Delay Finder vs. Delay Tracker

Delay Finder vs. Delay Tracker

Timing differences between measurement and reference signals can come from a number of things, including:

• Propagation time from speaker to microphone (measurement delay time will increase when mic is further from the speaker)
• Processing in the system under test (console, DSP, etc.)
• If using measurement and reference signals from different devices (like Multi-Device Transfer Function or Smaart Loopback), driver latency differences can also cause this.

This is where the Delay Finder and Tracker tools are useful!

Delay Finder

In Smaart’s Real Time mode, the Delay Finder is a feature that calculates the difference in time between your measurement signal and your reference signal. To initialize the delay finder, simply click the “Find” button on a running TF Engine.

The Delay Finder menu will open and automatically begin to calculate the timing difference between your measurement and reference signals. As we can see in this example, there is a 1.19 ms delay in the measurement signal (likely due to the short distance from the microphone to the speaker in this test setup). Positive values mean that your measurement signal is arriving after your reference and negative values indicate that your measurement signal is arriving before your reference.

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• Clicking “Insert” from this menu will set the delay of the TF engine to this value, adding the calculated delay value to the reference channel to sync it to the measurement channel.
• Clicking “Find Delay” will cause the Delay Finder to run again, allowing you to adapt to environmental changes in real-time.
• Clicking “Advanced” will bring up the Advanced Delay Finder menu (covered in another article)

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Delay Tracker

The Delay Tracker, however, can be activated by either clicking the “Track” button on an active TF Engine or by clicking the grey circle on an active TF engine, which will momentarily turn yellow before it returns to grey. While the color changes, it finds and then set the delay of that TF engine in one action. Double clicking this button will turn the circle red which will cause the tracker to run indefinitely, updating the delay in real time should it change. This can be helpful in scenarios where the delay may fluctuate, for instance if the measurement microphone is moved or you are measuring in a windy environment.

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Setting Delay On Multiple TF Engines

Additionally, in the “Timer” menu, there is a “Set Delay” and a “Track Delay” option with a checkbox. Starting the Timer Macro with this option checked will run the Delay Finder or Tracker for all active TF Engines, respectively. If both boxes are checked when running the macro, both functions will run on all active TF Engines, both setting the delay for each engine and continuing to update delay times as it continues to run.

Clicking "Track" on the Transfer Function menu to the right will also activate the Delay Tracker across all TF engines.