Hi All,
This is not about the soundbar and 4K. Probably your soundbar supports 4k.
The problem is due to the HDCP
standard. Solo 4K supports the latest HDCP 2.2 standard which unfortunately is not backward compatible with earlier standards (e.g. HDCP 2.0) that were built in devices through 2013, 2014, 2015.
Basically the HDCP 2.2 chip was not available at those years, but late 2015.
HDCP is used for DRM purposes in Sat receivers and in several devices.
You could Google up HDCP coverters that can be hooked on the HDMI cables to solve the problem. They are quite expensive, not sure they worth to buy. Here you can read full article on the issue: hdcp-error dot com.
I run into the same problem with my amplifier.
BR
Tibii