B&W 602 S3 - strange problem with tweeter

I have a pair of B&W 602 3's as my dronts. Since yeterday, I am noticing a strange problem. The tweeter of the left speaker stops producing any sound from time to time. One bang on top of the speaker kicks it into action. Anyone has had this problem?
There were no knocks or anything like that,and why should the bang on the speaker kick it into action once again?

It is within warranty, so should I ring B&W? How is the service from them? Do they replace speakers? It was bought only in September/October last year.

 

Assuming you are just using a single amp, check that the metal connector on the back of the speakers is firmly attached to both sets of terminals. If it is, there must be a problem with the driver.

Your first point of contact should be your dealer.

 

I am bi-amping my speaker,so there is no metal connector at all.

If it is a problem with the driver,will I have to take it to my dealer and back,or will B&W collect it and deliver it back. Or does it work differently?

 

Your dealer may be able to change the driver, if not he should arrange to have it fixed by B&W (I think this is correct but don't quote me). I doubt B&W would collect and deliver.

Have you checked the connection from amp to receiver and swapped the channel being used to make sure it isn't the amp?

 

Tried that,But I think it is a speaker thing.
With the same connection,just a little knock on the head does it!

 

Sounds more like a poor connection between the crossover and the drive unit. In other words, a lose wire.

If it is it will be an easy fix.

 

Try two things:
Swap both speakers for each other, and see if the defect is now "on the other side". If the defect is kept on the same side (that means, now it is on the other speaker), you know it is not a speaker thing.
Wire them without biwire, and see if it persists. If not, you know it is a problem of wiring.
It really does sound like a lose wire... Good luck!