Something that has always fascinated me is the dynamics of sound when installing speakers in the Mini. There are no “ideal” positions to put speakers in the Mini because of the way it was designed. We can get around this by building custom housings for component speakers to sit under the dash at the front.

To me an essential item in any build, even a budget install, is a subwoofer. These speakers give extra “oomph” to the bass notes of any piece of music and will give voices a warmer tone, helping to eliminate the harsh tinny sounds that is often apparent in the car. Yes, I know that’s a very simplified explanation. But, where to put it/them?

Well, the obvious place for most people is in the boot. This is ideal for most situations as sub-bass notes are not generally affected by direction. The notes that the sub will produce, generally 30-500hz, are felt rather than heard. Of course, putting a bloody great sub in the boot causes its own problems:

  1. You lose the boot space. I have a 10″ subwoofer on my back seat in a box. Putting it in the boot effectively fills the boot meaning it’s useless for anything other than the spare packet of fuses all good Mini owners should carry.
  2. The rear parcel shelf is effectively a wasted space. Many people (Rover included on later Minis) put a pair of speakers there. If you then put a sub in the boot then it can (and does!) interfere with the operation of the other speakers on the shelf due to the mass movement of air created by the sub.

There are other solutions. Of course there are! Elemental Designs make a 6 inch sub-woofer that has excellent power handling capabilities. With an appropriate enclosure this will fit beautifully in that wasted space under the rear seat.

I and a friend were trying to work out how much space is under the seat to allow the creation of the correct size enclosure so that the sub will still perform properly.

Not a great problem except that all the measurement he gave me were in millimetres. All the enclosure size calculators on the ‘net work in inches. This is because the speaker manufacturers give ideal enclosure sizes in cubic feet. Obviously this meant doing lots of conversion and confusion to get the appropriate numbers to plug into the calculator.

This morning I sat down for a few minutes and worked out the formula to convert length width and height in millimetres into cubic feet.

The formula (using standard mathematical notation):

(L*W*H) / 1,000,000 / 28.32

This is, obviously only for a square box. When I have recovered from the brain strain (I’m sorry, I’m not Phil) I will try and figure out conversions for triangular and odd shaped boxes.

In Car Entertainment is almost a passion and I will be talking about this much more in the near future.