A spectroscope displays a signal's spectral content — amplitude vs. frequency — in real time

A spectroscope (spectroscope~ in Max/MSP) is an analysis object that shows a signal’s frequency spectrum: the horizontal axis is frequency (0 Hz to Nyquist), the vertical axis is amplitude. It uses an FFT (Fast Fourier Transform) internally. Unlike a time-domain oscilloscope (scope~), which shows amplitude vs. time, a spectroscope reveals which frequency components are present. It makes the abstract concept of spectrum concrete: white noise appears as a roughly flat line; a sine wave as a single spike; a sawtooth as evenly-spaced harmonic spikes. Using a spectroscope alongside a filter or oscillator patch is the most effective way to observe spectral changes in real time.

Examples

noise~ → spectroscope~: flat white-noise spectrum visible. Adding a lores~ filter before spectroscope~: the spectrum rolls off above the cutoff. Watching it change as you move the cutoff slider makes filter behavior tangible.

Assessment

Describe what you would expect to see on a spectroscope~ when monitoring: (a) a 440 Hz sine wave; (b) a 440 Hz sawtooth; (c) pink noise.