sound part ii how do instruments make sound? well we already know that sound is a vibration. we have...

Sound Part IIHow do instruments make sound?

Well we already know that sound is a vibration. We have learned what sound looks like, and how sound changes amplitude and pitch.

So, how do instruments make sound? How do they change the pitch, and amplitude of the sound that they create?

There are four different types of instruments:

Percussion Strings

Brass

Winds

Although they all look and sound different, they all have one thing in common, they vibrate.

But where they are different is how they vibrate and how the instrument resonates the sound.

When an instrument resonates a sound, the material it is made from vibrates a certain way, producing a particular tone, or pitch.

Different materials will resonate in different ways. Such as brass and steel. Although they are both metals, they sound very different when they vibrate.

The same is true for organic material such as wood. Organic means it is grown. Wood is a very popular material to make instruments out of…

http://www.alliedlutherie.com/weekly5.htm

And you guessed it… different types of wood resonate differently, thus making different sounds.

http://www.alliedlutherie.com/weekly5.htm

So if I make two guitars exactly the same, but one made of mahogany and the other cherry, they will have subtle differences in the way they sound.

http://www.fretnfiddle.com/pages/fretwork.htm

So what is making the vibration with in the instrument itself? Well each instrument family works in a different way.

Let’s look at the percussion family first. When we hit the top of the drum we make the drum head vibrate, and it creates a sound.

This model shows us how the drum head vibrates after you strike it with a stick, or your hand.

Dr. Dan Russell Acoustics Animations

As the head moves up and down it creates a deep sound. The sound resonates along the wood barrel, and the sound comes out the bottom.

Dr. Dan Russell Acoustics Animations

Some drums can change there pitch by striking the head in different places. But they are limited as to what sounds they can produce.

Dr. Dan Russell Acoustics Animations

The String Family

Hitting a drum with a stick makes a great sound. However hitting a string instrument will not give you the same result.

Striking or hitting is only one way to create a sound.

The string family uses a method of rubbing or plucking to produce beautiful sounds.

Violins and Cellos are two instruments that are played by rubbing a bow over steel strings.

A guitar is not played with a bow, instead we use a pick to pluck or strum the strings.

Once the string is vibrating, the sound resonates into the wooden base around it. The sound bounces around the inside and comes out of the hole in the center of the instrument.

www.phys.unsw.edu.au/music

Note these two little pieces of wood. They are called a bridge. They are located at each end of the instrument.

Bridge

www.phys.unsw.edu.au/music

It is the job of the bridge to keep the string off of the guitar base. This allows the string to vibrate with out rubbing on the instrument.

Bridge

www.phys.unsw.edu.au/music

With out the bridge the string would vibrate for only an instant before the friction would stop the vibration.

Bridge

www.phys.unsw.edu.au/music

The string instruments can change their pitch to any note you want to play, simply by pushing down on a string on the neck of the instrument.

When you push down on the string you shorten its length, thus making the string vibrate at a faster rate.

The faster the string vibrates the higher the pitch. The slower the lower the pitch.

So in other words, when you push down on a string you shorten the length so it vibrates faster, thus making the sound a higher in pitch.

Winds and Brass

Reed instruments, like the saxophone, or clarinet use a “reed” to create the vibration.

The reed vibrates when the musician blows through it.

www.phys.unsw.edu.au/music

You hit the percussion instruments, pluck, strum, or bow string instruments; and you blow through a reed to play a saxophone. So how does a flute make noise?

Flutes use the air itself to vibrate.

When the musician blows into the bore of the flute. It causes the air to compress and vibrate, as it alternates going in and out of the flute.

Bore of the flute

The air jet alternates going in and out of the bore.

Players Lips

www.phys.unsw.edu.au/music

Wind instruments change their pitch by covering holes in the pipe. When the holes are covered it shortens the length of the pipe that the vibration can resonate in.

Open Closed

www.phys.unsw.edu.au/music

The shorter the length of the pipe used, the higher the pitch.

