finding a way to run power tools so they're slower and quieter

Power tools that cut metal (eg. cutting wheel, power nibbler, etc) are way too loud to run in my shared condo / apartment space. Is there a way to run these at a somewhat lower speed, so they cut a little slower but also more quietly?

• Angle grinders — Some angle grinders have a variable speed feature, which would allow me to reduce the speed to the minimum needed for each operation.
• Cutting — TODO: I feel like handheld plasma cutters are quieter than a bandsaw or metal chop saw, but I might be wrong. However, note that plasma cutters do put out fumes and dust, which could make it difficult to use inside a residence.