CHAPTER 5. HARDWARE CONSIDERATIONS

The Digital Versus Analog Issue -- Each method of sound production can do some things better than others. Digital circuits are generally more versatile, produce lower background noise and are less complicated than their analog counterparts. On the other hand, when they do exhibit background noise or distortion the sound is so much "rougher" than the analog equivalent that even a small amount is unacceptable.

Many listeners feel that the sounds produced by digital synthesizers are too "clean" or "incisive." They feel that analog instruments produce a "warmer" sound.

One reason for this perception is that digital instruments have so little background noise that the slightest imperfections stand out. Some instruments and recorders include circuitry that allows the player to add a slight amount of hiss and distortion in order to retain the analog illusion.

In addition, digital synths are programmed at the factory with virtually no filtering on the patches. By the time the new owner understands the menus enough to tame the higher harmonics, the sound impression is firmly in place. The truth is, analog synths can produce very clean, incisive sounds and digital synths can produce very "muddy" sounds.

What about buying some of that old, venerable analog equipment? Its main advantage is the ease and speed with which you can change its sound. Its disadvantages are: 1) it will be either monophonic or polyphonic up to, perhaps, six voices, and 2) it will not respond to MIDI commands. Although some companies offer kits that provide MIDI compatibility for their older instruments, such retrofits seldom respond to the full complement of MIDI commands.

Companies such as Korg and Serge build synths that use analog methods for producing sound but have all the programming advantages that MIDI provides.

If you do have some vintage equipment whose sounds you like you can still "have your MIDI cake and eat it, too." Record its sounds into a "sampler." A sampler is a digital recorder that has the same sound-processing features and editing menus as a synthesizer. It employs the MIDI protocol, so any sound you record with it can be manipulated from either your master keyboard or from the computer.

System Components -- A MIDI system resembles a stereo system in that its components can be either discrete units or elements of a larger unit. The system comprises these basic elements:

1. sound generators such as a synthesizer, sampler, or a drum kit;

2. sound processors such as a reverberation unit, digital delay, or a harmonizer;

3. the MIDI interface and related devices that connect the various units in a network; and

4. the computer.

A synthesizer can be contained within a keyboard, a module that fits in a standard equipment rack or built onto a "circuit card" that plugs into a computer's card slot. Sound processors can be separate units or incorporated into the synthesizer. The synth and the MIDI interface can, in turn, be two components of a "sound card."

In addition to its function as the player of sound clips for games and encyclopedias, a sound card can serve as your basic electronic music studio. It contains a MIDI-based synthesizer, digital sound recorder and player, an audio mixer, a joystick/MIDI port to which an external keyboard can be connected, and a port that operates a CD-ROM drive.

The onboard mixer accepts sounds from the card's synth and from external sources such as a microphone, tape player, CD player, or a musical instrument having an electrical output. A sound card is the vehicle you need if you want to use your computer as a storage medium for recorded sounds.

If the card is advertised as being "100% game compatible" it is most likely compatible with the "Soundblaster" sound card format which has become a standard. In that case it may contain two synthesizers. One is an FM synthesizer employed by the Soundblaster cards, and the other a MIDI GS-based unit containing sampled sounds and hybrids of sampled and electronic sounds. On some cards the sampled sounds can be replaced by sounds of your choice.

Some designers of screen readers have written drivers for the Soundblaster. However, it is not yet time to forsake the traditional speech synthesizer which is designed specifically for reading. It has pronunciation algorithms built into it, so its software requires a minimum of computer memory.

The MIDI Interface -- The computer is connected to your keyboard and other external components of the MIDI system via a "MIDI interface." The interface can be either a separate card, or part of a synth card or a sound card. In order to accommodate the greatest variety of software, your MIDI interface should be compatible with the MPU401 standard. If you want a "high end" interface that provides more than one MIDI-out port and data conversion features, the MPU401 standard should be one of its options.

Users of laptop computers are not left out. The MIDI interface can be either an outboard unit that runs from the serial or the parallel port, or a unit in the form of a PCMCIA card that slides into the computer. Developments are occurring rapidly in the field of laptops and interface technology. Ask the designer of the sequencer that interests you if they support the hardware you plan to use. Many accessories are available as PCMCIA cards but may not be supported by your sequencer.

Go on to Chapter 6.

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