I am sorry to report that I also have experienced the Low Volume issue or maybe the fading in/out ( hard to hear when volume is so low)
i ONLY use 3G and Skype ( over 3G), talking on the handset.

talking on a bluetooth Stereo headset Nokia BH-503 makes it even worse.
it is hard to accept not hearing other people if you are making biz calls...make you look stupid

I took mine to the shop, let's see how it comes back.

I have the same fading in and out problem. It only started up after the first couple of days though, very strange. I didn't have this problem before, it just kind of started all of a sudden. However, the speaker quality and headphone quality are still fine. Could be a hardware issue or maybe from some faulty programs? I did install a few programs over the last couple of days, some from the development repository. Any ideas? Did the flashing work for anyone else? So far one person did it successfully and one didn't.
Thanks,
Kham

Edit:I meant to say it only started up a few days ago. Not " after the first couple of days". It could have been moisture introduction into he speaker port. Did anyone else recall being in a moist environment, i.e. rain, near the sink, or maybe getting out of the shower then taking on the phone? I think this could be the root of the problem. Also, you guys think Nokia will cover it?

I've this problem too. The speaker sound fades in and out when talking with someone in the phone. I didn't have this problem before FW 1.1 update, it just suddenly appeared. I've installed apps from Extras-dev. S o my guess is:

1. Hardware Problem
2. FW 1.1 Problem (But only few people seems to have this problem, so it's hard to beleave that this is the reason. IMO)
3. Installed App from Extras-devel

Maybe i should re-flash my N900 too and avoid installing apps from Extras-devel /-Testing for a while. Then i could see if the problem is there.

I have these apps installed in my N900:

appwatch
Bluemaemo
Conky
Custom operator name applet
darksky-theme
DrNokSnes
Droid Fonts
Duke Nukem 3D CD version
easy-chroot
easy-deb-chroot
Extra Decoders Support
fApn
fm-Boost
fMMS
ForecaWeather widget
gTranslate
Headphone daemon
Hermes
iivilsteel-theme
iNES
ioquake3
Jagged Alliance 2
Leafpad
Maemo 5 (2.2009.51.1) FW
Maep
Matrix-theme
Mplayer
Nameday applet
ogg support
openSSH server
pymaemo-optify
qtify
Recorder
rootsh
ScummVM
sib
Simple Brightness Applet
Simple FMTX desktop widget
Subtitles support
systeminfowidget
Transmission
Tunewiki Desktop widget
VGBA
Wormux
Zeemote-Control Panel

It sounds pretty clearly like a hardware fault, at least in your case.

For other people who don't have as clear a set of behaviours as you see, two quick tests spring to mind:

1. Do you experience the volume fade problem when using the headphones that shipped with the device?
2. Do you experience the fade problem when using it on speakerphone?

Same problem here. I didn't notice it until after the FW update, but it seems like a hardware issue to me. No fading in and out when using BT. The problem is sometimes "corrected" when I push more firmly against my ear. How do I initiate a service call on this thing?

There is another big thread about how folks fixed this issue. The problem there was the slider cable being loose. They opened up the back cover (few screws) and reconnected the connecting ribbon cable firmly, that seemed to fix the problem.

Good Luck!

Can some mod please merge the threads then?
Thanks,
Kham

Which thread is that? I am unable to locate any decent solutions for this. I don't want to be separate from my phone -> Don't want to get it to repairshop.

I have the same fade problem!!!

The fading happens while talking to someone and it depends on how hard I press my ear against my phone..... shaking my phone around a little bit while calling also solves the problem, but it works the other way around too: if im walking, it can fade out and i wont be able to hear that person anymore... :P

The speaker works, so it MUST be some hardware (loose cable??) problem. If I plug it into my carradio or headphones, it works too,btw.

Important: Since a day, when I shake my phone, I hear something loose around where the ear-speaker is. Something is definately wrong inside my phone

Anyway, this phone is useless like this, because I can't make proper phonecalls anymore. For the people that dont know what the fade problem is: Imagine talking to someone at max volume and then out of nothing 5 sec at lowest volume and then back to max volume.
How can I fix it myself? I'm 700km away from the nearest Nokia service point. (They don't even sell this phone in my country...)