Soundbarrier iUSB400, Instruction Manual, Page: 8 / 13

Please note: As with any audio input device, plugging in a microphone or an instrument, or turning phantom
power on or off, will create a momentary spike in the audio output of your IUSB400. Because of this, we highly
recommend that you turn down the main output level and channel trims before changing connections or turning
phantom power on or off. This simple step will add years to life of your audio equipment.
2) 48-volt Phantom Power. The IUSB400 provides 48V phantom power for both microphone inputs.
Press the 48V button to enable phantom power for both microphone inputs.
WARNING: Phantom power is only required for condenser microphones and can severely damage some dynamic
mics, especially ribbon mics. Please consult your microphone’s documentation before enabling phantom power
on your IUSB400.
3) Input Gain/Trim Control. The se knobs provide the following gain structure: • Microphone: 60 dB of
variable gain (0 to +60 dB) • Instrument: 40 dB of variable gain ( -10 dB to +30 dB)
4) Clip Indicator. All channels feature clip LEDs next to the trim controls. The red clip indicator LED will
illuminate when the channel’s input signal reaches 0 dBFS. At this level, your mic preamp/line trim
signal will exhibit signs of clipping (distortion).
Power User Tip: Never run your input levels higher than the channel inputs can handle. If you overdrive the analog-to-
digital converters, it will cause digital distortion (digital clipping), which sounds terrible and cannot be undone.
5) Mixer. The Mixer knob allows you to blend your input signals with the playback streams from your
computer so that you can monitor your input signals without any latency (delay). If the knob is
positioned at 12 o’clock, the input signal and the playback stream will be equally balanced. Turning
the knob to the left will increase the level of the input signal relative to the playback stream; turning to
the right will increase the level of the playback stream relative to the input signal as illustrated below:
Power User Tip: When monitoring your inputs through Studio One or another DAW, it is important that you turn the
Mixer knob all the way to the Playback position. Monitoring both the input signal and the playback stream will create
a doubling effect that will make monitoring difficult
.
6) Phones. The Phones knob controls the volume of the headphone output on the rear of the unit. The
headphone amplifier is quite powerful, and the volume goes to 11, so use the maximum setting with
extreme caution.
7) Main. The Main knob controls the output level for the Main Outputs on the back of the IUSB400, with a
range of -80 dB to 10 dB.
8) Power LED. This LED will illuminate red when the IUSB400 is properly powered and synced to a USB
connection.
Rear-Panel Connections
9) ¼-inch Phones (headphone) Jack. This is where you connect headphones to your IUSB400.