Mutes on String Instruments
Using mutes on string instruments has some important things to consider and remember. Mutes as seen on this picture have no influence on the vibration of the strings but simply alter the way how the vibration of the strings is transmitted over the bridge (the wood “blade” where the mute sits on) into the body. Therefore, string mutes have only a very small influence on the volume of the instruments.
The essential effect of a mute is to give the instruments a more covered, less bright sound. There are a lot of different types of mutes (metal, rubber, wood etc.) though you should leave it to the musician to pick his/her favourite mute. Important to know is that when you need to rush to put the mute on or off, it will be quite noisy, so it is always better to leave enough time to change to or from mutes to do this silently.
The sound of muted strings is very oftem used in emotional warm string that use longer notes such as this theme from CAST AWAY, but also the very agressive main theme from PSYCHO uses the whole string sections under mutes for sound texture reasons. Unfortunately, many sample libraries only emulate the mute sound by filtering normal string samples which only approximates the very silky texture of real muted strings.