No sound with AppleTV

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Setup: Sony KDL-46V2500 television; AppleTV model A1625; Polk Audio Signa S2 sound bar.
HDMI connected to AppleTV and television. HDMI connected to sound bar and television. Optical connected to sound bar and optical out on television.

When television Input is set to TV, audio and video work normally. When television input is set to HDMI/AppleTV, there isn’t any sound through the sound bar.

Any idea what I’m doing wrong?