I have a 2005 Acura T/L and when I press the button to make a call, if I have the volume 1/2 way up, it is at the right level for the Bluetooth voice ... once the call is connected, I can barely hear the person I called so I have to turn it all the way up to even hear them. Then ... when I make the next call, the volume on the Bluetooth 'blasts' me out! Anyone experienced this???

 

I had a similar issue and I was able to correct it, but it's been years so bear with me. First recognize that the volume knob controls both the radio and phone call volumes, but they are different settings. Thus you can jack your radio up to whatever, but it won't affect the phone calls unless you change the volume during an actual phone call. (Makes sense, actually.) So first set both the radio and call volumes where you want them. I think the Bluetooth voice might also be controlled by the radio volume and that might fix it. Another possibility is that the Bluetooth voice volume is controlled by the Nav system volume. This is yet a third volume you access through the settings on your Nav screen - screen 1. Try that. Finally, I vaguely recall that with some phones changing the volume on the phone changes the volume through the Bluetooth. So set the Bluetooth voice volume where you like it, then adjust the phone's volume on the phone itself. As I type this last suggestion, I realize it sounds ridiculous, but I swear that worked for an old flip-phone I had (pre-iPhone days.) Sorry to be so vague about it, but I just don't recall exactly how I solved it, but it was one of these options. For what it's worth I also have an '05 TL, MT with Nav, and am currently running an iPhone SE (essentially an iPhone 6) through it.