These settings are very important in Overtone Analyzer because they determine the frequency and time resolution and other aspects of the spectrum and spectrogram. Especially the Time Resolution has a large influence to the kind of information that the analyzer will extract from a recording.
Sampling Rate
Sampling Rate determines the number of measurements (samples) per second recorded from the input source. You can measure frequencies of up to half the sampling rate. For example, if the sampling rate is 11025 samples per second, then the analyzer can measure frequencies up to around 5500Hz. Standard music CDs have a sampling rate of 44100Hz. This should be a reasonable setting for most practical purposes, as it gives a good balance between frequency resolution and sound quality (however, see the discussion below).
Note: This option is only available if you have not loaded any file or made any recording. The sampling rate of existing recordings cannot be changed. If you want to change the sampling rate and it is disabled, click on File / New first.
Frequency Resolution (FFT Size)
The frequency resolution is the smallest difference between two frequencies that the analyzer can distinguish. Internally, this setting is stored as the size of the Fast Fourier Transform, which is the number of points that are computed for each update.
A higher FFT Size gives you more accuracy and shows more detail in the spectrum and spectrogram, but it also requires more processing power and may slow down your computer. In general, you should choose the highest setting that still gives you acceptable performance when moving the range slider on the timeline.
Time Resolution (updates per second)
This setting determines whether the Analyzer should be more accurate in the Frequency or in the Time domain. In other words, are you more interested in measuring the exact pitch, or in measuring the melody (the variations of the pitch over time)?
Fewer updates per second will increase the accuracy of the pitch display but hide the melody, while more updates per second will cause the analyzer to show the melody more clearly, but with less accuracy in the pitch.
