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Old 17th December 2012
Gear Head

Originally Posted by Klaus View Post
Regarding the difference between polyester (Mylar®, PE) and PVC membranes in M7-size and style capsules:

To a trained ear, they do sound remarkably different, and should be auditioned by a potential buyer before a decision is made.

Additionally: current-generation PVC membranes should not be compared sonically to PVC material from a decade ago: Germany outlawed the previous PVC formulae, for environmental and health reasons (harmful during manufacturing, not after curing). Different formulae set up and dry differently and the differences in molecular structure of the materials (my guess) also change the membane's dynamic behavior.

Healthy PVC M7 capsules are not per se brighter than Mylar K47 models, though they differ in response in other ways: K47 are softer, less aggressive in the mids. However, with aging, PVC dries up, and, as the capsule's low end goes, one is left with the impression of increased brightness.
Hi Klaus, some interesting background info since I'm currently considering buying a Gefell umt70/71 (which uses an M7 capsule). I'm assuming the umt70 is one of the current generation PVC capsules? are you implying the new material is sonically better or worse?

Are there any recording comparisons between these different materials/capsules? (Though i imagine it might not be particulary valid to compare a decade old capsule with a new capsule given that the 'age' of the stretched material might be causing more sonic differences, than the actual formula of the PVC).