That's a really big clip - 18MB! That sounds more like a rotating metal to metal rub to me. How fast were you going, and how does the rate of the sound compare to your RPM? If you accelerate while it's "chirping" does the rate of the chirp change in proportion? Does it make the same noise parked with the AC on? Wondering if maybe your AC clutch has something loose or bent, or maybe a bad bearing? Clutch freewheeling is fine, but then when it locks for the compressor there's a rub/bearing noise?