tgourlie Posted July 28, 2005 Share Posted July 28, 2005 I stopped in at a local repair shop that also sells older vintage gear. While looking around I noticed a raw driver that looked familiar. It was a K-33-E. Picking up the driver I noticed that the voice coil had punched its way through the dust cap. The dust cap was still in place and did not have any other damage to it besides the voice coil partially sticking out. Needless to say the shop ordered the customer the pro series drivers for his horns. Quote Link to comment Share on other sites More sharing options...
BEC Posted July 28, 2005 Share Posted July 28, 2005 Terry could comment on this one and give approximate power levels required to perform this trick. Bob Crites Quote Link to comment Share on other sites More sharing options...
D-MAN Posted July 28, 2005 Share Posted July 28, 2005 Was it from a horn? The cone excursion is limited by the baffle (motor board) and that could explain it. Still, that WOULD take an "excessive dose" of juice to drive it through the cone without frying it first, I should think... I would guess that a sudden jolt of 500 watts or so ought to do it. DM Quote Link to comment Share on other sites More sharing options...
pauln Posted July 28, 2005 Share Posted July 28, 2005 May have been done when not mounted to motorboard or baffle/horn/load. Haven't you ever seen bare woofers laying on the back deck under the rear glass of a car? Quote Link to comment Share on other sites More sharing options...
D-MAN Posted July 28, 2005 Share Posted July 28, 2005 Yes, that could be the case too. But I can't feature the vc coming through the dust cover if the suspension is free to move to its limits... I'm sticking with the horn theory. DM Quote Link to comment Share on other sites More sharing options...
BEC Posted July 28, 2005 Share Posted July 28, 2005 I think you would have to somehow break the glue joint between the VC, cone, and spyder to have the voice coil come through the dust cap. I have seen a K-33 woofer that had been driven hard enough to eject the voice coil from the magnet gap. In that one, the cone, spyder and dust cap were still intact and the voice coil was crushed on top of the magnet assembly. Bob Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted July 28, 2005 Share Posted July 28, 2005 ---------------- On 7/28/2005 3:27:08 PM BEC wrote: Terry could comment on this one and give approximate power levels required to perform this trick. Bob Crites ---------------- Now Bob,...... you "tattled". Had installed the larger "other brand" mid horns & drivers atop heavily braced "75 CW bins that afternoon. After the sun set,(they only come out at night)me and the old woman sat down for a listen. Well, the sound was incredible. The K600/K55v horn-hash that makes you back away from CW DB's... didn't exist. We continued to ease the volume up and were busy re-hanging things that had come off the walls. Clip indictors were in plain view and never lit up. Somewhere around 121db measured at the sweet spot....A bad thing happened. Excessive diaphragm excursions? The coil extended out of the gap,came back off center and hung on the side. Bob believes, per the math, that around 350W into the woofer is required. I was "slammin" that night. Terry Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted July 28, 2005 Share Posted July 28, 2005 ---------------- On 7/28/2005 6:32:04 PM BEC wrote: I think you would have to somehow break the glue joint between the VC, cone, and spyder to have the voice coil come through the dust cap. I have seen a K-33 woofer that had been driven hard enough to eject the voice coil from the magnet gap. In that one, the cone, spyder and dust cap were still intact and the voice coil was crushed on top of the magnet assembly. Bob ---------------- Gulp....... Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 28, 2005 Share Posted July 28, 2005 We had this happen at my church with a dual 15" bass cabinet (similar to the JBL 4648, but with EV drivers). It didn't happen all at once though...prob over a period of 2 weeks. There was a slight buzzing sound (prob the surround seperating from the diaphragm) and then when the kick drum hit hard, the woofer got pushed out and twisted causing the VC to swing out of the gap and get lodged on the side...of course when the suspension pulled the driver back the VC made a big hole in the dust cap. It was wierd though because the VC was still connected to the spider and so the VC would still move, causing a nasty buzzing sound as it vibrated against the now floating cone (which also acted like a PR because the other driver was still pumping away). I'm not sure exactly what drivers are in the cabinet, but we've pegged a ratshack meter on the 120dB setting (so prob 130dB, but at least 126dB) in the rather large sanctuary (which seats hundreds of people...i think the max is like 600 or something). And yes we had ear protection on. I wonder how long the new replacement drivers will last for. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted July 29, 2005 Share Posted July 29, 2005 121 dB .... that magic Cornwall figure ... 5 seconds AFTER midnite, on the Doomsday clock...... Quote Link to comment Share on other sites More sharing options...
IB Slammin Posted July 29, 2005 Share Posted July 29, 2005 ---------------- On 7/29/2005 6:58:55 AM Duke Spinner wrote: 121 dB .... that magic Cornwall figure ... 5 seconds AFTER midnite, on the Doomsday clock...... ---------------- .....and 5 seconds before.... Quote Link to comment Share on other sites More sharing options...
tgourlie Posted July 29, 2005 Author Share Posted July 29, 2005 The woofer was from a Khorn. Customer has 6 pairs of Lascala's and 3 pairs of khorns throughout a very large home. The voice coil in discussion was in a khorn powered by a McIntosh.... are you ready for this... ...the suspense builds... ...MC2600!!!!!! But wait there is more... ...it was bridged to mono!!!!! 1200watts!!!! The coil looked like it was floating in the dust cap (if the cap were liquid) the cap looked perfect, no dents of tears. Just the half moon of a voice coil trying to escape. Quote Link to comment Share on other sites More sharing options...
scriven Posted July 29, 2005 Share Posted July 29, 2005 Big speaker, must need a big amp! Quote Link to comment Share on other sites More sharing options...
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