New LLE RSP Plugin (accurate, fast but untested?)

[HatCat]

You may send additionally helpful data if you wish but the most important thing I think is to try testing it with Project64 1.6.

Much of the audio issues are to blame over the RDB externals added to pj642.

Remember that pj64 1.6 does not let you pick RSP plugins and forcefully looks for the exact file name "rsp.dll", so rename of course if necessary.