Category Archives: Acoustics

“From the Mississippi Delta to South Australia,” by Alpha Unit

Don Morrison salvages old galvanized sheet metal from sheds and farms throughout Australia. The older the metal, the better, he says; some of this reclaimed metal is over 100 years old. He takes it to his workshop in Summertown, South Australia, where he fashions it into metal-bodied acoustic guitars. Of his material he says:

Galvanised iron, or Galvo, is now an integral part of the Australian landscape and it seemed natural (to me at least!) to try it in a resonator guitar. The result is a truly awesome sound, very loud but with a surprisingly rounded tone. I should call it the Transcontinental guitar – genuine Aussie material, genuine Delta sound!

That “Delta sound” refers to Delta blues, one of the early forms of blues. This music arose in the Mississippi Delta, which, despite its name, is not a part of the actual delta of the Mississippi River. Rather, it is located in the northwestern part of Mississippi, bounded by the Mississippi River on the west and the Yazoo River on the east.

This alluvial floodplain is one of the most fertile agricultural regions in the world. It was here that Black field hands created the music we call blues, using chants, “field hollers,” and songs to make their work go faster. Ed Kopp writes:

While blues lyrics often deal with personal adversity, the music itself goes far beyond self-pity. The blues is also about overcoming hard luck, saying what you feel, ridding yourself of frustration, letting your hair down, and simply having fun.

The best blues is visceral, cathartic, and starkly emotional. From unbridled joy to deep sadness, no form of music communicates more genuine emotion.

Although the sound of a resonator guitar is iconic to blues, blues musicians didn’t start out playing the resonator. The earliest bluesmen played an instrument called the diddley bow.

The diddley bow has been called “the godfather of American roots instruments.” It is the simplest form of the guitar and is the first type of slide guitar used in America. It was very easy to make, consisting of a string of wire tensioned between two nails on a board. A bottle or can wedged under the wire would create tension for pitch. The player would pluck the string while sliding a piece of metal or glass on it to produce notes.

One-stringed bow instruments date back to antiquity and developed in various parts of East Asia and in the west coast and Congo regions of Africa. Rural Black Southerners crafted these instruments and taught their children to play them. They would sometimes build one-stringed zithers on a wall, “with a strand of baling wire, two thread spools for bridges, and a half-pint whiskey bottle for a slider,” as slide guitar player Big Joe Williams recalled to one researcher.

Boys who showed promise on the diddley bow could graduate to a guitar if they were lucky enough to get a hold of one. Musicians such as Lightnin’ Hopkins, Elmore James, and B. B. King all first learned to play on the diddley bow.

Once musicians could afford guitars they quickly abandoned the diddley bow. And when the resonator guitar came along, they had a way to present their music to even larger audiences. The resonator, with its crisp metallic ring, created the signature sound of Delta blues. When you listen to Charley Patton, Robert Johnson, Son House, or Bukka White – among many others – you’re listening to Delta blues. Others, such as John Lee Hooker and Muddy Waters, started out playing Delta blues.

This Delta sound is what craftsmen like Don Morrison aim to re-create. His resonators, like the very first of their kind, have built-in amplification – a feature that came about by demand.

Back in the early 1920s guitar players performing with dance orchestras couldn’t really stand out from the other players. Since there were no amplifiers, guitars were considered a part of the rhythm section instead of lead instruments. A vaudeville performer and promoter named George Beauchamp wanted an acoustic guitar that could play melodies over the orchestral instruments. He turned to John Dopyera, a violin repairman and luthier whose workshop was close to Beauchamp’s Los Angeles home.

John Dopyera and his brother Rudy experimented with various designs to achieve a smooth and balanced amplified sound and decided to mount cone-like aluminum resonators, similar to speaker cones, inside a metal guitar body. Dopyera found that using three smaller cones instead of one big cone gave the guitar the sound he’d been looking for. The tri-cone resonator guitar was born.

Beauchamp was impressed with the new design and proposed a business venture to Dopyera, who agreed. They created the National String Instrument Corporation in 1927. National guitars quickly became best sellers. The company soon created a wood-bodied model.

There were differences, though, between Beauchamp and Dopyera. Beauchamp preferred a single-cone resonator, not only because it was louder but because it was cheaper to make. For Dopyera, excellent sound and quality were top priorities. The two men finally went their separate ways when Dopyera found out that Beauchamp had claimed the patent for the single-cone resonator. In 1928 Dopyera quit National, with the intention of manufacturing his own single-cone resonator. John and his brother Emil formed the Dobro Manufacturing Company (named for the Dopyera Brothers).

Because National held the patent for his single-cone resonator, John Dopyera had to develop a new style of single-cone resonator. The single biggest change that he made was to the bridge of the guitar.

On a standard acoustic guitar, the bridge is glued directly to the top of the guitar. It has several functions: it holds the strings securely, sets the spacing of the strings, and acts as an external brace to the guitar body. Its other important job is transferring vibrations from the strings to the soundboard of the guitar. On a resonator guitar, the bridge is a part of the resonator cone.

