Battery life isn’t the only complaint about Apple’s newest smartphone. Customers are reporting an issue with the device’s audio echoing during a voice call.

An Apple discussion thread is alive and kicking with hundreds of disgruntled iPhone 4S users that are complaining about an audio echo on the other end of the call when talking on the phone via an Apple hands-free headset.

And we thought that no one used a smartphone to actually call people anymore…

Users are reporting a significant drop in audio quality and heightened sound reverb when using the Apple hands-free headset. The audio seems to generally go down in quality as the call progresses, and then the person on the other end of the line starts echoing uncontrollably. Sites like BGR have been able to independently confirm this bug.

One thread member wrote:

“It does not occur immediately. It can vary from 30 seconds into a call and as far up to 9 mins in before it begins the annoying echo. If I unplug the headset it goes away but will return when I plug the headset back in.”

Another complaint:

“Same thing happens to me.  Very annoying.  But, the echo is on the other side of the conversation.  What I hear is the person sounds like they are all of a sudden really far away, but the volume of the voice increases and it’s scratchy.  At the same time this happens, the person on the other side of the call says there is all of a sudden an echo. I haven’t tried unplugging the headset yet, because I pretty much always use the headset and don’t want to give that up.  I just hang up and call the person back.  SOOOOOOO annoying!!!!  I’m on AT&T 32 GB black iPhone 4S.”

The bug seems to affect both Apple-branded wired headsets and third-party headsets:

“I am having the exact same problem with my Klipsch wired headset with AT&T.  I switch to the Apple wired headset which did not fix the problem.  I did not have this issue using the same headset with my 3Gs last week.”

A temporary fix involves turing the iPhone’s speakerphone on when the call begins to echo and then turning it off immediately after. This supposedly restarts the audio cycle and the call goes back to normal until the echo returns after a few more minutes. Many of the complaints seem to come from AT&T customers, but iPhones on other networks, like Rogers, are reportedly experiencing the same bug.

Have you experienced this audio bug when using Apple’s headset on the iPhone 4S? Tell us the details in the comments below!