I think I’ve found a solution to the feedback problems I was getting the Headway band pickup on my double bass. It isn’t very elegant but using a pair of socks to fill the two f holes greatly increases the headroom before feedback starts to occur. The band fits round the instrument inside a rubber tube and is less prone to feedback than some other forms of picking up the sound of the instrument but the huge body is designed as a wooden sound amplifier and, at electric gig volumes, has a tendency to get carried away.

What I need now is a neater method for plugging the holes and damping down vibrations but I think it is a useful step forward.