Mackie Onyx 1620i User manual

OWNER'S MANUAL
16-Channel Premium Analog Mixer
with FireWire
SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE
48V 48V 48V 48V 48V 48V 48V 48V

2 Onyx 1620i
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install in accordance with the
manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers,
stoves, or other apparatus (including amplifiers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type
plug. A polarized plug has two blades with one wider than the other.
A grounding-type plug has two blades and a third grounding prong.
The wide blade or the third prong are provided for your safety. If the
provided plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.
10. Protect the power cord from being walked on or pinched particularly at
plugs, convenience receptacles, and the point where they exit from the
apparatus.
11. Only use attachments/accessories specified by the manufacturer.
12. Use only with a cart, stand, tripod, bracket, or
table specified by the manufacturer, or sold with
the apparatus. When a cart is used, use caution
when moving the cart/apparatus combination to
avoid injury from tip-over.
13. Unplug this apparatus during lightning storms or
when unused for long periods of time.
14. Refer all servicing to qualified service personnel. Servicing is required
when the apparatus has been damaged in any way, such as power-
supply cord or plug is damaged, liquid has been spilled or objects have
fallen into the apparatus, the apparatus has been exposed to rain or
moisture, does not operate normally, or has been dropped.
15. Do not overload wall outlets and extension cords as this can result in a
risk of fire or electric shock.
16. This apparatus shall not be exposed to dripping or splashing, and no
object filled with liquids, such as vases or beer glasses, shall be placed
on the apparatus.
17. This apparatus has been designed with Class-I construction and must
be connected to a mains socket outlet with a protective earthing con-
nection (the third grounding prong).
18. This apparatus has been equipped with a rocker-style AC mains power
switch. This switch is located on the rear panel and should remain
readily accessible to the user.
19. The MAINS plug or an appliance coupler is used as the disconnect
device, so the disconnect device shall remain readily operable.
20.NOTE: This equipment has been tested and found to comply with
the limits for a Class B digital device, pursuant to part 15 of the FCC
Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equip-
ment generates, uses, and can radiate radio frequency energy and, if
not installed and used in accordance with the instructions, may cause
harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If
this equipment does cause harmful interference to radio or television
reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or
more of the following measures:
• Reorientorrelocatethereceivingantenna.
• Increasetheseparationbetweentheequipmentandthe
receiver.
• Connecttheequipmentintoanoutletonacircuitdifferentfrom
that to which the receiver is connected.
• Consultthedealeroranexperiencedradio/TVtechnicianfor
help.
CAUTION: Changes or modifications to this device not expressly
approved by LOUD Technologies Inc. could void the user's authority to
operate the equipment under FCC rules.
21. This apparatus does not exceed the Class A/Class B (whichever is
applicable) limits for radio noise emissions from digital apparatus as
set out in the radio interference regulations of the Canadian Department
of Communications.
ATTENTION — Le présent appareil numérique n’émet pas de bruits
radioélectriques dépassant las limites applicables aux appareils
numériques de class A/de class B (selon le cas) prescrites dans le
réglement sur le brouillage radioélectrique édicté par les ministere des
communications du Canada.
22. Exposure to extremely high noise levels may cause permanent hearing
loss. Individuals vary considerably in susceptibility to noise-induced
hearing loss, but nearly everyone will lose some hearing if exposed to
sufficiently intense noise for a period of time. The U.S. Government’s
Occupational Safety and Health Administration (OSHA) has specified
the permissible noise level exposures shown in the following chart.
According to OSHA, any exposure in excess of these permissible limits
could result in some hearing loss. To ensure against potentially danger-
ous exposure to high sound pressure levels, it is recommended that all
persons exposed to equipment capable of producing high sound pres-
sure levels use hearing protectors while the equipment is in operation.
Ear plugs or protectors in the ear canals or over the ears must be worn
when operating the equipment in order to prevent permanent hearing
loss if exposure is in excess of the limits set forth here:
Important Safety Instructions
PORTABLE CART
WARNING
CAUTION AVIS
RISK OF ELECTRIC SHOCK. DO NOT OPEN
RISQUE DE CHOC ELECTRIQUE. NE PAS OUVRIR
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK DO NOT REMOVE COVER (OR BACK)
NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL
ATTENTION: POUR EVITER LES RISQUES DE CHOC ELECTRIQUE, NE PAS ENLEVER LE COUVERCLE.
AUCUN ENTRETIEN DE PIECES INTERIEURES PAR L'USAGER.
CONFIER L'ENTRETIEN AU PERSONNEL QUALIFIE.
AVIS: POUR EVITER LES RISQUES D'INCENDIE OU D'ELECTROCUTION, N'EXPOSEZ PA S CET ARTICLE
A LA PLUIE OU A L'HUMIDITE
The lightning flash with arrowhead symbol within an equilateral triangle is
intended to alert the user to the presence of uninsulated "dangerous
voltage" within the product's enclosure, that may be of sufficient magnitude
to constitute a risk of electric shock to persons.
Le symbole éclair avec point de flèche à l'intérieur d'un triangle équilatéral
est utilisé pour alerter l'utilisateur de la présence à l'intérieur du coffret de
"voltage dangereux" non isolé d'ampleur suffisante pour constituer un risque
d'éléctrocution.
The exclamation point within an equilateral triangle is intended to alert the
user of the presence of important operating and maintenance (servicing)
instructions in the literature accompanying the appliance.
Le point d'exclamation à l'intérieur d'un triangle équilatéral est employé
pour alerter les utilisateurs de la présence d'instructions importantes pour le
fonctionnement et l'entretien (service) dans le livret d'instruction
accompagnant l'appareil.
WARNING — To reduce the risk of fire or electric shock, do not
expose this apparatus to rain or moisture.
Duration,
per day in
hours
Sound Level
dBA, Slow
Response
Typical Example
8 90 Duo in small club
6 92
4 95 Subway Train
3 97
2 100 Veryloudclassicalmusic
1.5 102
1 105 Matt screaming at Troy about
deadlines
0.5 110
0.25 or less 115 Loudest parts at a rock concert
Correct disposal of this product. This symbol indicates that this product should not be disposed of with your household waste, according to the WEEE Directive (2002/96/EC) and your national law. This product
should be handed over to an authorized collection site for recycling waste electrical and electronic equipment (EEE). Improper handling of this type of waste could have a possible negative impact on the environment and
human health due to potentially hazardous substances that are generally associated with EEE. At the same time, your cooperation in the correct disposal of this product will contribute to the effective usage of natural
resources. For more information about where you can drop off your waste equipment for recycling, please contact your local city office, waste authority, or your household waste disposal service.

