Mates...
I'm going to toss in some things that may be of interest to newbies and potentially some salty veterans of our beloved hobby. I have become inured to the slings and arrows over decades, so...
Every several months, unplug your gear and anything with a surge risk, then go to your electrical panel and flip the main and each individual circuit a few times.
Even if you do not have a dedicated line to your audio system, upgrade to at least a hospital grade outlet, even in apartments. If you must have other electrical devices on the same circuit in your apartment or dwelling, especially a fridge, furnace, or A/C...plan your listening around them if possible. Additionally, there are shunting plug-in devices that do help quiet their outlets, for little money. As a lifelong audio guy who rented for many years, I took it upon myself to meet my new neighbors, explain my hobby and show respect for their lifestyles. It works.
From the mountaintop...treat your room to match its loudspeaker placement and design. Nothing is more cost effective in creating the best sonics for that space. A couple clicks will find concrete information, sourced from reliable sites. Some offer a free evaluation of your specific room, following up with advice. Simply, not an area to skimp.
Level and physically isolate your electronics, taking care to not run power cords parallel to other cables, crossing them at 90 degrees if necessary. An inexpensive start for isolation is Vibrapods and Vibracones, paying strict attention to the weight of your boxes and location of pods, as recommended on their website (noting the added weight of plugs and cables.) Caution, the pods can mar surfaces. Playing cards serve well between them and surfaces.
Some have suggested placing weights upon loudspeakers, particularly monitors, without a "why." Judicious weight to deaden the box atop stable, non-resonating stands is important. Some go to lengths of shoring up the flooring beneath the stands like you might for a turntable. If that's not possible, experimenting with tiptoes may work. High-end manufactures go to heroic extremes to deaden materials surrounding drivers. Other inexpensive ways of deadening loudspeaker boxes include Mortite with flattened strips of lead inserts, maybe inside the box and crossover board. This can serve for corners of resonating windows also. At the very minimum, carefully tighten up the nuts that hold the drivers in place.
Over the years, my more elegant solution to reducing vibration and hysteresis is in carefully applied Marigo Tuning Dots to cabinets, and under the hood of electronics, crossovers, and connectors. This article is dated, yet no less applicable today: The Audiophile Voice | MARIGO AUDIO LAB
I'll stop here. As an ACTIVE music lover with a great passion for improving sound for myself and others, I remain alert for ways to promote great sound for anybody who may have interest. Just yesterday "The Audiopheliac," Steve Guttenberg released a video on his YouTube Channel...a studio tour and interview with pianist, composer, producer and arranger, David Chesky. David has spent his career improving upon and sharing great audio. He is graciously evenhanded in his patience and tolerance for others. allowing them space in their journey, and in how music works for them. A true Mentor.
For those of us more scientifically searching, the BACCH-dsP is firmly upon our audio horizon.
More Peace Pin (bold print for old eyes)