Considering running some 6.5 or 8" woofers for mid bass under the mid seats and the center console in my Burb.  Was wondering if it was omni directional...

Any frequency where the wavelength is longer than the diameter of the cone is omnidirectional. So yes, midbass will be omnidirectional for any 6.5" or 8" driver. However, being omnidirectional, which means the sound is radiated from the driver equally in all directions, does not mean driver placement no longer matters. Aiming of the driver doesn't matter when the sound is omnidirectional, but midbass is still stereo and contains "left" and "right" information. So for proper imaging speaker placement is still very important and you still want to have the drivers located as wide as possible in the vehicle. Placing midbass under seats or in the middle of the vehicle is terrible placement for midbass and will ruin the imaging and soundstaging by significantly narrowing or eliminating the "left" and "right" imaging and staging ques at those frequencies.

Moral of the story is that your plan won't work properly. Don't do it.

Thanks for this informative answer, Impious.
Would it be better to have one midbass driver under each seat ? Maybe downfiring ?

 

 

Sorry, OP.

No, under seats is a bad location, period. We localize midbass based on interaural time arrival differences ( ITD).....which is the difference in arrival time of the sound to our left and right ears. If the midbass is located directly under you, as it would be if you placed a midbass under the driver's seat, then there would be no difference in the arrival time of the sound to your left and right ears which would narrow the soundstage. A sound that should be located far left would instead be directly in front of you. Obviously by logical extension any speaker location directly in front, above or behind you would be equally bad. You want them to be as wide as possible to create the proper difference in time arrival to your ears for proper imaging and sound stage reproduction. We can't locate midbass frequencies vertically, so height position of the midbass speaker doesn't matter for imaging purposes. But horizontally, creating the proper ITD is essential to properly recreating the soundstage.

As for the center console/center of the vehicle idea....the problem with that should be obvious. Sounds from the "left" would sound like they are coming from your right.

i always always always learn something new every time u type a reply in that keyboard of yours impious..

 

thanks for that

for anyone who wishes to read more on the topic, http://en.wikipedia.org/wiki/Sound_localization

Thanks for the replies!  Made that decision easy.  Love this board.

No, under seats is a bad location, period. We localize midbass based on interaural time arrival differences ( ITD).....which is the difference in arrival time of the sound to our left and right ears. If the midbass is located directly under you, as it would be if you placed a midbass under the driver's seat, then there would be no difference in the arrival time of the sound to your left and right ears which would narrow the soundstage. A sound that should be located far left would instead be directly in front of you. Obviously by logical extension any speaker location directly in front, above or behind you would be equally bad. You want them to be as wide as possible to create the proper difference in time arrival to your ears for proper imaging and sound stage reproduction. We can't locate midbass frequencies vertically, so height position of the midbass speaker doesn't matter for imaging purposes. But horizontally, creating the proper ITD is essential to properly recreating the soundstage.

As for the center console/center of the vehicle idea....the problem with that should be obvious. Sounds from the "left" would sound like they are coming from your right.

Thanks Brad, please pass this along to BMW.