Voice Memos - visually low decibel level

Hi all,

I just bought a brand new iPhone 5s (coming with iOS 7.0.2) and I'm overall very happy with it. But when I opened the Voice Memos app and tried to record something I got a little bit worried that my mics might not be working properly or hopefully it's just a software thing.

First of all, I've already read quite a few threads both here and in the other forums about this app crashing down or not finalizing the recordings properly, I haven't tested it out yet. I have a different concern, when I tried to record my voice at a normal distance holding my iPhone in my hand streched out approximately 1.5 feet away from my mouth and speaking as I usually do (not too loud but kind of just like when having a conversation in a non-noisy environment), the waveform depicted in the app stayed almost flat which according to a scale on the right hand side means less -10 dB (or negative infinity as it would usually be gauged on professional sound equipment). I don't really think it's normal since the waveform is supposed to be useful for editing memos and it seems like the waveform will be visible either if the sound source is loud or close.

I'm particularly anxious for two reasons. Firstly, I often have to record stuff because I'm a student and a musician so I really need my mics to work properly. Secondly, I've had bad experiences with mics on other Apple devices. At some point the mic on my iPad 2 became very insensitive. I almost had to put it an inch away from my mouth for it to be able to record anything. Then I learned that vacuuming the mic helps but only for a while. It couldn't be judt dust or anything because at some point it would suddenly relapse into this condition the following day without gradually becoming less sensitive, it was just a snap and it wouldn't work well. Then something similar happened on my iPod 4th gen but I didn't even try to vacuum it. I dropped both of these devices but this problem appeared on my iPad befor that I believe. So I'm really worried about these mics problems being a seemingly common issue with Apple devices.

So I was wondering if anyone has similar problems/concerns. I haven't tried recording something really loud maybe such calibration will come handy. In my trial of the app I could hear the recorded sound (as if coming from a distance but quite passable). So I hope it's a software calibration rather than a hardware issue. I decided to carry out a test and since the volume of the sound is a difficult thing to reproduce in the exact same conditions I tried to set it up so that some of you might be able to repeat it if you want to compare our results. So I bought 'Blurred Lines' by R. Thicke on iTunes, a popular song these days, playbacked it on my iPod 4th gen at maximum volume (oops just realized I have an iPod volume limit set up at about 75%) placed at various distances from my iPhone 5s so that the iPod's top faces the iPhone's bottom.

Here are the results:

1 foot away - negative infinity

8 inch - almost the same

4 inch - topping at -10 dB

2 inch - -7 dB

0 inch (almost touching each other) - -3 dB sometimes going up to 0.

And by the way in the right hand corner there's a speaker sign which I assume means recording with a bottom mic for calling or the mic that's near the camera. The results are basically the same. And one more thing, when recording videos I get clear sound.

So if you got to the end of this post I know my experiment is kind of complicated, I just like to have this scientific approach. You can try to repeat it if you have time and can set up all the same conditions but otherwise any opinion/information will be very welcome.

Thanks in advance!