Alesis 1622 User manual

ALESIS
1622 Mixer
Reference Manual

TABLE OF CONTENTS
INTRODUCTION....................................................................................................................2
WHAT IS A MIXING CONSOLE?...............................................................................2
FEATURES................................................................................................................2
SECTION 1
DESCRIPTION OF CONTROLS................................................................................3
TOP PANEL..................................................................................................3
INPUT TRIM.....................................................................................3
EQ....................................................................................................3
SENDS .............................................................................................3
PRE-FADER SENDS............................................................3
POST-FADER SENDS.........................................................4
MASTER ASSIGN SWITCH .............................................................5
SUB MASTER ASSIGN SWITCH .....................................................5
MUTE SWITCH ................................................................................6
SOLO SWITCH.................................................................................6
PAN POT..........................................................................................6
CHANNEL FADER............................................................................6
SEND MASTERS..............................................................................6
TAPE/MONITOR SWITCH................................................................6
MONITOR VOLUME.........................................................................6
EFFECTS RETURNS .......................................................................6
SUB MASTER FADERS ...................................................................7
SUB MASTER TO MASTER ASSIGN SWITCH................................7
MASTER FADERS............................................................................7
BACK PANEL................................................................................................7
MIC/LINE INPUTS ............................................................................7
MICROPHONE INPUTS ...................................................................7
DIRECT OUTPUTS...........................................................................7
CHANNEL INSERTS.........................................................................8
SENDS .............................................................................................8
RETURNS ........................................................................................8
HEADPHONE...................................................................................8
SUB OUT..........................................................................................8
SUB INSERT ....................................................................................8
MAIN OUT........................................................................................8
MAIN OUT LEVEL SELECTOR ........................................................8
MAIN INSERT...................................................................................8
MONITOR OUT ................................................................................8
POWER SUPPLY CONNECTOR......................................................8
ON/OFF SWITCH.............................................................................9
SIGNAL FLOW IN THE 1622.....................................................................................9
SECTION 2
SETTING UP THE 1622 ............................................................................................12
CONNECTIONS TO THE MIXER..................................................................12
INTERFACING TO A MULTITRACK TAPE RECORDER:
4 TRACK THROUGH 8 TRACK RECORDING .....................12
INTERFACING TO THE MULTITRACK TAPE RECORDER VIA A
PATCHBAY ......................................................................................13
INTERFACING THE 1622 MIXER TO THE MIXDOWN DECK..........14
INTERFACING THE 1622 MIXER TO THE CONTROL ROOM
MONITOR SPEAKERS.....................................................................15
INTERFACING THE 1622 MIXER TO A HEADPHONE AMP............15
INTERFACING THE SENDS AND RETURNS OF THE 1622 MIXER TO
EFFECTS .........................................................................................15
INSERT INTERFACING....................................................................15
HOW TO ADJUST LEVELS ..........................................................................16

