I got the APC Line-R 1200VA Line Conditioner With AVR installed in front of the UPS and couldn't be happier now - it steps down the voltage and gives the UPS peace of mind.
Try the APC, not the most expensive thing but it's worked well for me.
https://www.scorptec.com.au/product/UPS/UPS/44933-VALUE1500E...
I also have one of their smaller BRICs for my HTPC / home NAS JBOD server: https://www.scorptec.com.au/product/UPS/UPS/40279-BR850ELCD
The voltage in that part of the house appears to be better, but the circuit is easily tripped when running toaster + micro or similar, so having these UPSes has taken a lot of frustration away.
Actually just checked my invoice and I got them both in 2012, which is a little while ago now, and they're still good with their original batteries.
Bad wiring and a sub-par setup will make that bleed right through your speakers.
There are definitely things which can perceptually detract from audio which people just don't think about.
I'm about to buy a couple power conditioners for my electronics because the wiring in my new apartment is garbage and every little spike in voltage comes through as a loud pop in my speakers and headphones.
But more subtly, my audio is constantly being degraded because I have a few cheap dimmers which cause a constant interference pattern in my electrical circuit that weren't a problem in my last apartments, and I can even hear fluctuations caused by my refrigerator if I listen closely.
And all of these things which can subtly degrade audio are 100x more of an issue when you're recording audio. Run any given song through a spectrogram analyzer and you'll usually see a horizontal line or two which could be anything from a little cable noise to a CRT screen.