My understanding is that DTS:X is able to utilise an existing 5.1 surround system to effectively provide a Dolby Atmos alternative.

Would it be possible for Meridian, if it so chose, to implement a DTS:X firmware update for past/present surround products (since such products already offer vanilla DTS)?

I’m not sure I fully understand your argument here - apologies if I’ve misunderstood. Both Dolby Atmos and DTS:X have algorithms (Dolby Surround and Neural:X, respectively) for upmixing existing 5.1\7.1 soundtracks and making use of the height channels. It’s quite effective and the results are often close to true Atmos\DTS:X. However, those height channels have to be physically present in the system in one form or another, they are not created by a psychoacoustic effect.

Edit: if you are thinking of the algorithm used for headphone listening, I don't know if is even possible to implement this for a floor standing system.

Meridian processors are currently maxed out at 7.1 channels . They are not capable of a minimal 7.1.4 Atmos setup . PLIIix and THX Ultra II Cinema only become available when there are 4 surround channels connected.

Both X and Atmos fall back to DTS Master-HD and Dolby True respectively if the system isn't at least 7.1.4 . Meridian doesn't decode either format at present.

~M~

I could be wrong, but I thought that SpinalTap was talking about the physical layout of an existing system. I'm sure I read somewhere that DTS:X was more flexible in this regard.

Yes, you could get object-based processing in a 5.1 system which may give improvements over standard DTS HD. However, I don't see such processing being done in the player and sending bitstream to the processor is not possible within M's current system architecture (at least for now). Edit: I should qualify that as bitstream from a HD audio source.