Loudspeaker Directivity
An Experimental Survey
Loudspeaker Directivity is the extent to which loudspeakers beam the sound towards the listener instead of broadcasting it in all directions around the room. Loudspeaker Directivity is the single most important loudspeaker property for 3D audio with crosstalk cancellation (XTC), since room reflections directly degrade the level of crosstalk cancellation. There is a very high correlation between loudspeakers with high directivity and high XTC levels. Consequently, the 3D3A lab is conducting detailed measurements of the directivity of various loudspeakers measured in the lab's anechoic chamber. At present the database contains the measured directivity data for six loudspeakers:
1. Ascend Acoustics CBM-170
2. GedLee Nathan
3. Genelec 8030a
4. Manger Sidekick
5. Spendor SA1
6. Tannoy Definition DC6i (Concentric)
Click on the above links to view the directivity measurements of a given loudspeaker.
The GedLee Nathan loudspeaker had the highest measured directivity of the above listed six loudspeakers tested so far.
If you know of any loudspeakers that may have higher directivity than the current winner of the directivity contest ( the GedLee Nathan) please inform the 3D3A Lab. We will try to acquire these loudspeakers and measure their directivity. (While many horn-based loudspeakers have high directivity, many of them suffer from strong spectral coloration, so we will not seek to test horn loudspeakers unless they are reported to have good frequency and impulse responses.)
Notes on the measurements: The directivity measurements were carried out in the anechoic chamber of the 3D3A Lab using a B&K Microphone Type 4189 placed 1.6 m from the loudspeaker being tested, and at the same height as that of the center of the loudspeaker's tweeter. The loudspeaker was placed on a rotation stage, which was turned by increments of 5 degrees. The data reduction and plotting were carried out using custom software developed at the 3D3A Lab. The measurements were taken by Lukasz Mosakowski under the direction of Prof. Choueiri.