the TV must have ARC if it has 4k. it can't be that old. maybe ARC isn't written on it. And the cable must be ARC-capable. Doesn't the soundbar have an optical input? PS: The soundbar alone does not bring ATMOS ;) Then I would buy a proper Yamaha 7.1 or 9.2 amplifier in your place and enjoy ATMOS.
Thank you, looked good until: * The VAX01202 can NOT be operated on an HDMI-ARC or HDMI-eARC connection of a soundbar. Only on a normal HDMI input of an AV receiver, for example "AUX" or "Bluray". If the soundbar has only a single HDMI connection, it is almost certainly an HDMI-ARC connection, which will NOT work with the VAX01202. The VAX01202 will not work with any Sonos sound system. * Unfortunately, I have the Arc. I probably won't be able to avoid replacing the TV. But I'm not doing it just because of Atmos.