Subject: AW: How good is inter-aural frequency or pitch matching in normal humans? From: Mathias Dietz <mathias.dietz@xxxxxxxx> Date: Tue, 30 Jun 2015 08:58:51 +0200 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Jan, dear List, This is a cool and interesting observation. We have recently finished a study on bilateral CI subjects from which two things may be relevant for you: 1) The electrodes that provide the same frequency band (typically electrodes with the same number) are nicely place-pitch matched in all subjects we measured. The maximum deviation is 1 electrode. This is presumably better than the actual place-of-stimulation match (which was not measured directly). We hypothesize that acclimatization / adaptation to the clinical electrode-frequency map is the reason. This is not in contradiction with your report, because we are not accurate enough to detect a difference corresponding to a semitone. 2) ITD sensitivity is not optimal for pitch matched electrodes. There are subjects which have no measureable ITD sensitivity for pitch matched electrodes but >80% correct if you move 4-5 mm away. >From the above I would say that there is no contradiction between the observation of your conversation partner and the assumption “that there has to be a good alignment of frequency channels going into the binaural centers of the brainstem”. Pitch does not require this alignment nor has it been shown to be a very good indicator. That still does not explain the different interaural pitch percept for your acoustic hearing listener so I pass on to the next… Best, Mathias -- Dr. Mathias Dietz Medizinische Physik and Cluster of Excellence Hearing4all Universität Oldenburg D - 26111 Oldenburg Tel. (+49) 441 798 5472 Email: mathias.dietz@xxxxxxxx WWW: http://medi.uni-oldenburg.de/52096.html Profil: http://medi.uni-oldenburg.de/members/mathias.dietz Von: AUDITORY - Research in Auditory Perception [mailto:AUDITORY@xxxxxxxx Im Auftrag von Jan Schnupp Gesendet: Montag, 29. Juni 2015 15:45 An: AUDITORY@xxxxxxxx Betreff: How good is inter-aural frequency or pitch matching in normal humans? Dear List, I have had a conversation with a musically keen retired physicist who assured me that when he holds up a tuning fork to one ear he hears the pitch of the tuning fork about a semitone lower than at the other ear. I had to say that I found that surprising. We always assume that there has to be a good alignment of frequency channels going into the binaural centers of the brainstem for example, and much effort is invested in trying to improve "inter-aural pitch matching" for cochlear implant patients. But I have to admit I know of no formal studies that have actually measured how good inter-aural pitch matching would be for normally hearing subjects, and whether a difference of a semitone (after all, only a few % in absolute terms) is absurdly large or within the expected human variability. Would any of you know of any papers that have looked at this? Best, Jan -- Prof Jan Schnupp University of Oxford Dept. of Physiology, Anatomy and Genetics Sherrington Building - Parks Road Oxford OX1 3PT - UK +44-1865-282012 http://jan.schnupp.net