L1® Model II Power Stand / Bass Line Out

Most of the information here was originally written for the L1 Classic and L1 Model I. I have verified with MikeZ-at-Bose, that this is applicable to the L1 Model II. The exception is that the crossover point is 200 Hz. The Classic/Model I crossover is 180 Hz. There is a little more detail about the L1 Model II crossover at the end. ST

Bass Line Out and B1 behavior

Hilmar-at-Bose. This is based on the design goal that “You should always sound the same; no matter how much Bass stuff is attached” I can try to explain my view of why this is a good design goal (of which you may disagree) but let’s look at the actual behavior first.

Note The Model II differs from the Classic and Model I in that the crossover is at 200 Hz for the Model II. The Classic and Model I crossover is at 180 Hz.

Without Bass Line out

• 1 x B1: 40Hz-200Hz, B1 specific EQ, some nominal gain that we call 0dB
• 2 x B1: 40Hz-200Hz, B1 specific EQ, -6dB as compared to nominal

With Bass Line Out

• 0 x B1 connected to Power Stand: 40Hz-200 Hz, flat, roughly the same gain as 2 B1
• 1 x B1 connected to Power Stand: 40Hz-200Hz, B1 specific EQ, -6dB as compared to nominal
  • If you use a PackLite^® power amplifier model A1 Extended Bass Package this is a total of 3 B1s
• 2 x B1 connected to Power Stand: 40Hz-200Hz, B1 specific EQ, -12dB as compared to nominal
  • If you use a PackLite^® power amplifier model A1 Extended Bass Package this is a total of 4 B1s

What this complex behavior does is the following. No matter if you attach 1, 2, or 4 B1s, you will get pretty much the same balance between all combined B1s and the L1s. It’s a little off for 3, 5, 6, 7 & 8 B1s, but still reasonably close.

It’s true that the user doesn’t have to re-EQ our systems if you add more B1s or even a PackLite with another pair of B1s. But that’s unique to our system, because we were actively measuring the number of B1s attached. So re-EQ is required, but the system is doing it by itself without any user involvement required.

With More Than 4 B1s

A little more insight. We actually can't measure the exact number of Packlites, 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. However, these are rare cases, and if you go through the trouble to hook up 8 B1s, I guess you are actually looking for something more bass heavy.

Don't ask how I know.

L1 Model II Crossover L1 Cylindrical Radiator^® loudspeaker

There is no change in crossover frequency for the Cylindrical Radiators® depending on the presence/absence of B1 Bass Modules attached to the Bass Module output. This is due to the design change (Cylindrical Radiator® is not ported whereas Classic and Model I are.) The L1 Model II is designed to always be used with at least one B1, whereas the L1 Model I / L1 Classic was designed to used with or without a B1 Bass Module.

Bass Module Output (powered output)

For the sake of those attaching third party passive speakers (an unsupported application).

Output if no B1 Bass Modules detected

• 40-200 Hz Bandpass (that is: NO B1 EQ)

If one or two B1 Bass Modules detected (or resistors used across NL4 2+ / 2- pins to emulate detection)

• 40-200 Hz with different EQ curves

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

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