Adding Cat Whiskers to your string will help
reducing overall shooting sound, as simple as
that. An improper installation however may lead
to drastic arrow speed reduction and possibly
reduce shot to shot consistency.
In this video Don Katsumi ( famous for his
acclaimed Boo Strings ) will guide you trough
this apparently simple job in order to do it
properly.
Video
3: How to add
Cat Whiskers your crossbow string