Princeton University  


Loudspeaker Directivity

An Ongoing Experimental Survey

Research Sponsored by the Sony Corporation of America


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.

A quantitative knowledge of loudspeaker directivity is also important for our ongoing Sony-sponsored research on head-externalization of 3D sound through headphones since some the relevant techniques rely on emulating the radiation characteristics of real loudspeakers.


The following is a list of the loudspeakers measured to date, in order of decreasing directivity:

Click on a plot or the name of the speaker to see the full measurement data and related info.



Manufacturer website

Directivity Ratings and Data

Horizontal directivity index: 4.25 dB
Vertical directivity index: 4.06 dB
Directivity index: 5.28 dB

View directivity index plots
Download directivity data

Horizontal Directivity

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Vertical Directivity

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Horizontal Directivity
Vertical Directivity

1. Sanders M11 (Electrostatic)



2. Quad ESL 57 (Electrostatic)


3. Janzen ZA2.1 (hybrid electrostatic)


4. GedLee Nathan (Waveguide/Dynamic)


5. Tannoy Definition DC6i (Concentric/Dynamic)


6. Manger Sidekick (Single bending wave transducer)


7. Genelec 8030a (Dynamic)


8. Spendor SA1 (Dynamic)


9. Ascend Acoustics CBM-170 (Dynamic)



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. These measurements have been taken by Lukasz Mosakowski, Tim Matchen, Joe Tylka, Rahulram Sridhar, Tony Jin, and Gianfranco Colombi under the direction of Prof. Choueiri.

If you know of any loudspeakers that may have particularly high directivity please inform the 3D3A Lab. We will try to acquire these loudspeakers and measure their directivity.

Coming soon on this page, directivity measurements for the following speakers: Avantgarde Solo (horn/concentric), OMA mini (horn/dynamic), Sanders M10 (electrostatic), and many others.