April 2016

Modes are an interesting, secret playground of engineers.  It seems like the idea of modes could be explained to first graders on a playground with a jump rope, but teachers in the US are probably too busy trying to make ends meet. Simply put, modes are naturally occurring motion or wave patterns (often sinusoidal) that are constrained to boundary conditions. A drummer can make at least  two distinct tones out of a drum based on where he strikes it. In the first image below, the drum is struck in the center, and the center vibrates up and down at the fundamental frequency. The perimeter of the drum head is constrained and thus is a zero crossing for any sine wave you can envision across the drum head. This fundamental frequency can be calculated from the tension and density of the drum head, if you are so inclined. The diameter of the drum head is 1/2 wavelength, as the perimeter of the drum is constrained. In the second figure, a second, higher order mode is created when the drum is struck well off center, and the pluses and minuses are vibrating in different directions.  Like many second order modes, this one is an octave above the fundamental, or twice the frequency. Additional modes are possible of course.  Evanescent modes are ones that are not supported by the structure and die out quickly, thus, if you somehow excited a tone that is 1.5X the fundamental on a drum head, it would be gone in an instant. How do I know this?  There is no way to constrain the perimeter of a drum head and get 3/4 of a wavelength.

Modes are not always vibrations and sinusoids.  Have you been to a gym where everyone in a line of people working out has a fan pointed at them? The air all converges at the wall behind the people, and there is very little apparent airflow for each individual.  You could make a wind mode by positioning fans on the walls of the gym to blow air clockwise, then they are not fighting each other, the breeze is stronger and less power is consumed.  Trying explaining this to a non-engineer at the gym is like beating your head against a wall.

Speaking of fitness, of you are overweight and out of shape, when you jog it is possible that parts of your body jiggle at harmonics of the jog frequency. Just an observation from someone that runs the Race for The Cure and other venues so I don't have to ever buy white tee shirts with ads all over them.

Speaking of waves, check John Shive's explanation of wave behavior, in a 1959 video produced by Bell Labs on our VSWR page.  It's worth 25 minutes of your time, or your money back.

# Vocal Fry

Another example of modes is in the way our vocal cords vibrate. Normal humans actually have three vocal modes (or registers) depending on how we tighten or relax our vocal cords.  Vocal fry is one of the modes, and it is becoming hard to ignore in the United States. Here is a great explanation of how it works:

Vocal Fry Explained

Personally, I sit on the "vocal fry is slightly annoying" side of things. It isn't that the sound of vocal fry bothers me so much, it's just that I notice and tend to focus on odd sounds rather than listen to what a person is saying. This NOT an efficient way to communicate, at least to me. No one ever said "Steve is a good listener" that I am aware of (but of course I might have missed such a compliment while I was thinking about something else).  You may have already heard me rant about sound sensitivity and people who were born with a special annoyance register for different sounds.  I am one of those misophonic people. Please don't scrape your plastic spoon in your yogurt cup near me if we are forced to eat together, if you want a ride back from the restaurant...

Young women are much more likely to use vocal fry than any other demographic. Some say this became popular when Brittany recorded Baby One More Time in 1999, when she was all of eighteen. It pays to be a Mouseketeer if you want to get into Pop Music!

Baby One More Time by Brittany Spears

Whether Brittany started it or not, there is plenty of debate about vocal fry, and in particular, whether it should be discouraged in the workplace. Funny thing is, it is almost a requirement for weather women on television to speak creak. Unfortunantely, if you search for "weather women" on youtube you are much likelier to observe men's obsession with their bodies rather than their voices, so I won't post an example of that here.

Almost all vocal fry criticism is aimed at young women:

We don't really see that much vocal fry among engineers, men or women, young or old. But we do see it a lot in entertainment! Maybe it is just a show business phenomenon? If you watch Keeping up with the Karadshians you will overdose pretty quickly on creaky voices.

Vocal fry has been around for a million years. If you don't believe that, maybe you will accept that Noah used vocal fry to communicate with some of his pets a few thousand years ago.  But when was it first recorded?  All three vocal registers were put into a song by Clarence Henry, in 1957. This is the best song to play to embarrass your teenage kids when they have friends over. Born in 1937 in New Orleans, you might still hear the Frogman sing his signature song at the New Orleans Jazz Festival which goes on around the end of April and the beginning of May every year. This is the kind of song that might have started in a nightclub, between acts, in order to give most of the band members a break.

I Ain't Got a Home, by Clarence Frogman Henry

By the way, it was not until 1977 that the color barrier was broken on the Mickey Mouse Club and it had its first African-American Mousketeer. Was this a coincidence that it happened over Walt Disney's dead body? Hmmmmm.....

An example of a man using vocal fry every day is Rush Limbaugh.  Go back and listen to him September 2007. Don't try to pay attention to his crude and cruel thoughts, just  try to listen to his radio voice. Note that like many DJs, he has turn up the bass on the audio to sound more manly.

September 2007

If you listen to him recently, you will notice he sounds like something from a horror show, the difference is vocal fry.  Below, Mr. Limbaugh gets started by comparing Hillary to a stripper, while his elderly white male listeners try to remember what it felt like back when they could more appreciate such thoughts of nude presidential candidates...

April 2016

The modal change in his radio voice might have something to do with losing his hearing, becoming more obese and mercifully getting closer to his final dirt nap.  More likely, he watches Keeping up with the Kardashians. That first audio sample was recorded just a month before the Kardashian show started.  QED, Limbaugh is a Kloset Kardashian Fan!

Pleasantly plump Armenian-American sisters pontificate in creaky voices

Check out the Unknown Editor's amazing archives when you are looking for a way to screw off for a couple of hours or more!

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