I have a set of Celestion C series speakers which includes a pair of C1's used for the front soundstage. I've already had to repair one where some muppet forget to fit one of the speaker screws and as such the speaker vibrated at high(ish) volume. Now I find the bottom speaker on the right hand unit crackles and pops at high volume. If I tajke the front off the unit and just lightly touch the cone it stops it (also affecting the sound output obviously). There is no visible damage and if I knock the volume back a few notches it sounds just fine. Anyone got any ideas? A call to Celestion next week but just wondered if it is likely fixable or does it sound terminal Thanks.