こんな感じかと。
#uselib "urlmon.dll"
#func CoInternetSetFeatureEnabled "CoInternetSetFeatureEnabled" int, int, int
// http://msdn.microsoft.com/en-us/library/ie/ms537168(v=vs.85).aspx
#define FEATURE_DISABLE_NAVIGATION_SOUNDS 21
#define SET_FEATURE_ON_PROCESS 0x00000002
// Navigate時の音を無効化(IE6&XPSP2以降で有効)
// http://www.usefullcode.net/2009/04/49_tabbrowser.html
CoInternetSetFeatureEnabled FEATURE_DISABLE_NAVIGATION_SOUNDS, SET_FEATURE_ON_PROCESS, 1
axobj ie, "Shell.Explorer.2", 640, 480
ie->"Navigate" "http://hsp.tv/"