The Boisterous Bluegrass Banjo

Can you imagine bluegrass music without a banjo?  If you’ve ever tried to play a bluegrass song without a Scruggs style banjo it might sound good, but odds are that people wouldn’t recognize it as bluegrass.  In fact, more than any other instrument, the banjo is what makes bluegrass sound like bluegrass.  What is it about this essential bluegrass instrument that gives the music such drive? 

This is the fourth installment in our series of chapters examining each of the standard bluegrass instruments and their roles in our music.  In this chapter, we will take a look at five things to know about the bluegrass banjo and then follow on with some demos.  We’ll conclude with a short history of banjos before the bluegrass era.

Why You Can’t Miss It 

Even the most casual observer wouldn’t overlook the sound of a banjo playing in an ensemble.  There is some good science[1] to the banjo’s loud and piercing tone.

If you put a signal analyzer on the banjo and subject it to a frequency analysis you will see that almost all the energy is contained within a 6KHz band[2].  This is a very narrow range and not at all like other instruments in a bluegrass band.  Concentrating the energy in such a narrow range makes the banjo naturally sound loud – especially considering this is the range of frequencies that the human ear is most sensitive to.  

Another reason that banjos are so loud is due to the efficiency of sound production.  The bridge of a banjo is directly coupled to the head with few energy losses (when compared to other acoustic instruments). The efficient coupling causes the relatively short sustain of the banjo note[3].   Since the energy is burst into a shorter note, it will sound louder in comparison to a more sustained note that distributes the same amount of energy over a longer time.  In addition, the vibrating head is a very efficient mechanism for transferring the acoustic energy to the air.  The net is that considerably less of the energy supplied by the picks ends up being wasted as heat as compared to other acoustic instruments.

Yet another factor in the banjo’s apparent loudness is the extremely high gain due to the focusing of the sound field to the front of the instrument.  Only a little acoustic energy goes to the top and back of the instrument.  If you are a banjo player, please remember this focusing effect – since your ears are located above and behind the diaphragm that is producing all the sound, the volume level that is heard in front of you is many times louder than you may think it is.

Further, if you think about it, the average banjo player flings considerably more of these penetrating notes into the air than anyone else during an average bluegrass song[4].  These factors raise the banjo to a prominence in the music that can’t be missed.  Just try not to drown out the mandolin player.  Please.  

Atomic Clock-like Precision 

They say that as young brothers, Earl and Horace Scruggs used to kick off a tune on banjo and guitar in their front yard, and then, while playing, would separately walk around the house in different directions, meeting in the back yard.  Since they both had the Scruggs “timing” gene, they remained synchronized even when out of earshot and were in exactly the same place in the song when they came back together. 

Earl set the bar for machine-gun like timing precision, and to my ear nobody has exceeded it.  He also set precedence for all Scruggs-style banjo players that came after him, and you can tell immediately if your local banjo player is respecting Earl’s timing dictum.  Listen to the spacing of the notes.  Unless our budding banjo player has the equivalent of Earl’s hypothalamus, he simply must practice with a metronome in order to play adequate banjo.  Or choose another instrument.  As mentioned above, banjoists are going to be spewing quite a few notes all over the place – and these notes had better be lined up with where all the other notes are occurring in the band.  A banjo that is not quite in time can really mush up a bluegrass band’s sound.

Archetypal Licks 

Simply put, there are certain mandatory banjo licks and backup moves that need to be played.  They make the music sound like bluegrass.  They can’t not be there.  The banjo player needs to repeatedly exploit on the order of half a dozen or so of these quintessential licks and approximately the same number of backup patterns.  At just the right places.  With just the right emphasis and timing.   Earl’s book has it all in there as does his playing on the Foggy Mountain Banjo album.  It is to be learned note-for-note.  Emphasis included.

