L1® Model II Power Stand / Bass Line Out
ContentsMost 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 as well. 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[1]. 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 all the references to 180 Hz below may actually be 200 Hz. We are just waiting for MikeZ-at-Bose to confirm one way or the other.
Without Bass Line out
- 1 x B1: 40Hz-180Hz, B1 specific EQ, some nominal gain that we call 0dB
- 2 x B1: 40Hz-180Hz, B1 specific EQ, -6dB as compared to nominal
With Bass Line Out
- 0 x B1 connected to Power Stand: 40Hz-180 Hz, flat, roughly the same gain as 2 B1
- 1 x B1 connected to Power Stand: 40Hz-180Hz, 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-180Hz, 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. [2]
With More Than 4 B1s
A little more insight. [3] 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 B1s 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 Output (powered output)
For the sake of those attaching third party passive speakers (an unsupported application).
Output if no B1s detected
- 40-180 Hz Bandpass (that is: NO B1 EQ)
If one or B1s detected (or resistors used across NL4 2+ / 2- pins to emulate detection)[4]
- ↑ Hilmar-at-Bose A1 PackLite Questions and More Bass Talk
- ↑ Hilmar-at-Bose Third Party Woofers
- ↑ Hilmar-at-Bose Third Party Subwoofers
- ↑ Hilmar-at-Bose talks about using resistors to emulate B1 detection
- 40-180 Hz with different EQ curves