Fender Series 3000 Owners Manual - Page 63

• • usually have low line-level outputs. Or, you can use the "preamp outputs," "tape outputs" or "auxiliary outputs" on your hi-fi preamplifer, receiver or integrated amplifier. Using Special Effects Devices Special effects devices may be connected to either the Effects mix or the Input Channel Insertion jack. These connections are discussed earlier in this manual. The most common effects include reverberation, instrument effects (fuzz, phasing, flanging, etc.), delay lines, expanders, and the various noise sources used in live theatre. A complete spring-type reverberation system is included in your 3000 Mixer. If the device is an instrumental special effect, it may be used primarily on one instrument. In that case, you would use it through the Insertion jack on one of the Input Channels of your 3000 Mixer (or connect it directly to the instrument itself). If the device is meant to enhance a voice, then you would, again, probably use it on a single Input Channel via the Insertion jack. Some effects, however, like reverberation, will probably be used on all instruments and voices. Use these through the Effects mix. Using Limiters and Compressors Actually, limiters and compressors are two versions of the same device. In fact, many such devices are called "compressor/limiters." An "expander" is a similar device. All three devices monitor the signal level and change it (like an automatic volume control) in some pre-determined way. A compressor reduces the level of high-level signals and increases the level of low-level signals. In other words, it reduces the "dynamic range" of the signal. Compressors are used by background music suppliers to keep the level of their music nearly constant, This allows the music in a department store, for example, to always be loud enough to hear (above crowd noise) but never so loud as to be annoying. You could use a compressor for the same purpose in mixing a quiet group for a hotel lounge. Compressors are also useful for tape recording. The dynamic range of live music must be reduced to fit the dynamic range capabilities of a tape recorder, and a compressor can be used for this purpose. Special noise reduction devices, like those made by Dolby and dbx and others are probably a better choice for this purpose, however. A limiter reduces the level of highlevel signals but does not affect lowlevel signals. While compressors are operating most of the time, a limiter only operates above a fixed "threshold." That is, the limiter begins to reduce the signal level only when it exceeds some preset level. Limiters are used by radio stations to avoid over-driving their transmitters. Limiters are used extensively in pro audio to keep the audio signal from overdriving a power amplifier (overdriving a power amplifier can cause clipping distortion and can even cause damage to the power amplifier and loudspeakers). The AGC in your 3000 Mixer is a form of limiter, preset to help you avoid overdriving the power amplifiers in your 3000 Mixer. External limiters are probably the best way of protecting your external power amplifiers and loudspeakers from damage and are an excellent way to help you avoid clipping distortion. An expander actually increases the level of high-level signals and reduces the level of low-level signals. Thus, an expander increases the dynamic range of a signal. Expanders in pro audio are used primarily for special effects. An expander, used improperly, could present a danger to your system since it could increase high-level peaks to the point of clipping. Equalization What Do We Mean By "Equalization?" The term equalization originally meant "to equalize the frequency response of a sound system to match a room." The term, equalization, however, now applies to just about any process that changes the frequency response of a signal. The Input Channel Equalization controls, for example, would probably be called "tone controls" on a hi-fi product. In pro audio, however, they are called "Equalization" controls. A "graphic" equalizer is so called because the position of its sliders form a curve, like a graph of the frequency response. Using Equalizers As we in "The Input Channel Equalization Controls," the Input Channel Equalization controls are used to change the tonal character of an individual voice or instrument. The Program and Monitor Graphic Equalizers (or an external graphic equalizer) are used to affect the frequency response of an entire mix to compensate for room acoustics, for example. Elaborate test equipment, including "pink noise generators" and "real-time analyzers" is available to aid in the process of room equalization. The instruction manuals that come with a real-time analyzer usually explain the process of room equalization or you can purchase one of several books on the subject including "Sound System Engineering" by Don and Carolyn Davis, published by Howard W. Sams. So-called "narrow-band" equalizers or "notch filters" are sometimes used to help stop feedback (howling) in a system or the ringing that comes just before feedback. Using equalizers to help control feedback is covered in more detail in the section entitled "Dealing with Feedback, Hum, Hiss and other Noises." An equalizer, of any type, is a powerful tool. Equalization can, indeed, 61