I have a shitty insignia receiver that is only rated for 6 ohm speakers according to the manual but a pair of suspiciously cheap ribbon speakers came up on craigslist that I'm probably going to get. The problem is that they have 4 ohms impedance. If I listen at a modest volume will I risk blowing my receiver?

The risk is more damage to the speakers than to the receiver.

is it from clipping?

and distortion.

I see, but please correct me if I'm wrong, I thought that was only a problem at loud volumes. I never listen to music with peaks over 70db.

running 4 ohm speakers with a receiver that is only rated for 6 ohms doesn't seem like a very good idea to me.

well shit. My roommate has an old JVC receiver that is rated for 4 ohms. I may have to swap them out.