8in p-p displacement at 25. Alas, the bad: on non-sine-wavy material, like the big drum hits on Copeland's 'Fanfare for the Common Man', the big gate slamming on Mussogorsky's'Great Gate of Kiev', or the ?kick-drum? on Dire Straits 'So Far Away', there is a low but quite audible noise on each thwump. Not a metallic rattle, not quite a flap, kind of a flubber. Rubbery sounding. Hoped it was just a bad example, but is identical in both.
So: any ideas what it might be, before I send them back? Otherwise a good fit for my needs, but don't think I'll accomodate that huge box unless the performance is uniformly good.
If any of you have a pair of the BPD1803s, I wonder if you could say if you have heard anything similar from those large cones? I'm looking for a driver with sufficient displacement to reach 110db down to 20hz in a ported box, while not requiring a dedicated amp. This driver will do it, but that noise...
Thanks for any advice guys, I haven't played with cones this size before, so would welcome any insights before I commit to a design.
Vince
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