@crown
®
*
System
®
Product Reference
SMX-6
™
Automatic Mixer
ENABLE
DSPI
L
M
P
+
–
+
–
+
–
+
–
+
–
AUDIO
IN
6
+
–
+
–
+
–
+
–
+
–
MAIN
OUT
IN
AUX
CTRL
RS232 / RS422
AUDIO
IN
5
AUDIO
IN
4
AUDIO
IN
3
AUDIO
IN
2
AUDIO
IN
1
120 VAC
60 Hz
20 W
AUDIO
OUT
2
AUDIO
OUT
1
BUS
STACK
IN
MAIN
BUS
STACK
IN
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
+ – + –
CROWN BUS
SERIAL DATA LOOP
INPUT
GROUND
ONLY
IN
OVERVIEW
What is an SMX-6?
The SMX-6 is a single rack space six by
two automatic mixer designed to be
configured with a computer and appro-
priate software. Once initially setup the
computer becomes optional. The key to
the ability of the SMX-6 operating as a
stand alone automatic mixer is distrib-
uted intelligence
™
. In an IQ System the
brains of the system live out in the sys-
tem. This means the audio system is not
going to be lost even if the computer or
communication cables fail. Due to the
modular nature of the SMX-6, multiple
units also may be used together to form
a wider or deeper automated mixer.
HARDWARE BLOCK DIAGRAM
Refer to the pictures of the front and rear
panels shown above and the block dia-
gram of the SMX-6 mixer on Page 2.
Audio Main Inputs:
Six balanced inputs
with removable 3 pin
barrier block. The
preamp stage in-
cludes:
• M/L/P switches
set each input to line level (L) with 0
dB gain, mic level (M) with 25 dB
additional gain, or phantom (P)
which is 25 dB additional gain and
+44 VDC phantom power.
• A trim pot at each input allows for
prefade gain adjustment of –12 dB
to +21 dB gain after the M/L/P
switch.
Prefade sensors at the output of each
preamp stage sense input audio level
just before the input signal is delivered
to the processor controlled VCAs. There
are two VCAs under processor control
at the output of each sensor. One VCA
controls the gain from input to output mix
1 and the other VCA controls gain from
the input to output mix 2. The net result
is 12 VCAs total, six per output mix.
Audio Stack Inputs:
Two inputs, one per output mix. Connec-
tions are via unbalanced RCA phono
jacks. These inputs are op-amp isolated.
There is no processor control of audio
coming into these inputs. The purpose
of the stack inputs is to allow construc-
tion of a wide mixer with more than six
inputs by taking the outputs of one mixer
and going into the stack inputs of a sec-
ond mixer. This means that main inputs
do not have to be used to expand the
effective size of the overall mixer.
Audio Main Outputs:
There are two summing
buses. Each summing
bus provides the out-
put mix for the corre-
sponding output chan-
nel. Op-amps buffer
the summing bus to the output connec-
tion and balance the audio output. The
outputs are via 3 pin removable barrier
blocks.
Audio Bus Outputs:
In addition to the two main outputs, there
are also two bus outputs. Bus outputs 1
and 2 provide the same audio output as
main outputs 1 and 2. Op-amps buffer
the summing bus to the output connec-
tion and balance the audio output. What
makes the Bus Outputs different are re-
lays under processor control which may
be used to turn on or off the Bus Output
drive. 3 Pin removable barrier blocks are
used.
Aux Port:
The unit is equipped with a TB-3M type
mini-XLR port. This port may be used to
provide a control signal or sense a con-
trol signal.
• Pin 1 is ground reference
• Pin 2 is output under processor
control. When on it provides 10 VDC
at 16 ma. When off it is open collec-
tor (high impedance).
• Pin 3 is sensing input. +5 to +30
VDC is sensed as a logic high. The
circuit floats, therefor tie to ground
or TTL source for definite high or low.
Indicators:
A Power light on the front panel indicates
the unit is plugged into AC mains and
AC power is available. A DSPI data sig-
nal presence indicator lights to indicate
communication or may be forced on via
processor control.
Crown Bus Port:
The Crown Bus is a serial data loop
where components are connected into
the loop and one component serves as
system interface for all. This unit may
serve as a system interface or may sim-
ply operate as a component on a Crown
Bus data loop. Although the Crown Bus
may function on a variety of media,
Crown uses a two-wire 20 ma current
loop for input and output Crown Bus
connections. On this unit connections
are made via 4 pin removable barrier
block. Even if the unit is communicating
directly with a PC via its serial port, it
always functions in software as an ad-
dressable component on a Crown Bus
loop. The unit must have a valid loop
address. A valid address is:
• 1 to 250 set via 8 segment DIP
switch
• No other SMX on the same Crown
Bus data loop may have the same
address.
SMX-6 SENSING MIXER
(Front Panel shown above, Rear Panel shown below)
Page 1 of 5
+
–
AUDIO
IN
1
L
M
P
0
-5
-10
-12
5
10
15
21
ADD 25
FOR MIC
+
–
+
–
AUDIO
OUT
1
MAIN
BUS
STACK
IN