SECTION 3
APPLICATIONS ........................................................................................................18
MULTITRACK RECORDING.........................................................................18
INTRODUCTION TO MULTITRACK RECORDING...........................18
RECORDING .......................................................................18
MONITORING......................................................................19
MULTITRACK MIX...................................................19
MONITOR SPEAKER (CONTROL ROOM) MIX.......19
CUE MIX..................................................................19
MIXDOWN ...........................................................................19
THE 1622 MIXER AND A 4 OR 8 TRACK TAPE DECK.................................19
USING THE 1622 MIXER TO RECORD
A SINGLE SOURCE TO 1 TRACK.......................................20
TWO OR MORE SOURCES TO 1 TRACK...........................20
2 OR MORE SOURCES TO 2 TRACKS...............................20
RECORDING TIPS...........................................................................21
HOW TO PLAYBACK FROM MULTITRACK.....................................21
HOW TO SET UP A CUE .................................................................22
MIXDOWN........................................................................................22
HOW TO CREATE A DEPENDABLE MIX........................................23
HOW TO GROUP SEVERAL CHANNELS TOGETHER
WHEN MIXING.................................................................................25
HOW TO PLAYBACK A MIX FROM THE MIXDOWN TAPE DECK..26
PLAYBACK TIPS..................................................................26
SOUND REINFORCEMENT APPLICATIONS IN MONO ..................27
USING THE SUB MASTERS............................................................28
LINE INPUTS USED AS ADDITIONAL MIC INPUTS........................29
USING THE SUB MASTERS FOR SEPARATE OUTPUTS ..............29
STAGE MONITOR MIX FROM THE PRE-FADER SENDS...............30
DEDICATED MIDI KEYBOARD MIXER.........................................................30
SECTION 4
TROUBLESHOOTING ..............................................................................................32
NO SOUND...................................................................................................32
NO SOUND WHEN CHANNEL IS SOLOED.....................................32
NO SOUND WHEN MONITOR LEVEL TURNED UP........................32
OVERLOAD PROBLEMS..............................................................................32
DISTORTION HEARD WHEN INPUT CHANNEL IS SOLOED..........32
DISTORTION IS BEING RECORDED ONTO TAPE, BUT DISTORTION
NOT HEARD WHEN INPUT CHANNEL IS SOLOED........................33
DISTORTION AT MIXDOWN MACHINE OR SOUND SYSTEM .......33
DISTORTION ON THE RETURNS....................................................33
SECTION 5
GROUNDING.............................................................................................................33
SECTION 6
SPECIFICATIONS .................................................................................................................35
GLOSSARY...........................................................................................................................36
APPENDIX.............................................................................................................................42
INDEX....................................................................................................................................44
BLOCK DIAGRAM................................................................................45

Alesis1622
Monolithic/Integrated Surface™ Audio Console
USER'S MANUAL

2
Alesis1622
Monolithic/Integrated Surface™ Audio Console
INTRODUCTION
The Alesis 1622 Monolithic/Integrated Surface™ Audio Console is a 16 channel, two buss
audio mixing console which features the new Integrated Monolithic Surface™ technology. This
technology makes available a number of features at low cost which previously could only be
found in much more expensive consoles .
The 1622 MIXER provides excellent sonic qualities, with extremely low noise and crosstalk, flat
wideband frequency response, and the superb sweet sound normally associated with consoles
costing many times more. Thus the 1622 MIXER can be used as an additional "Musical Tool" .
Because of the built-in flexibility of the 1622 MIXER, the unit is at home in any application, be it
recording, sound reinforcement, post-production, or as a dedicated keyboard mixer.
WHAT IS A MIXING CONSOLE?
As the name implies, a mixing console "mixes" audio signals together from various sources
(microphones, keyboards, tape machines, reverbs, etc.). But unlike a simple "mixer", a mixing console
is really the "brain" or center of the entire sound system, regardless of the application, since it not only
mixes the signals together, but also provides routing of these signals to tape recorders, effects devices,
and other audio systems. The console also allows for adjustment of monitoring levels independent of
recording levels.
FEATURES
•16 INPUT CHANNELS WITH EQ - Plenty of inputs for keyboards, microphones, or
effects
•6 AUXILIARY SENDS - Sends signal to up to 6 outboard effects devices, or 4
outboard effects devices and 2 mono or 1 stereo headphone cue mixes
•8 AUXILIARY RETURNS - Special dedicated inputs designed to blend the returns
of any combination of 8 mono or 4 stereo outboard effects devices
•SOLO FUNCTION ON INPUT CHANNELS - Enables any overloads or unwanted
background noise to be easily detected
•2 SUB MASTERS - Makes it easy to control several input channels with just one
fader (or two for stereo), or control record levels during multitrack recording
•CONTROL ROOM MONITOR SECTION - Sets a level for the control room monitor
speakers that is independent of the main mix
•ELECTRONICALLY BALANCED MIC INPUTS - A feature normally found on
consoles that are many times more expensive, this allows for both lower noise and
greater headroom in the most critical stage of the console
•MIXDOWN TAPE DECK RETURN - Allows you to hear playback of your mix from
the stereo mixdown tape machine just by flipping a switch
•INSERTS ON ALL INPUTS AND OUTPUTS - Allows for patching outboard signal
processing devices such as EQ's, compressors, and effects directly into the signal
path
•8 DIRECT OUTPUTS - Allows for the quietest operation by bypassing unused
electronics and sending the channel signal directly to the input of a Multitrack Tape
Machine

