Art Project Series User manual

USBMIX4
Four Channel Mic-Inst-Line Mixer - Computer Interface
Project Series
User's Manual

1
IMPORTANT SAFETY INSTRUCTIONS - READ FIRST
This symbol, wherever it appears, This symbol, wherever it appears, alerts you
alerts you to the presence of uninsulated to important operating and maintenance
dangerous voltages inside the enclosure that instructions in the accompanying literature.
may be sufficient to constitute a risk of shock. Please read the manual.
Read instructions
Retain these safety and operating instructions for future reference. Heed all warnings printed here and on the
equipment. ollow the operating instructions printed in this user guide.
Do not open
There are no user serviceable parts inside. Refer any service work to qualified technical personnel only.
Po er sources
Only connect the unit to mains power of the type described in this user guide or marked on the rear panel. The
power source must provide a good ground connection.
Po er supply
Use the external power supply for your local mains supply as provided with the equipment. If the provided
external supply does not fit into you outlet consult your service agent. Route the external power cord so that it
is not likely to be walked on, stretched or pinched by items placed upon or against.
Grounding
Do not defeat the grounding and polarization means of the external power supply.
Moisture
To reduce the risk of fire or electrical shock, do not expose the unit to rain, moisture or use in damp or wet
conditions. Do not place container of liquid on it, which may spill into any openings
Heat
Do not locate the unit in a place close to excessive heat or direct sunlight, as this could be a fire hazard.
Locate the unit away from any equipment, which produces heat such as: power supplies, power amplifiers and
heaters.
Environment
Protect from excessive dirt, dust, heat, and vibration when operating and storing. Avoid tobacco ash, drink
spillage and smoke especially that associated with smoke machines.
Handling
Protect the controls from damage during transit. Use adequate padding if you need to ship the unit. To avoid
injury to yourself or damage to the equipment take care when lifting, moving or carrying the unit.
Servicing
Switch off the equipment and unplug the power cord immediately if it is exposed to moisture, spilled liquid or
the power cord or plug becomes damaged during a lightning storm or if smoke odor or noise is noted. Refer
servicing to qualified technical personnel only.
Installation
Install the unit in accordance with the instruction printed in the user guide.

2
OVERVIEW
The ART USBMIX4 Microphone, Instrument, and Line Mixer/Computer Interface is a compact
versatile audio interface for your computer that converts analog signals from a variety of audio
sources to a digital signal that your computer recognizes. It can also be used as a standalone mixer
through the main mix outputs. The Built-in low latency digital effects add to the versatility. The
USBMIX4 provides a great starting point for personal home studio recording or for anyone wants to
do mobile location recording. Use the USBMIX4 to record pod casts, capture your latest idea for a
song, make voiceovers for your home movies, or record a jam with a friend - whenever and wherever
your creativity takes you!
Features
• Powered by a 5V DC IN jack (type micro B): or connecting to a USB power adapter
• CH1 and 2 Microphone (balanced XLR) inputs or instrument (unbalanced ¼-inch TS) inputs with
switchable impedances
• Switchable low noise +48V phantom power for microphones
• Balanced ¼-inch TRS inputs for stereo or mono line-level sources on CH3
• ¼-inch TRS output jacks work with balanced or unbalanced lines
• ⅛-inch TRS stereo Aux/MP3 input
• Stereo output, independent from the PC interface switch
• Stereo ¼-inch TRS headphone jack with independent level control for output monitoring
• Independent controls for both sets of inputs, main output, and headphone monitor
• Red LED signal/clip indicator for Ch1-2
• Switchable assignment of USB playback to channels 1 and 2 or monitor
• USB 2.0 compliant
• No special drivers are needed with most modern versions of Windows or Mac OS
• USB cable and Audacity recording software included

