I NEED TO REVIVE THIS THREAD WITH THE DEFINITIVE SOLUTION * WITHOUT VOICE MAIL *
Tested on One UI 2.5, Jan 2021, Samsung Galaxy S9 (Snapdragon model) BUT MUST WORK ON ALL TYPE OF ROM!!!
• Since I bought the Galaxy S9 I immediately noticed the problem: the high-fidelity sound just sounded like an OGG (inferior to mp3 file, like whatsapp audios) audio from whatsapp recorded on a galaxy pocket, no matter how high the quality of what I was hearing was, the bitrate seemed to go to the smallest ever evidenced in the entire history of mankind.
• HOW BAD IS THE SOUND: I could see that not only does the bitrate quality drop unbelievably, but ALL AUDIO IS TRANSFORMED IN MONO.Worse than a normal mono, it is a fake mono. In fact, it does not fulfill even the minimal role expected of a mono sound.Instead of joining the Right and Left channels, ONLY THE LEFT CHANNEL BECOMES TO EXIST AND IS CENTRALIZED, CANCELING ALL THE SOUND THAT SHOULD BE PLAYED ON THE RIGHT CHANNEL. I realized this with the song Oui ou Non, by my favorite artist, Angèle. At the beginning of the song there is a stereo separation of her voice, which is a delight to hear in high fidelity with Tidal Hi-Fi/Master. I could also see that DOLBY ATMOS affects this fake mono audio. In Dolby Atmos mode set to AUTOMATIC you can hear the right channel a little. In MOVIE mode you can hear even more, as this mode has surround sound that amplifies the stereo sound, so it is possible to hear with the left channel what plays on the right channel through that surround. In MUSIC mode it is IMPOSSIBLE to hear the right channel, the same way with Dolby Atmos disabled, as this mode does not apply surround and just maintain the original stereo separation without radical changes in the original file. Great for audiophiles who don't want their files to suffer so much changes, just delivering a more powerful and balanced audio, very decent. In VOICE mode there is minimal surround, so it is possible to hear the right channel even without its real operation, as the surround makes the left channel able to hear the sound with an amplified sound stage. TEST ON YOUR OWN WITH ANY STEREO SOUND TEST APP ON THE PLAY STORE AND CHANGE DOLBY ATMOS MODES DURING THE CALL.
• THE DEFINITIVE AND EASY SOLUTION: I had problems on the phone (via radio, like sms) Whatsapp, Discord, Viber, and others, BUT NOT WITH THE TELEGRAM. No, I'm not telling you to make these calls on Telegram. Just start a call on the telegram with someone who will not answer the call (this works for the person you want to call on WhatsApp or other apps because the call will work at the same time).
FIRST: PLAY A MUSIC AND LET IT PLAY. IF THE MUSIC PAUSES AT THE BEGINNING OF THE CALL, PLAY AGAIN.
Start the call on TELEGRAM FIRST and then call the person you want to talk to via the app you prefer. The call on Telegram will drop (will fail) because the person did not answer, and when that happens DURING YOUR CALL IN ANOTHER APP, the audio will return to normal. YOU ONLY NEED TO DO THIS. JUST MAKE A TELEGRAM CALL NOT ANSWERED WHILE YOU ARE IN A CALL IN ANOTHER APP LISTENING TO MUSIC.
YOU CAN ALSO JUST FINISH THE TELEGRAM CALL SINCE YOU HAVE STARTED THE CALL IN THE OTHER APP AND ARE PLAYING THE MUSIC.
I'm happy to have found the solution, I hope more people will find out.