Right, you may try to eq the xr to sr's response and see if you like it or not.

Awesome!

What you heard is the combination of excess 1.6k and recessed 4-8k. That is exactly what you described. As well as the 10khz. If you matched the 2khz you will see xr has more 10khz region than sr. It's all relative. Only thing you want from xr is just extra bass, other than that sr is superior...

https://clarityfidelity.blogspot.com/2016/10/etymotic-research-er4xr-iem.html. Also I have personally measured three pairs of xr and one xr as well as er4pt, hf5, er4b. Er4xr is essentially er4p with a little more sub bass and extra 10khz region.

It has two resistors inside. Initially used for er4pt to become an er4s. It will make er4xr a bit brighter, a bit more air, a bit better tonality. It will also make it much less sensitive. You will need more than double the volume control setting to have the same volume.

XR has increased response below 800hz and significant increase below 500hz. Also the 6-8khz is more recessed than SR.

How did I not think of this... XR is indeed warmer. Adding PtoS cable for it is necessary.

If you cannot insert deep enough, I suggest to perform the bi flange mod. Use the large 3 flange tip, and cut around the largest flange. Then you have two smaller flanges only with the stem intact. This way you can insert deeper.

Definitely not. Er4 is deisgned to utilize the canal resonant frequency to achieve flat high frequency response even after 10khz all the way to 16khz. use this: https://www.szynalski.com/tone-generator/ and set volume to 10% and sweep after 7khz to 14khz. Insert deeper until it's flat.

If 10k is a bit sharp you are simply not inserting deep enough. The volume in the ear canal will interfere with the peak frequency. You need to push it from 10khz to 13khz. So go deeper.

That's quite the opposite. That's exactly why I don't like Harman target. Which is more correct? Only way that you can do yourself is to compare directly to eq'd speakers. Then you will realize how accurately er4 represents the high frequency of the real speakers. How? It's an error done in...

Er4s/sr has more linear response after 2khz. er2se is a bit recessed between 4khz to 8khz. The sound is less natural this way.

I never had er3. But I assume it's in the middle or more towards er4 side.

In short er4s/sr is brighter and on the more neutral side in terms of tonality. Er2se is more balanced but tonality is slightly worse. Er2se actually benefits from stock foam tips which is quite surprising. And it's much less critical in terms of insertion depth. On the other hand er4s/sr you...

It's pretty easy to understand. No matter from what source, the response at ear drum should be the same. It can apply to iem, over ear, on ear, even speakers. Usually we take flat speakers in treated room as standard so we don't normally use it that way, but it's possible. Now, there are er4s...