Droning On and On 

The drone string is unique to the banjo and plays a critical role in the creation of the bluegrass sound.  It is often called the thumb string for the obvious reason that the right thumb almost always picks it.  As you may know, this string is pinched off at a higher place on the neck than the other four strings, making it shorter. This causes it to be higher pitched and shriller than the other strings and can be clearly distinguished from the din of the rest of the banjo’s multitudinous notes.  Further, as will be illustrated in the demos below, the Scruggs style forces the right thumb to repeatedly strike its namesake string in a highly syncopated and pulsing fashion, which is a big part of the magical rhythmic drone for which the banjo is known.

Beating Three Against Eight 

Scruggs style banjoists will always install three banjo picks. They are put on the thumb, index and middle fingers of the right hand (abbreviated T, I and M) and three is a number that doesn’t divide evenly into eight.  This creates a problem in trying to play a song in a bluegrass time signature, which has eight 16th notes.  Your first inclination is just to roll your three fingers sequentially and play T-I-M-T-I-M-T-I-M-T-I-M and so on.  The problem here is that, unless you are playing a waltz, important melody notes don’t occur in threes as your roll does.  The notes you really want to play will occur in twos and fours… i.e. at spots that align with eighth or quarter note spacings.  These melody notes are very awkward to play with a roll based on threes.  

This flummoxed quite a few three-finger banjoists in the early part of the 20th century.  One solution was to use only two fingers instead of three, which completely solves the problem:  melody notes will naturally show up on even boundaries.  Alternately, early three-fingered banjoists used something akin to a so-called “square roll” which repeats the thumb: T-I-T-M-T-I-T-M. This also solves the problem since you are back at T on all the two- and four-boundaries.  In either of these two approaches, all the melody notes fall right where they are supposed to be and “Oh Susanna” or “Jingle Bells” will sound just like it is written.  But it won’t sound like bluegrass.

We now know that by the year 1945, Earl had preserved the groupings of three and just kept rolling forward with T-I-M-T-I-M-T-I.  He also added a few other rolls that have three-groupings – these include playing that same pattern backwards and also playing it “reversed” (1/2 forward and then 1/2 way backwards)[5].  To solve the aforementioned problem with two- and four- boundaries, he moved the melody to fit the roll instead of altering the roll to fit the melody.  As will be shown in the demos below, this inherently causes the melody notes to be syncopated since they are played at unexpected places.  And boy does it sound like bluegrass.


Let’s take a simple song like Jingle Bells in order to illustrate some of the principles that were discussed above.  The bare melody, when played by the banjo, would go something like this:

A couple of things to note:  The melody is clearly there, but it is totally lacking in drive and syncopation.  Boring. 

Next, I’ll play Jingle Bells clawhammer style.  

Clawhammer is the style that preceded bluegrass and is still quite popular today in old time circles.  This rendition of Jingle Bells has drive and rhythm – the drone string is supplying a regular “beat” upon which the melody is being played.  In addition to plain vanilla clawhammer, I am occasionally using a technique called “drop thumb” to capture a few of the melody notes – and this has the advantage of syncopating them a bit.  You can hear that I’ve moved the beginning of the phrase “oh what fun it is to ride” to start on a delayed note (the “oh” …) by playing it with a “dropped thumb”. If you watch the video again, note at that spot (I’ve emphasized it for clarity) you can see that instead of continuing on with its usual assignment of plucking just the drone string, I “drop” my thumb down to the second string to catch that particular melody note.  This is the essence of syncopation – your ear expects to hear the note at one place and by delaying it, I am “surprising” your ear and consequently, your brain wants to pay attention to the music more.  I repeat that same trick several times in the last portion of the song.

Using the “drop thumb” technique in clawhammer style supplies some syncopation and interest to the music but it doesn’t yet contain quite the drive that a bluegrass banjo has.  Let’s put the finger picks back on and play Jingle Bells a third time, this time using Scruggs style:

This is starting to sound more like bluegrass.  It contains even more syncopation of the melody than the drop thumb technique did.  As discussed above in the “Beating Three Against Eight” section, in order for me to even fit the melody of Jingle Bells into Scruggs style roll I have to move melody notes around – some a little later and some a little earlier.  So, your ear is being continually surprised and it wants to continue to pay attention.  In addition, as was discussed in the “Droning On and On” section above, the Scruggs rolls force the drone string to ring in quite a syncopated and pulsing pattern. This is in sharp contrast to the clawhammer drone string in the second demo, which rings on a very regular non-syncopated pattern.  

