Well, too many words and no concrete recommendations, as usual. i assume original poster uses HDMI cable connection to the monitor. HDMI is particularly sensitive to impulse interferences as it uses weak signals (~800mV) at rather high frequency. Especially with a cheap cable having thin shielding. My advice is just to ignore this (I had this too when connecting my monitor to a Blu-Ray player with a long cable) or to use a better cable, with a thicker shield and preferably interference-suppressing ferrite core molded in the middle. Ferrite core breaks ground loops at high frequency, working as a transformer, and so makes the life in that respect better. You may try to clip a ferrite core / tube on the cable yourself if you have a spare from some other equipment.

Yeah I just checked and Ace does still sell it, although only one of the stores I see in my tri county area has it in stock. They have them on Amazon too.

The only commercial post top I saw on a house was a GE PM series post top that's painted black. Haven't seen it at night but it's been around (and still is) as long as I can remember.

@Cole D.: I have seen the Caretaker sold at an ACE Hardware. I think 29w 4000K for about 130 dollars and the refractor (sold separately) was either 20 or 30 dollars. Not sure if that ACE still sells them though.

I remember a dentist office I went to in the past that was basically in a house that was repurposed and rezoned for commercial use.

Inside had the typical layout of a house with the standard ceiling heights and such, but modified to be a dentist office with some modifications.

The lighting was a number of 4 & 2 bulb T12 surface mount troffers and wall lights which were 5000K. I don't think the electrical system there was too happy because the lights seemed flickery and briefly dimmed whenever a dentist started up a machine, and all the LCD monitors would go black for a second. 

I haven't been there in over a decade, I imagine it has since been changed with T8 and probably LED by now. This wasn't some sketchy place either, the dentist is a well respected one. The area is mostly modern commercial shopping buildings with a handful of old houses here or there that were there when it was all farmland, and are now used for businesses.

There is one important note to make: All things interconnected by anything else than just fiber optic or an Ethernet cable must be supplied from one single point (socket). That means the computer, monitor, those speakers, printer, etc, needs to be all connected into one common extension cord strip fed from a single wall outlet. Otherwise loops formed via mains wiring, mainly if the grounding conductors are connected far away, is an "inviting" thing for all kinds of disturbances. And these "disturbances" not only means spurious glitches or cracks when lights are turned ON/OFF, but also destruction of the equipment if a lightning strikes anywhere near your home (the magnetic field induces high voltage into such loops, this high voltage then fries the equipment).
And the eventual filter must be on the common feed into that extension cord strip.
Definitely do not connect just some devices behind the filter and some somewhere else, that would make the situation even worse.

And make sure all cords have grounding wire in a good order, even when many power supplies do not actually use it for direct grounding, they use it to prevent Y capacitors to pass mains AC leakage to the secondary side.
And do not use questionable quality power supply boxes for the notebooks, printers and so on, they may be lacking the EMC filtering normally mandatory (it is practically impossible to pass EMC limits without them) in such devices, as those filters cost quite some money but are not directly "visible" in the main performance (power, efficiency,...)...

Yeah I remember hearing about Princess Auto.

Similar to that, seems like there was a utility grade LED fixture being sold here in the US by some retailer, but I can’t place who or which one.

Maybe the Cooper Caretaker?

This topic has been moved to Site Questions & Suggestions.

https://www.lighting-gallery.net/index.php?topic=16487.0

First thing to try is to add a mains filter to your speakers' power supply. Something like this: https://elektrodump.nl/nl/lichtnetfilters/2442-lichtnet-rfi-filter-4a-250vac.html
This one is meant to build into a device. There are smaller ones too, just make sure they at least have a capacitor-coil-capacitor layout.
Make sure to hook the filter up to a grounded outlet, and if your speakers have it, to connect their ground too.
This will suppress the RF pulses that the various inductive loads create.

Before the filter, you want to put a surge protector. This is to short out any high voltage spikes that may be present on your mains, to extend the life time of the filter. They don't last forever.

I'm assuming active speakers with built in amplifiers here, not standard speakers with a separate amplifier.

In general, if literally all lights and the fridge do it, the issue is your speakers being too sensitive. But it's a fact of life that glowbottle starters and inductive ballasts puke out a ton of spikes and RF when starting. That's why many countries have strict RFI rules. If you have a ham radio operator nearby, you can ask them for help - they typically have a lot of experience with RFI suppression.

You also want to verify that the suppression capacitors in your lamps' starters are still in good condition, or that they're even just there.

Thanks for the answers. Apparently, all of my other fluorescent lights make that too.

But now, I came across another interference thing. I recently installed some speakers to my room, and they run on AC power. Basically ALL of my fluorescent lights, INCLUDING the ceiling light, cause interference to the speakers and it can be heard as loud pops. Can that be reduced somehow? Also, once my fridge turns on, a small pop can be heard too.

i’ll update you tomorrow since i don’t have it between my hands now. it also may be a strange tube since the rack were i found it said “85W 150cm” so it may be a strange size but i just assumed it was a mislabeling but i didn’t have time to check whether it’s 180cm or really 150cm (in that warehouse multiple things are mislabeled, such as ballasts labeled as rheostats)

it’s not 1.80m it’s 1.5m 
what kind of tube is this?
here’s it lit on a 65w ballast