Ardour is a very advanced audio program similar in some respects to ACID for Microsoft Windows. There are, of course, two major differences: This program is open-source, and free.
While I personally do not have much(read any) experience with audio production, this program seems to have many features, and is well worth checking out. It has, however, a small flaw that can severely frustrate almost any user. It uses an audio library called 'JACK'. JACK is an audio server that allows programs to easily interact and communicate with each other. The problem is, it can be very difficult to set up. From what I have seen, it is not a library that can be installed out-of-the-box. On a regular Linux kernel, it does not seem to work well, or indeed at all. This is because it requires the ability to run in realtime. On most kernels, regular users cannot run programs in realtime. Only the root user can. This means that you must install the Realtime or Low-latency kernels.
This seems like it can be a very difficult problem for most new users who are(or should be!) afraid to tamper with kernels. These users have two options:
1.) Try to install the Realtime kernel, which can at the very least be frustrating, or
2.) Download and install Ubuntu Studio, which is specifically designed for mutimedia production.
Links: http://ardour.org/
http://ubuntustudio.org/
http://jackaudio.org/
Will update Monthly/weekly. Or whenever the hell I like.