Help! Audacity 3.7.4 Audio and Background Noise Reduction

Hello everyone,

New here. First post. I am using Audacity 3.7.4 and I transferred audio from a cassette tape unto my Windows laptop. The tape was severely fast-forwarded to fit the entire contents on the tape. I am EXTREMELY Audacity illiterate, despite my best efforts to understand the system.

My question is two-fold; how do I permanently slow down the speed of the audio/speech and how do I remove the background scratchiness. For the second part, I’m not sure if that is even possible. But it would be amazing if it was!

Thanks everyone!

Effect → Speed and Tempo → Change Speed and Pitch. This changes speed and pitch together exactly like changing the speed of a record or tape.

Then Effect → Noise Removal and Repair → Noise Reduction. Noise Reduction needs you to supply a sample of noise only.

There is also a new optional AI Noise Reduction Plug-in (I have not tried it.)

Note that with noise reduction there sometimes be artifacts/side effects, especially if the noise is bad, and sometimes, "the cure can be worse than the disease."