[udauda]

Updated here:
http://rinchoi.blogspot.com/2010/05/how-deep-do-you-insert-you-er4.html
 
Etymotic Research approved the article.
 
This means that most of the IEM manufacturers have been hiding the most vital part of the equation in using IEMs- proper coupling of the earphone and the ear itself! Usually, conventional IEMs, especially custom-moulded ones(you better double check the custom-manufacturer's capability), reach no deeper than the 1st bend due to technical difficulties & safety reasons. This kind of shallow insertion would not secure the residual ear canal volume of 0.5cc(or the distance of 13mm from the eardrum to the tip of a sleeve), and cause some degree of linear distortion on IEMs. 

 

[udauda]

Updated on Dec. 21st, 2010.

 

[JackKontney]

Excellent topic, udauda.
 
Deep insertion is definitely (IMHO) a requirement to create a proper in-ear system. Sensaphonics requires ear impressions to go past the 2nd bend in the ear canal.
 
http://www.sensaphonics.com/Ear%20Impressions%20How2.pdf
 
Most people would benefit from a personal fitting with their audiologist to learn how to put their custom IEMs all the way in.