Owner's Manual

Top Panel Adjustments
3
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ΠAUX Gain Adjustment: In systems using both the link4's main speaker level and auxiliary inputs, this
gain adjustment is primarily for matching the AUX output level with that of the main source. It is
recommended to set the speaker level input gain(s) first, particularly if summing. For stand-alone
systems using only the AUX input, use this gain adjustment to match the source’s maximum unclipped
signal output and connected amplifier(s) input capability. For portable devices such as smartphones or
MP3 players, it is recommended to use the multi-function remote as the master system volume
control and leave the device at its maximum clean volume setting.
ŽClipping Indicators: These yellow LEDs indicate when the signal output from either CH1/2 or CH3/4
is at maximum level before clipping (distortion) occurs, whether the source is main speaker level or
AUX input. Each will be dimly lit just before the onset of clipping, and full bright at clipping. Since the
link4 can produce up to 10Vrms output before clipping, it is likely that gain(s) will need to be reduced
below the illumination point(s) to match your amplifier(s) maximum input capability or optimize
source volume range. Note that the AUX input is controlled by its own unified gain that affects all four
output channel pairs equally and will illuminate all LEDs simulaneously when clipping.
 CH1/2 Gain Adjustment: This gain adjustment is for matching CH1/2’s output signal level with the
source’s maximum unclipped signal range and the maximum input capability of connected
amplifier(s). When a 4-channel speaker level source is connected, CH1/2’s gain adjustment should be
used for matching output level with that set for CH3/4, particularly when CH1+3/2+4 summed input is
selected. If CH1/2 direct signal input is selected, adjust for any desired gain differences at the link4
while also minimizing amplifier gain settings for best S/N. Note that this gain adjustment will be
bypassed if input select is set to CH3/4 copy.
 CH1/2 Input Select: This 3-position switch is for selecting which signal is routed internally to CH1/2’s
output stage. It provides for 2-channel, 4-channel or summed input as follows:
‘ CH1/2 (Direct): For systems with a 4-channel speaker level source connected at the input
terminals, this setting routes the signal input at CH1/2 directly to its gain and output stages.
’ CH3/4 (Copy): This setting is for systems where only a 2-channel speaker level source is available
and is connected at CH3/4’s input terminal. When selected, the internal signal after CH3/4’s gain
stage is copied to CH1/2’s output stage. This bypasses CH1/2’s gain so all four output channels are
controlled together by CH3/4’s gain adjustment. If independent gain is desired for CH1/2’s output,
use jumper wires at the input terminals and select CH1/2 direct input instead.
“ CH1+3/2+4 (Sum): Selecting this setting will
sum CH1+CH3 (left) and CH2+CH4 (right) input
signals after their gain stages and route them
to their respective CH1(left) and CH2 (right)
outputs. For vehicles without an available full-
range signal, this setting can be used to sum
pre-filtered signals together to create a
useable full-range output. When a 4-channel
full-range source is available, this setting may
also be used to ensure CH1/2’s output will
always retain at least half signal, regardless of
the source unit’s fader position.
” CH3/4 Gain Adjustment: This gain adjustment is for matching CH3/4’s output signal level with the
source’s maximum unclipped signal range and the maximum input capability of connected
amplifier(s). For systems using all four channels of the Link4’s outputs, it is recommended to set gain
for CH3/4 first as the reference, particularly when summing and using its pass-through. Follow proper
gain setting procedures to ensure optimum source volume range with minimum chance for clipping at
any point in the signal chain. Aside from music, a 1kHz -10dBfs signal tone may also be used during the
tuning process to ensure proper headroom and gain overlap for typical music recording levels.
Level
Freq
CH3/4
Input
Level
Freq
CH1/2
Input
Level
Freq
CH1+3/2+4
Summed Output
Level
Freq
CH3/4
Output