Process Tab

The Response controls the length of time the computer listens for each pitch measurement. There's a trade-off involved: A higher number implies better pitch accuracy, but fewer measurements per second. Fewer measurements per second also requires less computer processing power. A lower number means more measurements per second, which will make rapid pitch changes easier to see, but it may cause a slow computer to bog down.

The actual number of measurements per second depends three numbers, the Response parameter, the Lowest Note in the Scale Tab, and the Sample Rate on the Audio Tab. Here are the number of measurements per second for the default Sample Rate of 44,100, for different values of Response:

Response   2     3     4     6     8  
Here's how the measurement time is computed: It is based on the time it takes a note to complete one cycle of vibration. This depends on the Lowest Note in the Scale Tab and the Sample Rate on the Audio Tab. The lowest note on a violin is 55 (G below middle C), which has a frequency of 196 Hz. If we choose a value of 4 for Response, then 4 cycles requires 4 / 196, or 0.0204 seconds. If we multiply that by a Sample Rate of 44,100 samples per second, we require a minimum of 900 samples per frame. Intonia will choose the next higher power of 2, or 1024 samples per frame. Since each frame overlaps the preceding one by 50%, the number of frames per second is twice 44,100 divided by 1024, or about 86 frames per second.

For following fast passage work, you may want to cut Response in half, for more frequent measurement. For tuning you may want to double or quadruple Response, for better accuracy. Response also affects Processor Usage: the smaller the number of cycles, the more frequency measurements per second, and the greater the load on the computer.