Hearing (my) hearing: pitch perception

Here is an attempt to model the way musical pitches sound to me nowadays. I hear two notes in place of the usual one. This phenomenon is called diplacusis. It is one of the many consequences of the hearing loss resulting from my Ménière’s Disease.

In future posts I will explore how I perceive timbre, localisation, idiom, etc. The changes are quite profound.

Digital technology is enabling us to do something that was previously impossible: to present to people with ‘normal’ hearing how someone like myself with hearing loss actually hears. It reminds me of that Marcel Duchamp note in the Box of 1914: “One can look at seeing, but one cannot hear hearing”. We are now in a position where this is no longer true!

Marcel Duchamp: Box of 1914.

 The following experiment is quite raw, but nevertheless gives a pretty good idea of how the diplacusis works, at least within my singing range. Bear in mind that the hearing loss is severe in my right ear and mild in my left. The experiment ignores tinnitus, which also intrudes.

First I played a piano note at a given frequency (rounded to a whole number). I checked with a fine pitch meter that the tuning was correct before proceeding.

I then blocked my right ear and sang the note I heard, checking against the pitch meter. The left ear (my ‘good’ ear) gives generally very accurate pitch, with a few slight deviations towards the lower and upper ends of my singing range.

I then blocked my left ear and performed the same exercise using my right. The following chart shows the pitches, and the difference. Pitch was not the only difference: for example, the perceived amplitude was considerably softer  from 138Hz downwards and fell away steadily. This is a typical hearing loss pattern in Ménière’s.

NoteFrequency in Hz (rounded)Left Ear difference (Hz)Left Ear Perception (Hz)Right Ear Perception (Hz)Right Ear difference (Hz)
 F#2/Gb2 92-19186-6
 G#2/Ab2 103-1102100-2
 A#2/Bb2 116-2114110-4
 C#3/Db3 138138132-6
 D#3/Eb3 156156151-4
 F#3/Gb3 185185180-5
 G#3/Ab3 207207204-3
 A#3/Bb3 233233229-2

What we can see quite clearly from this is that my diplacusis is active at all frequencies, but also variable. For some pitches, it is more than a semitone! For others, rather less. I hear these two pitches combined, with the out-of-tune one being softer than the in-tune.

What does this sound like? Here is my attempt to emulate this using appropriately detuned piano sounds. The ‘in tune’ note is louder than the ‘out of tune’ note, to reflect the hearing loss. The combination is pretty accurate, though, and by listening to this with by bad ear blocked I can get a better idea of what a normally hearing person would hear. There is a scale first, then the Bach Prelude No. 1:

 I then tried the right ear only wearing my new GNResound hearing aid. What is fascinating is that this does not remove the diplacusis, but it does reduce it and. strangely, makes it into a smooth deviation, getting larger as the pitch descends.

I’m not entirely sure what to make of all this, but it is interesting!

2 thoughts on “Hearing (my) hearing: pitch perception”

  1. What a fascinating experiment – though my sympathies for what much be an exquisitely difficult and painful experience for a musician.

    I note that the tuning differences make the scale painfully unlistenable to me, but hearing the notes in the context of the Prelude caused my brain to more easily focus on the in-tune notes, with the detune reduced to the kind of warbling you get on an old cassette. I guess the more notes I hear together (or in musical consort – these are arpeggios my brain is converting into chords) the less I can focus on the variation between any given two.

    1. Thanks David.

      Yes, that is exactly what happens when I listen to music. I hear “past” the out of tune notes, using my aural imagination to fill in what it should sound like.

      However, that is quite an effort and I tire of it rapidly, so I don’t listen to music so much these days.

Leave a Reply

Your email address will not be published. Required fields are marked *