I've seen a lot of questions about it since the release of 1964, and i decided to give a little explanation on what windows users should know about the RSP and sound plugins.
If you want to have a more technical explanation on the subject, i suggest you to read the help file provided with Mupen64, i've written a lengthy paragraph about how these things work.
From what i've seen, the best sound plugin for 1964 is schibo's audio plugin, i've tried using jabo's sound plugin and at least on my computer, it sounded worse. Anyway if you decide to try jabo's plugin, it can only be with a RSP plugin, either mine that is provided with mupen64 or jabo's that is provided with pj64. In the following text i'll suppose that you're using schibo's audio with 1964. If you're using pj64, mupen64 or most of the other emulators, the best plugin seems to be jabo's plugin. In pj64 and mupen64, a RSP plugin is provided by default, so it should work by default.
If you have a fast computer and don't like the sound you're getting from a HLE sound plugin, you can try using the pj64's RSP plugin. The only benefit you can have from pj64's RSP plugin, is better sound: no more compatibility, no better gfx, nothing else... but it costs processor time.
If you have a slow computer, in my opinion, you should use 1964 and i will suppose you do in the rest of this post (but it shouldn't be hard to get the same tricks working in others emus). That's a very fast core emulator. After that there's the graphic plugin, i can't tell you what's the fastest one, as it will depend on your video card. And finally, there's the RSP and Audio plugin that we will try to tune in this HOW TO.
Firstly, you can be happy with Schibo's audio plugin. It's a very fast plugin, but sometimes it sounds bad in my opinion, because it's using epsilon's audio code. So if you think it sounds bad as well and you're ready to try some configurations, continue to read, otherwise you can stop now
You can't use jabo's rsp plugin on a slow machine because it takes a lot of time. The first thing you can try is to use Azimer's 0.40 beta 2 plugin. On some computers it can sound very nice on some others it won't and in this case i've programmed a little solution.
Try using my RSP plugin provided with Mupen64. But you can't use it without changing the config because it will sound as bad as schibo's audio plugin So go to the RSP settings, and choose "Process ALists By RSP defined Plugin" and choose "Azimer's 0.40 beta 2" plugin in the RSP config dialog box.
Then go back to the 1964 config dialog and choose Schibo's plugin as the Audio plugin.
Run a game and enjoy the wonderful sound ! It should sound as good as lle but it's hle and fast
I hope this little guide can help some of you to have better sound
I know it's a bit tricky and maybe not worth the effort, i hope to find an easier solution in the future