Originally Posted by yuriv
Behold the punctured ear tips!
I very much like the results after I drilled very small holes in the supplied silicone sleeves. You may have to click on the above image to see the holes in the enlarged photo. (The story is continued from here: http://www.head-fi.org/t/594945/6-panasonic-rp-hje120-surprisingly-usable/15#post_8854187. Basically, I played with the cheaper Panasonic RP-HJE120 before deciding how to change the sound of the MH1C.)
I ended up making four tiny holes per tip--still a bit bassy, but I didn't want to overdo it. With this "mod", the bass response now more closely matches what I hear from live music. The timbre of musical notes has been improved since the proportions of the fundamental and the harmonics is in better balance. After some time with a tone generator and matching the volume, I can tell that (for my ears at least) the response above 1 kHz hasn't changed much.
I normally use a parametric EQ like Equalizer or Accudio, but many apps like Pandora, YouTube, and Netflix can't use them. The punctured tips have the potential to match the huge bass reducer filter that I use on the MH1C. They actually sound pretty good now. The time domain characteristics aren't completely independent of the magnitude response, so I would guess that the transient response has been improved also. I'd love to see impulse response and CSD measurements on these things after EQ or after using these tips.
Isolation isn't as good after the change, but I'd rather trade that for better spectral balance. Also, driver flex during insertion has been greatly reduced. The technique also worked for the HJE120, but I can see it working for any bassy IEM, e.g., UE100, Klipsch S4, etc.
If we can find a way to get controlled leakage from foam ear tips, we may be able to neutralize the sound of v-shaped IEMs.
I forgot the size of the drill bit, but I started with the smallest #80 wire gauge bit and went down from there. A #75 is still too small. With the one pictured above, it took many passes of the bit through the hole, and in both directions before I got the opening of the desired size. I had considered other ways of puncturing the sleeve, like using a needle tip with a soldering iron, but I never got to try them because the drill worked well enough.
Could you draw roughly what sort of eq curve this mod would mimick? How much bass cut at what frequencies, etc.? Really curious.
On another note... I'm so on the mh1 bandwagon! haha. I got a pair for $20 just to check them out. Completely blown away! These things are up there with the er4s to me. They are more bassy, but that isn't always a bad thing. First, I simply eq the bass down with ONE single eq point. Second, sometimes it is kind of relaxing and the bass doesn't interfere with the rest of the spectrum as much as on most other iems.
Anyhow, first thanks to clieos. I have to admit I was in denial when I started my iem search and he recommended what I consider "bass light" iems like the pfe112 and er4s. Now those are my absolute favorite iems (and now the mh1). The er4s is just excellent while the pfe is more flat bass to my ears but a bit uneven treble (just barely) and a bit of distortion that I'm starting to find is audible in that it keeps me from getting a perfect eq'd flatness. I just can only get "so far" with the eq. The er4s eq settings I use show how amazing the er4s is. Slight adjustments to the sub bass, but they handle it with ease.
The mh1 now is similar to the er4s. Less distortion and works well with eq. Like the er4s it is also a simple eq adjustment but the other direction. :-P Anyhow, I've heard some er4s user dislike the mh1, but I'm wondering if they have the mh1c or a "fake" or something else? Coming from two very flat iems the mh1 doesn't seem far off to me. In fact, because we tend to be less sensitive to bass frequencies and it's such a smooth "boost" by default, I find these to almost be as accurate in a way. Where the er4s lacks bass, the mh1 has excess bass for instance.
Anyhow, these are undoubtedly the best $20 earphones I've ever heard. I'm not going to replace my er4s or anything, but they are a very welcome addition. If you have any other recommendations clieos, you sure as hell got my trust. Everything you've recommended has been the best I've heard so far. Can anything best a pfe, er4s, mh1 combo? ha. :-P