99 times out of 100, it's wire management.
These clips are cute yet you don't need all this.
The Dollar Store is your best friend!
Purchase some tape and some tie wraps, an old bicycle inner tube might be found in the garage.
Begin by unplugging everything.
As you begin to repower all your devices keep low voltage away from AC as well as keep your data / router as far from all powered devices as possible.
Next you're going to look where each device sits and run your power chord as straight as possible to that device without, in a perfect world, crossing other wires.
*In ideal situations you wouldn't have all these devices plugged into one wall outlet yet this is a leased flat.
If this is your home, you'd also disconnect the ground wire to the power outlet and run another ground wire, minimum 6awg to a ground rod on the opposite side of your home from where your meter base is mounted.
Don't worry about all that.
Not necessary in most instances yet I recommend you purchase an "UPS" which will provide clean power as well as continued power in times of outages. This will give you the time to save data and shut equipment down properly.
This is also not required to clean up the hiss, clicks, distortion and slow data issues that most face.
Do you have every thing reconnected in as straight a line as possible?
Good
Go back to the sources and take up all unnecessary slack and wire wrap it. Use plastic tie wraps or tape. (Tape guts gummy and messy with heat, humidity and over time) You can even use rubber bands but for gosh sake Don't use metal coated twist ties!
This is what you want to see.
All powered equipment produces some type of EMI / electromagnetic interference yet you can minimize it's effect for a couple dollars.
This simple technique will clean up cross talk, hissing, buzzing and give your equipment the speed, data and clear sound you paid for.
