User manual AKG AS 4+3

[. . . ] To avoid hum or interference, route all audio lines, particularly those connected to the microphone inputs, away from power lines of any type. If you use cable ducts, be sure to use separate ducts for the audio lines. Be sure to disconnect the AC adapter from the power outlet before cleaning the equipment!Never use caustic or scouring cleaners or cleaning agents containing alcohol or solvents since these may damage the enamel and plastic parts. [. . . ] EXPANSION IN/OUT: These two 8-pin mini DIN sockets (also known as Hosiden or S-VHS sockets) let you daisy-chain up to 10 AS 4+3 automatic mixers. For this purpose you will need one or more optional IC AS8 connecting cables from AKG. You can set the CONTROL MODE functions on each mixer in the chain individually and the output parameters for all mixers on the last mixer in the chain only. ON: As long as the MIC 1 microphone channel is active, the level of all other input channels (MIC 2 to 4 and LINE 1 to 3) on this and any other mixers that may be connected to it will be reduced. OFF: The status of the MIC 1 channel does not affect the other channels. GROUND CONNECT: As long as this switch is in the ON position (down) the metal case of the mixer is electrically connected to ground and the shield connections of all input and output sockets. However, if you connect the mixer to other equipment that is grounded, too you may end up with a ground loop that causes hum. You can eliminate the ground loop (and the hum) by setting GROUND CONNECT to OFF (up). HOLD TIME 4s and HOLD TIME 8s: These two switches allow you to set the amount of time (1 to 12 seconds) for which the MIC inputs will remain on after the talker has stopped talking (see also section 4. CONTROL MODE Trimmers DUCKING ATTENUATION: This trimmer pot sets the amount by which the mic input channels MIC 2-4 and the line input channels LINE 1-3 are attenuated when MIC 1 places the mixer in Ducking mode. DUCKING ATTENUATION thus lets you define, for instance, how much quieter background music from a CD player will be heard while MIC 1 is being talked into. GATE ATTENUATION: This trimmer pot sets the amount by which all microphone input channels (MIC 1 to 4) are attenuated when there is no activity in them. GATE ATTENUATION thus allows you to define how loudly the microphone signal in a channel will still be audible even if that channel is off. This is rather important in discussions because a certain amount of ambient sound will remain audible even when nobody talks. You can use the front panel OUTPUT LEVEL control to set the output level. REC OUT: These two RCA jacks provide an unbalanced feed for a cassette deck or other recording equipment. LINE IN 1 to 3: These three sets of two RCA jacks each allow you to connect external audio sources such as CD players, tuners, cassette decks, etc. PHANTOM PWR: This DIP switch switches phantom power for the channel on (lower position) and off (upper position). +20 dB: In its lower position, this DIP switch increases the input gain by 20 dB (making the signal louder). With the +20 dB switch in its upper position, the input gain will remain unchanged (refer to Table 1 in section 4. If no activity is detected, the channel will automatically switch off after a delay you can set with the HOLD TIME switches. Note: The gates will not switch the microphone channels off completely but attenuate them by 14 to 26 dB. [. . . ] Ask the talker to produce a sustained sound, for instance, a whistle, and make it grow louder gradually. Set the appropriate GAIN controls such that all microphone channels involved will open simultaneously (at the same sound pressure level). As soon as MIC 1 INPUT comes on, the volume level of all other microphone and line inputs will be attenuated automatically. The control ranges from 20 dB (full CCW - high attenuation) to 9 dB (full CW - low atenuation). [. . . ]