Owner's Manual 3
Part No. SW0723 Rev. D 07/2011
©2011 LOUD Technologies Inc. All Rights Reserved.
Loosely based on a dream sequence in which the technical writer is given
keys to a sports car of his choice, unlimited gas, and closed roads. The dream
suddenly ends and reality kicks in. A mixer manual to write, a mixer manual
to write!
Set the levels
It’s not even necessary to hear what you’re doing to
set optimal levels. But if you’d like to: Plug in
headphones and turn up the phones knob just a little.
1. Turn on the mixer's power switch.
2. For one channel, press the solo switch in, and
the rude solo light will turn on.
3. Play something into that input at real-world
levels.
4. Adjust that channel's gain control until the
right main meter stays around the 0 dB LED
(marked "level set").
5. Disengage the channel's solo switch.
6. Repeat steps 2 to 5 for the remaining channels.
7. Turn up a channel fader to the "U" mark.
8. Slowly turn up the main mix fader until you
hear the signals in your speakers or
headphones.
9. If needed, apply some channel EQ wisely.
10. Adjust the channel faders to get the best mix.
Keep the gain controls and faders fully down on
unused channels.
11. During the performance, if you notice a channel
OL LED turning on during peaks, carefully turn
down that channel's gain control until OL does
not turn on.
FireWire
• Seepage34fordetailsofgettingstartedwith
FireWire.
• PCdriversareonthesuppliedCD-ROM.Mac
OS X contains built-in drivers, so no software
installation is required.
Other Notes
• Whenshuttingdown,turnoffanypower
amplifiers or powered speakers first. When
powering up, turn them on last. This will
reduce the chance of turn-on or turn-off
thumps.
• Alwaysturndownthephoneslevelwhen
making connections, pressing solo, or doing
anything that may cause loudness in the
headphones. This will help protect your
hearing.
• Alwaysturndownthemainmixleveland
control room level when making connections to
the mixer. Better yet, turn off the power.
• Savetheshippingbox!
Quick Start
We realize that you must be really keen
to try out your new mixer. Please read the
safety instructions on page 2, read this
page, and then have a look through some
of the features and details in this manual.
Setup
Use the mixer in a nice clean and dry environment,
free from dryer lint and dust bunnies.
Zero the controls
1. Fully turn down all the knobs and faders to
minimum, except for the channel EQ and pan
controls, which should be centered.
2. Makesureallbuttonsareintheoutposition.
Connections
1. MakesuretheACpowerswitchisoffbefore
making any connections.
2. PushthelinecordsecurelyintotheIEC
connector on the rear panel, and plug it into a
3-prongACoutlet.The mixer can accept
anyAC
voltagerangingfrom100VACto240VAC.
3. Plug a balanced microphone into one of the mic
XLR (3-pin) connectors. Or connect any line-
level signal (keyboard, or guitar preamp) to a
line input jack using a TS or TRS 1/4" plug.
4. If your microphone requires phantom power,
press in the 48V phantom power button.
5. You can connect a guitar directly to line inputs
1 or 2 without the need for a DI box. Press a
hi-z switch if you connect a guitar directly.
6. The insert jacks of channels 1 to 8 can be used
to connect an external effects or dynamics
processor into the channel signal chain.
7. Connectthemainoutputsofthemixer(either
XLR or TRS 1/4") to the line-level inputs of your
amplifier (with speakers already attached) or
to the line-level inputs of powered speakers.
8. Engage the main mix switch in the control
room/phones source selection, so the meters
will show the main mix levels in the next steps.

4 Onyx 1620i
Introduction
ThankyouforchoosingaMackieOnyx1620i
professional compact mixer. The Onyx-i series of mixers
offer built-in FireWire, along with the newest features
and latest technologies for live sound reinforcement
and analog or digital studio recording, all in a durable,
road-worthy package.
The Onyx 1620i is equipped with eight of our premium
precision-engineered studio-grade Onyx mic preamps.
Mackieisrenownedforthehigh-qualitymicpreamps
used in our mixers, and the Onyx mic pre’s are better
than ever, with specifications rivaling expensive
stand-alone mic preamplifiers.
Channels1and2featurehigh-impedanceinstrument/
line-level inputs so you can connect an acoustic,
electric, or bass guitar directly into the mixer,
eliminating the need for an external direct box.
Extremely adaptable DAW integration
Recording and Mixing
Channels,auxsendsorthemasterL/Rcanbesent
straight to your computer via FireWire for recording.
Pre/post EQ taps on every channel allow you to integrate
our renowned Perkins EQ into the record path. Plus, a
stereo return from your DAW, or iTunes®is assignable to
the control room section or straight back into channels
15-16 for mix integration.
Powerful Effects Engine
With aux sends 1 and 2 routable to your DAW, the
1620i allows you to use your favorite plug-in as a
realtime effect. Just route an aux send to your DAW,
apply the plug-in and assign your DAW outputs to the
control room or to channels 15-16 for instant integration
into the mix.
Live Recording
Live sound recording could not be simpler with the
1620i. The ability to record individual channels either
wet or dry allows for studio quality multi-track
recordings for later editing and mixdown. Or simply
record the main mix, allowing for immediate creation of
CDsrightatthegig.
Features
• Premium16-channelsuper-compactanalog
mixer with integrated Fire wire I/O
• 8monochannels(monomicandmonoline
inputs)
• 4stereochannels(stereolineinputs)
• 8Onyxmicpreampswithsoundcomparableto
boutique preamps
• 4-bandPerkinsEQwithsweepablemidson
mono channels
• 3-bandPerkinsEQonstereolinechannels
• FlexibleFireWireroutingwithupto16
channels pre/post EQ, aux sends and master
L/R routable to computer
• 2channelsofFireWiremonitoringroutableto
either the control room or channels 15 and 16
• 4independentauxsendswithseparatepre/post
switches
• Selectableinstrumentinputsonrsttwo
channels – no DI box is needed
• Individual48vphantompowerswitchesonall
mic inputs
• Talkbacksectionwithbuiltinmicandexible
routing
• "Planet-Earth"switchingpowersupplyfor
worldwide use
• Optionalrackkitavailable

Owner's Manual 5
How To Use This Manual
The first pages after the table of contents are the
hookup diagrams. These show typical setups for fun
times with your mixer.
Next is a detailed tour of the entire mixer. The
descriptions are divided into sections, just as your mixer
is organized into distinct zones:
• Backpanel
• Connectionsection
• Channelcontrols
• Mastercontrols
Throughout these sections you’ll find illustrations
with each feature numbered and described in nearby
paragraphs.
This icon marks information that is critically
important or unique to the mixer. For your own
good, read them and remember them.
This icon will lead you to some explanations of
features and practical tips. Go ahead and skip
these if you need to leave the room in a hurry.
Appendix A: Service information.
AppendixB:Connectors.
AppendixC:Technicalinformation.
Appendix D: Rack ear installation.
Appendix E: FireWire.
AppendixF:Modications.
Need help with your new mixer?
• Visit www.mackie.com and click
Support to find: FAQs, manuals,
addendums, and other useful
information.
• Email us at: [email protected].
• Telephone [phone] to speak with
one of our splendid technical support
chaps (Monday through Friday, normal
business hours, Pacific Time).

