- For the high driver, the reflection point will be between the height of the driver and the ear. If the panel extends to at least the height of the higher of the driver or ear, the point will be covered. Note that, depending on driver height, this reflection point may be above or below ear height.
- For the low driver, the point will also be between driver height and ear height but the lowest driver in a speaker (apart from some single driver speakers and high mounted monitors) is usually below ear height, and well below ear height at that. Provided the panel extends to below the lower of ear or driver height, that point will also be covered.
These 'rules' can result in a fairly low height panel if there isn't much height difference between the drivers and the speaker is placed close to ear height. You will always get better results with a panel at least 3' high, simply because it provides more surface area and more absorption as a result. Ditto for having a reasonable width. The panels I made use 2 insulation batt widths and 1 batt height, so the absorptive area is 860 mm wide (a little under 3') and 1130 mm high (a little under 4'). I think that makes a reasonable minimum size panel though some people may need higher panels because of speaker size, especially for vertical line arrays.
David Aiken