HW-MS650 paired with SWA-9000S has unexpected audio ‘echo’ from rear speakers
Something odd that I've just noticed, since bringing the rear speakers closer to the listening position on speaker stands, is faint audio, like an echo, of the main dialogue or music from stereo/mono sources.
I've seen messages about low volume issues from the surrounds, which I do not experience; but never this weird echo.
The unexpected audio is present on every sound mode, and obviously "surround" boosts the volume on the surrounds, and is entirely expected.
The typical setup is HDMI ARC from an 55MU8000 to the soundbar, with sound output set to Dolby Digital. Side note: I wish the telly would automatically pick up DTS from streaming apps, instead of defaulting to PCM. Have read this is by design, but that is bad UX. Anyway.
Setting the TV output to DTS Neo 2:5 provides nice surround sound effects; but leaving the output as Dolby Digital or PCM with a 2.0 audio signal, produces this peculiar echo on the rear speakers. The audio is both unexpected and undisirable, because it doesn't sound good. It is simply a quiet, sometimes crackly, version of the main stereo audio.
Have tried various things, like updating the firmware of the soundbar over the air, setting the surround speaker volume all the way down, and flipping between TV sound outputs. Seemingly no effect.
Playing music via the Multi-room app from Tidal, or Tune-in produces the same effect, on every sound mode.
While it's not a big issue with music, it is seriously distracting with dialogue, on TV shows.
This rear-speaker sound reacts to volume up/down, so it suggests this too is "by design"; but I don't want to manually turn off the rears just to silence this ghost signal.