Found in Space

Found in Space

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Look closely at the above image. Can you see a whole load of stars or just a vague homogenous glow? I hope it is the former as otherwise this entire post fails. Once more, I want to speak about separation in audio systems. This is a concept which many find extremely hard to grasp and is of total relevance as it is directly connected to the discernible difference between a good car audio system and a not so good one. But, rather than jumping in at the deep end as I am often accused of doing, I wanted to attempt to go back to first principles with the aid of a visual analogy of what I mean by “separation” and what it brings to audio pleasure.

Much recorded music consists of a number of sounds, whether they be musical instruments, pieces of electronics or things being hit, blown, bowed or squeezed into making a noise. The combined effect of the hitting, blowing, bowing and squeezing should cause joy for the listener and can convey a story in the same way that words and pictures in a book or magazine do. However, unlike reading a book or enjoying any other of the visual media available, it can be far more difficult to pick out individual elements from what you are hearing. When reproduced through a low quality system with poor dynamic range, frequency response and high levels of harmonic distortion it is often impossible for even the most highly-trained ear, to pick out individual elements from the whole. There is no space around the individual elements and so different sound sources or instruments can mask the notes or at least some of the harmonics of others (The harmonics provided by an instrument supplement the pitch of the note it is playing and define the timbre or distinctive characteristic of that particular instrument). If we step back to our picture of the night sky for example, we can see each star has space around it. If we were to be viewing the same scene from a road lit by powerful street lights we would not see anywhere near as many stars as the less bright ones would be masked by the ambient light (light pollution). If we looked at the same scene through frosted glass (distortion) a similar result would occur.  In an audio system with good dynamic range, low distortion and a complete frequency response from start to finish we should be able to hear the space around each instrument or sound source provided the sound engineer who put the recording together adhered to the basic principles of a good mix.

So, how does a sound engineer avoid different sounds interfering with or masking each other? Balancing the levels (volume) of each of the individual elements is usually the start point for this. By ensuring that a saxophone isn’t going to cover up all the keyboard players fancy notes for instance. But other parameters of the recording and stereo image are adjusted to help achieve separation. Similarly, a very bright star will be easier to see than a dim star but if the dim star can still be seen, a credible mix has been achieved. The equalisation (eq) of a particular instrument can help to highlight its tonal qualities. In our star-scape analogy this would be similar to identifying a star by its colour (“it’s the slightly yellowish one next to the slightly blueish one!”). An instrument’s position in the stereo image can be adjusted by using the pan control on the mixing desk. This is a little bit like the balance control on your home hi fi or car stereo except in those cases, the control affects the entire musical output whereas the pan control on a vocal at mixing desk level in a recording studio will move just that vocal to a point where it can be pinpointed and stand out from other vocals or instruments. In our star analogy, position is the same. If a star were to be positioned in exactly the same place as another from the viewer’s perspective then one of them wouldn’t be seen (although, there could be an addition of light output which would effectively create a false impression of a brighter single star). Think how disappointing the picture above would be if the detail could not be seen –  it is exactly the same with music!

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Hopefully, this introduction can help the reader to appreciate the importance of each of a system’s performance specifications: Frequency Response, Dynamic Range, Harmonic Distortion etc. (yes, there are more!) on the overall performance of a system and therefore the integrity with which it reproduces recorded music. Which element is the most important is an impossible question to answer. Better to approach your car stereo system as a whole and balance all of the elements within it to achieve the best balance possible for the budget you have available. There is little point in spending £2000 on a pair of speakers and connecting them to a £100 amplifier. You would be far better off spending £500 on speakers, £200 on a subwoofer and £500 on an amplifier (see the fabulous range of Audison Voce products here) and the rest on a first class installation. A specialist installer has direct experience of which bits of equipment work best together in order to achieve optimum performance for your budget. I would and will always suggest you visit a FOUR MASTER for the best advice available.

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