Tom Crown is considered one of the finest mute craftsmen around today. The products he has developed are top professional level and extremely well manufactured. They produce a unique, lovely sound and still allow the power necessary in large ensembles. Once you try these you will see why they are the professional choice. Tom Crown French Horn Transposing Mute. Transposing Indicates That The Player Must Transpose The Music One-Half Tone Lower To Compensate For The Shortening Of The Effective Overall Length Of The French Horn.