In 1995, the USB standard was introduced to reduce the number of different connectors on personal computers. Subsequently, MIDI over USB has emerged as an alternative that replaces two MIDI cables with a single USB link. In addition to being a common connector on personal computers, USB's higher transmission speed increases MIDI's flexibility by allowing MIDI to control 32 channels instead of the 16 specified in the original MIDI standard. USB connectivity is now finding its way into the digital piano. All current digital instruments still have 5-pin DIN connectors for traditional MIDI, but many now sport USB connectors as well. One thing to be aware of is that there are two types of USB connections that can appear on instruments. One, "USB to Device," allows direct connection to a variety of external memory-storage devices. The other, "USB to Host," allows connection to computers. If you plan to use these connections, you need to check the type of USB connections available on the instruments you're considering. Simply stating "USB" in the specifications doesn't tell you the type of USB connectivity provided.

External Memory

External memory consists of any storage device that's connected to the instrument rather than being built in. As instruments become more advanced, they can require larger amounts of memory to store MIDI recordings, audio recordings, additional rhythm patterns and styles, even additional voices. Since different users will put different demands on memory resources, it's becoming increasingly common for manufacturers to allow the user to attach external disk drives and USB flash memory to augment onboard memory.

Floppy-disk drives have long been popular on digital pianos. While the floppy disk is rapidly disappearing from the computer world, it has remained a staple of the digital piano due to the volume of MIDI files that have traditionally been distributed on floppies. These files run the gamut, from complete song arrangements to files that use the special learning features of a particular instrument model to guide you through the process of learning a new piece of music. It's now possible to download these files from the Internet, but getting them from the computer to the instrument hasn't always been a straightforward process. As this transfer process becomes more user-friendly, the floppy will become less important. However, many teachers still use instructional books that come with a floppy disk that contains files to be used in conjunction with the book, so we can count on the humble floppy disk to stick around for a while.

If the instrument you select has the capability to record audio to external memory via USB, you'll want to add an external, or desktop, USB hard drive. These audio recordings are saved as uncompressed .WAV files, typically at the same sampling rates (though not the same file format) used for commercial audio CDs: one five-minute song can consume up to 50MB of memory space. Not long ago, I might have suggested getting at least an 80-Gigabyte hard drive for this purpose, but it's becoming increasingly difficult to find external hard drives much smaller than 320GB, and Terabyte drives are now becoming increasingly common. Obviously, there's little need to worry about storage space.

The final external storage option — and my favorite — is the USB flash drive. These are the ultimate in handy storage and now range up to 64GB. Not only are they unobtrusive when attached to the instrument, but if your digital piano and computer aren't in the same room, they make file transfers quick and painless.

Computer Software

As mentioned briefly in the discussion of MIDI, perhaps the most powerful option that accompanies the digital piano is the ability to connect your instrument to your personal computer and enhance your musical experience by using different types of music software. Software can expand capabilities your instrument may already have, such as recording and education, or it could add elements like music notation and additional voices. While it's beyond the scope of this article to describe music-software offerings in detail, we'll take a quick look here at the different categories: Recording and Sequencing, Virtual Instruments, Notation, and Educational.

Recording can take two forms on the digital piano: data and sound. All models that offer onboard recording (i.e., nearly all of them) record MIDI data. This means that all of the actions you take when you play a piece — both key presses and control actions — can be recorded by a MIDI sequencer. But remember that a MIDI sequence, or recording, is data, not sound. Recording the actual sound of your music is a different issue, and few digital pianos can do this.