It's easy to be overwhelmed by the sheer number of computer-based music products available today. In this article, we'll describe the various categories of software you're likely to find at your local music dealer. Different as they are, bear in mind that all of these products are designed to allow your computer to participate in the art of making music and the joy of playing music.

All of the types of software described here are widely available for both Windows and Macintosh computers. Always be sure to check minimum hardware requirements before making your purchase so you know ahead of time whether or not your particular computer system is capable of running the software.

While the user interface can vary greatly from product to product, there are some basic features that are common to all MIDI sequencers. First of all, you'll always find an onscreen transport control, with tape recorder-like Play, Record, Stop, Fast-Forward and Rewind buttons.

Secondly, MIDI sequencers always provide numerous tracks into which data can be recorded. Just as a multitrack tape recording in a professional studio is constructed from a series of overdubs (where each instrument is recorded on its own track, often one at a time), so too is a MIDI sequence constructed from a series of tracks, each addressing a different sound within an electronic keyboard connected to your computer via a MIDI interface.

But where MIDI sequencers differ from tape recorders is in the extensive editing capabilities they provide. For example, they allow sections of music to be freely cut, copied, and pasted, enabling you to create whole new arrangements and orchestrations with the click of a mouse! Tempos can be changed without the pitch being altered, or the pitch can be freely transposed without affecting tempo (both feats are physical impossibilities on a tape recorder). MIDI sequencers also allow you to perform the finest "microsurgery" on your music you can imagine: even individual notes can be altered, inserted, moved forward or backward in time, or deleted altogether. You can also correct timing errors, change the dynamics of individual notes, or build carefully controlled crescendos or diminuendos. Some advanced MIDI sequencers even provide an onscreen mixing console so that you can adjust the level, pan position, and other variables for each track individually; your onscreen mixer "moves" can then be recorded and played back as part of the sequence itself (a process called "mix automation," normally found only in high-end recording studios). Best of all, MIDI sequence data is compact, so it can easily be stored on a floppy disk and shared with your friends and family; you can even exchange sequence files on the Internet, where literally thousands of "shareware" Standard MIDI Files are to be found.

Some advanced MIDI sequencing programs integrate digital audio capabilities, giving you the best of both worlds. With these programs, you can create a backing track with MIDI sounds and then overdub vocals and/or acoustic instrument solos, with both kinds of data playing back in perfect synchronization with one another.

Patch editors take things a step further. Not only do they allow for the transfer of sounds to and from your computer, they actually enable you to edit the sounds in your electronic keyboard directly from your computer screen. The primary advantage here is extra real estate; most electronic keyboards have a fairly small screen display that can only show a few sound parameters at a time, whereas even a small computer monitor is capable of displaying dozens of parameters. As a bonus, patch editors give you instant visual feedback of the resulting change made to the sound. For example, a graph of an envelope generator shape will typically be displayed instead of just the raw numbers that make up the various envelope components. This graphic will typically change in real time as you alter the envelopeùin fact, most patch editors let you change envelope shapes simply by selecting a segment and dragging it with the mouse!