To be honest mine hums when under load eg when i was restoring from backup i placed my ear on the back and could hear a noise like a HD spinning very faint.
I also upgraded mine to 10.02 and could when putting my ear on back sounded like a 56K dial up modem!!
But otherwise i dont hear anything when using the device for calls and stuff its only when i place my ear at back.
So much ive read around this subject and i think its the way they have been designed. As long as you cant hear it innday to day use then i dont think you should worry. If you can hear it whilst gaming, typing, watching videos etc then its an issue.
As for videos and hissing, many say the mic at back is too sensitive which could be fixed in a software update to reduce the sesitivity of the mic at back.
Honestly if its a defect id rather not take it back and get one thats worse. Id rather use it as it doesnt bother me and if Apple admit its a defect at least id get it swapped out down the line.
I also upgraded mine to 10.02 and could when putting my ear on back sounded like a 56K dial up modem!!
But otherwise i dont hear anything when using the device for calls and stuff its only when i place my ear at back.
So much ive read around this subject and i think its the way they have been designed. As long as you cant hear it innday to day use then i dont think you should worry. If you can hear it whilst gaming, typing, watching videos etc then its an issue.
As for videos and hissing, many say the mic at back is too sensitive which could be fixed in a software update to reduce the sesitivity of the mic at back.
Honestly if its a defect id rather not take it back and get one thats worse. Id rather use it as it doesnt bother me and if Apple admit its a defect at least id get it swapped out down the line.