How to Measure Speaker Dimensions
Speaker dimensions are calculated based on the effective vibration radius. That is, the diameter of the cone measured at the outer edge before it is pressed into the fixed rubber surround. By convention, speaker sizes are expressed in inches.
Most people use metric rulers. To determine the size in inches, measure the cone diameter in centimeters and divide by 2.54 (since 2.54 cm equals 1 inch).
Common Speaker Size Specifications
- 4-inch speaker: Diagonal distance between screw holes is 11.5 cm, adjacent hole spacing is 8 cm, and the speaker diameter is 10 cm.
- 5-inch speaker: Diagonal distance between screw holes is 13.5 cm, adjacent hole spacing is 9.5 cm, and the diameter is 13 cm.
- 6.5-inch speaker: Diagonal distance between screw holes is 15.5 cm, adjacent hole spacing is 11 cm, and the diameter is 16.5 cm.
- 4x6 inch speaker: Adjacent screw hole distances are 12.3 cm and 7.3 cm.
- 6x9 inch speaker: Adjacent screw hole distances are 16.5 cm and 11 cm.