PS1 Power Stand / Bass Line Out

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Bass Line Out and B1 behavior

The behavior of the bass line out and B1 Bass Module outputs on the L1 Classic / L1 Model I / L1 Model II are based on the philosophy that adding B1 Bass Modules should give the user more dynamic range (can play louder) but should not alter the tone of the instrument, including tone adjustments made using the R1 Remote, the T1 ToneMatch Audio Engine or other tone-shaping equipment.

This philosophy is notably different from other manufacturers, who take the approach that it's okay (or desirable) that adding more bass speakers causes the instrument tone to become "bassier".

With this philosophy in mind, here is how the bass line out and B1 outputs work.

No cable plugged into the Bass Line out

B1s connected	Output	EQ	Bass Signal Gain	Notes
1	40Hz-180Hz	B1 specific EQ	Reference Level
2	40Hz-180Hz	B1 specific EQ	Reference Level -6 dB	Why? Because when you add a second B1, if you did not change the signal strength you would get 6 dB more bass relative to the mids and highs. This would alter the tone of the instrument. To keep the tone the same, while still allowing the more dynamic range (system can play louder by 6 dB) the signal level must be reduced by 6 dB.

Cable connected to the Bass Line Out

B1s connected	Output	EQ	Bass Signal Gain	Notes
0	40Hz-180Hz	Flat EQ	Reference Level -6 dB
1	40Hz-180Hz	B1 specific EQ on Bass Line Out and B1 Out	Reference Level - 6 dB	If you are using a PackLite® power amplifier model A1 Extended Bass Package this is a total of 3 B1s (2 on the A1 and 1 on the Power Stand)
2	40Hz-180Hz	B1 specific EQ on Bass Line Out and B1 Out	Reference Level -12 dB	If you are using a PackLite® power amplifier model A1 Extended Bass Package this is a total of 4 B1s (2 on the A1 and 2 on the Power Stand)

With More Than 4 B1s

The Power Stand does not measure the exact number of PackLite^® power amplifier model A1s, so there is a slight error if you use anything but 1,2, or 4 B1s.

For 6 B1s you will be 3.5 dB bass heavy, for 8 B1s it'll be 6 dB heavy.

B2 EQ

Bass Line Out: Model II post firmware 1.4 with System EQ 1.04

September 2012

Bose released Model II Power Stand Model II firmware 1.4 with System EQ 1.04 to support the B2 Bass Module with the three position Bass Level Switch ( + Normal - ). Note: Support and behaviors for B1(s) is unchanged.

The behavior of the bass line out with the B2 Bass Module Bass Module outputs on the Model 1S and Model II are based on the philosophy that adding B2 Bass Modules should give the user more bass output immediately. This changes the tonal balance as soon as you add a second B2 using an PackLite^® power amplifier model A1 connected to the Bass Line Out. This is unlike the behaviour with B1 bass modules where the signal is attenuated as you add more B1s to maintain the tonal balance at lower volume levels.

Note: If no bass modules are detected at the Bass Module Output the Bass Line Out EQ will be set to the B2 curve with the B2 switch set to Normal.

— Source Craig-at-Bose

No cable plugged into the Bass Line out

B2 Bass Modules connected	Output	EQ	Bass Signal Gain	Notes
1	40Hz-200Hz	B2 specific EQ as set by the B2 Bass Level Switch ( + Normal - ) is present at the Bass Module Out and the Bass Line Out	Reference Level	There are three B2 EQ settings possible using the B2 Bass Level Switch ( + Normal - )

Cable connected to the Bass Line Out

B2 Bass Modules connected	Output	EQ	Bass Signal Gain	Notes
0	40Hz-200Hz	B2 EQ as though B2 attached and B2 Bass Level Switch set to Normal position	Reference Level	This presents the B2 EQ with the B2 Bass Level Switch set to the Normal position. (No resistance detected between the 2+ and 2- pins of an NL4 plug)
1	40Hz-200Hz	B2 specific EQ as set by the B2 Bass Level Switch ( + Normal - ) is present at the Bass Module Out and the Bass Line Out	Reference Level	If you are using a PackLite® power amplifier model A1 Extended Bass Package this is a total of two B2s (one on the A1 and one on the Power Stand)

Powered Subwoofers

The Model II is an integrated system that supports Bose B1 and B2 bass modules. Connecting powered subwoofers to the Model II Power Stand Bass Line Out is not supported because EQ curves for the B1 or B2 are present at the Bass Line Out. This may or may not result in good results with a powered subwoofer.

If you want to use a powered subwoofer, connect your signal source to the subwoofer and connect the subwoofer high pass filter output to the L1® (any model).

Output if no B1 Bass Modules detected at the Bass Module Output (powered output) the signal at the Bass Line Out is:

• 40-180 Hz with B2 EQ applied if you have the current L1® Model II Power Stand Firmware Updates
  • If you do not have the current firmware the signal at the Bass Line Out is: 40-180 Hz Bandpass (that is: NO B1 EQ)
• The system Crossover for the Cylindrical Radiator®s is 180 Hz

If one or two B1 Bass Modules is detected or emulated using resistors across NL4 2+ / 2- pins

• 40-180 Hz with different EQ curves
• The system Crossover for the Cylindrical Radiator®s is 180 Hz

For details on how to do this see: Activating B1 EQ Curves and Using a Different Sub

Note — Operation of the B2 with the Model I/Classic is only supported with the B2 Bass Level Switch set to Normal.

See: Is the B2 Bass Module Compatible with the L1® Classic or Model I

Bass Module Output (powered output)

For the sake of those attaching third party passive speakers (an unsupported application), the output characteristics are the same as for the the B2 Bass Module (section immediately above).

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Original Source - Hilmar-at-Bose