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Rugged steel case

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Operation and Connections
USB jack (type B): or connecting to a computer using the included USB 2.0 cable. When connected
to a computer, the computer supplies power to the mixer and audio data can be sent between the
mixer and computer.
Note: Please do not connect any device to this USB jack other than a personal computer or
tablet devices.
5V DC IN jack (type micro B): or connecting to a USB power adapter or USB mobile battery.
Note: 1) Please read the safety precautions for the USB power adapter or USB mobile battery you
are using.
2) Use a USB power adapter or USB mobile battery that can supply power via a USB micro B plug
based the following USB standards:
Output voltage: 4.5 V to 5.2V
Output current: 500mA or greater
Combo input (combined jack XLR, bal./ ¼-inch jack) for channel CH 1 , for the connection of a
microphone via an XLR plug or an audio source with line signal level via a Phone plug.
Mono input (combined jack XLR, bal./ ¼-inch jack unbal.) for channel CH 2 for the connection of a
microphone via an XLR plug or an audio source with line signal level via a Phone plug.
+48V phantom s itch / [+48V] Led: When this switch is turn on , the [+48V] lights and DC
+48V phantom power is supplied to the XLR plug connected to the channel 1, Turn this switch on
when using a phantom-powered condenser microphone.
Note: Be sure to leave this switch off if you do not need phantom power. ollow the important
precautions below, in order to prevent noise and possible damage to external devices as well as the
mixer if you turn this switch on
Be sure to leave this switch off when you connect a device that does not support phantom
power to channel 1.
Make sure to turn this switch off when connecting/ disconnecting a cable to/ from channel 1.
Turn the level knob of the channel 1 to “0” (minimum) before turning this switch on /off
PAD s itches: Turning the switch on will attenuate the sound input to the unit. If you hear
distortion or the [CLIP] Led lights frequently even if the [GAIN] pot is turned fully to the left, turn this
switch on.
Note: Turn the level pot to minimum before toggling the [PAD] switch on and off . Otherwise,
noise may be produced.
Impedance s itch, for channel CH 2: press the button when an electric guitar or an electric bass
with passive audio pick-up has been connected to the jack ¼-inch.
Stereo input (¼-inch jack, bal.) for channel CH 3 - Ch 4 for connection of an audio source with line
signal level; when connection a mono source, use the left jack only.
Gain s itch: Determines the basic volume for each channel 3/4. Turn this switch on if you hear
distortion.

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Note: Turn the level knob to minimum before toggling the [GAIN] switch on and off
Otherwise, noise may be produced.
Stereo output (Phone jack, unbal.) for connection of an amplifier or another unit, e.g. a second mixer.
Stereo output: Used to connect to another mixer or recorder. The signal output from this jacks is not
affected by the [ TO PC ] slide switch or the MAIN MIX[ ] knob.
Phone/Monitor Output (¼-inch jack) for connection of stereo headphones (minimum impedance 8Ω)
for monitoring the sum signal [independent of the PHONES/MONITOR control.
Gain Control to adjust the input amplification, for channel CH 1 and channel CH 2.
Equalizer to adjust the high frequencies ( HIGH ) and low frequencies (LOW), for each input channel
CH1 and CH2.
Pan Control, for channel CH1 and CH2, to send the mono signal in, creating a stereo field.
Level peak indication, for channel CH1 and CH2.
Level control for channel CH1 and CH2.
HEADSET connections (MIC/PHONES).
Headset microphone input jack: or connecting to the microphone for your headset.
Normally this plug is color-coded in pink. The audio input here is sent to channel 1.
Note: If a microphone is connected to the [ HEADSET ] microphone input jack, the sound from the
microphone or instrument connected to the CH-1 input jack on channel 1 is cut off.
Headset headphones output jack: or connecting to the headphone for you headset.
Normally this plug is color-coded in light green. The same sound as for the headphone output
jack is output.
Note: If a headphone plug is connected to the [ HEADSET ] headphones output jack, the
sound output from the headphones output jack is cut off.
AUX/MP3 input jack (⅛-inch jack): This is an auxiliary input jack. It supports a stereo plug. You can
connect a smart phone, MP3 player or other device and use applications to trigger sound effects or
background music. Use the controls on the connected device to adjust volume.
TO PC slide s itch: Select the sound to send to the computer
[ DRY CH 1-2 ] : Send the audio after the [GAIN] knob adjustments (dry signal) from channel 1
and 2 directly to the computer. The audio that is sent is not affected by the level knob adjustments.
The audio is routed to channels 1 and 2 (guitar and vocal, etc.) can be recorded separately, as
with an audio interface.
[ INPUT MIX ] : The audio input into the mixer and is mixed in stereo, is then sent to the computer.
The Audio input from the computer is not sent back to the computer.
[ LOOPBACK ] : The audio input is routed to the mixer and the audio played on the computer are
mixed in stereo and then sent to the computer. This setting is used primarily for webcasting.
Note: To prevent feedback when using audio recording/playback software, use either [DRY CH 1-
2] or [INPUT MIX]
Level control for channel CH3-4

