Mac Recording Audio Issue


New Member
Trying to record a video with multitrack audio.
I'm recording an audio track ('1st audio track') using Garageband. I output it as .wav file.
The recording when played back through quicktime, iTunes, VLC is perfect.

I then record a video with "multi-track' audio as follows:
Video is through OSB using the Mac camera.
I play the pre-recorded'1st audio track' using the Soundflower 2ch plugin (through iTunes) as 'system audio'.
I record a '2nd audio track' using a USB mic in OSB.
As I record, the '1st audio track' sounds perfect, and I play & sing with it.
The finished mp4 video is fine, the '2nd audio track' recorded along with the video sounds fine, BUT the '1st audio track' is poor quality (tinny)

I've used the onboard microphone with the same result.
This same problem shows up in Camtasia.
I'm new to this so something is wrong with my setup, or????

Other than that OBS works great.
Please help.