What do glaciers and in-ear monitors have in common?

I just returned from an Alaskan cruise.  Much to my disappointment there was no penguin fishing and I never did see an Atlantic salmon, but other than these two let-downs, it was a great trip.  We visited Juneau, Skagway, and Ketchikan.  “Ketchikan” is a Northwest First Nation word meaning “many-jewellery-shops-for-tourists-near-the-cruise-terminal”.

It occurred to me during the trip when I was watching a glacier calve- a section of the ice breaking off and falling into the ocean- that glacier calving is very much like speech.  I am sure that everyone else on the cruise felt the same way.

When a sheet of ice falls off of a glacier, you first hear the high-frequency cracking as the ice breaks free, and then a moment later, you hear the low-frequency rumbling as it crashes into the sea (and hopefully not onto the ship).  This is a linear progression- first one sound, then another.  There is never a point when the two sounds coincide.  The low-frequency sounds are never simultaneous with the high-frequency sounds.

Well, this is identical to speech (in quiet).  We hear the lower-frequency sonorants (vowels, nasals, and liquids), and then in a different time period (a moment later) we hear the higher-frequency obstruents (affricates, fricatives, and stop consonants).

The auditory input of hearing a glacier calve is similar to that of conversational speech.

When it comes to music, this is characterized by simultaneous occurrence of sound, much like speech in noise. In music, this is called harmony.

Now let’s combine glaciers and in-ear monitors for musicians.  Although there is no definite research on this issue, in-ear monitor manufacturers market their devices based on the number of receivers.  A single receiver device (like most hearing aids) sells for less than one with more receivers. There is an underlying assumption that more is better (or at least more expensive) than fewer.  This doesn’t seem to be the case with hearing aids, however.

It is assumed that a multi-receiver device (such as most modern in-ear monitors for musicians) can route the transduction of high-frequency music energy through a different mechanism from the low-frequency transduction of music energy.  After all, a receiver whose diaphragm is waggling quickly for high-frequency sounds, can’t be as efficient as if it were waggling slowly for the lower-frequency sounds.  This seems to be the intuitively obvious reason for going with more receivers.  It is especially obvious for music where low-frequency bass notes occur simultaneously with the higher-frequency treble and harmonic notes.

Having said this, I have been unable to locate any research that demonstrates that this assumption is valid. If indeed there is some validity to this assumption, then the effect would be greater for music than for speech.  Speech in quiet, never  has low- and high-frequency components simultaneously, yet music does.

This is an experiment that needs doing. Not only would it provide support (if the assumption is true) that more is better than fewer (at least for music), but there may be some data supporting the contention that even for hearing aids (especially for speech in noise) more than one receiver may be the way to go.  Or perhaps not, if indeed, more is not shown to be better than fewer.

Just a thought and a possible future experiment to be done.  What a neat thing to do for a Capstone project!

 

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About Marshall Chasin

Marshall Chasin, AuD, is a clinical and research audiologist who has a special interest in the prevention of hearing loss for musicians, as well as the treatment of those who have hearing loss. I have other special interests such as clarinet and karate, but those may come out in the blog over time.

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Dan Schwartz

Maybe the high frequency sounds were still there, but you couldn’t hear them because of upward spread of masking? After all, you can’t hear the piccolo when the bassoons are playing.

“When a sheet of ice falls off of a glacier, you first hear the high-frequency cracking as the ice breaks free, and then a moment later, you hear the low-frequency rumbling as it crashes into the sea (and hopefully not onto the ship). This is a linear progression- first one sound, then another. There is never a point when the two sounds coincide. The low-frequency sounds are never simultaneous with the high-frequency sounds.”

Esther Sokol

So, you didn’t go on the boat excursion to spot bald eagles and sea lions and more in Ketchikan–with the boat captain/musician? A character. He pulled out his red! trombone to call the whales, ha. There are musicians there: weekly band rehearsals, with doctors, etc. All that said, this is a thank you for the Widex referral. I had the appointment with the area audi who has musician clients (who I know)! She heard you speak last year in Atlanta! I am trying to be hopeful that a Dream machine next week will turn out to be the successor to my Atlas aids. A coincidence: I was stopped in traffic recently near the audi location and chanced to notice a piano shop: Yahama Pianos! So while she doesn’t have one in her office, I could arrange to check out the latest-to-be adjustment two blocks away, hooray! Lastly, I performed at… Read more »