Scope~, Number~, Spectroscope~
In this lesson (in class) you have seen the object number~ several times.
This object has turned out very useful because it allows us to see what happens in numbers inside a signal. If scope~ and spectroscope~ give us a visual representation respectively of the time domain and frequency domain of a signal, with number~ we literally can see the variation in pressure as amplitude oscillating from -1 to 1.
Number~ is useful to show the various modifications a signal can take if multiplied, subtracted v.ia the mathematical signal operators. A signal oscillating from -1 to 1, if multiplied by 100, it will then oscillate between -100 and 100 (e.g. it is used in FM synthesis, for the modulator); a signal that needs to be reduced in amplitude as it is too loud, if multiplied by 0.5, will tunr out to osicllate between -0.5 and 0.5.
From left to right: a normal signal oscillation, a signal oscillation multiplied 100 times, a signal oscillation scaled by half (remember: multiplying a signal by 0.5 is the same as dividing it by 2)
Mathematical operators
Mathematical operators are objects that perform math in Max. They can be data math operators or signal math operators. The right-to-left Max rule is on with data math operators: a number into the right cold inlet cannot produce any output unless some other data has passed through the left hot inlet:
With audio signal math operators instead, although there is always a right-to-left computational order, the output is always present and updating, as the right-to-left computations complete very quickly.
Different uses of multiplier object *~
In this Lesson 2 we have seen multiplier used in three different ways. It can be used for:
- amplitude control (identical as using a gain~ fader to control volume)
- modulation
- mixing signals
Modulation is a form of amplitude control, in continuous change as it is done by an oscillator.
left to right: amplitude use, mixing two signals (and amplitude use too at the same time), amplitude modulation