I don't have other digital source.
They are connected to Denon receiver using HDMI. My Denon has only one HDMI input. So the problem happens when I have the new SONY BD player connected to Denon. Once this happened, I tried my old OPPO DVD player and get the same results. So I suspect the receiver is damaged.
So I borrowed a Pioneer receiver. I have both my BD and DVD connected to the pioneer receiver. I remember the sound is fine when I played CD on both players via HDMI. But when I played blue ray disk on my SONY BD player, I lost the front right speaker again. Then play CD on either my DVD or BD player on Pioneer receiver doesn't have front right speaker sound too.
So my suspection is the new SONY BD player caused the damage of both receivers.
So looks like I need get a good BD player (may be from OPPO) and a new receiver (Since my old Denon only has one HDMI input) and get my friend's receiver repaired (that one is still in warrenty)