Some audio pessimists are convinced that because a stereo recording and reproduction system can only sample a couple of infinitesimal points within the overall ‘sound field’, it is futile to imagine that the result can be anything but a pale imitation of the real thing.
Others are convinced that although the efforts of recording engineers mean that the recording itself is passable, the problem is that speakers playing in a real room are not conveying it to their ears accurately enough. They attempt to alter what comes out of the speakers in order to compensate for the room.
And stereo itself when reproduced over speakers is assumed to be so flawed due to crosstalk to the ‘wrong’ ear that it can’t possibly work, and we must be deluding ourselves if we think it does.
These are assumptions made by people who cannot allow themselves to enjoy their audio systems. I suggest they are fixated on the wrong things and the situation is much better than they imagine. A different way to view the problem of audio is this:
It is a mistake to think that the aim of the system is to recreate the precise waveform that would have reached the listener’s ear at the actual performance. It is not practically achievable, would not necessarily reproduce a realistic perception of the actual performance in the context of the listener’s own room anyway, and also it is not necessary. Most people couldn’t even tell you which of two plausible versions of the waveform are absolutely correct, and that is because they’re not hearing a waveform; they’re hearing musical and acoustic ‘objects’. It is the relationship between those objects that is paramount.
An ‘object’ could be:
- A voice
- A choir
- Silence
- A sad note
- A happy chord
- Song lyrics
- A violin
- A rhythm
- An orchestra
- A concert hall
- Tension
The primary aim of a hi-fi system (as opposed to a kitchen radio, for example) is to maintain the integrity of single objects and the separation of different objects.
The secondary aim of the hi-fi system is to present the objects in a plausible way that allows for the normal behaviour of the listener; the sound basically appearing to emanate from in front of the listener, separable by distance and direction, without strange acoustic sensations if they turn to talk to their neigbour.
And that’s it. Everything flows from there.
- Harmonic distortion (and the corresponding intermodulation distortion) smears objects together.
- Bumps and dips in the frequency and phase response of a speaker smears the objects together and punches holes in the integrity of the objects.
- Noise smears itself over all the objects, obscuring their separation.
- Limited bass damages the integrity of certain objects and smears those objects together.
- Timing errors smear objects together. Resonators in speakers (e.g. bass reflex) that take time to ‘get going’ and time ‘to stop’ damage and smear the objects together.
- Stereo obviously aids in separating objects. Just a pair of speakers provides a continuous spread of individual, separate acoustic sources. And stereo over speakers isn’t flawed; the crosstalk to the ‘wrong ear’ is how it produces the image in the first place.
- Realistic volume helps to elevate objects above the noise floor, with a more natural sound due to our hearing’s volume-dependent frequency sensitivity.
So some objects make it out of a kitchen radio OK: a rhythm, a melody or the words of a song. But other objects may be severely damaged or smeared together. On a hi-fi system you might hear two separate guitars but on the radio they’re just a wash over the whole sound. On the hi-fi you hear a startling, deep bass note, but on the radio there’s nothing.
And the hi-fi system does things ‘without trying’ – which is why some people can’t believe it’s doing them. The stereo system with speakers automatically creates a two-way interaction between the listeners and the performance because both are subject to the listening room’s acoustics. This also solves the problem of how to cram a concert hall into the listener’s room as well as the more intimate performances. Is the aim for the musicians and venue to come to the listener or for the listener to go to the performance? The stereo system with speakers creates a hybrid: regard it as the listener’s room being transported to the venue and its end wall being opened up.