BMW 850i A-Pillar Speaker Size
The BMW 850i A-Pillar accommodates a 2 inch speaker size. Compatible types for the location include tweeter replacement audio system units. These specifications cover the 1991 model year.
| Year | Type | Size (inch) |
|---|---|---|
| 1991 | Tweeter | 2 |
Speaker Types
| Type | Description |
|---|---|
| Tweeter | A small driver built for high frequencies, typically from about 2,000 Hz to 20,000 Hz. It adds treble detail and clarity and is usually mounted near ear level or aimed at the listener. |
Additional Notes
- The A-pillar is a structural column running along the front windshield edge of a vehicle, positioning speakers at ear level for front-seat occupants and directing sound toward the listening area.
- A-pillar speaker enclosures are typically shallow and narrow, reflecting the limited depth and width of the pillar's interior cavity, which constrains the physical dimensions of compatible drivers.
- The 2-inch diameter specified for the BMW 850i A-pillar represents a small driver footprint suited to the tight spatial envelope of pillar-mounted locations.
- At 2 inches, a driver's cone surface area is minimal, limiting low-frequency excursion and output, which makes the frequency response of such a driver inherently biased toward upper-midrange and high-frequency reproduction.
- Tweeters are high-frequency drivers designed to reproduce the upper portion of the audible spectrum, generally from around 2 kHz upward, handling the range where detail, air, and transient clarity in audio content reside.
- A tweeter's crossover point determines the frequency at which lower content is rolled off, protecting the small driver from excursion damage caused by bass energy.
- Tweeter placement in the A-pillar of the BMW 850i positions the high-frequency driver close to the front occupant's ear level, reducing the path length between driver and listener compared to door or dash-mounted positions.
- Short path length from a tweeter to the listener reduces time-of-arrival delays relative to woofers mounted lower in the door, which has implications for phase alignment in a multi-driver system.
- The directional characteristics of tweeters are narrower than those of larger woofers, and A-pillar placement allows the driver to be aimed toward the primary listening position rather than firing into door panels or floor areas.
- The compatibility of only the tweeter type with the 2-inch A-pillar location in the 1991 BMW 850i reflects the physical and acoustic constraints of both the driver size and the installation space.