6 Onyx 1620i
Contents
IMPORTANT SAFETY INSTRUCTIONS ........................ 2
QUICK START.......................................................... 3
INTRODUCTION ...................................................... 4
YOU ARE HERE ....................................................... 6
HOOKUP DIAGRAMS............................................... 7
REAR PANEL...................................................... 10
1. POWER CONNECTION ............................... 10
2. POWER SWITCH....................................... 10
3. FIREWIRE CONNECTIONS .......................... 10
4. LEFT/RIGHT XLR MAIN OUTPUTS.............. 11
5. MAIN OUTPUT LEVEL................................ 11
6. AUX SENDS 1-4........................................ 11
7. AUX RETURNS 1-4 ................................... 11
8. INSERT (CH. 1-8)...................................... 11
CONNECTION SECTION....................................... 12
9. MIC INPUTS ............................................. 12
10. MONO LINE INPUTS (CH. 1-8)................... 12
11. STEREO LINE INPUTS (CH. 9-16)................ 13
12. CTRL-RM OUT .......................................... 13
13. LEFT/RIGHT 1/4" MAIN OUTPUTS ........... 13
14. ALT 3–4 OUT............................................ 13
15. TAPE INPUTS ........................................... 14
16. TAPE OUTPUTS ........................................ 14
17. HEADPHONE OUTPUT .............................. 14
CHANNEL CONTROLS ......................................... 15
18. HI-Z SWITCH (CH. 1 AND 2 ONLY) ............ 16
19. LOW CUT (CH. 1–8 ONLY)......................... 16
20. 48V PHANTOM POWER............................ 17
21. GAIN CONTROL ........................................ 17
22. SEND FIREWIRE PRE/POST ....................... 17
23. INPUT (LINE OR FW 1-2) .......................... 17
24. HIGH EQ .................................................. 18
25. HIGH-MID EQ FREQUENCY (CH. 1-8) ......... 18
26. HIGH-MID EQ LEVEL (CH. 1-8)................... 18
27. LOW-MID EQ FREQUENCY (CH. 1-8).......... 18
28. LOW-MID EQ LEVEL (CH. 1-8) ................... 18
29. MID EQ LEVEL (CH. 9-16).......................... 18
30. LOW EQ ................................................... 18
31. AUX SENDS 1-4........................................ 19
32. PAN......................................................... 19
33. MUTE SWITCH AND ALT 3–4 ..................... 19
34. –20 AND OL LEDS..................................... 20
35. CHANNEL FADER....................................... 20
36. SOLO ....................................................... 20
CONTROL ROOM/PHONES AND METERS ............ 21
37. MAIN MIX................................................ 21
38. TAPE, FW 1-2, ALT 3-4.............................. 21
39. ASSIGN TO MAIN MIX .............................. 21
40. CONTROL ROOM KNOB ............................ 21
41. PHONES KNOB ......................................... 22
42. LEFT/RIGHT LEVEL METERS....................... 22
43. RUDE SOLO LIGHT .................................... 22
44. SOLO MODE ............................................. 22
AUX MASTER..................................................... 23
45. MASTER AUX SENDS 1-4 .......................... 23
46. PRE/POST................................................ 23
47. MASTER AUX RETURNS 1-4 ...................... 23
48. RTN TO AUX 1.......................................... 23
49. POWER LED.............................................. 24
50. AUX SEND 1-2 TO FW 13-14 .................... 24
TALKBACK ......................................................... 24
51. TALKBACK MIC ......................................... 24
52. TALKBACK LEVEL....................................... 24
53. DESTINATION: PHONES, AUX 1-4 .............. 25
54. TALKBACK SWITCH ................................... 25
MAIN MIX......................................................... 25
55. MAIN MIX................................................ 25
56. ASSIGN TO FW 15-16............................... 25
APPENDIX A: SERVICE INFORMATION.................... 26
APPENDIX B: CONNECTIONS.................................. 27
APPENDIX C: TECHNICAL INFORMATION ................ 29
APPENDIX D: RACK EAR INSTALLATION ................. 32
APPENDIX E: FIREWIRE......................................... 33
APPENDIX F: MODIFICATIONS ............................... 37
LIMITED WARRANTY............................................. 39

Owner's Manual 7
This diagram shows an electric guitar connected to the channel 1 line input via an amplifier modeler,
a bass guitar connected directly to channel 2 (hi-z switch in), microphones connected to the channel 3-8
mic inputs, a drum machine connected to the channel 9-10 stereo line inputs, and a keyboard connected
to the channel 11-12 stereo line inputs. An iPod®dock connects to the tape inputs.
A dynamics processor is connected to the insert jack of channel 2 to work its magic on your bass.
Vocal compressors are connected to the channel 3 and 4 inserts.
A reverb unit receives a mono input from the aux 3 send (in post-fader mode), and its stereo outputs
connect to the stereo aux 3 return inputs. A delay processor receives a mono input from the aux 4 send
(in post-fader mode), and its stereo outputs connect to the stereo aux 4 return inputs.
A plethora of SRM450v2 powered speakers are strewn across the stage as monitors for the band;
they are connected to the aux 1 send jack (in pre-fader mode). A Mackie SRM150 powered speaker is
connected to aux send 2 as a monitor for the keyboard player. Aux 2 is set to pre-fader using the Aux 2
pre/post switch in the Aux Master section. Headphones are used to monitor levels.
The club is driven by connecting a pair of HD1801 powered subwoofers and a pair of HD1531
powered speakers to the main left and right outputs.
A laptop computer connects to a FireWire port, allowing the 2-channel main mix, individual channels,
and the aux sends to be recorded. Two channels can be played back from your audio production
software. These can enter as either a source for the control room and phones, or channels 15 and 16.
Typical Club System
SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE
48V 48V 48V 48V 48V 48V 48V 48V
SRM150
Powered Monitor
for keyboard player
(Aux Send 2)
Microphones
Bass
Guitar
iPod
Docking Station
Headphones
HD1531
Powered Speaker
Main Right
HD1801
Powered
Subwoofer
HD1801
Powered
Subwoofer
HD1531
Powered Speaker
Main Left
Mackie SRM450v2
Powered Speakers
(Stage Monitors)
Aux Send 1
Delay (Aux Send 4)
Reverb (Aux Send 3)
press FW button ( ) to send
FW 1-2 computer output into
mixer channels 15-16
Dynamics Processor (Bass)
Compressor (Vocals)
Send
Return
Return
SendCompressor (Vocals)
Return
Send
Amplifier
Modeler
Electric
Guitar
press HI-Z
button
Drum
Machine
Keyboard
Laptop Computer
with audio production
software
press FW button ( )
to send main mix to computer
via FireWire channels 15 and 16
Set Aux 1, 2 PRE for monitors
Set Aux 3, 4 POST for external processors
Hookup Diagrams

