Expected AC compressor behavior?

Hello all, a quick question about the AC compressor. I've been so busy working on other things, that honestly I still don't know if my AC is functional or not. I've never tried it on a very hot day where the air coming out would be noticeably cooler, and given the current weather it may be a while. I just switched it on in the first time in probably a year... the fan works fine, but I didn't hear the usual compressor coming on sound or experience any noticeable engine bog down (but then again due to a lack of progress on the fuel system its still improperly idling at 1500rpm and quite loud).

Any thoughts? Should the compressor clutch kicking on be fairly noticeable?

 

Disclaimer: I know that was stupid question, but every car I've worked on to this point has no A/C to begin with. I don't even know where to start, this is a topic I have literally no experience. My guess is the system is low and then I get into the fun search for R12. But this car has surprised me in unusual ways before and a "silent" compressor was well within my limits of expectations for only a partial failure. Just not sure where to draw the line.

 

Thanks for the responses. Sounds like I do have an issue. I'll get someone who knows what they're doing to check the charge.