Hardware & signal path
Audio interface
An audio interface converts between the digital signal inside software and the analogue signal a mixer or amplifier accepts. In a timecode rig it also converts the other way, digitising the control signal coming off the turntables.
In practice
Raise the buffer until the dropouts stop, then stop — every increase is delay you will feel.
Set it once, on the machine and at the settings you actually play with, rather than at a clean desktop with nothing else running. Use the outputs the interface intends: balanced connections where they exist, and line level into the mixer rather than a headphone output pressed into service, which is the usual source of a signal that is somehow both quiet and distorted. And check whether yours is class-compliant or needs a vendor driver, because the second answer means an operating-system update can take you offline until a new driver appears.
Buffer size
Stability against latency
Line level, balanced
How to connect it
Class-compliant?
What an OS update can break
Where these come from: Setup practice for computer audio, not catalog figures — `songs` holds no property of an audio file or a signal chain at all. For what we can measure, see the rate the chain runs at.
Why it matters
It is the component people forget they own, because on a controller it is built in. It becomes visible the moment something goes wrong — dropouts, latency, a channel that will not appear — and none of those are software faults.
Its settings trade two things against each other. A small buffer makes the software respond instantly and risks audible dropouts; a large one is stable and adds delay between moving a control and hearing the result.
Frequently asked
Do you need an audio interface to DJ?+
Only if the rig does not already contain one. Controllers and club players have one built in; a laptop with timecode turntables needs a separate interface to digitise the control signal.
What buffer size should you use?+
The smallest that runs without dropouts on the machine you actually play on, with everything you normally run open. Anything larger adds delay between the control and the sound.
Why is my sound quiet and distorted?+
Often a headphone output being used as a line output. Use the interface’s line outputs at line level into the mixer, and set the level with the mixer’s gain rather than the interface’s volume.
Related terms
DVS
A DVS — digital vinyl system — plays software tracks from real turntables or CD decks. A control record carries a timecode signal, an interface digitises it, and the software follows the position and speed of the platter.
Timecode vinyl
Timecode vinyl is a record pressed with a control signal instead of music. DVS software reads that signal to work out where the needle sits and how fast the platter is turning, then plays a digital track to match.
Controller
A controller is a jog-wheel-and-mixer surface that drives DJ software on a computer. It sends control messages rather than making playback decisions, and usually carries the soundcard that turns the software’s output back into sound.
Sample rate
Sample rate is how many times a second a digital file measures the waveform, in kilohertz. CD audio is 44.1 kHz, and the number sets the highest frequency the file is able to carry.
Explore: Sample rate · Mixing guides · BPM tapper · All DJ terms