8 Onyx 1620i
This diagram shows an electric guitar connected directly to the channel 1 input (hi-z switch in), a bass
guitar connected directly to channel 2 (hi-z switch in), a mic'd-up acoustic guitar connected to the
channel 3 mic input, studio mics connected to the channel 4-8 mic inputs, an electronic drum set
connected to the channel 9-10 stereo line inputs, a keyboard connected to the channel 11-12 stereo line
inputs, and a keyboard mono output connected to channel 13 (left input). A CD player connects to the
tape input.
A multi-FX processor is connected to the insert jack of channel 1 to work its magic on your guitar. A
dynamics processor is connected to the insert jack of channel 2 for your bass. An effects processor is
connected to the insert jack of channel 3 for the acoustic guitar. Compressors are connected to the insert
jacks of channels 4-6 for vocals.
Mackie HR824mk2 powered reference monitors are used for your control room listening. The
engineer's headphones are used to monitor levels. Aux 3 is set up to provide the feed to a headphone
amplifier and your band's headphones. A digital reverb receives a mono input from the aux 4 send, and
its stereo outputs connect to the stereo return inputs.
A desktop computer connects to a FireWire port, allowing the 2-channel main mix, individual channels,
and the aux sends to be recorded, and two channels to be played back using audio production software.
Mixer channels 15-16 can play the 2-channel signals from your computer if the FW 1-2 switch at the
top of the 15-16 channel strip is engaged. Aux 1 and 2 can be sent via FireWire to a software effects
plug-in.
Typical Recording System
SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE
48V 48V 48V 48V 48V 48V 48V 48V
Effects Processor (Acoustic)
Digital Reverb
(Aux Send 4)
Electronic
Drum Kit
Computer with
audio production
software
Studio
Microphones Mackie
HR824mk2
Powered Reference
Monitors for
Control Room
Keyboard
Keyboard
Headphones
Headphone Amp
(AUX Send 3)
CD Player
Engineer’s
Headphones
Dynamics Processor (Bass)
Multi FX Processor (Guitar)
Compressor (Vocals)
Electric
Guitar
Bass
Guitar Acoustic
Guitar
mic’d up
press HI-Z
buttons
press FW button ( )
to send main mix to computer
via FireWire channels 15 and 16
press FW button ( ) to send Aux 1
and Aux 2 to computer via FireWire
channels 13 and 14
press FW button ( ) to
send FW 1-2 computer output
into mixer channels 15-16

Owner's Manual 9
Post-Production System
This diagram shows a voice-over microphone connected to the channel 1 mic input, a video deck's
audio output connected to channels 9-10, with its audio inputs receiving the main mix from the
1/4" outputs. A synthesizer is connected to channel 11-12, and an electronic drum kit connected to
channel 13-14.
An effects processor and a sampler each receive a mono input from an aux send (post-fader), and
their stereo outputs connect to the respective stereo return inputs. A keyboard controller is attached to the
sampler. Headphones are used to monitor all levels, using a headphone amp with multiple headphones,
including one in the voice-over booth.
A pair of Mackie HR824mkII powered reference monitors are connected to the left and right control
room outputs for careful and accurate monitoring in the control room.
A desktop Mac or PC is connected to a FireWire port, allowing the 2-channel main mix to be recorded
and two channels to be played back. Two cinema screens are connected to the desktop, one displaying
audio and the second for video. A RAID rack is attached to the computer for mass storage. A recorder is
connected to the main outs, and utilized as the master recorder.
SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE MUTE
Headphones
Headphone Amp
Voice-over
Microphone
Voice-over booth
Synthesizer
Electronic
Drum Kit
Effects Processor
Effects/ Sampler
Mackie
HR824mkII
Powered
Reference
Monitors for
Control Room
Desktop
Mac or PC
Keyboard Controller
Cinema Display for Audio Cinema Display for Video
RAID rack
Video Deck
record
play
Recorder
press FW button ( ) to send
FW 1-2 computer output into
mixer channels 15-16
press FW button ( )
to send main mix to computer
via FireWire channels 15 and 16
Set Aux 1 & 2 POST for
for external processors

