recording through mic on laptop

I am trying to convert cassettes to MP3 using Audacity. I have male RCA cables from cassette deck to male 1/8th mic input on my laptop. When recording it sounds fine, when playback, it sounds muffled, “computerized”, volume goes up and down… I have tried different settings, yet get the same result. Cassettes play fine over the stereo. Am I doing something wrong, or is this program just not compatable ? Thanks for any help.

This isn’t as plug and play as it would seem. Newer Windows laptops are business machines designed for voice conferences to the home office and other corporate activities. They’re not music machines. The processing that cleans up echoes and noise from your conferencing voice hates music.


Also most laptop “mic” inputs are designed for a “computer microphone” and nothing else. They will be overloaded by the line-level signal of your cassette deck. Your best option is to add an external USB interface such as the Behringer UCA-202.