A/C compressor question

As you can well imagine, living in Tucson, the A/C spends a lot of time running. In fact, my battery guess-o-meter said 32 miles this morning, primarily due to the heat.

My question is more curiosity than need-to-know, but I've listened to the compressor many, many times and it sounds like it is a variable speed unit. I did some searching on this forum and learned that the compressor is A/C (alternating current), 3-phase, and 300 volts. But, I did not find an answer as to whether it is multi speed or variable speed.

My home A/C compressor is multi speed, so I'm familiar with that as the two different speeds are very distinctive. The Volt, however, certainly sounds like a variable speed unit. Just curious if anyone knows for sure.

I was certainly pleased to read in my searching that the A/C compressor is considered part of the Voltec system and is covered under the powertrain warranty. Another big plus for the Volt, and for GM.