Posted by: Andrea Day | March 29, 2015

The Barbershop big “O”

Recently, the LABBS quartet champions were asked by the organisation to host a quartet education day for it’s members.  Being exceptionally lucky to be part of the QCs after winning my gold with The MIX in 2012, I wanted to offer up some of my skills and knowledge to those looking to work towards and achieve the same goal.

As ever, I’m never one to go down a well trodden path, so I decided to offer something rather different to the delegates and help them understand what an overtone actually was – what else did you think the big “O” was referring to?!

So, once again, as the pretty pictures were made I thought it was about time I share here too.

To understand some of the background to this post, I recommend that you read my previous blog posts:

or you are familiar with a spectrum analysis, frequencies, the principal of harmonics and the difference between just intonation and equal temperament – (now that sounds like a scary list!).

Here goes:

We know that when we sing a note, that we can tell the difference between one person singing it and another because it has a different finger print.  There is a main (fundamental) pitch that is sung and then other notes are added in above it to make it sound more interesting. Your ear just hears the overall sound and can’t distinguish each of the notes above the fundamental – unless you really REALLY listen.

Remember the flute and the violin example?

20131218-074433.jpg

Lets say that they are both playing an A at 440hz, the first spike that we see  on the left is the fundamental note at 440hz and then added to that are various other notes added in which gives it it’s own audio finger print.

Lets use some techy terms… the note that the instruments play or one that we sing is called the fundamental frequency and the notes that are above this to give it its character are called harmonics. The graph below is the spectrum analysis of a singer singing an A – can you spot the relationship between the frequency of the fundamental note and the frequency of the 1st harmonic?

 

Screen Shot 2015-03-25 at 22.26.07

 

Its double.

And doubling the frequency means?……… that the notes are octaves.

This is a sine wave, we have come across it before here.  Its pure and simple and sounds like this;

 

This is a square wave of the same fundamental frequency. Listen – and I mean REALLY listen. What makes it different to the sine wave? What do you hear above the fundamental frequency?

 

Sing the A along with it then sing the octave above (it’s the interval at the beginning of “Somewhere Over The Rainbow”) Can you now hear the octave above?

Thats the first harmonic!

Here is the spectrum analysis of the square wave.

Screen Shot 2013-12-17 at 20.06.14

You can see that there isn’t as much of the first harmonic as there is of the fundamental frequency so it can be harder to hear – but it’s there.  If you have really keen ears, you might even be able to hear the second harmonic – but I wont ask you to sing it – unless you are Tim “Nine Octaves” Waurick.

Here is where we get to the exciting stuff…..

Lets take a really typical barbershop A chord and look at what frequencies that the chord consists of; Bass on the root (I), lead on the 5th (V), tenor above the lead on the flat 7 (VIIb) and the bari with the left overs as normal on the 3rd (III). (This is just one example of literally thousands of chords and combinations that we could choose.)

Screen Shot 2015-03-28 at 11.43.34

When we sing, we don’t all sound like a sine wave, so we know that there must be some harmonics in our voices which give them their character and unique finger print.  We know that the 1st harmonic is an octave above the note that we are singing and that the second harmonic is the octave above that.  So, here is what the frequencies look like if we expand the table to include the 1st and 2nd harmonic.

Screen Shot 2015-03-28 at 11.43.57

 

Spot anything – look at the numbers… in the lead and bass specifically.  Use what you know about just intonation…. can you see it?

There are two frequencies on this table which are as close to identical as you can get.  The 1st harmonic in the lead  (1318hz) and the 2nd harmonic in the bass (1320hz).  See it now?

As we learnt in Tuning; the Barbershop way we know that 2hz is a teeny amount and that when we sing, we use a different way of tuning chords that uses our ears.  These small differences in pitch are what great barbershoppers correct while they are singing without even knowing it, – this what makes barbershop different to other styles of music.

Lets have a look at a simplified spectrum analysis for this chord:

Screen Shot 2015-03-29 at 09.50.01

It looks a bit confusing at first, but work through it.

  • See the fundamental frequency that each part is singing on the left; we hear this as the predominant note of the chord.
  • Then look at the middle section where you can see smaller amounts of the 1st harmonic
  • Then look to the right – even smaller amounts of 2nd harmonic.
  • Find the 1st harmonic of the lead note in blue and the 2nd harmonic of the bass note in red.

When you add the amount of 1st harmonic in the lead, with the amount of 2nd overtone in the bass (add a little tuning tweak at the same time) – hey presto – there is your overtone and your “expanded sound” that the judges like so much.

It’s a pitch that no-one is singing but there is just as much of it as there is of the fundamental frequencies that are being sung so often sounds like a 5th voice.

So, what does this mean for your barbershop singing?

  • Overtones are the result of getting everything else right; when you get your vowels matched, the tone that you create across the quartet or chorus matched and most importantly get the tuning right, then you will create overtones. Without the basics being bob on, the overtone will be as elusive as ever.
  • Creating overtones is hard – first work on creating a strong 1st harmonic when all of you are singing in unison.  Sing the fundamental frequency all together on one word – have the pitch of the octave above in your head and see if you can hear it when you all sing together.  Hold the word out and play with the vowel shape and tuning until you can hear it.  This forces you to listen and listen hard!
  • Once you have the unison sound cracked, add on your note for your part – hold the word out and play with it again until you feel that you lock in the chord.
  • Often the baritone or tenor will need to play with their tuning to make the chord lock.  If you are struggling – duet the bass and lead together first – they normally  (but not always!) have the simplest lock to achieve first and then the tenor and bari can fit into it.

Creating overtones is one of the pinnacles of barbershop singing and often the one that can make your hairs stand on end. It’s a real skill that can take years of looking for the right people to sing with and hours of dedicated and focused practice. But, as soon as you find them, you will be hooked and looking for your next fix!

I love hearing about what you find useful from my blog posts and also where you are from – please feel free to leave a comment or ask any questions!

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Responses

  1. […] spectrum – wanna find out if you are creating overtones, you can actually SEE them using this […]

  2. Enjoying your sharing of knowledge!!!! Yours in song, Bill.


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