I think you need more info about the Meridian outputs. I doubt that a manufacturer would use XLR a connector for a single-ended signal, although this can be done. If that is true you need an appropriately wired RCA on the other end of the interconnect.
I think that what you may have in the Meridian is a "quasi-balanced" output. The (+) signal pin is active, but the (-) pin just has a resistor so that its output impedance is the same as the (+) pin. Such an interface when connected to a balanced (active) input circuit will exhibit the same noise imunity as a "true" balanced interface where both (+) and (-) signals are active. If this is the case you should use a regular balanced interconnect.
I think that what you may have in the Meridian is a "quasi-balanced" output. The (+) signal pin is active, but the (-) pin just has a resistor so that its output impedance is the same as the (+) pin. Such an interface when connected to a balanced (active) input circuit will exhibit the same noise imunity as a "true" balanced interface where both (+) and (-) signals are active. If this is the case you should use a regular balanced interconnect.