Rudy Osorio, formerly head of DVDs, has been appointed head of music. Osario has been at the retailer for 18 years. His is succeeded by Charles Fotheringham who has been promoted from the role of commercial manager after 10 years at HMV.
Osario and Fotheringham will report to Warren, along with head of games Tim Ellis.
Chief executive Simon Fox said: 'Under Gary's leadership and with the expertise of Rudy and Charles and their respective teams in place, I am confident that the HMV product department is ideally placed to work even more closely with our strategic partners to maximise the many commercial opportunities that will arise in the year ahead.'
Last month, the group said its strategic plan announced in March to drive cost efficiency, protect and revitalise its core business and grow revenue from new channels is on track.
The group's profits before tax and exceptionals halved to£48.1 million in the 52 weeks to April 28, but trading in June rose, with like-for-like sales up 3.8 per cent. Group sales rose 3.8 per cent to£1.89 billion, but like-for-likes slid 3 per cent.