Call Volume

[monicakm]

Most people I've talked to using my GW have had no issues with the volume or quality of my voice. But, I've gotten a few calls where after several hellos the caller just hangs up. All the volume settings I've found on are set from 8-10 but during a call, the volume is 6 and can't be set higher. Just got a call from my husband and he heard the first "hello". Entire conversation was heard just fine. Can you adjust your call volume more than 6? Not ringtone, but the speaker volume you see when you tap on the speaker icon during a phone call.
Thanks