Which M + S cables are you using to the DSPs? If it’s not the original Meridian cable, you could do worse than pick up a new pair with the original cable and connectors (Meridian Digital Link) which is what they would have originally been tuned by Bob Stuart with. Always sound great to me and Chris does a great job of making them up to original spec.

It also neatens the install, rather then having separate signal/control cable flapping around.

HC: 861v4/ID40/LPS, DSP5000, DSP5000VC, DSP3100, SW1600, HD621, Oppo BDP-105, Sony VPL-HW55ES
2-Channel: Oppo BDP-105, TEAC VRDS-7/Trichord Clock 3/PSU, 551, Quad 303, Harbeth Compact 7ES-3, Kimber cables, Russ Andrews mains and supports.
Previous Meridian: 5000C, 5200SL, 7200.2, 6000, 562V.2, 568.2mm, 800v4, 808.2i, 818v2/v3, 861v8, 502