Shure manual FP410 Portable Automatic Mixer

Shure Incorporated

222 Hartrey Avenue

Evanston IL 60202-3696 U.S.A.

Model FP410 User Guide

FP410 PORTABLE AUTOMATIC MIXER

The Shure Model FP410 is an automatic microphone mixer designed for use in a wide variety of multi-microphone speech pickup applications. Shure IntelliMix delivers flawless auto- matic mixing by combining three unique functions:

Noise--Adaptive Threshold,

MaxBus, and

Last Mic Lock--On.

Noise--Adaptive Threshold distinguishes between constant background noise (such as air conditioning) and rapidly changing sound (such as speech).This function continuously adjusts the activation threshold so that only speech levels louder than the background sound will activate an FP410 channel.

MaxBus eliminates the poor audio quality that results when a talker is picked up by more than one microphone. It does this by controlling the number of microphones that may activate for a single sound source. With MaxBus, one talker will activate only one FP410 channel, even if multiple microphones are “hearing” that talker.

Last Mic Lock--On maintains a seamless audio mix by keep- ing the most recently activated microphone open until a newly activated microphone takes its place. Without Last Mic Lock-- On, a long pause in conversation may allow all microphones to turn off, and it may sound as if the audio signal has been lost. Last Mic Lock--On ensures that background ambience will al- ways be present.

Multiple miking situations—with a number of talkers partici- pating—have always presented problems for the audio techni- cian. If too few mics are used, the coverage of each talker may vary, with one talker (nearest the mic) being louder and clearer than the next. Talkers farthest from the mics will sound “echoey” and reverberant, as very little of the direct sound from their mouths reaches the microphones. If too many mics are used, there’s more background noise and reverberation pick- up, as well as less gain before feedback if a sound reinforce- ment (PA) system is used.

It’s somewhat like having multiple video cameras all fo- cused on the same subject. If these camera signal are com- bined, the result is a blurred image. When multiple micro- phones are open for a single talker, the result is a blurred audio signal. But it’s often not practical for someone to turn mics on when they are needed and off when they are not. The answer is the FP410 automatic microphone mixer.

The FP410 automatically attenuates (turns down) any mi- crophone not being used, greatly reducing the excess rever- beration and feedback problems associated with the use of conventional multiple microphone and mixer techniques. When a new talker starts to speak, the FP410 immediately se- lects and silently activates the most appropriate microphone. Shure IntelliMix electronic signal processing enables the FP410 to provide clear, natural voice pickup. The FP410 sig- nificantly reduces the problems of “boomy” or “muddy” sound, insufficient sound level (because of feedback or “howling”), and operator errors. In fact, operator errors are virtually elimi- nated because the FP410 needs no operator or technician for continual adjustment—once set up, it is completely self--suffi- cient.

The FP410 has numerous applications in video production and audio recording, broadcasting, and sound reinforcement. In any speech pickup application where multiple microphones are required, the FP410 dramatically improves audio quality. Switching from manual to automatic operation allows an indi- vidual talker’s voice to rise above the background noise and reverberation to become clearer and more intelligible.

Each FP410 handles up to four microphones or line--level signals. Any high quality, low--impedance, balanced micro- phone using a dynamic or condenser* transducer (including wireless and shotgun types) can be used. Additional FP410 mixers can be interconnected using the rear--panel link jacks. Complete manual operation is also available using a front--pa- nel selector switch.

The FP410 is supplied with optional bumpers (feet) for use on horizontal surfaces, a short cable for linking two FP410 mix- ers, and a rack--mounting kit for installation in a standard 483 mm (19--inch) audio equipment rack.

The FP410 (100 to 120 Vac operation; line fuse 0.1 A) is also supplied as the Model FP410E (230 Vac operation; line fuse 0.05 A), and its line cord contains a Schuko ac plug.

*Self--powered or operable on 14 or 48 Vdc phantom power.

Features

Reliable, quick--acting, noise--free microphone selection----

automatically adjusts to changes in background room noise

Front--panel channel gain and master controls operate as in conventional mixers

Selectable hold time keeps microphones on during short pauses in speech

E2000, Shure Incorporated 27B8392 (TB)

U.S. Patent 4,658,425; other patents pending Printed in U.S.A.