The new Studio Six Digital Transfer function includes the most-used Transfer Function features in an easy-to-use GUI package.
With Transfer Function, you can make changes to a sound system without having to run pink noise or swept sine waves through the system. This allows you to monitor system performance, or make adjustments, while the system is in use and the crowd is in the room.
Since this module was developed solely by Studio Six Digital, and uses no Rational Acoustics Smaart code or algorithms, it is branded under our name only.
See our new demo video of Transfer Function:
Transfer Function is by definition a dual-channel measurement, and so to use it you need a two-channel input device. iAudioInterface2 was designed specifically with Transfer Function in mind, since it includes a microphone input, and a second line input for the reference signal.
You can also use other two-channel interfaces, such as the original iAudioInterface.
Here is Transfer Function on iPad, showing a running trace (green and blue), and a recalled trace (yellow and magenta). The coherence plots for both measurements are shown, in red and dark red:
Included in Transfer Function are:
The magnitude graph is used to show the difference between the reference signal and the test signal. Typically, the reference signal is pink noise, although you can also use mono program material (music) and still get good results.
The graph auto-centers around the 0 dB axis, so it's easy to see how the test signal differs from the reference signal.
The phase graph shows the relative phase of the signal, and is useful for setting crossover points.
The coherence graph is used as a measure of the reliability of a set of averaged transfer function measurements. 100% would mean that you are seeing highly correlated graphs, and thus the information on the magnitude and phase graphs would be accurate.
It may be useful to only display transfer function plot data when the coherence is above a certain threshold. This helps you know that the information being shown is reliable. To do this, you can set a coherence blanking threshold in percent, on the setup screen.
When the blanking threshold is greater than 0, plot data will only be shown that has a corresponding coherence greater than the threshold.
Typical coherence blanking values are 20-50%.
Since it is critical that the time offset between the reference and test signal is known, there has to be a way to accurately compute the time delay between these signals. Our impulse response based delay finder does just this.
Just tap the delay value to bring up the Delay Finder panel. You select an FFT size, which sets the longest delay that you can measure, and tap Find. The delay will appear, and you can apply it to the measurement.
Select the FFT size and windowing, display type, turn Peak Tracking on or off, set Coherence Blanking, turn on the Coherence plot on or off, select High Contrast mode, control audio pass-through, turn on Difference mode, or lock the graph scale.
For the full user guide, Click Here.