must convert low quality clip, but to what??

I’ve just started learning my way around Audacity, and my hope is to use it to put together a radio podcast of music, voice-overs, and the occasional sound effect or recorded snippet. The first little project I tackled was to take a phone message and edit it. While I’m quite pleased with the content of the finished snippet, the low quality of it seems to be dragging down the fidelity of the music I lay it on top of. The original phone msg was a WAV file, 8 kHz 16 bit mono at 128 kbps. After chopping it up and rearranging it a bit, I exported as mp3 (perhaps THAT’s part of my problem?) that’s also 8 kHz mono at 128 kbps (properties doesn’t tell me if it’s 16 bit). So now I lay that 6 second snippet over the intro of a song (an mp3 that’s 44kHz Stereo at 128kbps) and export THAT as mp3. That new mp3 sounds like crap, as it’s 8kHz/128kbps Stereo. Exporting it again as a WAV isn’t any better, although it’s 256kbps and, at 10MB, twice the size of the mp3 version (but it’s still 8kHz).

It has been suggested that I need to “convert” that phone msg clip to higher quality before mixing it with the song, but convert it to what (and how)? Thanks in advance for any assistance!

You can see the sample rate of a project at the lower left corner of the window where you can also change it (44100 is the standard).

In your case the project rate got probably changed to 8000 (phone quality) when you first imported the phone clip.