Hi thanks for asking. I’m hoping someone with more first-hand experience will weigh in on this as I personally haven’t used it with Roll 20 but I have used it with Discord.
As my party is usually only 1 or 2 players at a time, I directly stream the Syrinscape Online Player into Discord and that works perfectly for us but with more people, Discord may prioritise voice chat and may affect the sound quality coming from Syrinscape but I can’t say for sure as I haven’t experienced that.
The Syrinscape Online Player works alongside Discord and VTT’s meaning you do need to have it open in the background or you can search the forum for setting up your own discord bot to use with Syrinscape. That could possible be a good solution for keeping any strain on connections to a minimum rather than everyone having to have the Syrinscape Online Player open maybe.
Edited to include some extra info on this point: Streaming Syrinscape through Discord causes a continual data stream. When using the Online Player App, it downloads all the data it needs, caches it and - unless you trigger something new - plays it from the cache and doesn’t need any more data downloading/streaming. So actually using the app is straining a connection far less than streaming it through Discord.
Otherwise, the short answer is that you will need to have Roll 20 and Syrinscape and Discord open at the same time.
Good news is we’re currently working on making it easier to share sound with your players so new, awesome things are coming soon but for now, there’s no way (to my knowledge) to use Syrinscape directly within Roll20 and I assume thats mostly due to the fact they have their own jukebox.
My other half uses Roll 20 and Syrinscape easily. As far as I know they do their video and voice chat directly within Roll 20. I’m pretty sure they don’t use Discord. He has 2 screens, the Syrinscape Online Master Interface open on one screen and Roll 20 on the other screen and that works REALLY well. It does require some screen space, especially if you’re going to be controlling Syrinscape and triggering music or sounds during the game but for the most part, it can be in the background. I’ve seen some people have 2 applications (Syrinscape and Discord) open at the same time, side-by-side on one screen and that looks cool so if you can figure that out, that could be a solution.
As for your question about Syrinscape SuperSyrin and Online. Syrinscape Online is only made available with a Supersyrin sub.
I hope that helps but as I said, I hope someone with first-hand experience of using with Roll20 will weigh in.