Closed

www.phys.unsw.edu.au/music

The longer the length of the pipe, the lower the pitch.

www.phys.unsw.edu.au/music

www.phys.unsw.edu.au/music

Look at the difference between the wave lengths, of the two flutes. Which one has the lower pitch?

Lower

Brass

No reads to blow, no strings to pluck, no skins to hit, nothing but brass. Musicians just don’t blow into a trumpet... They Buzz!

A buzz of the lips that is. When the musician buzzes his lips into the mouth piece it creates the vibration. The vibration then resonates throughout the instrument.

Brass instruments change their pitch much the same way wind instruments do. They change the distance the vibration travels before it leaves the end.

Most brass instruments have a system of valves that shorten or increase the path of the sound on its way out.

Again the shorter the distance the higher the pitch. The longer the lower!

Trombones use a slide that increases and shortens the distance within the tubes.

When you put all the instruments together it sounds something like this...

Using these words tell how each of the following

instruments produces its vibration

Its time to play...

Traditional Indonesian Drum

The alboka is a double hornpipe or clarinet native to the Basque region of Northern Spain.

Two European pan flutes

Oh look... There is the bow!

shofar is a ram's horn that is used as a musical instrument for religious purposes. It is used on Judaism's high holy days of Rosh Hashanah and Yom Kippur. The shofar originated in Israel for Jewish callings.

The hammered dulcimer is a stringed musical instrument with the strings stretched over a trapezoidal sounding board.

A Bell is usually an open-ended hollow drum which resonates upon being struck. The striking implement can be a tongue suspended within the bell, known as a clapper.

The Ghaychak or Ghijak is a round-bodied musical instrument with 3 or 4 metal strings and a short fretless neck

The bugle is one of the simplest brass instruments; it is essentially a small natural horn with no valves. All pitch control is done by varying the player's embouchure, since the bugle has no other mechanism for controlling pitch

Steel Drum originating in the twin island state of Trinidad & Tobago located in the Caribbean.

CriteriaOver and

Above+ 1-5

Extra Points

Exceeds Standards

Meets Standards

Below Standards

My Mom and/or Dad

did it

Creativity60%

Stradivarius Reincarnate+ ______pts

Les Paul Wept60 pts

Yamaha couldn’t’ have built it better59-50 _____ pts

Rocks in a coke bottle...

a timeless tradition

49-1_____ pts

And they did a great job too!

Zero pts

Quality of Sound 20%

Perfect Pitch+ ______pts

Finely Tuned20 pts

Eight notes make an octave

19-15___ pts

Slightly out of tune

14-1____ pts

Wow, and it sounds great

too! Zero pts

Quality of Work 20%

Made by a Grandmaster

Craftsman+ ______pts

Exquisite Workmanship

20 pts

Looks Great19-15__ pts

The paint was still wet

14-1____ pts

Dad did a great job with the

band sawZero pts

ManualOptional 10%

What can I say, perfection squared

+ ______pts

Letter perfect10 pts

Short and sweet9 pts

Printed off of the web or poorly

written8-1 _____pts

Embossed typeface, nice

touch MomZero pts

Home Work: Go home and look at your instrument, does it have what it needs to have? Does it have a resonance chamber? What vibrates? What amplifies the sound? Can you change the pitch? Can you change the tone? If you can’t...

SOUND PROJECT IS DUE THURSDAY

DECEMBER 17TH

Additional Images from ???

Used with permissionAnd

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Teacher Lecture Notes

This is a straight forward introduction to sound. Follow up this lesson with tuning forks. Allow students to explore with them after they have been instructed how to use them. Ask the question: How can you hear it best? (pointing the tines at your ear) How can you hear it the longest? (Placing the base of the fork on your skull) Can you hear through your elbow? (Place the base of the fork on the big bone in your elbow, while with the connected arm, place a finger in your ear.) Have fun!!!

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