Adventures In Audio
What is a 'natural sound' in audio?

David Mellor

David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of Adventures In Audio.

Monday May 23, 2011
FREE EBOOK DOWNLOAD ►

Do your recordings sound natural? Or do they sound 'microphony', electronic or digitally processed? How can you tell?

The other day, I found myself advising someone that their recording of speech was good but it didn't sound natural. I further advised that the sound quality they had achieved was commonly heard on the radio, but it would be tiring to listen to for a long period, if the recording was part of an audio book for example.

It's worth reflecting for a moment on what we would consider naturalness, in a recording, to be. Fortunately we have examples of natural sound around us all the time, so there is plenty of material for comparison.

Perhaps the most useful natural sound is the human voice. Our ears are very closely attuned to the sound of the voice and we hear it all the time, and - most importantly - pay close attention to it. Of course I do mean the human voice as produced from a human larynx, throat and mouth, traveling directly through the air to your ears, not via a loudspeaker.

Let's consider therefore how we can compare the natural human voice with the sound of the voice reproduced via a loudspeaker.

Firstly, the person we choose to provide our hypothetical example of human speech should have a reasonably normal quality of voice. Professor Stephen Hawking writes excellent books on cosmology, but he isn't going to make a good example. Neither would a 40-a-day smoker. But we don't have to be too choosy. Apart from a few wayward examples, almost anyone would do.

Now we have to consider context. Should we consider the example of a friend spotting you from the other side of a busy road and shouting you a greeting? Well we could, but it doesn't have a lot of commonality with anything we would be likely to do in audio.

What about a lover whispering sweet nothings into your ear? That might be a desirable scenario, but the sound of the voice at extremely close range is difficult to mimic accurately. It's an interesting challenge, but we need something simpler.

So what about someone talking to you in a normal voice from a distance of two meters? That's just over six US feet.

This is a good test because it is a commonplace situation with which we are all very familiar. Also, it is practical to simulate with audio equipment. Bear in mind that most loudspeakers have at least two drive units and a certain amount of distance is required to allow the sound to integrate. A distance of one meter wouldn't be enough as small changes in listening position produce significant changes in perceived sound quality (and that is something to consider when using near-field monitors).

So imagine this... There is a visually opaque but acoustically transparent curtain in front of you, behind which there is a person, ready to speak from a prepared script (or you could do it in the dark). And also there is a loudspeaker, mounted with its central axis at the same height as your volunteer's mouth and as close as possible to one side. Through this loudspeaker will be played a recording that this same person made earlier. An assistant has previously checked that everything is working and that the levels are very similar.

So now you hear a voice. Is it human or is it the loudspeaker? Now you hear another voice. Or is it another voice? Is it perhaps the same sound source? Or has the source changed but there is so little difference that you can't tell?

You could carry out this experiment for real. Or you could consider it to be a test of naturalness in audio, and have this thought in your mind next time you need a recording to sound natural. Listen to your recording and ask yourself whether you would be fooled.

Although the human voice is the supreme test of naturalness in audio, it is also worth considering whether your recordings of acoustic instruments, including drums, sound natural. And if they don't sound natural, should you be trying to get closer to a natural sound, or are you trying to improve on nature?

Of course, naturalness isn't always the requirement. But it is a very useful benchmark of audio quality. Listen to your recordings closely and ask yourself which aspects don't sound natural. And whatever doesn't sound natural, ask yourself whether it is a defect, or an improvement.

Like, follow, and comment on this article at Facebook, Twitter, Reddit, Instagram or the social network of your choice.

Come on the Audio Masterclass Pro Home Studio MiniCourse - 60 great hints and tips to get your home recording studio MOVING

It's FREE!

Get It Now >>

Electric guitar - compress before the amp, or after?

How to choose the best key for your song

What is comb filtering? What does it sound like?

NEW: Audio crossfades come to Final Cut Pro X 10.4.9!

What is the difference between EQ and filters? *With Audio*

What difference will a preamp make to your recording?

Watch our video on linear phase filters and frequency response with the FabFilter Pro Q 2

Read our post on linear phase filters and frequency response with the Fabfilter Pro Q 2

Harmonic distortion with the Soundtoys Decapitator

What's the best height for studio monitors? Answer - Not too low!

What is the Red Book standard? Do I need to use it? Why?

Will floating point change the way we record?

Mixing: What is the 'Pedalboard Exception'?

The difference between mic level and line level

The problem with parallel compression that you didn't know you had. What it sounds like and how to fix it.

Compressing a snare drum to even out the level

What does parallel compression on vocals sound like?

How to automate tracks that have parallel compression

Why mono is better than stereo for recording vocals and dialogue

Clipping and compressing a drum recording to achieve an exciting sound texture

What can we learn about room acoustics from this image?

Can you hear the subtle effect of the knee control of the compressor? (With audio and video demonstrations)

What is the best studio microphone?

What is the Neve sound? (Using the Slate Digital FG-73)