Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Meridian Special Edition Loudspeakers

The actual bass chassis from the legacy speakers are not produced anymore from SEAS since a while.

That's the reason why M made that rings I guess since the SL version to adapt the new bass chassis (doesn't automatically means they are better) on the DSP housing/box.

So there is no need and usage for those rings on legacy DSP except the advantage of a better and more longterm reliable mounting and sealing.

But as the "old" bass chassis are different to the new ones, you can't use the new rings with old bass chassis.

As you say correct, the distance of the chassis to the housing will change, this shouldn't be important on the bass, but could change the mid chassis dispersion characteristics. So I suspect the SE series have also a deeper chassis mounting groove to make space for the rings so finally the chassis is at the same surface/level as without rings.