Reddit reviews Brinmar SBUHD Universal-Fit Air Conditioner Compressor Sound Blanket Wrap (#0421A)

Air source heat pumps lose efficiency as outdoor air temperature drops. The compressor has to work harder. Put an acoustic blanket like this one around the compressor(s). It'll reduce the dBA level by 40%. Much cheaper than an acoustic box.

https://www.amazon.co.uk/dp/B008J5H6I2/ref=as_li_ss_tl?slotNum=2&language=en_US&ie=UTF8&linkCode=g12&linkId=a1294a23791123d47df71a7ad2727573&imprToken=pxv32azsr7mR3hiGlzI67w&tag=hitthegolbal-21

Like 3.5' x 2.5'. Or, at least, I think that large noisy vent in a central location is the return...

Aftermarket compressor sound blanket wraps are indeed a thing I don't know much about them either.

• New units are tons quieter. That, and moving it would be the best way to solve it, but not the cheapest.
  
  
• A compressor blanket might help somewhat if yours doesn't already have one. Be sure to shut off the power before digging around in there. Check the size, but this is one product in that category. https://www.amazon.com/Brinmar-SBUHD-Universal-Fit-Conditioner-Compressor/dp/B008J5H6I2
  
  
• Have an HVAC tech check pressures and temperatures, and adjust "freon" charge if needed. Under or overcharged units can be noisy.
  
  
• Don't restrict the airflow. The install manual for your condenser unit will call out the minimum required clearances. Three foot is a general rule from what I have observed.

And I'll thank you too.

https://www.amazon.com/Brinmar-SBUHD-Universal-Fit-Conditioner-Compressor/dp/B008J5H6I2

That stuff is not cheap. :-(....but still doable.

there is this for ac, very expensive though
https://www.amazon.com/Brinmar-SBUHD-Universal-Fit-Conditioner-Compressor/dp/B008J5H6I2

You can insulate the compressor no problem. They are cooled by the refrigerant and the motor heat removed via the condenser, so insulating the compressor itself won't cause any problems... though personally I would leave the electrical area exposed to allow heat from the relay to escape.

Air conditioners often insulate their compressors to reduce noise and condensation, and use covers like these: https://www.amazon.com/Brinmar-SBUHD-Universal-Fit-Conditioner-Compressor/dp/B008J5H6I2

Not sure on your use of material. You can poke it around anything you think is rattling I guess. Compressors in bar bridges tend to be pretty quiet, so it could be a pipe just gently tapping away on a metal edge somewhere. Usually no fan motors associated with bar fridges, so it's unlikely to be a fan.