Software Audio Programs
This is an attempt by me to bring some clarity in using audio software under Linux and Ubuntu and Debian distro's in particular. It has been commented that Linux offers only basic audio programs in terms of application, manipulation and conversion this, is to put it simply not true. However the methods by which we install these programs via the native package manager does not guarantee successful audio function.
Advanced Audio Programs
Often advanced audio programs (unlike stand alone applications such as mplayer, xine vlc) are used in conjunction with other software audio programs, this presents somewhat of a problem in that any program using ALSA (Advanced Linux Sound Architecture), OSS (Open Sound System), PulseAudio and perhaps others will tend to exclusively capture the audio device. Once captured other programs cannot use the same driver already in use by another application.
You can test this theory yourself by running two or more programs that use audio as an output. As an example start the application "jackctl" and "mplayer". If you have started jackctl first then this would have attached itself to use the audio driver, any other application that does not use a jack plugin would find it hard if not impossible to utilise the sound driver because it is already in use.
Assuming your audio is working you should be able to display the Volume Control Preferences similar to this image below this will confirm the driver you system is currently using. If your system is not using ALSA there may be a good reason why it doesn't however ALSA is generally accepted as being the de-facto standard on most Linux Systems.
As a general rule if audio does not work with one distro try another, the newer the distro, the better the chance you have to find a functioning audio driver that works with your system. It should be noted that Linux on a Laptop can be sometimes be difficult not to install but to function, this is due to the fact that the technology incorporated often moves more rapidly for Laptops than Desktop PC's.
Generally all the applications in this audio section will be using "Jackctl" that is to say that although some of these applications can be used without "jackctl" we will be using them in conjunction with this program for reason that should be obvious later.