If we now summarize all our reasoning, we need come to the following:
For individual capture, we need to use the icon of the corresponding group, adding some sign to it to understand that this is a capture, for example:
For combined capture, considering two and more icons make it clear that we are seeing a capture, we can really abandon the globe icon, and accommodate up to 4 well-readable icons:
This is a really nice solution and is intuitive enough that you can remember it once you know what the dots represent. Its also exactly the categories that need to be asked to finish a new capture, before being able to save it.
I’m pretty sure NeuralDSP can come up with a good solution in terms of visual, but let me just remind you that 10% of male (and a bit less than 5% of female) guitarists and bassists are color-blind.