I am using a Nokia Lumia 820 with a flip casing like this:

http://www.rockphone.cn/Html/Product/128.html

During calls, people complain that they could not hear me clearly. Words are broken intermittently. If I switch to loudspeaker -> no problem, they can hear me very clearly. Video recording is also fine -> sound is normal. I have confirmed that the microphone is not blocked by the casing (I don't use any screen protector yet). I have done a hard reset, but the problem persists.

When I remove the flip casing, there's a marked improvement in clarity and words are not broken anymore. Could there be another mic somewhere (which I cannot see physically) or the Lumia noise reduction feature is too sensitive that it has to be used without any casing?

Anybody else facing this problem?

I think i've read this issue somewhere in this forum or another forum... they find out the reason to be the case is blocking the mic... So perhaps you could try to locate the mic and see if your case has block the mic or not...

I have confirmed that the primary mic is not blocked by the casing. But I understand L820 has 2 HAAC mics, but I am not sure where it is located. The location of the second mic is not mentioned in the manual or any sources on the internet. It could be the way the sound waves get cancelled out by the Lumia noise-reduction feature when talking with the flip casing, but that is just my guess.

I will try with the single hardcover casing (non-flip type) when it arrives from ebay to see if the problem remains.

I have the same Audio Problems with my Lumia 820. It seems to be a software problem in the noise reduction. There is no patch, but Nokia seems to work on it. The second mic seems to be near the camera on the backside. Try to use a bluetooth headset. Perhaps it works better.

Even though the situation improves without cover, it's still not good enough, with echo and clarity issues. Anyway, I have sent in my phone to Nokia Care and see if there is anything they can do with it.

Update us after you get back your baby !.

I have gotten back my phone from Nokia Care yesterday. They informed me that initially they had changed the mic but the voice quality was still not satisfactory, so in the end, the changed the motherboard too.

After getting back the phone, I tested without any casing and my voice came out clearer than before (also without casing) on the other end of the line. So, to a certain exent, the repair did improve the call quality.

When I put in the Rock PU leather flip casing, the problem came back. I changed the casing to the Nillkin matte hardcover and the problem disappeared. Then I realized the difference in the design of the camera/flash opening for both the casings. Rock flip casing covers the whole protruding camera assembly except 2 small holes for the flash and lens. On the other hand, the Nillkin casing exposes the whole camera assembly in a long rectangular hole opening; where you can even see the words 'Carl Zeiss'. For Rock flip casing, these words are covered.

Under bright lights, I can see a small dot in the gap between the body and the camera assembly (below 'Carl Zeiss'). To test it, I go to video mode and blow softly at the camera near the dot. When I play back the video, the loud whooshing sound confirms that the secondary mic is near the camera assy; and this mic is used for noise-cancelling during normal voice calls. I suspect the exact location of the mic is around the dot below 'Carl Zeiss'. With the Rock flip casing, this mic would be covered up and caused the voice call problems.

I am not sure if the Rock casing design is similar for L620 and L920. Not to mention that the camera assy design and secondary mic location are also different for the other 2 Lumias.

do u mean the problem happened because the casing block the mic? but as u said, it also not clear when take out the casing before u have changed motherboard...

yeah, i am quite sure the rock flip casing design for 820 is the culprit. Whether or not the motherboard was the problem in the first place, i am not sure now, because my office has very bad mobile signals. But at home where coverage is good, i can replicate the problem just by replacing the cover.

The fact that the Nokia Care staff said the mic was not clear could point to the possibility that the board too had a problem.

This post has been edited by weim76: Feb 2 2013, 11:21 AM

I'm experiencing the same issue. Was asked to speak louder everytime when there's a call.

Based on my experience with my own unit, i can think of the following possible causes:
1. Hardware - mic or board malfunction
2. Mic blocked by poorly designed casing. This mic is near the rear camera assembly.
3. Poor mobile signal coverage.
4. Persistent background noise, eg. Car aircond blowing directly at u while talking on the phone, or nearby machine humming sound can affect the noise canceling feature.

Guys.. U can change the shells.. Dun need casing bro..

Haha, true. But there are other reasons for using a casing other than for the fear of scratches to the back shell.

Currently I am using the Nillkin hardcover matte back casing because:

1. I want a better grip. The original black matte shell feels more slippery when naked.

2. I cannot stand the sight of sweat/oily stains on the naked back shell.

3. The back camera assembly is protruding from the back shell. With the Nillkin back casing, I can put my phone on a flat surface without worrying about scratches to the camera assembly. Same thing when I slide my phone in and out of the pocket.

actually what is noise cancellation feature?

General description - may or may not apply specifically to Nokia Lumia or it's implementation in the software.

http://en.wikipedia.org/wiki/Noise-canceling_microphone