For single-cone resonators, the cone has either a “biscuit” bridge or a “spider” bridge.

The National resonator used a biscuit cone, which is convex (pointing outward). Inside the tip of the cone sits a round wooden bridge (the biscuit), and set into the bridge is a small piece typically found on a guitar bridge – the saddle. The saddle keeps the strings elevated at the preferred height above the fretboard. The saddle transfers the string vibrations to the bridge and the bridge transfers them to the cone. The cone in turn vibrates, moving the air volume inside the guitar out through the sound holes.

For his Dobro resonator, John Dopyera decided to make his cone concave (pointing inward) and used an eight-legged “spider” bridge which straddled the cone. The vibrations from the strings travel from the saddle and down the spider “legs,” providing the cone with eight contact rods for vibration. The result is a loud, full-bodied tone.

Resonator guitars became popular in both blues and bluegrass. Dobro-style guitars, especially wood-bodied ones, were preferred by many bluegrass players. Blues players tended toward National-style tri-cone resonators. But plenty of guitarists break with tradition and use resonators in their own preferred ways.

Players liked resonators because, being louder than regular acoustic guitars, they could play for larger crowds in rural areas that didn’t have electricity for amplifiers. Street musicians, who had to set up without amplifiers, liked resonator guitars for the same reason.

Don Morrison makes both single-cone and tri-cone resonators. For his popular Rustbucket model, he says he flattens the corrugated steel sheets by walking on them so he can fit them through his ancient set of sheet metal rollers. Some of this old metal will still bear the makers’ stamps: Trademark Redcliffe, for example, or Lysaght Queen’s Head Australia or Emu Best. You’ll see these stamps on the backs of his guitars.

On some Rustbuckets he takes naturally weathered Galvo and adds an artificially rusted cone and sound holes, giving the guitar a distinctive, vintage look.

When he isn’t building resonators, Don Morrison is performing music, often Delta blues. During the ’90s his band, The Elmores, played blues classics by Elmore James and John Lee Hooker. He and his band Prawnhead are also a part of a “roots revolution” in popular music.

We honed our style on the streets and markets of Adelaide. We found the faster we played, the more money we made. We don’t play blues or folk, we don’t play country, we don’t play bluegrass, nor do we play rockabilly. But we play a mixture of all of those. We call it bluebilly.

Image courtesy of Slide Guitar for Beginners

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Filed under Acoustics, Africa, Alpha Unit, Antiquity, Asia, Australia, Blacks, Folk, Guest Posts, History, Labor, Modern, Music, Race/Ethnicity, Regional, Rock, South, US, USA

Red Army Choir Doing “Annie Laurie”

From 1963 at Albert Hall, London. That space was the only space in the UK large enough for the Choir. The acoustics in that arena are very bizarre such that the top levels hear the music some time after the conductor has moved his arms to indicate the movements. The recording spent a lot of time in the USSR, went on sale there, was then remastered in Russia and appears now for the first time. Amazing singing.

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Some Thoughts on the Bass in Acoustics and Music

The bass instrument, and the frequency it plays at, is interesting. It is difficult for the human ear to hear it. You will realize this if you ever put on a recording of music with electric bass guitar in it and try to listen for the bass. You can hear it best if you turn the bass up all the way, and it helps if you have a seasoned ear.

The question arises that if it is so hard to hear, why even bother to have an electric bass in rock music (I can’t speak for other forms of music)? The reason is that without a bass guitar, rock music sounds really bad. I’m not sure why it sounds bad, but it just does. You need the bass.

The bass actually has interesting effects in rock music. Although you don’t really hear it with your ears, you do feel it with your body. What is it about rock music that makes you want to get up and dance and move about, or head-bang? It’s the bass. The bass actually goes into your body, creates a strong feeling, and makes you want to react to it.

Bass waves are pretty interesting acoustic critters. While treble waves only go a few feet (Yes, it is true), bass waves can actually go for miles. Bass waves are so powerful that they can actually bring down buildings if they are loud enough.

Sounds are classed in a tripartite fashion – treble,  midrange, and bass. Bass might be necessary for rock music, but it’s nearly or totally useless for human speech. That is because human speech only operates in the treble range and in the upper half of the midrange.

Human speech does not use the bass range at all. We can make sounds in the bass range, but they won’t be normal speech sounds – they would just be weird, non-speech noises. Animals sometimes make bass sounds when they vocalize, like the low growl of the cat.

This is why if you really want to hear a speech recording well and have bass and treble knobs handy, you should turn down the bass and turn up the treble. You can turn up the treble all the way and turn down the bass all the way if you have to. The reason is that bass does absolutely nothing beneficial for human speech whatsoever in a recording – all it does it muddy things up.

You also hear difficult speech recordings better if you turn up the volume. The increased volume alone enables you to make out a difficult accent better.

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