Are you are you attempting to control channels on the TV or a cable box?

Cable box.

However, if I get really close to the TV the remote will change channels

I just found out that I have 30 days to return it this system if this doesn’t get fixed.

Hmm. How could the Arc disturb the connection between cable box and TV?

Just use the CEC protocol to control your TV and connected peripherals - see this link:

https://en.wikipedia.org/wiki/Consumer_Electronics_Control

CEC is enabled. This is what I just found out; 1. my Samsung TV remote is controlling the TV volume over wifi. BTW IR is ""ON" on Sonos app.

2. I cannot turn off the soundbar with any remote control, it has to be done manually 

3. My cable box (spectrum) remote can control the TV, channels and volume; however I would need the Samsung remote to access the other features such as Netflix, prime, youtube etc.

Note the soundbar has no ability to be switched off (other than by unplugging it from power at the wall). It’s meant to be in standby/sleep mode when not in use and is always ready to be used as a Music speaker aswell as a TV speaker … so no remote will power it off. There are options in the App to switch off LED light etc.

It sounds like you need to set your cable box to be controlled by your Samsung TV remote - check your TV user manual for ‘universal remote’ control of connected devices - note these things are not anything to do with your Sonos soundbar by the way, it’s just a case you need to setup your Samsung remote.

I don’t use infrared on my soundbar (by choice) as I just control it over CEC but if you want to use the TV remote to control the soundbar (for music) when the TV is ‘off’, then perhaps leave IR enabled, but that’s entirely up-to you.

The Samsung TV remote worked perfectly until the SONOS ARC was installed, hence not a TV issue.  In fact last night I unplugged everything (power and HDMI) cables.  The TV was turned on without the ARC soundbar connected and the Samsung TV remote totally worked.  Then as soon as I connected the SONOS soundbar I lost the capability to change channels, the TV remote control can still change the volume though on the soundbar.

I am personally stumped at to why attaching any soundbar to any TV would stop its remote changing the TV channels, so you are perhaps best to speak with both Samsung and Sonos Support Staff and see if they can assist you, rather than posting here to the Sonos ‘user’ community.

To help get you started, it maybe best for you to go onto reproduce the issue and submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and then contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to resolve the matter. 

I think a CEC blocker installed between TV and ARC would help. Also, if you can find the option on your TV, experiment with enabling and disabling RS-232 control. In your setup RS-232 is meaningless, but I’ve seen some reports complaining that it’s setting can cause trouble on some SAMSUNG’s.