Etymotic ER-4S Measurementse
I actually kind of like these. Tonally they remind me of the AKG K701, but the 701s have this wierd plasticky sound which I could never get over. Also, despite the ER-4S' slight upward tilt, they do not sound cold or clinical, which I feel the 701s can be. Many HF's have applauded the ER-4S for their midrange tone, and I concur. Perhaps the broad 3kHz bump is boosting the harmonics with vocals. The midrange presentation is very similar to some of those full-range horn speakers with rising response.
Deep insertion is a must, but it still did not bring out the bass for me. I had to rely on EQ to boost the bass (including lower mids) to warm things up a little bit. These are an enjoyable listen if you don't mind the FR balance. I think most would prefer something bassier or warmer. I also felt there was a slight peak around 8kHz, which seems to be hinted at in the FR before the cutoff; but we don't see a significant trace of his on the burst decay. In any case, his peak wasn't bothersome.
The ER-4S are very inefficient IEMs, but I found them to sound good and work well without an amp, as opposed to something like the slightly more efficient UERM, which I feel needs an amp for it to open up. Maybe it's because the UERM has a crossover in the way.
Finally, the usual stuff applies: FR gets cutoff around 8-9kHz due to limitations of the coupler (it's just not accurate).
Also R channel is moved down 1db on the FR chart to provide better viewing clarity of the individual responses.Reminder: stuff past 9k is probably inaccurate. Especially the sharp peaks. Those peaks are the effect of the ear canal and the IEM. Personally I don't think they are heard as measured.