My vacuum makes a loud noise like a soccer horn going off, and neighbors are yelling at me for it! how do i make it quiet? its a bissel.

I've owned a Bissell Clean View II for a number of years and recently it started making a loud noise when turned on. Best described as a loud humming noise. This was accompanied by poor vacuum performance. It would leave lots of debris on the floor or drop some back after initially sucking it up.
After searching Bissel forums for answers with no luck, I decided to take it apart to see what was up. The noise was coming from the motor housing. After getting it apart by taking about ten screws out, I found the source of the problem. There is a built in relief valve in the motor housing. Although it looked fine, I decided it (the spring that holds it closed) had become weak over the years and was being sucked open under normal use. I removed the valve, disassembled it and stretched the spring slightly. After reassembly, I tested it by putting my hand over their air intake. The noise was gone. I used the vacuum and it works perfectly. If you don't feel comfortable taking the vacuum apart, have a professional do it. If you know your way around basic mechanical devices, it's an easy fix. By stretching the spring, it may not relieve strain on the motor as designed. For factory renewed performance, you could just replace the valve with a new part.

If you haven't changed the belt recently I would try that. Worn belts can cause funny noises sometimes. You can get Bissell replacement belts here:

www.bissellbelts.com