Ok, so I have only read about one person even mentioning the background hiss on the N800. If you use high quality headphones (I am using Etymotic ER-4P) you will clearly hear a very irritating and omnipresent background hiss. The hiss is masked when playing a movie or mp3's but it is still there.

Frankly, I am shocked at the extremely low quality mp3/sound player the N800 makes. I owned a N770 and heard no hiss from these same headphones. What gives? I was thinking of adding one or two 16gb SDHC cards to make a 16-32gb all round player, but the sound quality and price of 16gb cards might make this impossible. Has anybody tried to max out on 16gb x 2 sdhc cards? I would think at least a few people would have tried to make the N800 a 32gb beast.

Speaking about sound, my FM radio behaves quite erratically. I get sound, fuzzy at times, but sometimes it sounds like it's mono and other times stereo. Anyone else have this problem? I don't really like FM radio anyway, but it's the principle that counts.

I haven't listened to anything but lower bitrate movies and fm radio on my tablet so far, but I have noticed fuzz (and mono output) when the headphone jack is not firmly seated. It takes quite a shove sometimes to get it in there, I otherwise have not noticed and sound issues (using decent over the ear sennheiser headphones). I don't want to suggest the obvious, but check the jack,other wise sounds like you might have a bum audio circuit.

i noticed something similar on my unit. ill examine it further.

The hiss is extremely annoying. It's a known issue. One of the firmware updates did lessen it, but it's still there.

Same issue here with the Shure E3C
The hiss starts when I play a track on the media player (OS2008)
and it stops as soon as I press the stop button.
The hiss is very noticeable during quiet passages in a song.
Any idea on what is the cause of this problem?

The N800's sound quality isn't spectacular, but it's not awful either. I've noticed that several music player programs on the N800 have their own volume controls which operates independently in combination with the N800 system volume control. If you have the app volume control turned down and the N800 volume control turned up to compensate, you will probably get fuzzier sound and more hiss.

That's the signal fading in & out. It is partly due to the crappy antenna (headphone wire). Sometimes I wish there was a mono button somewhere as it can be quite annoying with headphones on, but overall the radio's pretty good considering it was originally a non-feature. . .

BTW, I have an N800 and haven't yet noticed the hiss problem.

Speaking of the radio, I was thinking about making a joke about it being on without the headphones as a cause of the white noise. That happens to me a lot since the radio app is on the desktop...

I recieved my N800 at christmas and immediately dropped in 2 16gb cards, as it is replacing an archos gmini400 as well as a 770. Listening to music and videos on the supplied nokia headset has been fine with no hiss or anything. However, I was disappointed to find that like the 770 the sound level out of the 800 is a lot lower than the archos. I pipe the sound through an MP3 transmitter, and now have to turn the volume way up on the car radio, and that is after I have ran MP3gain and rasied the gain on all my MP3s.
Other than that one gripe I have found so far that the 800 is a great allround media player.

Gaz

I have alot of hiss with my KOSS PortaPro headphones. This noise I hear is quite dirty really and its actually very audible for everyone. It is also there on every press with the pen on the screen, for about 2-3 seconds. Just after the click sound there is a following hiss and hum. Quite bad really. And there is small cracking sounds followed by hiss quite randomly at normal use. It actually gets so annoying that I have to mask it with playing music in media player or take my headphones off. For me this seems to be a quite big malfunction?/bug?

The in ear plugs that comes with the N800 is to low to really notice it.

Is this a known issue that perhaps could be fixed?

I noticed my N800 making a faint hissing sound one day for no apparent reason, and I discovered that the FM radio was accidentally activated, so that's a good suggestion to check it.