10 Onyx 1620i
Onyx 1620i Features
Rear Panel
1. POWER CONNECTION
Thisisastandard3-prongIECpowerconnector.
Connectthedetachablelinecord(includedinthebox
with your mixer) to the power receptacle, and plug the
otherendofthelinecordintoanACoutlet.TheOnyx
1620i has a universal power supply that can accept
any
ACvoltagerangingfrom100VACto240VAC.Noneedfor
voltage select switches. It will work virtually anywhere
in the world. That’s why we call it a “Planet-Earth” power
supply! It is less susceptible to voltage sags or spikes,
compared to conventional power supplies, and provides
greater electromagnetic isolation and better protection
againstAClinenoise.
Disconnecting the plug’s ground pin is
dangerous. Don’t do it.
2. POWER SWITCH
Press the top of this rocker switch inwards to turn on
the mixer. The front panel power LED [49] will glow
with happiness, or at least it will if you have the mixer
pluggedintoasuitableliveACmainssupply.
Press the bottom of this switch to put the mixer into
standby mode. It will not function, but the circuits are
stilllive.ToremoveACpower,eitherturnofftheAC
mains supply, or unplug the power cord from the mixer
andtheACmainssupply.
As a general guide, you should turn on your
mixer first, before any external power
amplifiers or powered speakers, and turn it off
last. This will reduce the possibilities of any
turn-on, or turn-off thumps in your speakers.
3. FIREWIRE CONNECTIONS
FireWire is a high-speed two-way interface for
connecting digital devices. Two FireWire connectors
allow the transfer of digital audio to and from your
computer or digital audio workstation (DAW) with
ultra-low latency. Usually, only one connector is used.
The FireWire interface provides the following outputs
to your computer:
• Channels1–16,tappedpre-fader,andeither
pre-EQ, or post EQ (your choice).
• Auxsends1-2foreffectsplug-inroutingor
alternate mix recording.
• Left/rightmainmix.Theleft/rightmainmix
at the FireWire output is not affected by the
main mix level control (important for recording
live).
Use FireWire to record a live performance directly to
your
computer, then you can mixdown to a stereo mix
later. Or you can use FireWire to turn your Onyx mixer
into a high-quality
computer audio interface for your
DAW.
FireWire also provides a return for two channels from
a DAW or computer. This can be routed through the
control room/phones via
the FireWire button [38], to
monitor the computer audio
through your control room
speakers or headphones (or through the main
speakers if assign to main mix [39] is selected). In
this way, you can listen to pre-recorded songs and
iTunes
®
as intermission music, or examples of how the
practice sessions should really sound.
These same two channels from the computer can
also be chosen as inputs to channels 15 and 16,
allowing you to adjust the gain, EQ, level, and pan, as
1 2
3
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5
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Owner's Manual 11
well as to solo, and add to aux send 1-4. This is routed
using the FW/line input selector [23] on channels 15
and 16. This is useful for live performances, where
those 2 channels might have, for example, a software
synthesizeryouaretriggeringfromaMIDIkeyboard,
and you want to treat the softsynth as "just another
instrument," with equal processing and routing
options as the hardware keyboards coming into the
other channels.
TheFireWireinterfaceworkswithbothPC(using
ASIOforWindowsXPandVista)andMac(CoreAudio
forMacOS10.4.11orhigher).
4. LEFT/RIGHT XLR MAIN OUTPUTS
These male XLR connectors provide a balanced
line-level signal that represents the end of the mixer
chain, where your fully mixed stereo signal enters the
realworld.Connectthesetotheinputsofyourmain
power amplifiers, powered speakers, or serial effects
processor (like a graphic equalizer or compressor/
limiter). It provides a fully balanced signal that is the
same level as the 1/4" TRS main out jacks [13] on the
top panel.
5. MAIN OUTPUT LEVEL
When this switch is out (+4 dB), the XLR main
outputs [4] provide a "+4 dBu" line-level signal. You
can then connect these outputs to the line-level inputs
of power amplifiers, powered loudspeakers, or serial
processors.
When the switch is pushed in (mic), the XLR main
outputs are attenuated to microphone level. You can
then connect these outputs safely to the microphone
inputs of another mixer, providing a submix for
keyboards or drums, for example, in a live sound
application. The main outputs can then be plugged
directly into a stage snake, and appear back at the front
of house console like any other microphone level source.
When mic is engaged, you can safely plug the
XLR main output into a mixer's microphone
input, even if it provides 48 V phantom power.
The switch is recessed, to reduce the chance of
accidently turning it on or off when plugging things in.
6. AUX SENDS 1-4
These 1/4" TRS connectors allow you to send balanced
or unbalanced line-level outputs to external effects
devices, headphone amplifiers, or stage monitors. These
could either be passive stage monitors powered by an
external amplifier, or powered stage monitors with
built-in power amplifiers. All aux sends are independent
of each other, so you can set up to four separate aux
mixes. The overall aux output level can be adjusted with
the aux send master controls [45].
The aux sends can either be pre or post fader,
depending on the position of the pre/post switches [46].
For stage monitor work, use pre, so the stage monitors
do not increase in volume when the channel faders are
adjusted. Imagine how upsetting that can be to big hairy
drummers. This allows you to set up the monitor mix
and levels just right, and not have it change every time a
channel fader is adjusted.
For external processors, use post. In this way, the feed
to external processors will vary with the channel faders,
so the level of any returned effect (like an echo) will
also change if the channel fader is changed, keeping
them in the same ratio (wet/dry).
7. AUX RETURNS 1-4
These 1/4" TRS stereo input connectors allow you to
add the stereo processed output from external effects
processors or other devices to the main mix.
Level adjustment of the incoming signals is made with
the aux return controls [47].
The signals going into aux return 3 can also be added
to aux send 1 by engaging the return to aux 1 switch
[48]. For example, you could add effects from an
external effects processor to your stage monitors.
You can also use these inputs to add any stereo
line-level signals to your main mix, so it could be
another line-level source, not just an effects processor.
If you are connecting a mono source, use the left
(mono) aux return input, and the mono signals will
appear on both sides of the main mix.
8. INSERT (Ch. 1-8)
These unbalanced 1/4" jacks on channels 1-8, are for
connecting serial effects processors such as
compressors, equalizers, de-essers, or filters. The insert
point is after the gain control [21] and low cut filter
[19], but before the channel’s EQ and fader [35].
The channel signal can go out of the insert jack to an
external device, be processed (or whatever) and come
back in on the same insert jack. To do this requires a
standard insert cable that must be wired thusly:
Tip = send (output to effects device)
Ring = return (input from effects device)
Sleeve = common ground
“tip”
This plug connects to one of the
mixer’s Channel Insert jacks. “ring”
tip ring
sleeve
SEND to processor
RETURN from processor
(TRS plug)

12 Onyx 1620i
Microphone-levelsignalsarepassedthroughthe
mixer's splendid microphone preamplifiers to become
line-level signals.
PHANTOM POWER
Mostmodernprofessionalcondensermicsrequire
48V phantom power, which lets the mixer send low-
currentDCvoltagetothemic’selectronicsthroughthe
same wires that carry audio. (Semi-pro condenser mics
often have batteries to accomplish the same thing.)
“Phantom” owes its name to an ability to be “unseen”
bydynamicmics(ShureSM57/SM58,forinstance),
which don’t need external power and aren’t affected by
it anyway.
Phantom power for each channel can be selected
using that channel's phantom [20] switch.
Never plug single-ended (unbalanced)
microphones, or ribbon mics into the mic
input jacks if phantom power is on. Do not
plug instrument outputs into the mic XLR input jacks
with phantom power on, unless you are certain it is safe.
10. MONO LINE INPUTS (Ch. 1-8)
These 1/4" jacks share circuitry (but not phantom
power) with the mic preamps, and can be driven by
balanced or unbalanced sources.
To connect balanced lines to these inputs, use a 1⁄4"
Tip-Ring-Sleeve (TRS) plug, wired as follows:
Tip = Positive (+ or hot)
Ring = Negative (– or cold)
Sleeve = Shield or ground
To connect unbalanced lines to these inputs, use a
1⁄4" mono (TS) phone plug, wired as follows:
Tip = Positive (+ or hot)
Sleeve = Shield or ground
Insert jacks continued...
Insert jacks can be used as channel direct outputs;
post-gain, and pre-EQ. See the connector section on
page 28 (figure G) showing three ways to use inserts.
Connection Section
This is where you plug in things such as: microphones,
line-level instruments, guitars, effects, a recorder, PA
system, powered monitors, powered subwoofer, etc.
Checkoutthehookupdiagramsforsomeconnection
ideas. See Appendix B (page 28) for further details and
some rather lovely drawings of the connectors you can
use with your mixer.
9. MIC INPUTS
This is a female XLR connector, that accepts a
balanced microphone input from almost any type of
microphone. The microphone preamps feature our Onyx
design, with higher fidelity and headroom rivaling any
standalone mic preamp on the market today.
The XLR inputs are wired as follows:
Pin 1 = Shield or ground
Pin 2 = Positive (+ or hot)
Pin 3 = Negative (– or cold)
We use phantom-powered, balanced microphone
inputs just like the big studio mega-consoles, for exactly
the same reason: This kind of circuit is excellent at
rejecting hum and noise. You can plug in almost any
kind of mic that has a standard XLR-type male mic
connector.
Professional ribbon, dynamic, and condenser mics all
sound excellent through these inputs. The mic inputs
will handle any kind of mic level you can toss at them,
without overloading.
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Owner's Manual 13
The line-level inputs of channels 1 and 2 can also
accept instrument-level signals if the hi-z switches
[18] are pressed in. This allows you to connect guitars
directly to channels 1 and 2, without the need for a DI
box. The input impedance is optimized for direct
connection, and high-frequency fidelity is assured.
11. STEREO LINE INPUTS (Ch. 9-16)
These 1/4" jacks can be driven by balanced or
unbalanced sources.
To connect balanced lines to these inputs, use a 1⁄4"
Tip-Ring-Sleeve (TRS) plug, wired as follows:
Tip = Positive (+ or hot)
Ring = Negative (– or cold)
Sleeve = Shield or ground
To connect unbalanced lines to these inputs, use a
1⁄4" mono (TS) phone plug, wired as follows:
Tip = Positive (+ or hot)
Sleeve = Shield or ground
If you just have a mono source, plug it into the left
input (labeled left/mono), and the signal will appear
(as if by magic) equally on the left and right of the main
mix.
12. CTRL-RM OUT
These 1/4" TRS jacks provide balanced left and right-
line-level outputs
to run studio monitors in the control
room.
Connecttheseoutputstotheinputsofan
amplifier, powered speakers, or recording device.
The source that plays in the control room,
headphones, and meters can be selected using the
switches [37, 38] in the control room/phones source
matrix:
• Themainmix,ifmainmixisselectedasthe
control room/
phones source
• Tapeoutputs,iftapeisselected
• Alt3-4outputsifalt3-4isselected
• A2-trackFireWirefeedfromyourcomputerif
FW 1-2 is selected
• Acombinationofallfourabove
Except for main mix, whatever is playing in these
outputs can also be routed to the main mix if assign to
main mix [39] is engaged. (The main mix input to the
control room is disconnected if assign to main mix is
engaged.)
The headphones and meters play the same program
as the control room. The meters show the levels prior to
the control room and phones level controls.
13. LEFT/RIGHT 1/4" MAIN OUTPUTS
These 1/4" TRS output connectors provide the
balanced or unbalanced line-level output of the main
mix to an anxiously-waiting world. This is the same
signal that appears at the XLR main outputs [4] on the
rear panel, except it is not affected by the main output
level switch [5].
Connecttheseoutputstothenextdeviceinthesignal
chain, such as an external processor (graphic equalizer
or compressor/limiter), external power amplifiers
running passive loudspeakers, or to the inputs of
powered loudspeakers. They could also be connected to
the inputs of a balanced 2-track recorder, when doing a
"live to 2-track" type recording.
14. ALT 3–4 OUT
These 1/4" TRS jacks provide a balanced line-level
signal that can provide an alternate stereo mix for
recordingorsubgrouping.Connecttheseoutputstothe
inputs of an amplifier, powered speaker, or recording
device.
Any channel whose mute switch [33] is engaged, is
added to the alt 3-4 outputs.
The alt 3-4 output doesn’t have a master level control.
All the channels assigned to the alt 3-4 bus are summed
together (post-fader and pan) and sent directly to the
alt 3-4 out.

