How To Do You Measure the Quality of Your AC Power?

The responses above vary so much between “the power utility will do nothing so long as you have electric service” to “the power company will really help you with testing and equipment changes to arrive at a high quality of electric service.”   So, it really varies that much from one locale to another, and it is the luck of the draw what assistance you will get?

My experience (not particular to electric service or its affect on sound quality) is that the utility always wants me to have a professional check and repair problems within the home first before the utility will send anyone out.  The technician, having checked a few things, says “I checked the box and your outlets, so if you are still having problems you will need to call the utility . . . Just what are you trying to do? . . . Oh, I don’t know about that. I just verify that you have electric service and you do.”

The utility company in my area uses higher gauge wire than what is used for the service feeder. I guess they don't have to worry about the wire getting hot because it's in open air.

The dimming lights synchronized with bass notes or walking on a tread mill is a dead giveaway that power is a problem. When contacting your power company make sure you tell them about this problem up front. They should take you very seriously just based on this one factor. Even a 15 amp standard circuit should not experience a significant voltage drop from a typical Class A/B amp running at normal volumes.

The dimming lights are a result of voltage drops when there is just a modest demand on the circuit. That means that no power conditioner will solve the problem. You are going to have to tackle the source of the issue which is your power (you knew that).

When approaching your power company I would suggest that you communicate that this is concerning you from a safety perspective. Don't just complain about your SQ - some people might just roll their eyes and blow you off. When you say the word "Safety" they are going to perk up and listen. Tell them that you have researched this symptom and found that it could be an indicator of a serious problem in your electrical service.

If you don't have a multi-meter you can pick one up for about 50 bucks. You can do a simple check of your AC voltage and you can get a sense of how much the voltage is dropping when you crank up your system. This will be good information to have if your power company responds poorly.

Thanks to jea48 and a few others for excellent detailed information. Except for the usual snarky drivel this has been a very informative thread.

Take a look in these videos from Shunyata Research. Power is their area of expertise. You may find some practical guidance on them. Good luck.
https://www.youtube.com/watch?v=4qCK--lRFd0
https://www.youtube.com/watch?v=LHXP19fXN60&t=39s
https://www.youtube.com/watch?v=Z6f1kwyZbM8&t=35s

I have a dedicated line into my system. 
Pretty quiet. I have had few problems.