In Reply to: good point! posted by centaurus3200 on March 2, 2007 at 09:37:21:
As one of the engineers form the "old school" KEF I can confirm that the inner roll is indeed important. It is not there to simply keep crud out of the gap, though it does serve that purpose too.
Because of the use of the force cancelling rod, used to reduce vibrations in the cabinet, we had to eliminate the conventional dustcap in order that the rod could connect to the magnet. This not only opened up the voice coil gap to contaminants but also lost the seal between front and back of the cone. There is an air leakage path around the voice coil. Coupled cavity loading is sensitive to leakage between the front and rear chamber, causing shifts in the requency response away from optimum and allowing air to chuff at large displacements of the cone. We therefore developed a rolling seal to overcome these problems.
So, the short answer is "yes, you need the dustcap". Could you get away without it and not notice? Perhaps, but it would not be performing to the fullest level to which it was designed.Regards
Andrew
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Follow Ups
- Re: good point! - twinny2nd 15:02:47 03/06/07 (1)
- thanks andrew! - centaurus3200 15:10:42 03/06/07 (0)