rocknroller
Active Member
I consider myself pretty experienced with speakers and speaker repair. I have replaced dozens and dozens of deteriorating surrounds, recap crossovers etc. However I have an issue with a KLH Model 5 cab that I'm not sure of and need some (expert) advice.
When playing music and pushing any volume of bass, the woofer burps, which has always been an indication to me of voice coil rubbing when the surrounds appear to be good. I took the woofer out and pressed evenly on the cone in and out. What I expected to find was a rub throughout range or most of it. What I actually found was a rub only at the extremes (way in or way out.) When pulling the cone out, it feels like the cone is being stopped at the end. When pushing in, it's more of a typical rub at the far end. The surround is intact and I honestly wouldn't have thought twice that it might need replacing before, but now I'm wondering. The surround is is reverse surround type (meaning it scoops inwards towards the cabinet, unlike most surrounds that bow outwards) and made of a cloth surround, as opposed to more typical foam etc.. I've never actually done one that was this direction or of this rubber type, clearly a different material then typical surrounds.
So my question is - is more like that the voice coil is really shot on this woofer, or that the surround simply is not strong enough to "hold" the woofer in place properly (not so much left/right/up down, sagging etc, but more from the point of the speaker excursion. As I mentioned, in what I would consider to be the normal excursion range of the speaker, I feel no rubbing. It only seems to be at the extremes.
When playing music and pushing any volume of bass, the woofer burps, which has always been an indication to me of voice coil rubbing when the surrounds appear to be good. I took the woofer out and pressed evenly on the cone in and out. What I expected to find was a rub throughout range or most of it. What I actually found was a rub only at the extremes (way in or way out.) When pulling the cone out, it feels like the cone is being stopped at the end. When pushing in, it's more of a typical rub at the far end. The surround is intact and I honestly wouldn't have thought twice that it might need replacing before, but now I'm wondering. The surround is is reverse surround type (meaning it scoops inwards towards the cabinet, unlike most surrounds that bow outwards) and made of a cloth surround, as opposed to more typical foam etc.. I've never actually done one that was this direction or of this rubber type, clearly a different material then typical surrounds.
So my question is - is more like that the voice coil is really shot on this woofer, or that the surround simply is not strong enough to "hold" the woofer in place properly (not so much left/right/up down, sagging etc, but more from the point of the speaker excursion. As I mentioned, in what I would consider to be the normal excursion range of the speaker, I feel no rubbing. It only seems to be at the extremes.