Description

The radiation behavior of different full range drivers is investigated. Drivers were measured at angles from 0° to 90° in 10° steps. Magnitude responses are 1/3 octave smoothed to improve visibility of general trends in radiation patterns.

All drivers were measured in-room in different closed prototype enclosures. The drivers have not been equalized.

Measurements were taken with REW 5.01b22/b23. Measurement mic: EMM-6, calibrated. Mic distance: 1m. All impulse responses are gated at 4.5ms to obtain quasi-anechoic results; resulting frequency resolution is about 200Hz. Speakers were placed on a block of Basotect.

Measurements

1. Dayton PS220-8 (8", with whizzer and phase plug)

2. Markaudio Alpair 7.3 (4", no whizzer)

3. SEAS FA22RCZ (8", with whizzer)

4. Tymphany TC9FD18-08 (3.5", no whizzer)

5. Visaton BG20 (8", with whizzer)

Discussion

All drivers have widely varying magnitude responses on- and off-axis. The responses off axis change rapidly in shape and level. As a result all drivers need to be equalized, preferably at angles with low angular response differences in order to achieve the smoothest response within the listening window. This would be 0° for all drivers (see this comparison). The listening window is generally small as radiation becomes very directional with increasing frequency.