You would think that with the general level of background noise experienced in workplaces, on traffic-filled streets, in bars and clubs and even in the home, our voices would be used to powering out sound and filling large spaces with ease.
Hardly any of us has a problem with shouting at sports events, singing along with bands or talking animatedly across crowded bars. But if the bar were to fall silent just as we were speaking out, even the most confident of us would feel like dropping through the floor with embarrassment.
It is that experience (the experience of having to fill silent spaces with our own loud voice) that few of us feel at ease with when we have to give a presentation. Yet that kind of speaking voice is already practised and waiting to be used if only we'd give it a chance.
Unlike the situation in the bar - the silence during a presentation is intentional. It signifies that people want to hear what we have to say. They expect us to tell them our ideas in a self assured manner and want us to succeed.
To fuel that success we must have a plentiful supply of hot air on tap because the louder we want to speak the larger the reserve of breath we will require.
In an ideal presentation, brain waves fuelled by the air we breathe in get transferred onto sound waves fuelled by the air we breathe out and wing their way through space to expectant listeners.
As long as the air breathed-in is drawn deep into the lungs at the lowest part of the rib cage nearest to the waist, it can easily tank up our ideas and activate our voices. But if we only draw breath into the upper chest, we find ourselves with scant reserves that keep needing to be topped up.
The hypertension this creates causes ideas to peter out and words to dissipate long before they can reach the ears, let alone impinge on the minds, of any listeners.
What goes on inside our heads when we talk in public determines what goes on behind our backs once we've had our say. Hot air pulsing up through our vibrating vocal cords, absorbs their fundamental sound and flows into all the resonant spaces that lie inside our heads right behind our faces. There it gets pummelled by the tongue into vowels, consonants, words and phrases and only after that Ė and as long as the lips and jaw are open - can it propel itself out into the open as a distinctive message from a distinctive voice designed to resonate with an audience.
To fully take in that message, audience members must be kept topped-up with air too. It is the responsibility of presenters to see that their listener's can stay alert.
One way to ensure air intake is to provide an opportunity for audiences to chat briefly amongst themselves - ideally just before you start to synthesise the proceedings and make your concluding remarks.
Fuelled with the right amount of air that final cadenza delivered with sufficient vocal pyrotechnics will colour your whole presentation and elicit admiring comments even from the most seemingly disaffected listener.