The Orban Model 412A/414A Compressor/Limiter is a general-purpose AGC device of highest professional quality. It can perform compression and peak limiting simultaneously with unusual freedom from side-effects. The flexibility and natural sound of the 412A/414A make it applicable in virtually all areas of professional audio: recording studios, broadcasting, sound reinforcement, public address, motion picture sound, etc. However, it is not optimized for overmodulation protection of broadcast transmitters; the Orban OPTIMOD-AM, -FM, or -TV should be used in such applications. The product is available in both single- (412A) and dual- (414A) channel versions. (For clarity, only the 414A will be referenced in this manual.) The dual-channel version is equipped with a coupling switch which forces the gain of both channels to be equal, tracking the channel demanding the greatest amount of gain reduction. This preserves correct imaging in stereo applications. However, the stereo coupling switch does not couple the operating controls, and these are ordinarily set identically in stereo operation. (If they are set non-identically, the gain of both channels will still be equal, tracking the channel demanding the highest amount of G/R. However, the control circuitry will respond differently to material in the two channels even if a mono feed is used. This might be useful for special effects.) Attack and release times are both program-controlled, but can be scaled faster or slower by means of front-panel controls. This results in maximum flexibility, plus extremely natural sound over a wide range of control settings. The 414A Compressor/Limiter is equipped with electronically-balanced input and output, and is compatible with the levels and impedances found in both professional and semi-professional applications. RF suppression applied to the input, output, and power leads enables use in relatively high RFI fields such as those common in broadcasting. Because the front-panel controls are marked in a familiar way, you may be tempted to jump right in without reading the manual. However, if you take the time to review the Description And Function Of Front-Panel Controls and Operating Instructions in Part C, you will find that there is "more than meets the eye" inside the 414A, and that the time you take reading the manual will be well-rewarded by a greater understanding of the unit's potential.