14 Onyx 1620i
15. TAPE INPUTS
ThesestereounbalancedRCAinputsallowyoutoplay
atape,CDplayer,iPod®dock, or other line-level source.
The tape in jacks accept an unbalanced signal using
standard hi-fi hookup cables.
Push in the tape button [38] to route the tape input
to the control room and phones outputs [12, 17]. This
allows you to play back recordings of your mixes.
Push in the assign to main mix button [39] to route the
tape input to the main outs [4, 13]. This allows you
to play
back music between sets over the main PA speakers.
Pushing tape in the source matrix and
pushing assign to main mix can create a
feedback path between tape in and tape out.
Makesureyourtapedeckisnotinrecord,recordpause,
or input monitor mode when you engage these switches,
or make sure the control room level control is turned all
the way down first.
16. TAPE OUTPUTS
ThesestereounbalancedRCAoutputsallowyouto
record the main stereo mix onto a tape deck, hard disk
recorder,orautomaticCDburner,forexample.This
lets you make a recording for posterity/archive/legal
purposes whenever the band gets back together again.
The tape output is the stereo main mix, and it is
affected by the main mix level [55]. The output could
also be used as an extra set of main outputs for feeding
another zone.
17. HEADPHONE OUTPUT
This 1/4" TRS connector supplies the output to your
stereo headphones. It is the same signal that is routed
to the control room outputs [12], as determined by the
control room/phones source matrix [37, 38]. The
volume is controlled with the phones knob [41], right
next to the control room knob [40].
Whenever a solo switch [36] is engaged, you will
only hear the soloed channel(s) in the headphones.
This gives you the opportunity to audition the channels
before they are added to the main mix. (Solo signals
reaching the headphones are not affected by the
channel level or main level, therefore turn down the
phones level first, as soloed channels may be loud.)
The phones output follows standard conventions:
Tip = Left channel
Ring = Right channel
Sleeve=Commonground
WARNING: The headphone amp is loud, and
can cause permanent hearing damage. Even
intermediate levels may be painfully loud
withsomeheadphones.BECAREFUL!Alwaysturnthe
phones level control [41] all the way down before
connecting headphones or pressing a solo switch, or
doing anything new that may affect the headphone
volume. Then turn it up slowly as you listen carefully.
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Owner's Manual 15
Channel Controls
The vertical channel strips look very similar, and have
a only few differences between them. Each
channel works independently, and just controls the
signals plugged into the inputs directly above it.
Here are a few features and differences:
Mono Channels 1-8
• Thesearemonochannels,andtheircontrols
affect either the mono mic input or the mono
line-level input.
• Channel1and2eachhaveahi-zswitch,soyou
can connect guitars directly without the need
for a DI box.
• 48VoltPhantomPowercanbeselectedforeach
mic input.
• Highpassltersaffectsboththemicandline
inputs.
• Gaincontroladjuststhemiclevelandline
level.
• The4-bandEQhasshelvinghigh,shelvinglow,
and peaking hi-mid and peaking lo-mid with
adjustable mid frequency.
Stereo Channels 9-16
• Thestereochannelseachhavetwoline-level
inputs.
• Formonosources,usetheleftinputonly,and
it will appear equally on both sides of the main
mix.
• Gaincontroladjuststhelinelevelonly.
• The3-bandEQhasshelvinghigh,shelvinglow,
and peaking mid EQ.
• Channel15and16haveaswitchtoselect
FireWire inputs instead of the analog line
inputs.
“U” like Unity gain
Mackiemixershavea“U”symbolonalmosteverylevel
control. It stands for “unity gain,” meaning no change in
signal level. The labels on the controls are measured in
decibels (dB), so you’ll know what you’re doing
level-wise if you choose to change a control’s settings.
SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE
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16 Onyx 1620i
18. HI-Z SWITCH (Ch. 1 and 2 only)
Engage this switch if you want to connect guitars
directly to the 1/4" line inputs of channels 1 or 2.
Without this switch, you need to use a DI box first,
before connecting guitars. If these switches are not
pressed in, guitars will not sound good, particularly the
high frequency response.
Plugging a guitar into a lower-impedance
line-level input
can result in the loss of high
frequencies, causing an unnatural and dull
sound.
Normally, you must use a direct box
between a guitar and a mixer’s input, which serves to
convert the impedance of the guitar from high to low.
The hi-z inputs on channels 1 and 2 make the need for
a direct box unnecessary. However: The hi-z inputs are
unbalanced (when the switch is in), so if you’re doing a
live show and running a long cord between the
instrument and the mixer (say over 25 or 30 feet), it is
best to use a direct box with a balanced output to avoid
picking up noise over the length of the cord.
19. LOW CUT (Ch. 1–8 only)
The mono channels each have a low-cut switch (often
referred to as a high-pass filter) that cuts bass
frequencies below 75 Hz at a rate of 18 dB per octave.
The low cut switch affects both the mic and line
inputs.
We recommend that you use low-cut on every
microphone application except kick drum, bass guitar,
or bassy synth patches. These aside, there isn’t much
down there that you want to hear, and filtering it out
makes the low stuff you do want much more crisp and
tasty. Not only that, but low-cut can help reduce the
possibility of feedback in live situations, and it helps to
conserve amplifier power.
Another way to consider low-cut’s function
isthatitactuallyaddsexibilityduringlive
performances. With the addition of low-cut,
you can safely use low equalization on vocals.
Manytimes,bassshelvingEQcanreallybenetvoices.
Trouble is, adding low EQ also boosts stage rumble, mic
handling clunks and breath pops from way-down low.
Applying low-cut removes all those problems, so you can
add low EQ without blowing your subwoofers.
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Owner's Manual 17
22. SEND FIREWIRE PRE/POST
Each channel of the mixer can send a FireWire output
to your computer or DAW. The FireWire output from
each channel can be tapped before (pre) or after (post)
the channel EQ. (The output is always pre-fader).
If you want the mixer EQ to affect the FireWire
recording, then set this switch to post. This is useful
in recording channels in a studio (where the recording
includes the beneficial effect of our Perkins EQ).
If you would rather record the straight signals from a
live performance, and EQ them later in your DAW, then
set this switch to pre. This is good for live work, where
you may have added EQ to adjust for the room, and yet
not want this added to your recording.
23. INPUT (LINE or FW 1-2)
Channel15and16caneitherbefedfromthe1/4"
line level inputs, or by two outputs from a computer
via FireWire. This switch lets you choose which to use.
Either way, the channels receive line-level analog audio
signals just prior to the gain control, so channel setup,
gain adjustment and EQ adjustment are the same for
line or FireWire. This is useful for virtual instruments
that want to be "just another channel" among hardware
instruments.
CHANNEL EQUALIZATION (EQ)
TherearetwodifferentavorsofEQ:
MonoChannels1-8
4-band EQ with shelving high, shelving low,
and peaking hi-mid and peaking lo-mid with
adjustable mid frequency.
StereoChannels9-16
3-band EQ with shelving high, shelving low, and
peaking mid EQ.
Shelving means that the circuitry boosts or cuts all
frequencies past the specified frequency. For example,
the low EQ boosts bass frequencies below 80 Hz and
continuing down to the lowest note you never heard.
Peaking means that certain frequencies form a “hill”
around the center frequency.
With too much EQ, you can really upset
things. We’ve designed a lot of boost and cut
into each equalizer circuit because we know
that everyone will occasionally need that. But if you max
the EQ on every channel, you’ll get mix mush. Equalize
subtly and use the left sides of the knobs (cut), as well
as the right (boost). If you find yourself repeatedly using
a lot of boost or cut, consider altering the sound source,
such as placing a mic differently, trying a different kind
of mic, a different vocalist, changing the strings, or
gargling.
20. 48V PHANTOM POWER (Ch. 1–8 only)
Mostmodernprofessionalcondensermicsrequire
48V phantom power, which lets the mixer send low-
currentDCvoltagetothemic’selectronicsthroughthe
same wires that carry audio. (Semi-pro condenser mics
often have batteries to accomplish the same thing.)
“Phantom” owes its name to an ability to be “unseen”
bydynamicmics(ShureSM57/SM58,forinstance),
which don’t need external power and aren’t affected by
it anyway.
Press this switch in if your microphone requires
phantom power. (Always check the position of this
switch before connecting microphones.)
Never plug single-ended (unbalanced)
microphones, or ribbon mics into the mic
input jacks if phantom power is on. Do not
plug instrument outputs into the mic XLR input jacks
with phantom power on, unless you know for certain it
is safe to do so. Be sure the main level [55] is turned
down when connecting microphones to the mic inputs
when phantom power is turned on, to prevent pops from
getting through to the speakers.
21. GAIN CONTROL
If you haven’t already, please read the level-setting
procedure on page 3.
The gain knobs adjust the input sensitivity of the mic
and line inputs. This allows signals from the outside
world to be adjusted to run through each channel at
optimal internal operating levels.
If the signal originates through the mic XLR jack,
there will be 0 dB of gain with the knob fully down,
ramping to 60 dB of gain fully up.
Through the 1⁄4" line input of channels 1-8, there is 20
dB of attenuation fully down and 40 dB of gain fully up,
with unity gain "U" at 11:00.
Through the 1⁄4" line input of channels 9-16, there is
20 dB of attenuation fully down and 20 dB of gain fully
up, with unity gain "U" at 11:00.
This 20 dB of attenuation can be very handy when you
are inserting a hot signal, or when you want to add EQ
gain, or both. Without this “virtual pad,” there is more
chance of channel clipping.

