The discussion on the possibility of having a real stereo effect by placing a stereo microphone inside a parabolic dish has never found a definitive answer. Or rather, it has been concluded that the main subject is exactly in focus in the central position (therefore with a monophonic effect), while the surrounding “soundscape” is recorded with a stereophonic effect. Together with Prof. Gianni Pavan (CIBRA / Università di Pavia) we asked ourselves what would happen if two mono parabolic microphones were positioned, each with a distinct signal on its channel. Obviously the answer is simple from a theoretical point of view: each of the two parabolic microphones sends the signal on the channel to which it is addressed. But what is the practical stereophonic effect that results? To try to understand the effects, we assembled a set with two parabolic dishes with an effective diameter of 32 cm for each element, 10 mm Omni directional capsules were used. We have achieved an effect very close to the double of the spacing used for binaural recordings.
Here are two examples:
in the first file, on a windy evening (you can hear the wind in the leaves), a Tree pipit Anthus trivialis song, from the minute 2:13 to the minute 2:24, on the back of the dishes, first a motorcycle passes from left to right, immediately after a vehicle passes from right to left;
in the second file Tree pipit Anthus trivialis song, there is no trace of wind, on the back of the dishes there is a chorus of crickets (Gryllus campestris), while in front of the microphones some flies fly between the two microphones.
measures in millimeters
Comment by Rob Danielson U.S.:
Definitely true stereo.
The shared imagery between the two channels has spaced omni like qualities.
~ strong foregrounding
~ Tree pipit tone seems very accurate to me.
~the phasing with the sustained insects at 10 and 2 o’clock adds depth
~there’s low end drop off under 200 Hz ,When I boosted under 200 Hz the image got wider
Comment by Vicki Powys, Australia:
That set up seems to work very well, at least for a single species in focus, lots of detail there plus the sense of stereo so that the breeze sounded real rather than just noise. What struck me was the realism of the bike and car seeming to be right behind me! The crickets were dulled somewhat, being behind the mics and dishes.