## Bass Reflex speaker

I’ve always been fascinated by the pyramids and their so-called “mysterious powers”. While messing around on a notepad one day, I found a unique ratio to them, which allowed me to find a way of dimensioning speaker boxes so that odd harmonics would not colour the sound and which allows good bass response from reasonably small speaker cabinets. I call this the

This is where the tweeter and midrange speakers are housed. The lower half of the speaker cabinet is perfectly square and is where the woofer fits. See the perfect 3d view of the speaker above.

This then is how the correct dimensioning is obtained. The “GP” ratio can be expressed mathematically as:

GP ratio = SQRT of 2 = 1.4142

The drawing we have made is my logo.

**GOLDEN PYRAMIDAL RATIO**, or the ‘GP’ ratio for short. Start off by drawing a horizontal line on a pad, say about 80 mm long. Take a drawing compass centred on this line and using a radius of about 30mm draw a circle. Now draw a line perpendicular to the first through the centre point till it bisects the circle. Label the four points on the circle ABCD starting from the l\h side or 9 'o clock position. Draw two lines from the top of the vertical line at point B down either side to A and C. You should now have a pyramid in the upper half of the circle (highlighted in red). Mirror the pyramid in the bottom half as you did in the upper half. Take the compass again and keeping the original dimension of the circle (*do not disturb this setting at all**during this whole process i.e. the 30mm*), draw an arc on side AB using point B as the centre and label this as E. Do the same on side CD on the lower pyramid using point C as the centre and label as F. Join the two arcs EF with a line which is parallel to BC. Rotate the page 45 degrees and you will see your speaker box. If you now divide the height BC by the width EB you get the figure of 1.4142. This is your “GP” ratio. Notice how the line EF that you have just drawn bisects the horizontal line AC, label this point as G. Using the compass centred at F, you will note that an arc cuts point G exactly,*if you haven’t disturbed the original setting of the compass, that is*. Using point C as the centre, draw an arc on BC and label as H. Draw a line between GH and you now have a narrow rectangular box in the upper half of your speaker.This is where the tweeter and midrange speakers are housed. The lower half of the speaker cabinet is perfectly square and is where the woofer fits. See the perfect 3d view of the speaker above.

This then is how the correct dimensioning is obtained. The “GP” ratio can be expressed mathematically as:

GP ratio = SQRT of 2 = 1.4142

The drawing we have made is my logo.