18 Onyx 1620i
24. HIGH EQ
The high EQ provides up to
15 dB of boost or cut above
12kHz,anditisalsoat(no
boost or cut) at the detent. Use
it to add sizzle to cymbals, an
overall sense of transparency,
or an edge to keyboards, vocals, guitar and bacon frying.
Turn it down a little to reduce sibilance or to mask tape
hiss.
SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE
48V 48V 48V 48V 48V 48V
21
22
24
25
26
28
30
31
32
33
35
36
34
27
9
10
18
19 20
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
25. HIGH-MID EQ FREQUENCY (Ch. 1-8)
This knob ranges from 400 Hz to 8 kHz. This
determines the center frequency for the EQ filter, and
allows you to zero in on the precise narrow band of
frequencies you want to have affected by the high-mid
EQ [26].
26. HIGH-MID EQ LEVEL (Ch. 1-8)
The high-mid EQ provides up
to 15 dB of boost or cut at
2.5kHz,anditisatatthe
detent.MidrangeEQisoften
thought of as the most dynamic
because the frequencies that
define any particular sound are almost always found
within this range. For example, the female vocal range
as well as the fundamentals and harmonics of many
higher-timbred instruments.
27. LOW-MID EQ FREQUENCY (Ch. 1-8)
This knob ranges from 100 Hz to 2 kHz. This
determines the center frequency for the EQ filter, and
allows you to zero in on the precise narrow band of
frequencies you want to have affected by the
low-mid EQ [28].
28. LOW-MID EQ LEVEL (Ch. 1-8)
The low-mid EQ provides up
to 15 dB of boost or cut at
400Hz,andisatatthedetent.
Frequencies affected typically
include the male vocal range as
well as the fundamentals and
harmonics of many lower-timbred instruments.
29. MID EQ LEVEL (Ch. 9-16)
The mid EQ provides up to 15 dB of boost or cut at
2.5kHz,andisatatthedetent.
30. LOW EQ
The low EQ provides up to
15 dB of boost or cut below
80Hz.Thecircuitisatatthe
center detent position. This
frequency represents the punch
in bass drums, bass guitar, fat
synth patches, and some really serious male singers who
eat raw beef for breakfast.
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15
20 Hz 100 Hz 1k Hz 10k Hz 20k Hz
–15
–10
–5
0
+5
+10
+15

