AUDI cd has no sub?

[R6RY D]

help needed, my 2001 a4 has a concert cd fitted, was working fine, but all off a suddenly, when i put a cd in, it has no sub ? yet the radio is fine any ideas? ta

[blaineuk]

have you tried turning the bass up with the cd on.

[R6RY D]

yeah, its like its totallt dead but works , with radio on??? doing my head in poxy thing