I really don't know what to make of Jitter!
A lot of fuss is still made about jitter, but while it is potentially a serious issue it's rarely a practical problem these days simply because equipment designers and chip manufacturers have found very effective ways of both preventing it and dealing with it.
That is
Sound on Sound, a magazine which I have, for years, been regarding as true to its name:
very sound on sound. The
these days of the article is 2008.
2008, problem sorted. 2013, everyone is seeking to escape from the serious and sound-damaging problems of jitter. What happened in those five years? The hifi-manufacturer-made, stand-alone DAC exploded onto the scene. Is there a connection? Is this a problem that the marketing men have resurrected just to be able to tell us that
their product has it beaten? No prizes for guessing what the cynic in me says! Let us remember, that this is not something that is restricted to the engineering labs of audio companies: there is a
vast amount of digital communication going on in the world, and the size and value of the
non-audio digital industry probably makes the whole of the hifi industry look like a part-time chai shop. Isn't it the work, theory and practical, of those engineers that trickles out to other industries like hifi etc? Even if specific developments are subject to patents, the knowledge is there.
Actually, I wish they hadn't called it "jitter!" the word is too easy. It sounds like wow, flutter or flicker: words that exactly describe both the problem and its symptom, and the symptoms are easily detected by the sensitive ear or eye.
So what is jitter and
what does it sound like? What it is is technical, more so than wow or flutter, etc, but not impossibly so: it is a timing error in the stream of bits arriving at the DAC causing it to mistake some 1s for 0s, or 0s for 1s, and this it is trying to reconstruct the analogue music from wrong data.
It is a timing error. But does this translate into a timing error in the music? Not exactly: if the music were to miss a beat we would have far worse problems that jitter! The error is in the bits, not the bytes. Like a spolling mistake in a word, the word is still there but
some-how-not-quite-right.
An audiophile connects up a box, sits down, listens with a growing frown and announces: "It's bad! I can hear jitter!" What are they hearing? How do they know it is
jitter, and not, perhaps, some incompetent design element or faulty component?
I have always been inclined to believe
Sound on Sound. They are about studio and pro audio. They do not do the audiophile thing. Jitter had ceased to be a problem a decade or more ago. Nice, simple, end to the story.
But wait... If I search and dig, I can post links to articles by engineers which do
not say that jitter was fixed and we should mostly just forget all about it. So, at the end of the day, I'm back where I started: I really don't know what to make of jitter!