Understand Sync Tones: Part 1
Understand Sync Tones: Part 2
All About Sync Tones
One of the great things about Kompoz is that it allows us to work
remotely with other musicians, often a half a world away and a dozen
time zones apart. It means that anyone, anywhere can be your virtual band mate.
That's pretty awesome. But when your drummer lives in Kalamazoo and your guitar
player is in Liverpool, chances are pretty good that they'll be using
different recording software, and probably different audio encoders and compression algorithms.
This presents a problem that sometimes results in the individual tracks of a song
getting out of sync -- out of alignment -- with each other.
This can happen because audio encoders will pad or even eliminate silence at the beginning of
a track for the sake of compression optimization.
Let's say you've recorded a killer drum line. You save it as an MP3 and upload it to Kompoz.
When you listen to the file, there's maybe a second of silence, then your drums kick in -- sounds great.
Your guitar player imports that track into his Pro Tools, arms a new track for recording, and starts
laying down a great rhythm in-step with your drumming. It all sounds perfect on his workstation
and he exports just his guitar track to an MP3, then uploads that to Kompoz. But what he doesn't
realize is that his MP3 encoder added an extra few milliseconds of silence at the beginning of
his MP3 in order to get a good byte-alignment and better overall file compression.
The problem now is that when you import his new guitar track into your workstation, the two
tracks will not start at exactly the same time, and you'll get noticeable track drift as the song progresses.
That's just one example of how tracks recorded by different people using different tools can get out of sync.
A good engineer with lots of time can usually spot that and correct the problem. But when you're dealing with
multiple tracks from multiple people, why bother?
What's the Solution?
Fortunately there's a rather easy solution to this problem. The trick is to add a sync tone at the
beginning of each recorded track. And the key is that everyone has to agree to use the same exact sync tone.
The sync tone acts as a sort of audible marker -- a tic -- that can be used to both visually and audibly
line up each track and lock them together.
Each time a new track is recorded, the sync tone must be routed to the new track so that it becomes part of that track.
When tracks with these markers are imported into your workstation, they can be aligned with great precision.