reporting in too

does yours have hissing sound when playback video of your test recording?

after they restore with iTunes, still got thte hissing sound when record  videos multiple times.

now on chat with apple support

I have not, will try. My Week 38 is much quieter though the phone speaker is not as loud as the original Week 39 batch.
@benny888 not much hissing noise on yours I suppose? Heard week 40 and 41 are good batches.

how obvious it is?
You try your old iPhone and see, I tested with my 5s, 6s, all having the minor hissing 

I don't think that's the hissing sound. Because using my 5S and Note 5. Both have this sound. The previous video by another user can be confirmed to be hiss sound

here

ic, where is and how many authorized service center ?
yes i don't want any refurbish unit....

The service guy also say got hissing sound while he test record my video

I tried taking video on my ipSE and i also notice that the videos do have a "static like" sound in the background of the video. Im guessing that the static like sound in the ip7 videos are considered normal?

Good day from machines

Please be informed that your product has been restored, diagnosed and tested ok.

We have escalated this issue with Apple. Kindly contact AppleCare at 1-800-803-638 for any enquiries. We are unable to replicate the reported issue.

Your unit is ready for collection at our Service Centre. Kindly arrange to drop by our Centre from 9:00am to 6:00pm, Monday to Saturday

Thank You

i only can get my phone back on Saturday morning though. Hope it's working well when i get my unit back.