I listened to the example at http://www.srmathias.com/huggins-pitch/ and I hear the tones. But a deeper inspection shows that taking the differences of the magnitude responses after FFT results in quite big deviations, even > 10 dB. So it seems that the allpass delays are not really allpasses without influencing the magnitude response.
2016-06-26 3:14 GMT+02:00 Alan Wolfe <alan.wo...@gmail.com>: > Oh nuts. I guess my understanding of the effect was incomplete. > > I'm not using an all pass filter no, I'm just delaying the entire signal. > > Thanks you guys, I'll try with an all pass. > On Jun 25, 2016 4:43 PM, "Jon Boley" <j...@jboley.com> wrote: > > Alan, > > I'm on a phone and don't have headphones on me, so I haven't listened to > your examples yet. However, it sounds like you are applying a broadband > delay. > > Huggins pitch typically works when you apply a narrowband delay (i.e., > with an allpass filter). The pitch corresponds to the frequency that is > delayed. > > So, can you clarify - are you using an allpass filter to delay specific > frequencies? > > - Jon > > > > > On Jun 25, 2016, at 4:15 PM, Alan Wolfe <alan.wo...@gmail.com> wrote: > > Hey Guys, > > I'm trying to make an implementation of the Huggins Binaural Pitch > illusion, which is where if you play whitenoise into each ear, but offset > one ear by a period T that it will create the illusion of a tone of 1/T. > > Unfortunately when I try this, I don't hear any tone. > > I've found a python implementation at > http://www.srmathias.com/huggins-pitch/, but unfortunately I don't know > python (I'm a C++ guy) and while I see that this person is doing some extra > filtering work and other things, it's hard to pick apart which extra work > may be required versus just dressing. > > Here is a 3 second wav file that I've made: > > http://blog.demofox.org/wp-content/uploads/2016/06/stereonoise.wav > > The first 1.5 seconds is white noise. The second half of the sound has the > right ear shifted forward 220 samples. The sound file has a sample rate of > 44100, so that 220 sample offset corresponds to a period of 0.005 seconds > aka 5 milliseconds aka 200hz. > > I don't hear a 200hz tone though. > > Can anyone tell me where I'm going wrong? > > The 160 line single file standalone (no libs/non standard headers etc) c++ > code is here: > http://pastebin.com/ZCd0wjW1 > > Thanks for any insight anyone can provide! > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp > > > _______________________________________________ > dupswapdrop: music-dsp mailing list > music-dsp@music.columbia.edu > https://lists.columbia.edu/mailman/listinfo/music-dsp >
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