When manufacutres provide distortion graphs - is this taken with the driver mounted in no box? Or with a box? JBL's freq response measurements for 2226 for example is done in 280L sealed box, but they dont state what they do for distortion measurements. Since the box has quite an impact on the distortion, I'd imagine that manufactures MUST do it free air otherwise comparing distortion curves is useless if they are all in different boxes. But is this so?

When not mounted in a box, distortion is way higher. Would it be fair to say that the graphs are a bit ambiguous because it doesn't represent how it will perform in a box, which could be a fair bit better? Or is it still OK for comparison sake?

Thanks!
Adrian