I just upgraded to a galaxy s9 running android 8. I am using iGO nextgen (israel) and when the voice plays it starts out very quite and like your in a concert hall. The vice slowly gets louder and begins to sound normal. If it's a short phrase the voice never sounds normal. I have tried many different tts programs with the same result. I am also using the same voice files that I had on android 6 with no problems. Is anyone else having the issue or know how to correct it?