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Level control for USB playback.
POWER switch of the mixer.
POWER ON indication.
USB recording level meter: If the level of the audio sent to the computer exceeds -20dBV, the green
led light up; If the level reaches 3dB before clip level, the red led light up. To send an appropriate
audio level to the computer, adjust the audio level of each channel until the green led remains lit and
the red led flashes only momentarily when there is an extreme audio level present .
Monitor Mute s itch: When this switch is on , the audio input to channels 1 and 2 are muted
from the MAIN MIX [ ] output jack, the HEADSET output jack, and PHONES output jack
(direct monitoring is O ).
Level control PHONES/MONITOR for the headphone output MONITOR/PHONES and [ HEADSET ]
headphones output jack.
MAIN MIX control Allows you to set the level of the output signal sent via the outputs MAIN MIX,
AUX out and the USB port.
Applications
This compact 4-channel audio mixer with USB interface is suited for universal applications, e.g.
or audio recording on the computer. The mono input channel allows to connect a (phantom-
powered) microphone; The stereo input channel allows to connect an audio source with line signal
level. In addition, the mixer is provided with connections for a recorder and headphones. The
mixed signal is sent to the output via ¼-inch jacks and the USB port. It is also possible to use the
USB port as an input to transfer audio data from the computer to the mixer. When connecting the
mixer to a computer, power is supplied via the USB connection. When operating the mixer without
a computer, either use a suitable power supply unit with USB connection to operate the mixer.
Operations
Prior to power up or power down, the output controls PHONES/ MONITOR and MAIN MIX
should be turned back to “0”.
1) As audio sources, microphones and/or audio sources with line signal level (e.g. effect units,
musical instruments, players) can be connected to the four input channels.
2) Mono channels CH1 and CH2:
3) Combined XLR/¼-inch jack are available as inputs
- Connect microphones to the balanced XLR jack.
- or phantom-powered microphones, You must engage the 48V phantom power switch
for channel CH-1 XLR jack. When the switch is engaged, (switch position =on) the
Phantom power LED is illuminated to indicate that Phantom power is being used.
4) Caution! Do not connect a microphone with unbalanced output via XLR plug; it may be damaged by the
phantom power function. To prevent switching noise, only activate or deactivate the phantom power when

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the mixer is switched off or the output controls are set to “0”.
5) -Connect mono sources with the line level to the unbalanced 1/4" jacks. It is also possible to
directly connect musical instruments of high impedances (electric guitar, electric bass) to
channel CH-2 jacks: in this case press the button for impedance switching for the channel.
- Stereo channels CH3/4 :
6) Stereo sources with a line level may connected to the ¼-inch jack of channel CH3/4, (L=left
channel, R= right channel). The jacks of channel CH3/4 are balanced, however, it is also
possible to connect units with unbalanced output via two-pole plugs. or connecting a mono
unit to channel CH3/4, use Left jack only: Then the mono signal is internally sent to the left
channel and the right channel.
7) Connect stereo headphones (impedance ≥8 OHM) to the ¼-inch jack PHONES/MONITOR or
the ⅛-inch jack HEASET headphone output jack.
8) The sum signal adjusted with the control MAIN MIX is present at the stereo output MAIN MIX
OUT.
9) Here e.g. an amplifier or a second mixer may be connected. The ¼-inch jacks are unbalanced.
10) To switch on the mixer, set the POWER switch to position ON. The power indication POWER
lights up.
Operation ith a computer
1) When operating the mixer with a computer, either use the audio software supplied with the
operating system or an audio software installed additionally. Various programs for audio
reproduction/ recording are available on the internet free of charge.
2) Boot up the computer and connect the USB jack to a USB port at the computer via the
USB cable provided. The USB interface of the mixer is recognized by the computer as an
external unit for audio input and audio output, depending on the operating system e.g. as
“USB Audio CODEC”. The required drivers (standard drivers of the operating system) are
available on the computer.
3) Note: If not all drivers required are available on the computer, install them, e.g. via the original CD of
the operating system. If necessary, restart the computer after installation.
4) Activate the audio program used and make the necessary adjustments for the audio
reproduction via the mixer or audio recording from the mixer.
5) If no audio recording or audio reproduction is possible, check in the system settings of the
computer if the USB interface has been selected for the audio input or audio output.
6) Hint: If the mixer is connected both to a computer and to any units which are earthed via their mains
cables (e.g. amplifiers), ground loops may occur due to hum interference. To eliminate them, the mixer
can be connected to the respective unit via a ground isolator.

