Sonic Foundry Acid provides an easy, intuitive method of producing music. The environment allows you to build songs in much the same way that you would build a crane out of an Erector Set - you take the pieces and assemble them one at a time into a song. The pieces (called loops since they can repeat) can be ones supplied to you by Acid, or ones you record yourself, or a combination. You can even record directly over the top of an existing Acid arrangement! The results, even those produced with Acid's own loops, is copyright-free, and can be used anywhere!
Some hints about purchase, use and installation:
The End Product
Acid requires very little musical knowledge to produce simple loops - rhythmic but repetitive musical "environments." These can be useful for short backgrounds for videos or PowerPoint presentations. However, to actually construct songs, you'll still need to know something about rhythm, pitch, key, and song structure. If you have a tough time visualizing things in your head, you can "storyboard" songs much like a video - decide what key, what tempo, a rough idea about how many measures long each verse or other song structural part will be, and, within them, how many measures for each chord. Of course, nothing need be fixed in stone, but it's too easy to start dragging loops onto the timeline, and it's easy to get lost! It is also important, if this is going to be a project in creativity, that some content (vocals, lyrics, etc.) be original, and structured in advance.
The Acid environment consists of a timeline running across the top, various tracks you will be placing on the timeline, and then a window at the bottom which can toggle between "Explorer View" where you select new loops, and "Propertives View" where you adjust the aspects of each loop. There is a master volume level at the bottom right, and individual volume levers as sliders on each track. You set the key and tempo at the bottom of the tracks area.