You may be looking for Piccolo Books.

A piccolo was a musical instrument from Earth, which had a sound not dissimilar to a recorder. The Fourth Doctor carried one and was fairly adept at playing it. Once, when on the trail of Pescatons in the London Underground, he told Sarah that he "always played the piccolo when [he was] nervous". He felt that it "relieved the tension".

This trait proved useful, as the Pescatons were vulnerable to high-pitched noise. Sarah noticed their vulnerability when the Doctor was offhandedly playing the instrument and encouraged him to play more loudly. (AUDIO: Doctor Who and the Pescatons)