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Why the B1 Bass Module is not a subwoofer.

Originally posted by Hilmar-at-Bose — Thu December 01 2005 06:13 AM:

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

  • Subwoofer is a low frequency extension, but the system can also work without it
  • Bass module is a integral part of the system with dedicated non-overlapping frequency range.

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

Just my 2c