ProLevel for Android

This simple app is extremely limited and I think it is only listening to the microphone from the Android and not its onboard audio board

This is exactly what I was looking for, however I do wish it read the output levels as well, not just input.. for example listening to the current output of my music and volume cuts in FCP to ensure I have the same levels throughout.

When the app works, it's fantastic! I love to monirot the levels from my two USB mics. But whenever I am recording my podcast the app usualy crashes after about 10 minutes, which causes the recording to also stop in GarageBand. Maybe it does not support two mics at a time or also being open with GarageBand.

Soundflower is no longer supported, and without that external tool, this paid software can't be used for measuring or monitoring computer audio. Will be figuring out how to get a refund.

I use this with an external audio interface to monitor the levels going into my streaming encoder. It's great, and the RMS + Peak meters are a lifesaver, as is the clipping indicator. Love that it shows how many frames in a row were clipped. If you're using it with something like a UAD Apollo, you can monitor the system output by sending the Android's output to a virtual interface on the Apollo, and then chosing those inputs (UAD 9/10 are the first set of virtual interfaces). You can also create other meters that are showing what's coming from other interface inputs. If you're trying to monitor the levels of the system audio out, you'll need to use something like Soundflower (Open Source) or Loopback ($99 from RogueAmoeba, so not the cheapest solution).