Hi, ever since installing Audacity 4 my Audacity 3 is not seeing any input during record. It’s just flatline when I hit record. (I’m doing occasional cassette capture with a RCA-to-USB capture cable. Been away from it for awhile, just now getting back to it.) When I bring up Audacity 4 there’s signal there. All the audio setting look fine in both - the correct input device is shown in both, channels and sampling rate and so forth. I’m comparing in both the audio setup button window and in the preferences windows. Any thoughts. I’m on a modern iMac (M4 processor) with uptodate MacOS. In both cases I’m bring that Audacity up without the other one being up.
Go to System Settings → Privacy and Security and check that Audacity (3, not Audacity 4) has been granted access to use Microphone.
That mic permission point is a good shout, macOS treats Audacity 3 and 4 as separate apps so one can have access while the other does not. I had something similar with an old USB cassette cable, it showed up fine in the device list but stayed flat until I quit everything and plugged it back in after granting permission. Worth checking Audio MIDI Setup too, just to see if the cable is actually showing an input signal there before Audacity even gets involved. If it is, and 3 still stays flat after a restart, I would try a fresh recording with nothing else open.