The HAAS Effect! Demonstration (use headphones)

[k4kyv]

The Haas effect is a psychoacoustic effect, described in 1949 by Helmut Haas in his Ph.D. thesis. It is often equated with the underlying precedence effect (or law of the first wavefront). Haas found that humans localize sound sources in the direction of the first arriving sound despite the presence of a single reflection from a different direction. A single auditory event is perceived. A reflection arriving later than 1 ms after the direct sound increases the perceived level and spaciousness (more precisely the perceived width of the sound source). A single reflection arriving within 5 to 30 ms can be up to 10 dB louder than the direct sound without being perceived as a secondary auditory event (echo).

I found this demonstration, using a monaural program source, no less than amazing.

http://www.youtube.com/watch?v=UQOkSF8auFc

[ke7trp]

Pretty cool Don.  I have used delay on home theatre.  Thats how they work.  Delay on each channel.  I did not understand what "A BOOT" means.  He kept saying that over and over. 

C

[W2PHL]

You can experiment with the Haas effect quite easily if you have a SDR receiver. Simply tune a conventional receiver to the same frequency as the SDR. If you have a mixer, SDR goes in one channel, old school receiver in the other. The slight demodulation delay in the SDR is perfect for the Haas trick. Works FB!
 I haven't tried this yet but I bet if you used separate antennas for the receivers, as in a diversity system, the effect in the headphones might be real interesting.

Phil

[W3RSW]

The QS1R and K3 and I think most other SDR and analog/DSP receivers have delayed binaural, quasi stereo, built in as switchable options.  No need to have separate receivers.

The I/Q 90 degrees phase difference is very similar effect to delay line audio of one channel vs. the other that Don referenced.
Interesting effect and does kind of have directional spaciousness.

In the QS1R's case, audio is generated directly on board with a T.I. PCM 1771 24 bit DAC with self contained stereo headphone amplifier. Very low latency compared with that from a sound card and decent specs. (98db SNR, 0.007% THD+N)

Elimination of fatigue to my ears is switching between regular single channel audio and the binaural mode, not listening to one or another exclusively.