Bose Personalized Amplification System Troubleshooting Manual page 17

1.3.2 Implementation
The power stands detects:
a) The number of bass modules B1 connected to "Amp3 out". This is done by measuring the
impedance between pins 2+ and 2- of the "Amp 3 out" connector. The B1 bass module has a
10k ohm resistor between those to pins.
b) The insertion of a 1/4" jack into the "Bass Line Out". A normalling connection of this jack is
connected directly to a flag pin on the DSP.
Depending on these detections, the PS1 will change system EQ and limiter settings. This infor-
mation is collected by the DSP and determines EQ and limiter settings through a lookup table:
Number Impedance,
of Bass Amp3
Modules 2+ - 2-
0 infinity
1 10k ohm
2 5k ohm
0 Infinity
1 10k ohm
2 5k ohm
?? 0
Table 5. EQ lookup table for all operational modes
1.3.3 Debug Mode
Debug mode is entered when a resistance of 1k ohm or less is detected between pins 2- and 2+
at the "Amp3 Out" connector. In debug mode, all system EQ's are set to "flat" and the internal
limiters are bypassed. Most measurements should be done in debug mode.
A simple way to switch between the different modes is to create a "dummy" cable that brings out
pins 2- and 2+ to a banana plug. The modes can be switched by applying different numbers of
10k ohm resistors or a short between the leads of the banana plug. Pins 1+ and 1- of the
"dummy" cable can still be routed to a Speakon
THEORY OF OPERATION
Bass Bass
Send EQ
connected
No 0
No 1
No 2
Yes 3
Yes 4
Yes 5
Either 6
17
LA Comment
EQ
0 No bass module:
L1: Select highpass at 110Hz
B1: 40-110Hz flat bandpass
1 L1: crossover at 180 Hz
B1: "nominal EQ" +6 dB
1 L1: crossover at 180 Hz
B1: "nominal EQ"
2 This mode is for use with external
powered sub.
L1: crossover at 180 Hz
B1: flat 40Hz to 180Hz
1 Undefined state, user may be using
rd
an external 3
single B1
L1: crossover at 180 Hz
B1: "nominal EQ"
1 This is the nominal case with an
additional external power stand
connected
L1: crossover at 180 Hz
B1: "nominal EQ" -6 dB
0 Debug Mode: all EQ and limiters
are by-passed.
® connector to attach B1 bass modules.
party device with a