3

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SECTION 1
DESCRIPTION OF CONTROLS
TOP PANEL
INPUT TRIM
The INPUT TRIM is a variable gain control that allows the preamp stage of the mixer to boost
the level of a mic or line level signal being fed into the input. The input section of any mixer is
the most critical due to the high gain required to amplify such a low level signal (such as that of a
microphone) to a usable level. If the gain is set too high, a hot signal from a synthesizer or loud
vocalist will cause the input stage to overload and distort. If the gain is set too low, additional
gain must be added at some other point in the mixer (such as the faders) which could cause
excessive background noise at the output.
EQ
The equalizer, or EQ, section consists of simple bass and treble controls similar to that of a
guitar amp or home stereo. EQ allows for any tonal shaping that might be required by a signal.
For the technically minded, these are known as shelving equalizers and have turnover points at
10KHz and 100Hz. This means that the maximum boost or cut begins from 10KHz (and 100Hz
for the low frequency EQ) and maintains this "shelf" or plateau from 10KHz to 20KHz. The
frequencies below 10KHz are also affected, but less and less so as the frequency of the signal
gets further away from 10KHz. See Figure 1
FIGURE 1
HI AND LO SHELVING EQ OF THE 1622 MIXER
-15dB
+15dB
100Hz 10KHz
SHELF
+15dB
-15dB
0 dB
Frequency
0 dB
SENDS
SENDS (sometimes called "Auxiliary Sends" or "Aux's") are adjustable feeds from the input
channel that are used to send part of the signal to an outboard effect, like a reverb, delay, or
chorus, or to set up a separate cue (headphone) mix for musicians headphones during recording
and overdubbing. There are two different types of SENDS included in the 1622. These are:
PRE-FADER SENDS
SENDS 1 and 2 are derived from the signal path before the Channel Fader. This means that
movements of the channel fader will have no effect on the amount of signal being sent to any
equipment connected to these SENDS. For this reason, these auxiliary sends are normally used
as cue sends (sends to headphones while recording) because any movement of the channel

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faders will not upset the headphone balance. Pre-Fader SENDS can also be used to send a
signal to outboard effects as well. See Figure 2A and 2B
FIGURE 2A
PRE-FADER SEND LEVEL FROM THE 1622 MIXER TO EFFECTS DEVICE WITH CHANNEL
FADER UP
SIGNAL
PRE-FADER SEND
MASTER
INPUT
FADER UP
FIGURE 2B
PRE-FADER SEND LEVEL FROM THE 1622 TO EFFECTS DEVICE WITH CHANNEL FADER
PRE-FADER SEND
TO HEADPHONES
OR EFFECTS
+3
0VU
-10
-20
-30
-40
-50
-60
INPUT
LED METER
INSTRUMENT/MIC
EFFECTS DEVICE
B. PRE-FADER SEND
WITH
CHANNEL FADER DOWN
CHANNEL
FADER
POST-FADER SENDS
SENDS 3 through 6 are derived from the signal path after the Channel Fader which means that
their levels will be changed in direct relationship to the Channel Fader level. This means that
when the Channel Fader is either increased or decreased, the send level will also be increased
or decreased and the effects (or headphones) would get louder or softer. Since this wouldn't be
too great for a headphone balance, these Post-Fader sends are normally used to send to
outboard effects devices such as reverbs. Unlike most other mixers which may have only 1 or 2
Post-Fader Sends, the 1622 MIXER has a total of 4 Post-Fader Sends. See Figure 3A and 3B
FIGURE 3A
POST-FADER SEND LEVEL FROM THE 1622 MIXER TO EFFECTS DEVICE WITH CHANNEL
FADER UP

