I have listened to these off and on at meets. I've always heard there are the bass-lite and bass-heavy versions. I mostly have heard the bass-heavy versions. However, I've always have maintained, after listening to them, that the bass-heavy versions are actually quite neutral and pleasant. I know @Donald North is a big fan of these headphones. And he always brings them with him. In fact, I believe his amps have a special output specifically to drive these headphones. @Donald North seems to be a big fan of open baffle speakers. And in fact, he offers one such speaker set: The DNA Sequence Speakers (http://www.dnaudio.com/DNA Speaker.html). The closest thing I can think of to an open baffle speaker in the headphone world is the AKG K1000. And it offers a lot: Single driver, open baffle, balanced response, you name it. At the last meet I heard them again, and I was yet again impressed. I was told for the nth time these where the bass-heavy K1000, and that drove me to go "fuck it I'm measuring these". @Donald North saw me and went like "What you doing there chief?!" I thought about stopping and putting everything back together, since I did not ask for permission (sorry @Donald North). But in the end he supported the effort and we went ahead. He already told me many times that he also felt these were not bass-heavy at all. I fully agree with him. Anyhow. Here are some measurements: Frequency Response Impulse Response Right Impulse Response Left CSD Right CSD Left It is hard to measure these, and I believe the coupler does interfere with the measurements in the high frequencies. I also felt there was more lower bass than the measurements suggest. In terms of sound, I find these very engaging. Probably the best AKG headphone that there is.