Fibe tv, sound comes on 1-2 second after changing channel

I have Fibe Bell tv and when I had cable, there was no lag on the sound when changing channels. Then I switched to Fibetv and since then there's a lag. My nephew has a Yamaha receiver and has no lag when changing channels. I even upgraded the HDMI to a network Hdmi and no luck.

Anyone familiar with this problem, Here in Canada Fibe tv comes through the phone line( internet) I don't know what's called else where.

thanks