[jaddie]

The change in altitude results in two things: a reduction in air density and a rduction in air pressure, but since the two effects virtually cancel, they can be ignored. That leaves temperature and humidity, of which temperature has the significant effect, humidity very minor.

But all of this is meaningless if you don't have a lot of air for sound to go through. Last I looked there wasn't much air between my headphones and my eardrums, even less between my IEMs and my eardrums.

If listening at high altitudes seems to sound different to you, you should look for a cause other than the air itself as the transmission medium.

 

[DunninLA]

I searched for this topic and this old thread came up.

I find that on airplanes, the bass of my IEMs, several different, seems to drop by several Dbs and the sound becomes thinner. I've given some thought to this, and think it probably has more to do with the vibration of the airplane's engines masking the vibration of the bass. Either that or bass in thinner air of higher altitude has less impact upon my eardrum than bass at sea level. My bet is on the vibration issue.

 

[bigshot]

At higher altitudes, there is less air pressure. Your ears can pop to acclimate to the change in pressure, but the pressure in a plane keeps changing as the cabin pressurizes and depressurizes as it ascends and descends. Your inner ear is constantly different pressure than your outer ear. It's going to mess up your hearing.

 

[redrol]

I do high altitude running with IEMs a lot. I get to rock out for like 5-8 hours 3 days a week like this. I usually start around 8500ft and summit around 12k and sometimes 13k. You DO need some kind of vent system with an IEM or else gotta pull them out every 10 mins depending on accent rate AND pop the ear drums by yawning or similar. It's kind of annoying to be honest. As far as cold weather, the IEMs are in my ear holes so they stay reasonably warm to the touch. The cables on the other hand turn into coat hangers because I assume the plastics they use. I've never heard humidity do anything except make the bore/acoustic nozzle filters clog up. Again, very annoying.

So basically mostly its a non-issue.

 

[Blackwoof]

Balanced armatures seem to be more robust to differing pressure levels & flex. Since It was great I could play pool without hearing stuff suddenly distort like many Dynamic headphones/IEM's do. Even the ER2SE could sometimes if I removed them without pausing the song. Which makes sense since BA's diaphragm is stiff metal than the thin plastic film on DD's.