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Topic: Audibility of difference signal (Read 20660 times) previous topic - next topic
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Audibility of difference signal

Reply #25 –
So I made a few trials with my new soft :

Quote
We can localize 500hz sound to 1-2deg asimuth angle in forward direction. Thats around 13usec interaural delay

- First, to localize with sine is not the best method  : the "bonger", a 15 sines transient gives much better results.
- 2 samples interaural delay is easy to detect, 1 sample is a bit more difficult (that is 22us)

In that case the signal difference is much easier to hear even at -30dB (on headphones) than to ABX the original signals.

So even for this kind of "distortion", the difference signal method seems for me more efficient.
I then tried with other forms of distortions : imbalance, phase response, filters, THD, frequency response, in every case the difference signal was much easier to detect than to ABX both signals.

The idea of Kees seems to be a good one.
If somebody has ideas about forms of distortion that should give another result, let us know.

Audibility of difference signal

Reply #26 –
We should decrease the volume until the difference signal is no more audible, while the original are still audible, then try to ABX  again the interaural delay.
Maybe starting with a bigger delay would help in this case.

Audibility of difference signal

Reply #27 –
Quote from: Pio2001 on
We should decrease the volume until the difference signal is no more audible, while the original are still audible, then try to ABX  again the interaural delay.
Maybe starting with a bigger delay would help in this case.

Good idea. It seems that the choice of stimulus might be important too. See the quote below. I suppose music could be considered "broadband noise" in this respect

"In response to 500 Hz tones, the just noticeable difference (JND) in ITD (Interaural time difference) is nearly constant at 10 usec as a function of ITD (Domnitz and Colburn, 1977). For broadband noise, however, the JND is three to four times larger and systematically increases as ITD increases (Mossop and Culling, 1998).
Previous studies have shown that ITD acuity near the midline is consistent with the responses of single ITD-sensitive inferior colliculus (IC) neurons (Skottun et al., 2001; Shackleton et al., 2003). Because IC neurons are tuned to a wide range of ITDs, application of the lower envelope hypothesis to ITD discrimination predicts uniform acuity for all ITDs. However, this contradicts the observation that ITD JNDs in response to broadband noise systematically increase with ITD (Mossop and Culling, 1998)."

source:
A Physiologically Based Model of Interaural Time Difference Discrimination
Kenneth E. Hancock and Bertrand Delgutte
The Journal of Neuroscience, August 11, 2004

Audibility of difference signal

Reply #28 –
Quote from: jlohl on
Quote
We can localize 500hz sound to 1-2deg asimuth angle in forward direction. Thats around 13usec interaural delay
- First, to localize with sine is not the best method  : the "bonger", a 15 sines transient gives much better results.
- 2 samples interaural delay is easy to detect, 1 sample is a bit more difficult (that is 22us)

In that case the signal difference is much easier to hear even at -30dB (on headphones) than to ABX the original signals.
So even for this kind of "distortion", the difference signal method seems for me more efficient.
Could you post your bonger samples and their A-B that you ABXed? I'd like to listen.
It really really did sound different. Not in a placebo way.
 

Audibility of difference signal

Reply #29 –
Quote
Could you post your bonger samples and their A-B that you ABXed? I'd like to listen.

I simply used the Distrorder software.
Sine and bonger generator, interaural delay, A minus B function, ABX (not complete), .wav recorder are all included. It's free but it works only on windows. If you don't use windows, I can record the bonger and A-B. Just let me know.