subterFUSE

Gecko.... you are correct with your "stereo should be stereo" viewpoint.

However, stereo systems are designed with good room acoustics in mind.
When Totem builds and tests those speakers of yours... they do so in a professionally designed room. This room is absolutely empty except for the speakers. There's nothing in the way to disrupt the soundfield. The listener should also be positioned in the "sweet spot".

A car, by contrast, is a HORRIBLE acoustic environment. The shape of the interior is terrible. There are glass walls everywhere which deflect sound. And you are sitting on one side or another. Achieving high-end home system quality in an automobile is very difficult.

It can only be achieved by a few methods:

1. By moving speakers to better locations, such as kick panels. The distance from the drivers (I mean the car driver, not the speaker... hehe) ears to each door is very different. From the drivers ear to the kick panels on both the driver and passenger side of the car is much more equal.... not perfect, but much better.
This helps move the sweet spot. This method helps the soundstage for both driver and passenger.

2. Processing can be used to move the perceived sound source via time alignment. This puts a slight delay on the speakers closer to the driver, so that the sound from both sides of the car arrives at the driver's ear closer to the same time. This method works.... however only for the driver. The passenger's side sound worse this way than with no processing.

3. Install compression horns (aka WaveGuides) under the dash. This is actually just a version of option 1 above. Compression horns are designed to fit under your dash, and the distances from listener's ear to each one is about the same. Horns are also great because they are a single piece replacement for both tweeters and midrange/midbass. They are highly efficient, and the sound quality can be excellent. I had a pair of Image Dynamics CD2 Comp horns in an old car, and they were incredible.

4. Install a center channel speaker, and use processing. This is what BMW has done. They use a center channel speaker to create a strong frontal image. The processing filters out certain frequencies and routes them to the front, or to the other speakers. Vocals are directed to the center channel, while less-directional sounds like bass are allowed to fill the car from all sides.



These are the only ways I know of to get truly high quality sound in a car.

BMW chooses to do the center channel/processing method for a number of reasons.

1. Installing speakers in odd placements like the kickpanels would cut down on legroom. Most people would not like them there.

2. Installing compression horns is highly expensive. A pair of the Image Dynamics horns I was talking about is about $1000, before installation. Additionally, the horns make the dash about 2 inches lower.... so many people would not like the reduced legroom.

3. Another reason BMW doesn't use higher-end equipment is because they want brand recognition with the stereo. They will sell more audio systems if people know the name of the company (ie Harmon-Kardon, Bose). Car companies use these name-brand stereos because when most people see the name, they know it.... and think it's good. How many people do you think know about Totem speakers? Not many. So would selling a car with Image Dynamics horns get a lot of people excited? Probably not.

4. The more speakers a car company installs, the more people think the stereo must be good. Most people will simply assume that the car with the most speakers sounds the best.


But.... when it comes down to it.... it is just not practical to install a high-end stereo. Few people have the need or desire for it. BMW wants to appeal to as many people as possible... and most people don't know enough about audio to appreciate a superb system.

Gecko

Thanks for the explanation.

Have you ever listened to the HIFI versionof BMW?