Quote: The answer is not necessarily. The enclosure can affect both FR and waterfall. FR spikes correlate highly with waterfall ridges. Here are a couple observations - and you guys are free to come up with your own. I can always test hypotheses by removing the driver from the enclosure and measuring it. The area below ~2.5k after the initial ~1.5ms on the CSDs do reflect more on the interplay between the driver and the enclosure than the driver itself. One of the reasons is that most small drivers of this size are not going to ring there (except DJ100). Very open phones such as the Sennheiser HD558, HP1000, HD800, and SR80i are going to measure cleaner in that area. Although it should be noted that the SR80i has an obvious 2k ridge from the enclosure if left untreated. Sennheiser is really good in designing their cups. I've really come to appreciate the engineering that's behind their headphones even though I keep poking them at their claims that the HD800 is "neutral". Sharp ridges, especially after 2.5k tend to indicate driver ringing regardless of enclosure. Grados are a good example. HF2 seriously rings at 3.5k, 5k, 9k. The SR80i has certain ridges that no modification (Dynamat, felt, cups, etc.) will ever mitigate. Finally there is the one caveat which gets to the heart your question. Enclosures can affect driver ringing by extending their decay over time. I suspect that in the more closed phones, there is no place for the energy to dissipate. In fact, the enclosure may even provide a a trampoline effect to keep it going forever, e.g. DJ100.