Bose acoustimass

[djronbxs]

Hi,

how does bose produce that sound with that small drivers and enclosure ? is it a transmission line or those it have some electronics inside to produce the sound like that ?


thanks

 

[GM]

Greets!

Assuming you're referring to the bass module, yes to both: http://www.bose.com/controller?even...NT&url=/popup/tech_details/pop_am_am16_15.jsp

The satellite speakers are heavily EQ'd custom single drivers in a tiny sealed alignment.

GM

 

[linuxguru]

At the risk of stating the obvious, there are far better-sounding satellites than the 2" satellites of Bose Acoustimass, at a fraction of the cost. In particular, the well-known silent gap between 200 to 280 Hz that exists in Bose Acoustimass satellites can easily be filled by using inexpensive (<$10) 3" full-ranges. For instance, check out the Zaph Audio bookshelves with 3" HiVi drivers:

http://www.zaphaudio.com/audio-speaker18.html

For the main Bose Acoustimass Bass unit, it is easily surpassed by a whole lot of designs that use a single, larger driver - starting at ~5.25" and higher. The 8" Pioneer BF20FU20 "Bofu" full-range driver at $25 is the best example, but there are numerous others.

The only thing going for Bose is the WAF (Wife Acceptance Factor) of small and inconspicuous components. But there's a price to be paid for that - which is poor sound quality.

 

[djronbxs]

but the acoustimass is a transmission line or what ?

 

[lne937s]

The "acoustimass" module is not a transmission line, but rather a bandpass box- the order of which depends on the model. These enclosures increase output in a narrow range. It uses this combined with EQ and emphasizes frequencies that people are sensitive to (80-100Hz) rather than attempting to play low bass frequencies (20-40Hz)

Sixth order bandpass:
http://www.carstereo.com/help/Articles.cfm?id=32

http://www.intellexual.net/bose.html

http://www.greengart.com/Columns/column005.htm#Column 5 Update

 

[djronbxs]

but the latest acoustimass subwoofer are not indise the encolure there are two under the box facing the floor

 

[lne937s]

I found what you are talking about... Well, it has a resonant cavity and a very long port that looks like it takes up about as much volume as the cavity. Almost like a transmission line, but not quite... Kind of like a hybrid between transmission line and ported box.

 

[djronbxs]

so for a resonant cavity what are the tuning formulas ?

 

[lne937s]

look at a vented box.

Consider it a really long port...

http://www.geocities.com/f4ier/vented.htm