Sync Delay Calculator
Convert musical delay values into milliseconds, samples, frames, negative pre-delay, latency compensation, and bar or beat offsets for DAW, video, MIDI, and live playback sync.
Start with a real timing situation: each preset fills tempo, note division, measured delay, sample rate, frame rate, compensation, and musical position values.
Sync Delay Breakdown
| Division | Quarter Factor | At Current BPM | Typical Sync Use |
|---|
| Offset | Milliseconds | Samples | Frames |
|---|
| Source | Entered Value | Milliseconds | Alignment Action |
|---|
| Scenario | Starting Range | Best Unit | Use When |
|---|---|---|---|
| Vocal slapback | 80-180 ms | Milliseconds or 1/16T | Short delay that reads as width before it becomes an echo. |
| Dotted eighth echo | 0.75 quarter | Dotted eighth | Rhythmic repeats need to lock with guitars, vocals, or synth lines. |
| Hardware synth return | 2-15 ms | Samples | External instruments return through converters and mixer paths. |
| Video lip sync | 1-3 frames | Frames | Dialogue or cue hits are checked against a picture edit. |
| Live wireless IEM | 2-8 ms | Milliseconds | Wireless, digital console, or plugin paths need performer alignment. |
| Negative drum pull | -5 to -30 ms | Negative delay | Room, sample, or parallel track should feel earlier against close mics. |
Timing problem often develop during the recording of sound in that the various element of that sound are not created at the same time. For instance, a vocal track may arrive behind the beat of the song by a few millisecond. Additionally, a vocal may arrive in a room monitor after the singer has moved on to a new phrase.
Each of these different elements of sound must be synchronize to one another. The process of ensuring that the elements of sound created in a recording are synchronized is referred to as sync delay management. Sync delay management isnt always about achieve zero delay.
Fixing Timing Problems in Audio Recordings
Sync delay management is often about deciding which element of sound should be synchronized with which other element. To understand sync delay management, it is first important to separate the element of sound that is to be measured from the element of sound that is to be corrected. For instance, a quarter note divided by 120 beat per minute is 500 millisecond.
Any other note division are represented as fractions of those quarter notes. A calculator can help to calculate the number of millisecond that each different division of a note will be. However, the calculator does not have the ability to make a decision as to which note division should be select as the target for sync delay management.
In most cases, latency is not a single number. For instance, latency can be the round-trip delay of a signal through an audio interface and converter. Additionally, latency can be the delay of a plugin that introduces latency through its oversampling function.
Additionally, latency can be the delay of software that is used to wirelessly send audio between two or more location. Each of these time measurement can be determined by the plugin. Each of these delays should be added together once they are determined.
Once they are added together, a decision must be made as to whether the total latency is to be applied to the track, the monitoring path, or the musical delay. Another factor to consider in audio sync delay management is the fact that video files exist on there own separate time clock from audio files. Each frame of video at 24 frame per second is 41.67 millisecond.
Each of these time unit is much larger than the time units of the audio files. Thus, a single frame of video can lead to a lip sync issue. Here, a decision must be made as to whether the performance should be shifted to compensate for the single frame of video, or whether the looseness of the performance is an acceptable trade-off.
Another factor that should be considered is that sync delay management can target element other than the downbeat of the current bar. For instance, many sync target will be cues that are supposed to hit on a certain bar and beat within the song. Any delay from a target beat to the current beat can be calculated.
This type of delay can be accounted for in the same way as any other delay. Fractional beat and whole bar can be selected as targets for sync delay management. Finally, sync delay management may target an event that happens before the current time.
For instance, a track may be delayed in order to make a vocal that is recorded in a room arrive at the same time as a vocal that is recorded close to the singer. Additionally, sidechain trigger may need to be delayed in relation to the audio that is to be compressed. Thus, an event that is delayed before the current time may be necesary.
Another decision that must be made with sync delay management is which measurement to trust. For instance, a loopback tool may read a latency of 3.2 millisecond. However, a different measurement tool may read 256 sample of latency.
These two different measurement are not in conflict with one another. Each is measuring a different element of the signal path. The latency of the signal through the audio interface and converter can be different than the latency of the signal through the audio plugin after it has entered the computer.
It is important to keep these type of measurements separate from one another. In addition to these differences, the timing target that is calculated may need to be rounded to the nearest whole sample. Audio workstation typically create audio samples in whole numbers.
Thus, fraction of a sample will not improve accuracy. An option to round the calculated timing target may help to reveal the difference in timing if the target is rounded to the nearest sample. For most projects, the timing between an element and the current time will remain the same whether it is rounded or not.
However, there may be a rare situation in which the fractional time is to be left unrounded and assigned to the audio workstation. A reliable sync delay management session will measure the timing of the sound elements after the signal path is completed. Each element within the signal path should be measured and accounted for when creating the sync delay management session.
Once the signal path is completed, the timing of the sound element can be introduced into the sync delay management calculator. The sync delay management calculator may reveal the amount of time that the element should be corrected to achieve the target. Thus, using the sync delay management calculator in this way will remove the need to guess at the amount of time that the element should be delayed.