6
POST-FADER SEND
TO HEADPHONES
OR EFFECTS
+3
0VU
-10
-20
-30
-40
-50
-60
INPUT
LED METER
INSTRUMENT/MIC
EFFECTS DEVICE
A. POST-FADER SEND
WITH
CHANNEL FADER UP
CHANNEL
FADER
FIGURE 3B
POST-FADER SEND LEVEL FROM THE 1622 MIXER TO EFFECTS DEVICE WITH CHANNEL
FADER DOWN
POST-FADER SEND
TO HEADPHONES
OR EFFECTS
INSTRUMENT/MIC
EFFECTS DEVICE
B. POST-FADER SEND
WITH
CHANNEL FADER DOWN
CHANNEL
FADER
+3
0VU
-10
-20
-30
-40
-50
-60
INPUT
LED METER
MASTER ASSIGN SWITCH
Routes the channel signal directly to the MASTER Stereo Buss.
SUB MASTER ASSIGN SWITCH
Routes the channel signal directly to the SUB MASTER.
MUTE SWITCH
Turns the channel off. The MUTE switch does not affect the signal on SENDS1 and 2 but will
mute SENDS 3 through 6.
SOLO SWITCH

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SOLO disconnects the normal signal feed to the monitor speakers and replaces it with the signal
present at the Channel Fader. When a channel is soloed, the signal will be heard in mono
regardless of the position of the pan pot, and without any effects via the Sends and Returns.
Soloing enables the engineer to hear exactly what is being recorded by eliminating the masking
effects caused by the presence of other signals. When soloed, distortion caused by overloading
or other undesired background noises in an input channel can be heard easily.
SOLO switches can be used at any time without interrupting the signals sent to the headphones
or recorded on tape since the soloed signal is only heard through the Monitor Speakers. By
engaging additional SOLO switches, as many signals as desired can be soloed simultaneously.
PAN POT
The PAN POT places the signal of the channel anywhere in the stereo field between the left and
right channels of the MASTER or SUB MASTERS (or both) depending upon which is assigned.
If the PAN is set all the way to the left, the signal will appear only on the left SUB MASTER or
MASTER fader. If the PAN is set all the way to the right, the signal will appear only on the right
SUB MASTER or MASTER fader.
CHANNEL FADER
The CHANNEL FADER determines the overall volume level of the channel. It is normally best
to keep this FADER at about the 3/4 level for the most headroom and least background noise.
SEND MASTERS 1 through 6
This is the overall master for the corresponding SEND of each channel. Therefore, if the level of
SEND 1 was too hot and causing distortion, the overall level could be trimmed by adjusting
SEND MASTER 1, which would lower the signal without having to individually adjust each
channel SEND.
TAPE/MONITOR SWITCH
When the 1622 MIXER is used for recording, this switch will determine what you hear in the
control room monitor speakers. When in the TAPE position, the signal from the Mixdown Tape
Deck will be heard and can be adjusted from the MONITOR VOLUME pot. When in the
MONITOR position, the signal from the console, as adjusted by the MASTER Faders and
MONITOR VOLUME pot, will be heard.
MONITOR DEFEAT SWITCH
This switch will mute the signal going to the control room monitor speakers in the event that it is
necessary to monitor with headphones via the headphone jack. This switch has no effect on the
signals appearing at the MASTER Faders.
MONITOR VOLUME
The MONITOR VOLUME Control adjusts the volume level of the control room monitor speakers
only. When the 1622 is used as a recording console, it is necessary to be able to control the
level of the control room monitor speakers and the MASTER Fader output levels independently.
Without the separate MONITOR VOLUME control, both the control room speakers and the
mixdown tape level would be controlled by the MASTER Faders, which would cause either a
distorted or noisy signal going to tape when the speaker levels were correct, or too loud or soft
speaker levels when the tape machine levels were correct.
EFFECTS RETURNS
The EFFECTS RETURNS are additional inputs (besides the 16 Channel Inputs) especially for
outboard effects such as reverbs, delays, chorus, etc. These inputs eliminate the need to
connect effects to channel inputs and, therefore, keep the input channels available for additional
microphones, synthesizers, etc.
There are 8 EFFECTS RETURNS on the 1622 MIXER . RETURNS 1 through 4 each have a
PAN control which allows the the return signal to be placed anywhere in the stereo spectrum
from left to right. RETURNS 5 and 7 are permanently assigned to the Left MASTER Buss, and
RETURNS 6 and 8 are permanently assigned to the Right MASTER Buss.
SUB MASTER FADERS