I have this strange problem with skype. I have a USB headset pluged in my gentoo box. /dev/dsp points at /dev/sound/dsp1 and everything works fine: I can play music with xmms and other apps. However, when I use skype, only my mic is working. When I call somebody or receive a call, they can hear everything I say, but I cannot hear a thing. I seem quite opposite to what kind of problems other people is experiencing.

I suspect it has something to do with the duplex mode but I have no idea how to set that up. Could anyone please help me?

I have a very lightweight installation with fluxbox and alsa. I run a kernel 2.6.7.

Could be a duplex issue, but I doubt it. Since you're running a 2.6 kernel you are probably using the ALSA snd-usb drivers right? This driver supports Full Duplex as long as the device does, and I can't imagine why it wouldn't. I've used USB headsets (Logitech) before with TeamSpeak, among other things. Have you tested the headset with e.g. TeamSpeak?

As to what the problem could be, I can't really say without knowing a bit more about your setup (what type of device, what your ALSA setup is etc) - one guess, though maybe far fetched, is that the headset registers two separate DSP devices (one input, one output) instead of one. I've never heard of any device that does that though, but it could be worth checking.

One more thing you could check, although it might sound stupid, is if dsp1 is indeed the headset and not another USB audio device such as a webcamera. Yes I know it sounds silly, but as much as I hate to admit it in public I have wandered into that trap once before. I have a logitech QuickCam Zoom and a Logitech USB headset - the quick cam has a builtin mic. The cam got dsp1, headset dsp2. By a mistake I set TeamSpeak to use dsp1 for input and output - with the result that the mic on the camera worked but I couldn't hear anything. Took a while before it dawned on me.

Hmm I've just tried the teamspeak client for linux, and it works out of the box! Both headset mic and speakers. It is by the way a logitech headset.

I dont think that it registers two devices. In /dev/sound, I only have a dsp and dsp1 (dsp being my soundcard). Also if that was the case, teamspeak should'nt be working either, right?

It can easily be ruled out that it is not a webcam that takes over; my headset is the only device connected to my machine at the moment.