I don't think anything pertaining to you is very clear...

you better contact your network provider they should be able to assist you. Has the signal always been poor?

Maybe your phone signal is not good or the corresponding function on the phone doesn't work well.

I've found the sound to be clear but the signal strength cuts out sooner than my last phone.

Yeah, if there has a problem with your cell phone about the voice, you should just adjust the The volume by going to the volume settting. But if there is no problem with your cell phone, probably there is a bad signal and your cell phone can not receive very well, you should change a place to get better signal.

Yup, when my phone is having a poor signal. Check your signal first and if it's full you'll probably need to have your phone checked as it may be that the phone is grounded or static

when I am on a call the other party cannot hear me well. they are telling me that my voice sound muffled and it is not clear. I have to constantly repeat myself. Has anyone faced this issue?