The spectral response of the trumpet varies dramatically depending on its performed pitch and dynamic. The shape of a spectrum can be measured in terms of its spectral centroid, which is closely related to subjective brightness. We observe that trumpet spectra with the same centroid have similar spectral shapes regardless of their pitches. Based on a training set of 15 trumpet tones, a family of spectral envelopes has been created, each formed by averaging spectra with similar centroid values. For synthesis, a source spectrum is first sampled from the highest centroid spectral envelope. The remaining spectral envelopes are approximated by means of a variable low-pass filter. For each note produced, the filter is swept according to a time-varying centroid. Amplitude and frequency control functions are also matched. The result is a method that efficiently synthesizes convincing trumpet tones across the instrument's pitch and dynamic ranges using a wavetable and a centroid-controlled filter. [References: 13]
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