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Mixing audio sources
The following steps merely serve as an aid, other ways of procedure are also possible.
1) As a basic setting first:
a. Set all controls GAIN, EQ and PAN to mid-position.
b. Turn all control LEVEL back to the left stop.
2) To adjust a mono channel to an optimum level, feed an audio signal to the channel and turn up
its control LEVEL approximately to mid-position. Adjust the control GAIN of the channel so that
the clip light activates on peak levels. Then adjust the sound with the controls EQ: High for the
high frequencies, LOW for low the bass frequencies. As the sound adjustments affect the
channel level, readjust the gain adjustment, if necessary.
3) Then turn the control LEVEL back to the stop and make the same adjustments for the second
mono channel.
4) or the sound adjustment of a stereo channel turn the controls LEVEL of the remaining
channels back to the stop and turn up the control LEVEL of the stereo channel so that the
sound can be optimized.
5) or the mono channels place the mono signals in the stereo sound with the PAN controls.
6) Adjust the desired overall volume with the control MAIN MIX. However, if the output level of the
mixer is too high for the following unit, the sum signal must be adjusted to a correspondingly
lower level.

9
SPECIFICATIONS
Input Connections XLR balanced /¼-inch balanced “Combo” jack (Ch1 input)
XLR balanced /¼-inch unbalanced “Combo” jack (Ch2 input)
¼-inch balanced or unbalanced (Ch3-Ch4 inputs)
⅛-inch balanced (Aux)
Output Connections ¼-inch TRS balanced (Main Mix outputs)
¼-inch TRS stereo (Stereo output)
⅛ +¼-inch TRS stereo (Phones/Monitor output)
Input Impedance 240k Ohms (Inst-HiZ), 20k Ohms (Line) (Ch1-Ch2, Ch3-Ch4 1/4" inputs)
>4k Ohms (Ch1-Ch2 XLR input)
Output Impedance 440 Ohms (balanced 1/4"), 220 Ohms (unbalanced 1/4") (Main Mix)
100 Ohms (Monitor output) 2k Ohms(Stereo output)
requency Response 20 Hz – 20 kHz (+0, -1 dB)
THD <0.02% @ 1 kHz
CMRR >52dB typical
Phase Response All connections are phase coherent
Signal to Noise Ratio >90dB typical (Ref 0dBu)
Equivalent Input Noise -120dBu typical (XLR balanced, max gain), -95dBu typical (¼-inch)
Maximum Input Level +8dBu (XLR input), +16dBu (¼-inch input)
Maximum Output Level +15dBu (Main Mix outputs), +14dBu (Monitor output), +12dB(Stereo output)
Maximum Gain
(In to Main Out) +60dB (XLR), +47dB (¼-inch) (Ch1 input)
+55dB (XLR), +37dB ¼-inch (INSTR.-HIz) (Ch2 input)
+5dB (¼-inch) (Ch3-Ch4) inputs
(In to USB) +46dB CH1 (XLR) bal., +40dB CH2 (XLR) bal.
+32dB CH1 (¼-inch input bal., +17dB CH2 (¼-inch input bal.)
+33dB CH1 (¼-inch unbal.), +23dB CH2dB (¼-inch unbal.)
+46dB (⅛-inch) (MIC to CH1)
-8dB (¼-inch) (CH3-CH4)
-8dB (⅛-inch) (AUX IN)
(USB to Out) +18dB (Main Mix outputs), +18dB (Monitor output)
Phantom Power Switch selectable, +48V DC, filtered, current limited (CH1 only)
A/D-D/A 16 Bit, 44.1 kHz or 48 kHz, USB selectable from computer
0.4 ms A/D latency @ 44.1 kHz
Computer Interface USB Class compliant plug-and-play Mac and PC interface
Chassis Type All steel black finish
Power Requirements Via USB port(5V/500mA) of the computer or via power supply unit provided and
connected to AC100-240V 50/60Hz
Dimensions (HWD) 1.75-inch x 5.1-inch x 7.5-inch
45mm x 130mm x 191mm
Weight 1.56 lbs. (.71 kg)
Note: 0 dBu = 0.775Vrms
ART maintains a policy of constant product improvement. Therefore, specifications are subject to change without notice.
Go to .artproaudio.com for the latest information and support.

.artproaudio.com
E-mail: [email protected]
© 2016 Applied Research & Technology
USB Mix4 185-5004-101
Four Channel Mic-Inst-Line Mixer - Computer Interface