Using a Different Sub

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Using a Different Sub

Classic This information is applicable to the L1® Classic
L1 Model I This information is applicable to the L1 Model I

The following notes are compiled from a discussion on the Bose Community Message Boards. Using a Different Sub (October 2005). These are still applicable to the L1 Classic and L1 Model I.

These predate the L1 Model II but are largely applicable. Note: The crossover point for the Model II is 200 Hz rather than 180 Hz documented below for the L1 Classic and L1 Model I. On the L1 Model II the crossover point is fixed at 200 Hz and does not change regardless of whether or not there are B1s attached to the Power Stand.


Question

What are the problems or benefits of plugging in a different sub cabinet to the PAS. It it even possible or feasible. Say you have a 4 ohm 250 watt EV sub with a 15 inch speaker and you plugged into it instead of the B1. What could you expect and is there any possible damage you could cause.

or could you use that instead of a second B1 for more bottom.

Breaking this down into several smaller questions we get:

Q: Can you cause any damage to the Power Stand or the speakers by using a third-party loudspeaker?

A: The powered Bass Output of the Power Stand is rated to provide

  • 125 Watts at 8 ohms
  • 250 Watts at 4 ohms

Be careful that whatever you connect to the Power Stand Bass Output is compatible with this. Note: On the L1 Classic, this connection is called Amp3 Out, and in later versions that connection has a blue background.

Q: What is the Crossover Point for the powered Power Stand Bass Output?

A: This depends on if there are if there are B1 Bass Modules attached. There is a hard cut off at the frequencies noted, for the signal provided to the Cylindrical Radiator® loudspeaker.

  • 110 Hz when there are no B1 Bass Modules connected to the Power Stand Bass Output.
  • 180 Hz if there is something (even a dummy plug) is inserted into the Bass Line Out jack on the Power Stand.
  • 180 Hz when there is one (or two) B1 Bass Modules connected to the Power Stand Bass Output. If one or two B1 Bass Modules are detected then proprietary EQ is applied to the output to optimize the performance of the B1s.

Q: What is the Frequency for the unpowered Power Stand Bass Line Out?

A: This depends on if there are if there are B1 Bass Modules attached. There is a hard cut off at the frequencies noted, for the signal provided to the Cylindrical Radiator® loudspeaker.

Q: Can I mix B1 Bass Modules with other subs?

A: This is not recommended. [1]


Q: Why does Bose call the B1 a Bass Module instead of a sub.

A: Here is the story as far as I can tell: Originally the term "subwoofer" was used in movie theater sound systems. There the standard is still 5 full-range channels and one subwoofer channel. The subwoofer channel has signifcant spectral overlap with the main channels. Typically the main channels start at 40 Hz or 50 Hz and the subwoofer ranges from 30ish up to about 120 Hz. The Subwoofer can produce some serious bass level, but fidelity is not much of an requirement, as they are mainly used for sound effects (explosion, the ominous rumble, etc.)

In contrast a multi-way PA of the time had between 2 and 4 different speakers all dedicated to specific non-overlapping frequency areas. The bass produces were typically called bass-bins or bass cabinets and not subwoofers, as they actually do something different.

Bose was probably one of the first (if not the first), that made the split system (single bass box, multiple small satellite) commercially successful for home use with the AM-5 speaker. As commonplace as it is today, at the time it was a pretty radical idea and many, many audio experts stated that can't possibly work (sounds familiar ?). Anyway, as we tried to name the black bass-producing device, we felt bass module was a good choice as it was functionally different from a subwoofer.

After it turned out, that the concept did indeed work many more manufactures turned out products in the same category and in the process subwoofer became the common term. Maybe the marketing departments wanted to imply that it's similar to a real movie sound system, maybe they just didn't know the difference.

So in short, IMO the difference would be a) Subwoofer is a low frequency extension, but the system can also work without it b) Bass module is a integral part of the system with dedicated non-overlapping frequecny range.

Of course, in the end it's just nit-picking and common use defines language more than any technical specification.

Just my 2c

Hilmar[2]


  1. ↑ Hilmar-at-Bose mixing subs with B1s not recommended
  2. ↑ Hilmar-at-Bose talking about subwoofers and bass modules.
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