Hi. I’m trying to get the challenges “Numbing Expert” and “Music soothes the Soul”, and I’ve found a number of boomboxes in containers in Nyhamnen near Östervik. But it seems they don’t respawn at the regular rate - at least it seems car engines and ammo boxes have respawned (after 4 hours), but not the radios.
Does anyone know the actual respawn time? Or any other good places to collect many radios/boomboxes?
Thanks 
The industrial area slightly northwest of Östervik should have some. I would also recommend checking Boo Bruk AB, there might also be some in Fiskebäck.
Do you have DLCs?
Radios are quite often spawned at Dump Hatches. Brevken camping (NW of South Coast) is a good looting place for these hatches. Requires FNIX Risng.
Himfjall’s radios are all respawnable AFAIR. Even first island’s safehouse have one. Require Alpine Unrest DLC.
I don’t have FNIX Rising, so take this with due caution, but as far as I could tell, radios and boomboxes don’t respawn at all. I have picked up most of them on the mainland, and they’ve yet to reappear after hundreds of hours of playtime. I got scarred for life by this discovery, so I never picked them up un Himfjäll later on 
Boomboxes in warehouses (the ones with 10 gas cans inside) do respawn every time you reload the game.
For example there are two of these warehouses in F23 Överby Air Base.
Thanks a lot for the suggestions guys. A lot of the comments make sense, also as to why some of the radios and boomboxes seem to never respawn. I have all the DLC, and I’ll go look at the alternate suggestions again.
Thanks a bunch! 
I can’t find any radio/boombox in those two warehouses, I never play in multiplayer should that matter for respawning? I did find one on the first roof level of the Red brick (ATC) building. Not sure if that one will respawn.
Here’s a guide to the boomboxes at Överby Airbase, Österviks Industriområde and Hjortqvarns Sågverk. The placement of the boombox is the same in all warehouses with this layout.
So this is 6 boomboxes that can be farmed over and over again. This is by far the most effective I’ve seen, so huge thanks to 0L0 for the tip!
Warehouse 1 in Överby (and boombox placement inside all similar warehouses)
Warehouse 2 in Överby
Map of Överby Airbase
Map of Österviks Industriområde
Map of Hjortqvarns Sågverk
Fast travel to Kalkbrottet up in the north. The boombox in the warehouse respawns every time you leave and revisit the area. Just sayin’… 
That must be the same type of warehouse then - good to know.
I have updated the GZ-Map 3 with all the boombox locations I could find so far. I only took warehouse locations that had a white car door at the wall where also a boombox stood in the rek.
Updated map:
Wouldn’t it be easier mid/late game just to create radios and boom boxes from schematics so you only create them when needed?
Radios are at the top of the tree and Boom boxes further down…(Then I realised I’m 2-3 years late lol)
it was much easier in 1989 to buy blank cassettes from wallmans and share with a friend with the dual boombox 
now, the dual cassette boomboxs are illegal & Wallmans not allowed to sell anymore
