My version is for Lexus GS 3ed Generation with nav and an OEM Mark Levenson AMP.
My external ML AMP is connected. My Lexus has 12 speakers.
With all wireing connected correct and the OBD port plus the data connection to the AMP, I had audio issues with small popping but what concerned me was the audio was loud every time I started the car or would reboot the PX6.
After talking with a P.A tech I could tell he had no clue. He told me the settings I wanted to adjust in the Android Settings - Sound, it would not save after I change it and reboot.
I found that all the Android units have hidden audio settings and on the new 2021 PX6 the Factory Settings are locked out. A code display will not display to access the Factory Settings. Some or all of the audio settings are in that, Factory Settings.
After days of trying things I found that two things may help the loud audio issue for a work around.
1.Volume Lock (Play Store, AD supported)
2. Musicolet. (Play Store, Free)
I used Vollume Lock to show and display hidden audio settings. Problem is that after you adjust audio in Volume Lock it also changes back after boot.
I found out that installing Musicolet and adding music, I loved this player more than the Android default. Then I found that if you open Equalizer and it opens its Musicolet version that works good however I like the DPS EQ on the Android better.
So, I then found that if you go to Musicolet EQ setup and CHANGE the EQ to use System EQ, it opens a hidden system EQ !!
I adjusted the hidden system EQ to lower ALL EQ settings to about 5% lower, evenly on all frequency, it did affect all other audio settings, audio player, bluetooth and radio. It lowered all audio sound with the hidden system EQ. IT KEPT ITS SETTINGS AFTER BOOT!!
All my audio sounded fantastic. It was no longer loud after boot or car start. The popping was gone also.
What I think was happening was the preamp inside android was to loud and the system EQ fixed it by lowering all frequency down 5% or more.
So, I hope that helps.
So far I love the Android. Only if P.A techs would find a fix for the boot logo. The P.A boot logo no longer works with the new 2021 PX6. I am stuck using logos / car photos that are not my Lexus...