I guess the logical question would be why would you keep a case that causes interference to the speakers, whether or not it might cause damage. Just the esthetic of listening is sort of affected..you think? However, I would think that it would affect battery life since the speaker is working twice as hard due to the impedance of the case. Might also cause it to run hotter and possibly lead to a blown speaker. Not worth using the case in my opinion.:vamp::questionmark: