how do you get a mp3 to sound like a tape playing

[russellw]

The usual purpose of audio utilities is to remove the various artefacts that come from vinyl and tape mechanisms but there are probably a couple of things you can do to an MP3 file to make it sound closer to audio tape:

1. Reduce the frequency response to about 15 kHz as that was about all the format was good for.
2. Introduce a tape 'hiss' at around 500 Hz - most audio software will have a tone generator to do this.
3. If you want to get more authentic, you could add a small amount of low-level pitch modulation (probably using vibrato) to simulate the effect of tape transport.

Of course, you could just record your MP3's to a tape recorder.