Tutorials and Topics - Peabody Computer Music

Tutorial 4Fundamentals:Routing signalsThe subpatch AtodB uses a reference amplitude of 1 in the formula shown above, andconverts the amplitude to dB.The contents of the subpatch AtodBSince the amplitude received from the uslider will always be less than or equal to 1, theoutput of AtodB will always be less than or equal to 0 dB. Each halving of the amplitude isapproximately equal to a 6 dB reduction.AtodB reports amplitude in dB, relative to a reference amplitude of 1• Change the position of the uslider and compare the linear amplitude reading to thelogarithmic decibel scale reading.Constant signal value: sig~Most signal networks require some changing values (such as an amplitude envelope tovary the amplitude over time) and some constant values (such as a frequency value tokeep an oscillator at a steady pitch). In general, one provides a constant value to an MSPobject in the form of a float message, as we have done in these examples when sending afrequency in the left inlet of a cycle~ object.However, there are some cases when one wants to combine both constant and changingvalues in the same inlet of an MSP object. Most inlets that accept either a float or a signal(such as the left inlet of cycle~) do not successfully combine the two.78