I think this might possibly explain why live instruments/speakers sound better than headphones, which in turn sound better than IEMs.
Try this experiment.
1. Plug a Y splitter into your headphone jack, so that a single headphone jack has been converted into two headphone jacks.
2. Plug a device that allows you to control the volume on a headphone line into one of these outputs. Plug your IEM into this line.
3. Plug a closed back headphone into the other of the two outputs.
4. Put on the closed back and play the music at an enjoyable level. Don't be stingy but not uncomfortably loud either.
5. Now put only the left ear cup of the closed headphone to your left ear, sealed tight. Make sure the right cup of the closed back is not playing music into your right ear. You need a moderately flexible headphone to do this.
6. Put the right ear part of your IEM into your right ear.
7. Now adjust the volume going to the IEM so that the music is perfectly balanced in your head between left and right. At this point you can be certain that the sound reaching your ear nerves is of identical power between your left and right ear.
8. Use a decibel meter to measure the decibels entering your ear canal out of the headphone and the IEM, using e.g. the method in the attached pictures.
You'll see that the decibels entering your ear canal from the IEM are much much higher than those coming out of the headphone. Like 10-15 db higher. But they both sound like they have the same volume level to your ears, as proven above.
The only conclusion from this is that a lot of the IEM's sound/volume/power is dying off in that one inch space between your ear opening and the part of your ear that actually has the nerves that hear sound. On the other hand, the headphone's sound is not dying as it travels that space, probably because the headphone's sound waves are more robust as they travel through your ear canal. To define that term, robust, they are more robust in the same way that the sound from a speaker is more robust. A speaker that puts out, say, 70db within one inch puts out 60 db five or ten feet away (without changing the volume of the source). A headphone that puts out 70db within one inch puts out like nothing five feet away, and very very little just say a foot away. An IEM that puts out 70db within a few mm puts out almost nothing just a few inches away.
Bottom line -- speakers put out sound that travels very well through space, headphones put out sound that travels less well, and IEMs put out sound that doesn't travel well at all and which decays off in a few inches. Now which of these three operates more closely to sound put out by actual instruments and singing voices? The speakers. If I play a guitar from 10 feet away the audience can hear it. So a guitar's sound has that "robustness" you see in the sound of a speaker, and it's not like the sound of a headphone, and certainly not like that crap put out by an IEM. I think this characteristic may be why speakers / live instruments sound better than headphones, which sound better than IEMs.
Share your thoughts if you have any.
Edited by ag8908 - 4/10/14 at 10:20pm