Pre-Bluegrass Banjo

I’d like to conclude with a short history of the banjo – before Bill Monroe invented Bluegrass in 1945.  There is widespread agreement that the banjo originated in Africa and was brought over to America by enslaved people as part of the tragic “middle passage.”  Early American banjos, or “banjars,” were fashioned by the enslaved with a calabash gourd as a body, a head made of groundhog hide, a fretless wooden neck and three or four strings. The names of the black American musicians who mastered the 4-string gourd banjo are unfortunately lost to history but one or more of them taught Joel Walker Sweeney to play a gourd banjo in about 1823.  It is highly likely that the all-important drone string and its rhythmic implications were already an integral part of the banjo when Sweeney learned to play it but he is given credit for adding a fifth (lower in pitch) string and a wooden sound box (instead of a gourd) to the instrument’s design.  Sweeney and others like him ushered the banjo into its heyday as part of the minstrel era in the mid-1800s.  Featured in blackface acts, the banjo became wildly popular and unfortunately has remained somewhat associated with minstrel shows in our collective memory. 

Back in those days, banjos were plucked with a style variously called clawhammer or frailing.  This is the style that came over from Africa and that I demonstrated in the second video.  To play clawhammer style banjo, your hand needs to take the rough shape of a hammer – if you make a hitchhiking pose with your right hand and slightly loosen your fist, you can see it sort of looks like a clawhammer.  Now turn your hand 180o and situate it right above your air banjo.  The surface of the fingernails rap (twice in a row) downwards onto one or more (non-thumb) strings and the thumb then naturally hooks onto the thumb string.  The resulting highly rhythmic “bump-ditty-bump-ditty” droning is characteristic of this style and can be quite hypnotic.  All this stuff so far happened before Earl showed up at the Grand Old Opry just before Christmas in 1945, which, as we now know, changed everything.





The Bluegrass Voice

[1] See Dr. James Rae’s excellent analysis in chapter 5 of this reference <link> for more details.  Note that this is the same Dr. Rae that works with Steve Huber as a PhD consultant for his TrueTone banjos (featuring an HR20 tone ring and an engineered rim).

[2] Unlike other acoustic instruments, the fundamental frequency of a banjo has less energy than the upper partials; most of the sound energy is contained in the first five overtones.  In fact, the low “D” string has nearly 100% of its energy in overtones and not the fundamental – in this case, your “ear” is inferring the fundamental tone from the overtones.

[3] Note that if the impedance was exactly matched and the coupling was 100% efficient, there would be zero sustain and the note would be all over at once – it would sound like a rifle shot. 

[4] In fact, the note count for the 16 measures in a typical banjo break is over 100 and when you consider that the banjo typically rolls continuously, a three verse + chorus song with breaks will contain almost 1000 banjo notes.  The bass will have only supplied about ¼ of those notes in that same time period.  If you attend a bluegrass performance and stay thru one entire set, your ear will have ingested well over 10,000 banjo notes.

[5] You will also need to add in “escape” notes – between two and four of them.  These are extra notes that will allow one of these “three-” rolls to even up the time at the end of a measure. For example, a measure of eight notes could be played in a forward roll as T-I-M-T-I-M-T-I and then repeated again starting with T.  The last two notes – the T and the I – are escape notes since they even up the roll and allow it to repeat again.  If the forward roll spans two measures, there will need to be either one or four escape notes at the end to get back to the even measure.   For example, T-I-M-T-I-M-T-I-M-T-I-M-T-I-T-M.  If the forward roll is sustained for three measures (or any multiple of three measures), no escape notes are needed.