Technical "Strange belt sound" on startup (1.6 16V)

[fiatritmo]

My Stilo 1.6 tends to have a "strange belt sound" on startup, but it disappears after a few minutes.

Does anyone recognize what the sound indicates, and whether something needs to be fixed?

For a video clip, see

 

[danhans115]

That sounds like the aux belt. Might just need a new belt as that noise it the belt slipping.

My old alfa 156 used to do this, I squirted loads of WD40 on it which made it go away and come back 100x worse.

 

[Deckchair5]

Good call on the aux belt. 1st task is make sure it's tensioned correctly. Alternator is working hard to recharge the battery after first starting the engine so that's the biggest load