Owner's Manual 19
31. AUX SENDS 1-4
These controls allow you to set up to four independent
mixes, typically for running stage monitors or external
effects processors.
The controls are off when turned fully down, deliver
unity gain at the center, and can provide up to 15 dB
ofgainturnedfullyup.Chancesarethatyouwillnever
need this extra gain, but it's nice to know that it's there
if you do.
Aux Sends 1-4 [6] are line-level outputs, and are used
if you want to connect external processors, powered
stage monitors, or external power amps with passive
stage monitors. Aux Returns 1-4 [7] are line-level
inputs, typically used to return the output from external
processors back to the main mix.
Carefullyadjusthowmuchofeachchannelappears
in your aux mixes. For example, if you are running stage
monitors, and someone wants "more me, and less them,"
adjust these carefully.
The aux sends can either be pre or post fader,
depending on the position of the aux pre/post switches
[46]. For stage monitor work, use pre, so the stage
monitors do not increase in volume when the channel
level is adjusted. For external processors, use post. In
this way, the feed to external processors will vary with
the channel level, keeping them in the same ratio
(wet/dry).
32. PAN
For mono channels 1-8, this control allows you to
adjust how much of the channel signal goes to the left
main mix, and how much goes to the right main mix.
It has no effect on the aux, as these are mono. In the
center position, the mono channel is split equally to the
left and right.
Pan also affects the channel output to the Alt 3–4 mix
if a channel mute switch is engaged.
For channels 9-16, pan acts in a similar way to a home
stereo balance control (panning left turns down the
right channel, and panning right turns down the left
channel).
If you have a stereo source and the mixer's stereo
inputs are already taken, connect the source's left
output into channel 1, and the right into channel 2. Pan
the channel 1 fully left, and channel 2 fully right, then
the source will appear in the main mix in full stereo.
Thepancontrolemploysadesigncalled“Constant
Loudness.” If you have a channel panned hard left (or
right) and then pan to the center, the signal is
attenuated about 3 dB to maintain the same apparent
loudness. Otherwise, it would make the sound appear
much louder when panned center.
33. MUTE switch and ALT 3–4
Thedual-purposemute/alt3-4switchisaMackie
signature. When Greg was designing our first product,
hehadtoincludeamuteswitchforeachchannel.Mute
switches do just what they sound like they do. They turn
off the signal by “routing” it into oblivion. “Gee, what
a waste,” he reasoned. “Why not have the mute button
route the signal somewhere else useful, like a separate
stereo bus?”
So mute/alt 3-4 really serves two functions—muting
(often used during mixdown or live shows), and signal
routing (for multitrack and live work) where it acts as
an extra stereo bus.
To use this as a mute switch, all you have to do is not
use the alt 3-4 outputs [14]. Then, whenever you assign
a channel to these unused outputs, you’ll also be
disconnecting it from the main mix, effectively
muting the channel. The mute switch also disconnects
the channel from the post-fader aux send bus. The
channel’s signal is still present on the pre-fader aux
send bus, so muting a channel does not affect your stage
monitors, and the quiet and gentle disposition of your
lead singer.
To use this as an alt 3-4 switch, all you have to do is
connect the alt 3-4 outputs to whatever destination you
desire. Here are two popular examples:
When doing multitrack recording, you can use the
alt 3-4 outputs as a stereo or dual-mono feed to your
multitrack.
When doing live sound or mixdown, it’s often handy
to control the level of several channels with one knob.
That’s called subgrouping. Simply assign these channels
to the alt 3-4 mix, engage alt 3-4 in the control room/
phones source matrix [38], and the signals will appear
at the control room [12] and phones [17] outputs. If
you want the alt 3-4 signals to go back into the main
mix, engage the assign to main mix switch [39] and the
control room knob [40] will control the levels of all the
channels assigned to alt 3-4.
Another way to do the same thing is to assign the
channels to the alt 3-4 mix, then patch out of the alt
3-4 out (left/3 and right/4) back into an unused stereo
channel (9-16). If that’s your choice, don’t ever engage
the mute/alt 3-4 switch on that stereo channel, or you’ll
have every dog in the neighborhood howling at your
feedback loop.
Another benefit of the alt 3-4 feature is that it can act
asan“a”(afterfaderlisten).Justengageachannel’s
mute/alt 3-4 switch and the alt 3-4 switch in the source
matrix and you’ll get that channel, all by itself, in the
control room and headphones.

20 Onyx 1620i
34. –20 and OL LEDs
These LEDs indicate the channel’s signal level after
the gain and EQ controls, but just before the channel’s
level. So even if the level is turned down, you can see if
a signal is present, or if the channel is being overloaded.
The OL (overload) LED will come on when the
channel’s input signal is too high. This should be
avoided, as distortion will occur. If the OL LED comes
on regularly, check that the gain control [21] is set
correctly for your input device, and that the channel
EQ is not set with too much boost.
The –20 LED comes on when the channel signal
strength has reached that level.
35. CHANNEL FADER
This is the last control in a channel’s signal path, and
it adjusts the level of each channel onto the main mix.
The “U” mark indicates unity gain, meaning no increase
or decrease of signal level. All the way up provides an
additional 10 dB, should you need to boost a section of
a song. If you find that the overall level is too quiet or
too loud with the level near unity, check that the gain
control [21] is set correctly.
36. SOLO
Whenever a solo switch is engaged, you will only hear
the soloed channel(s) in the headphones and control
room. This gives you the opportunity to audition the
channels before they are added to the main mix or alt
3–4 mix. You can still hear, even when the fader is down.
Solo is also used to set the gain of each channel
correctly. When a channel is soloed, you can adjust the
channel gain [21] until your input source reaches the
level of the 0 dB LED of the right meter.
Solo signals reaching the headphones and
control room are not affected by the channel
level or main level; therefore, turn down the
phones level [41] and control room level [40] first, as
soloed channels may be loud.
The rude solo light [43] will turn on as a reminder
that what you are listening to in the headphones and
control room is just the soloed channel(s).
For stereo channels, the mono sum of the left and
right is soloed.
Soloed channels are sent to the source mix, which
ultimately feeds your control room, phones, and meters.
Whenever solo is engaged, all source selections (main
mix, alt 3-4, tape, and FireWire) are defeated, to allow
the soloed signal to do just that—solo!
SOLO SOLO SOLO SOLO SOLO SOLO
MUTE MUTE MUTE MUTE MUTE MUTE
48V 48V 48V 48V 48V 48V
21
22
24
25
26
28
30
31
32
33
35
36
34
27
9
10
18
19 20