Bad Call and Siri audio on CarPlay

Hi everyone,

tricky question only for experienced users.

I have a Seat Ibiza Connect 2015 and I'm experiencing the following problem.

When my phone is connected through Apple CarPlay, the audio coming from voice calls and Siri come out only from the front TWEETERS, resulting in a metallic and low volume voice (unusable to make/reicive phone calls).

Navigation voice from Maps and Google Maps also has this problem.

Music audio audio from Apple Music, Spotify etc.. instead WORKS PERFECTLY.

Everything (voice, siri, music etc..) worked properly until around April/May 2021.

My Iphone X is updated to iOS 15.2.

I tried to change the cable (I use the original iPhone white cable), to change I think every possible audio, bluetooth and accessibility setting, to forget the car as device in CarPlay settings, to turn bluetooth on/off, to initialize all the settings in the iPhone and I still have this problem.

My iPhone perfectly works in my friend's car CarPlay (it worked even before doing all the stuff mentioned above) so I tought it was a problem of my infotainment system.

Plot twist: my girlfriend's worn out iPhone 8 works perfectly with my CarPlay.

My car infotainment is a MIB2 with the following specifics: Hardware H24 and Software version 0241.

I tried to adjust some setting and eventually initialized all the settings in the system and it didn't solve the problem.

So I managed to update it the 0346 version and I still have the problem. (I may update to the 0479 versione but I don't think this would solve the problem).

Can some good sould help me to figure out which can be the source of this problem?

Thanks.

Tip: approx one month ago I received a phone call through CarPlay and magically it had perfect sound!

disappointed that it lasted only some minutes then switched to the "normal" crackling metallic tweeters sound.

Pro tip: The built-in voice control of my infotainment system gives the confirmation sound of voice commands through the tweeters (the sound is the same metallic sound that I'm struggling with) and it used to do this even before the appearance of my CarPlay problem. So they may be related.