Example Data Table
| Case |
Raw readings |
Corrections |
Mean delay |
Use case |
| Audio interface loop |
12.4, 12.6, 12.5 |
1.0 ms device offset |
11.5 ms |
Driver timing check |
| Speaker distance test |
35.0, 35.3, 34.9 |
3 m acoustic path |
26.5 ms |
Room alignment |
| Video sync test |
48.1, 47.8, 48.0 |
No path subtraction |
48.0 ms |
Picture timing |
Formula Used
Raw delay = detected tone time − sent tone time.
Round trip delay = raw delay ÷ 2.
Acoustic path delay = path length ÷ sound speed × 1000.
Corrected delay = measured delay − device offset − output latency − input latency − acoustic path delay.
Sample offset = corrected delay × sample rate ÷ 1000.
Jitter = sample standard deviation of corrected readings.
Standard error = jitter ÷ square root of reading count.
Confidence range = z value × standard error.
How to Use This Calculator
Enter the sent tone time and detected tone time. Use milliseconds for timing fields.
Select one way or round trip testing. Round trip readings are divided by two.
Add known latency values. These are removed from the measured delay.
Paste repeated readings when you have them. Separate values with commas, spaces, or new lines.
Enter sample rate, tone frequency, and frame rate. The tool converts delay into useful production units.
Press calculate. The result appears above the form and below the header.
Use CSV or PDF download buttons to save the result.
Test Tone Delay Guide
Why Delay Matters
A test tone delay check compares when a known tone starts, with when it is detected. The gap is useful in speaker alignment, recording systems, video sync, hearing tests, and lab timing. A small delay can feel harmless. Yet it can cause comb filtering, late cues, or poor lip sync.
Statistical View
This calculator treats the reading as a timing sample. You can enter one delay from timestamps. You can also paste many delay readings. The tool then reports the mean delay, jitter, spread, standard error, and confidence interval. This makes the result more reliable than one isolated number.
Corrections
Corrections are important. Output latency, input latency, device offset, and acoustic travel time can change the final answer. The calculator lets you subtract these values. Round trip tests can also be divided by two. That helps when a tone leaves one device, returns through another path, and is measured again.
Conversions
The sample conversion is helpful for digital audio work. Milliseconds can be changed into samples using the chosen sample rate. A 48 kHz system has forty eight samples in one millisecond. The tone cycle count shows how many waveform cycles fit inside the measured delay. The frame conversion helps video editors compare delay with picture timing.
Consistency
The statistics section helps judge consistency. Standard deviation is used as jitter. A low value means the delay is stable. A high value means the timing varies between tests. The confidence interval estimates a likely range for the true mean delay. More readings usually reduce that range.
Targets
Use the expected delay field when you already have a target. The calculator shows the error from that target. Positive error means the tone arrived late. Negative error means it arrived early. This is useful when tuning delays for monitors, wireless links, interfaces, or playback chains.
Best Practice
For best results, run the same tone several times. Keep levels safe and avoid clipped audio. Use the same start threshold on every run. Note the sample rate and all hardware buffers. Record room distance too. Even short air paths add measurable milliseconds during careful calibration and repeatable comparison logs. Export the CSV or PDF after each setup. Those files make it easier to compare tests, document fixes, and repeat the same method later.
FAQs
What is test tone delay?
It is the time gap between sending a known tone and detecting it. The result helps measure audio latency, sync error, or signal path delay.
Can I use repeated readings?
Yes. Paste readings into the repeated readings box. The calculator finds the mean, jitter, spread, standard error, and confidence range.
What does jitter mean here?
Jitter is the standard deviation of corrected delay readings. It shows how much timing changes across repeated tone tests.
When should I use round trip mode?
Use it when the tone travels out and returns before detection. The calculator divides the raw reading by two before corrections.
Why subtract acoustic path delay?
Sound needs time to travel through air. Subtracting path delay helps isolate electronic, software, or device delay from room distance.
What is sample offset?
Sample offset converts milliseconds into audio samples. It helps editors and engineers shift tracks by a precise digital amount.
What does target error show?
Target error compares the corrected mean delay with your expected delay. Positive values are late. Negative values are early.
Can I export the result?
Yes. After calculation, use the CSV button for spreadsheet data. Use the PDF button for a simple report.