What I'd like to know is what it is about CIEMs that makes it so hard to measure them? One thing that gave me pause about buying the 4.A's was the side doesn't listen frequency response where others do. I'm starting to wonder if it isn't that Heir Audio isn't guessing or fluffing the data and is, instead, only showing what it knows for certain.
It's the coupling of the tips to the measurement system, and achieving a proper seal, that causes the problem.
Universal IEMs work because they are made to fit most ears, and therefore fit well into the "fake ear" system. Customs are made to fit only a single set of ears. Taking measurements at the base of the canal is possible, but doesn't reflect the real world conditions in which they would be used.
I'm not exactly clear how other companies like UM do it. There are also many options in the measurement equipment for smoothing, averaging, and otherwise tweaking the data. It isn't designed to be tricky, but rather as a tool.... which of course doesn't mean that it can't be used to make graphs look better. I'm not accusing UM of doing anything wrong, just stating the facts. Basically it comes down to this - UM graphs are only useful for comparison to other UM graphs. Just like Tyll and Purrin always say their graphs are not to be compared against other sources.
