What model is your TV and how is the Arc connected to it? Are you watching a Dolby Digital 5.1 or Dolby Digital Plus 5.1 source?

TV is a TCL 65S535. I have the Sonos ARC connected via the HDMI eARC connection.  The issue is consistent across Atmos, Digital+, and standard Dolby Digital.  

What specific issue are you having with the Arc other than it doesn’t sound as good as the Beam?

Also, be sure you have your TV audio settings set to Pass Through not Auto.

Okay, just finished a retune process.  Sounds WAY better now.  No more harsh sibilance and the clipping in loud spoken voices seems to have gone away.  Never had a failed Truplay setup before but clearly it can happen.  For now I’m a happy camper. 

I have to use auto detect. Pass through results in 2.0

The Pass Through setting is the ideal setting because it results in the original audio being unchanged by the TV - stereo 2.0 audio sources will play in stereo 2.0 and Dolby Atmos audio will play in Dolby Atmos. The Auto Detect setting allows the TV to convert all audio to the highest quality audio the Arc supports.

Pass through on my TV  results in PCM 2.0 regardless of the source or encoding.  Had the same results with the BEAM.  Back to the anemic, sibilant sound this morning.  I have seen many others are hearing/having the same disappointing sound quality.  All of my other SONOS products are excellent.  

It’s strange, I’ve seen a few other reports of disappointing Arc sound quality online, but i have had no issues with mine. It’s indisputably way better sounding than the beam I had before and the playbar I had before that. Seems there is either something funky with your TV output or you have a faulty Arc. 

@chwdroid What other options do you have on your TV other than Auto Detect and Pass Through? Have you adjusted the Arc’s EQ settings? Also be sure Night Sound and Speech Enhancement are both turned off.