I want to talk to you today about how it is I talk to you.
Critical to human existence
is that our voices define who we are.
My voice is me.
Your voice is you.
Voice is our main means of communication, evolved over millennia.
And I want to argue today
that there are three vocal resiliences for humans.
We need our voices for all kinds of things.
We transmit verbal information, ideas, feelings, emotions.
But more to the point, our identity.
You answer the phone,
and very often you recognize somebody
before they've even said what their name is.
It's also the way we call for attention if we're in trouble.
And of course,
it also provides the lyrics in singing.
So voice is fundamental to human living.
In speech,
in different acoustic situations,
in the presence of competing sounds
and in song,
over millennia.
And part of what I want to say today reflects on the millennial part of this.
But first, let's look at the three resiliencies.
And before we do,
I want just briefly to think about the role of hearing,
particularly the role of mankind's creation of devices
that can play very loud sounds.
Sounds that are louder than any human voice can produce
through the application of electronics.
So over roughly the last 130 years,
we have the potential
to break the human communication voice-to-ear train
because we are damaging hearing over just a century and a bit,
having evolved over millennia, our communication system.
So these are my three resiliences.
The first is resilience to other sounds in the environment.
The second is allowing us one-to-many communication.
And the third is to preserve the voice over millennia.
But I want us to remember,
there is little resistance to loud human-made sounds.
And that, I would argue, is an issue that's getting worse.
We need to act to both understand the problem
and to protect our hearing.
Many of us carry devices around which can cause hearing difficulty
if you play them too loud.
And hearing issues, of course,
these are not on an evolutionary time scale.
These are on a very short time scale.
So here's the first one,
other sounds in the environment,
sounds of nature.
We have evolved a redundancy in our speech specifically
that allows us to hear speech in the presence of natural sound.
So if, for example, there's a thunderstorm
or there's heavy rain,
then there is what we call masking in the sound.
And I'm going to do a little experiment.
I want to demonstrate that you can understand my voice
even if we cut the high end off or cut the low end off.
So the way we're going to do this
is we're going to listen to the low end first.
And I'm hoping that my microphone is connected now to a filter
as I give you a demonstration of just the low end.
And I hope you can still understand me.
And now would you switch it so we only hear the high end,
a so-called high-pass filter?
And now, I hope you can still understand me,
even though I sound a bit sibilant.
I hope you all understood what I was saying.
Now, that means
that if you're only able to hear the low end
because of some high frequency noise that's in the environment,
we can still communicate as human beings.
And vice versa.
If you can only hear the high end because there's rumbles of thunder
and other things going on,
we can still communicate.
It's a wonder of vocal evolution.
Resilience two.
Now, I have to admit, I'm cheating.
I am talking one-to-many,
and I'm wearing this thing
and you can hear me because of the loudspeakers.
But if I was an opera singer on this stage,
I wouldn't have a microphone,
I'd have an orchestra between me and you
and loads of people in the auditorium.
And yet, you can hear the words of the opera singer without a microphone,
without loudspeakers.
And the way they do it
is they engage that aspect of the human voice,
which I won't use over a microphone.
And the way that works is this.
The voice box or the larynx, the picture in the middle,
is here in the neck, it's where the Adam's apple is.
And of course, we have two ears.
When I do that kind of sound,
I create a narrow tube,
as shown by the light blue arrow in the larynx area.
And that tube matches in dimensions
the tube here and the tube here.
So in engineering terms,
we set up a transmitter and a receiver
that are tuned to work together.
And again, that is an evolved way
in which the larynx has developed to allow us to do it.
And you don't have to be a trained opera singer.
If you're in danger,
you know how to do this
because it's a natural,
something that's stored in the brain from evolution,
which you can switch in in time of real need.
Let me go to the third one.
Now, this is the one that's been alluded to,
was the question that our group asked:
Can we recreate the sound of a 3,000-year-old mummy?
It's an interesting question,
and the answer is that we can
if we can recreate the tube between the larynx and the lips,
because that's the tube, the so-called vocal tract,
the mouth and throat,
that I'm using now as I speak to you.
And here is the very image.
This is a 3D plastic vocal tract.
And if I put it next to mine, you can see it’s about the right shape.
And we then put this on an artificial larynx,
which is the loudspeaker in the picture, that's two in from the top.
We can then play a sound through the loudspeaker.
And we get the sound of this vowel.
(Sound)
Of course, it's not speech
because to speak, I have to move my vocal tract,
I have to move the articulators.
And this, of course, is solid.
But in this particular case, Nesyamun,
the hieroglyphics shown on the right there,
in English, that hieroglyphic means true of voice.
And Nesyamun wrote
that he expected his voice to be heard in the afterlife.
So this work was not just a technical “Can we make the sound?”
It also had a message, particularly to Egyptologists,
who study mummies,
of something rather special.
So we are hearing a voice from three millennia ago.
So as I started, my voice is me.
Your voice is you.
Our modern, noisier world is a challenge.
And it's a challenge from the last 100 to 150 years.
And it's something that we need to think about.
We need to think about it in terms of the numbers of humans
who are getting hearing problems because of the noise around us.
And if we're going to thrive as humans,
we need to communicate with each other
and we need our voices to do that.
And I've suggested three areas of vocal resilience.
So please, look after yours.
Thank you.
(Applause)