Which is the best music instrument for my hard of hearing child?

From time to time, I receive telephone calls and emails from the parents of hard of hearing children asking about which musical instrument their children should play.  Actually I receive this type of communication almost weekly!

This is really two questions in one- (1) which is the best instrument that would allow them to play, monitor, and gain some proficiency in, given a high frequency hearing loss and (2) which instrument would not further damage my child’s hearing status.

I usually try to answer the second question first.  It’s an implicit question and usually is not explicitly asked but is at the back of the mind of most parents.  And the answer is that your child is no more, nor less, susceptible to further hearing loss from music than someone with normal hearing.  The same precautions should be considered for your child as any person playing music.  At this point I generally talk about the series of flat attenuation hearing protectors such as the ER-15 Musicians’ Earplugs.

But back to the first question….  Let’s assume that the child has a “typical” bilateral high frequency hearing loss.  The choice then is a musical instrument that has all of it’s fundamental, and most of its harmonic range below 1000 Hz.  Recall that harmonics will fall in a higher frequency range than the fundamental (the actual note name), and depending on the instrument, this may be at integer multiples of the fundamental (e.g. stringed instruments, saxophone, bassoon, oboe) or at odd numbered multiples of the fundamental (e.g. clarinets, trumpets, and other brass).

If the harmonics fall in a region that is at 3x, 5x, 7x,.., the fundamental then we call this a quarter wavelength resonator instrument- brass instruments are notorious examples.  And if the harmonics fall in a region that are integers of the fundamental,  (2x, 3x, 4x,…) then these instruments are called half wavelength resonator instruments- stringed instruments are typical examples of this.

Well, why the physics lesson?  If the instrument functions as a half wavelength resonator the harmonics are more tightly packed together and there are more energy cues within a given range.  If a trumpet and a viola both play C (262 Hz fundamental) then the trumpet essentially generates 1/2 to 1/3 of the harmonic energy that the violin does.  The following chart shows this phenomenon for a 250 Hz fundamental (I’ve rounded numbers down for convenience):

For a viola, the playing of a 250 Hz fundamental would generate three harmonic (cues) in the region of 1000 Hz or below (500 Hz, 750 Hz, and 1000 Hz).  In contrast, a trumpet playing the same 250 Hz fundamental note would only generate one harmonic below 1000 Hz- namely 750 Hz.  The one half wavelength resonator viola would generate three times the harmonic cues which are more tightly packed into the hard of hearing child’s near normal auditory range.

So…

Question: What is the best instrument for a hard of hearing child?

Answer:  An instrument that generates sufficient bass music and which is a one half wavelength generator.  This includes the cello and bass stringed instruments, the saxophone and bassoon woodwind instruments, and believe it or not, the clarinet.

It turns out that the clarinet functions as a quarter wavelength resonator instrument for only the lower register but functions more like a stringed instrument in its upper register.  And a clarinet is a lot easier to carry home from school that a saxophone, cello, or bass!  This can be easily verified using your real ear measurement system when someone is playing the clarinet.

I must admit to a bit of bias since I am a clarinet player, but it does share the two important properties- tightly packed harmonics where it counts (higher register) and its highest note (high C) is around 1000 Hz.  And perhaps of greatest importance, it’s easy to carry home!