Should we use microphones to imitate our ears? Or should they be used in an entirely different way?
Comment from a Audio Masterclass visitor...
My name is Amit Shtriker and I am a relatively young engineer (24 years old with around 5 years of experience). I really enjoy reading your articles, and I feel that a lot of them really share good ideas to learn from.
I've read your article about placing mics high, and I have to say you are bringing a good point here. As an engineer who learned mostly from other engineers in studios and from experience, of course I believe we should try different placements, but I don't think that you can make a point by describing how placing mics at the height of the ear supposed to sound more natural.
If so, we would mic everything with just one or two mics. That means, why most of us are separately miking the snare and the kick so close? I am pretty sure no one would listen to the snare putting his ears next to the hi hats... And why do we place the overhead mics from above the kit? I don't think it's in order to justify the name "overheads".
I am also completely sure that when listening to a pianist playing we don't put our heads above the piano strings, but it's the most common place for mics to be.. And maybe we shouldn't mic an electric guitar cabinet, but only the air around it (at ears height)...
I guess you got my point. After all, the ears' off axis frequency response and pickup pattern are not much identical to those of microphones (and I am really sorry if I am wrong here, I haven’t checked it myself).
And the reason we have ambient (room) mics is to have a set of two tracks (or one) that supposed to imitate the sound of only two ears listening, and we hardly ever (unless wanted by the production and sound design) use -only- the ambient mics but we mix them with the "unnatural" closed miked or overhead miked signals.
What you didn't mention is that when we play back our music, we are not only listening to the instrument's sound coming through the air directly, what we hear is the sound coming through air, microphones, electronics, speakers, and then through the air to our ears – so there's a change in the instrument's color when it passes through this long "unnatural" path.
And if we are talking specifically about strings, then the reason of miking from above (for me), is that it feels a bit more "airy" and smooth then miking the front of the instrument, and of course it all depends on the type of sound wanted and personal taste.
My point is, if we were trying to use microphones to imitate the position of our ears, so we wouldn't use multi-miking techniques at all, would we?
Thank you very much, and keep the great articles coming!
David Mellor responds...
Your letter presents the opposing, and valid, case to my thoughts on placing microphones by first considering the natural listening position.
A long-held goal in audio has been the ability to capture the natural sound of instruments. Imagine if you could listen to a recording with eyes closed, and not actually know for sure whether it was a recording or a real instrument, or group of instruments.
Well, that never happens, and in any case you could only get close if you listened on electrostatic loudspeakers. Conventional moving coil loudspeakers always give the game away.
So it seems that engineers have pretty much given up and accepted that a natural sound is impossible to capture. You can get close, but never all the way.
Once the desire to capture a natural sound is given up, then the next option is to capture a sound that is enjoyable to listen to, and don't bother whether it is natural or not.
I think it is clear that if you wanted to capture a natural sound, then the typical listening position would be an essential factor to take into account, if not mimic exactly.
But if you want a sound that pleases, even if it is not natural, then the normal listening position is irrelevant.
But there is a third view... microphones are actually very different to the human ear. The on-axis response of the human ear is like a mountain range and the off-axis response even more jagged. But this helps us hear the things we need clearly, and locate directions precisely.
So placing a mic with a flat on-axis response and a smooth, if not flat, off-axis response in the natural listening position is not comparing like with like.
Possibly a mic position should be sought that compensates for the differences between microphones and the ear, and using multiple microphones rather than just two may help.
There are no rules or laws of sound engineering, but its always worth considering why we do things, rather than doing things 'the way they are always done'.
- For a natural sound, consider using the microphones in the natural listening position (but probably they will need to be closer).
- If you don't require a natural sound, position the microphones anywhere that gets the sound you want.
- Consider that the differences between microphones and the human ear might possibly be compensated for by creative positioning and techniques.
- Don't just do things 'the way they have always been done' (but consider why they are always done that way!)