Discrimination of musical instrument sounds resynthesized with simplified spectrotemporal parameters

Abstract

The perceptual salience of several outstanding features of quasiharmonic, time-variant spectra was investigated in musical instrument sounds. Spectral analyses of sounds from seven musical instruments (clarinet, flute, oboe, trumpet, violin, harpsichord, and marimba) produced time-varying harmonic amplitude and frequency data. Six basic data simplifications and five combinations of them were applied to the reference tones: amplitude-variation smoothing, coherent variation of amplitudes over time, spectral-envelope smoothing, forced harmonic-frequency variation, frequency-variation smoothing, and harmonic-frequency flattening. Listeners were asked to discriminate sounds resynthesized with simplified data from reference sounds resynthesized with the full data. Averaged over the seven instruments, the discrimination was very good for spectral envelope smoothing and amplitude envelope coherence, but was moderate to poor in decreasing order for forced harmonic frequency variation, frequency variation smoothing, frequency flattening, and amplitude variation smoothing. Discrimination of combinations of simplifications was equivalent to that of the most potent constituent simplification. Objective measurements were made on the spectral data for harmonic amplitude, harmonic frequency, and spectral centroid changes resulting from simplifications. These measures were found to correlate well with discrimination results, indicating that listeners have access to a relatively fine-grained sensory representation of musical instrument sounds.

Perceptually Correlated Parameters of Musical Instrument Tones

“…The objective of this study (McAdams et al, 1999), originally published in 1999, was to investigate the relative importance of some different spectrotem-poral parameters by simplifying musical sounds with respect to these parameters. The stimuli prototypes (reference sounds) consisted of tones performed on seven different instruments: clarinet, flute, oboe, trumpet, violin, harpsichord, and marimba at pitch E b 4 (311 Hz).…”

“…Three projects are reviewed, a timbre discrimination study (McAdams et al, 1999), a timbre dissimilarity judgment study with MDS solution Hall et al, 2010), and a timbre transposition study (Beauchamp, Bay, 2008).…”

“…Reasons for choosing these parameters are discussed in the timbre literature (see Hajda (2007) and Donnadieu (2007) for reviews.) Methods for measuring and varying them are given in (McAdams et al, 1999) and (Beauchamp, Lakatos, 2002).…”

“…For pitch normalization of harmonic sounds it is generally acceptable to make certain that the fundamental frequencies are the same. Duration is a bit more complicated, but a method is given in (McAdams et al, 1999), where attack and decay structures are retained and the total duration is reduced to a standard 2 s.…”

“…The parameters to be identified from the sounds are first of all the time-varying amplitudes and frequencies obtained from spectral analysis. Then, more detailed, possibly perceptually important parameters can be inferred, such as attack and decay times, spectral envelope features (such as spectral centroid, spectral irregularity, and spectral flux), vibrato characteristics, and inharmonicity (McAdams et al, 1999;Beauchamp, Lakatos, 2002).…”