Before I begin, I hope that it's okay if I post these. The unit was measured using dual flanged tips for best fit into the Vibro Labs Veritas IEM measuring unit that I have. I currently have it going directly into my motherboard for the time being so take them for what you will. Pictured here is the RHA T20 measured with each filter available. As you can see, based on my measuring system, it looks like nothing changes except slight variations from 2k and up. It appears that the bass is unchanged. I have listened to the reference filters a lot and I'm not sure what they intend by calling them reference, but they're certainly far too bassy to be considered a reference IEM. The bass isn't particularly sluggish or loose, but it impedes on the midrange detail. Midrange and treble are rather quick, but the uppermids have heavy sibilance and sound far too forward. I just put on the treble tips and initial impressions are that the sibilance doesn't seem to be as much as reference despite the bump in treble. I haven't listened to the bass filters yet. Anyway, I wanted to get some quick measurements and some feedback. I'm working out the bugs with the measuring and will be getting a better soundcard soon.