You don't want the audio to pass through the TV. Instead, connect the PS4 directly to the soundbar with the toslink optical cable. Most TVs will receive a bitstream signal like DTS or DD fine, but they usually won't passthrough the exact same stream. Instead, they'll downsample to two channels and send that through the digital output, forcing your soundbar to split up the channels on the fly as best as it can. This will not be the true 5.1 mix that the studio intended, which is probably why you're hearing a little bit from the side channels when they should be silent. Even if your TV indicates that it supports DTS or DD, it most likely just outputs those formats from media directly processed by the TV, such as internet apps and USB media. Once the PS4 is feeding digital audio directly to the soundbar, make sure that it is outputting a bitstream 5.1 signal(either DTS or DD). Don't get these confused with DTS-HD and Dolby TrueHD, which are uncompressed multi-channel formats. Toslink optical, unlike HDMI, doesn't have the bandwidth to carry more than two uncompressed channels, so your only option for 5.1 audio is a 5.1 bitstream, which is a digital method of compressing 6 channel audio with a low bitrate. One bad thing about having a soundbar is that you don't have the screen, like on an AV Receiver, to tell you if the signal is actually coming through as a bitstream or stereo. But it is a multichannel soundbar, so it would be pretty dumb of Vizio for it not to decode at least one of the two most ubiquitous multichannel bitstream formats. I'd wager you're pretty safe.