Filtering alters timbre, but nearby spectral boosting can partially offset the loss

Evidence

A related and important area of signal processing to filtering is equalization. Unlike filtering, equalization is not interested in removing frequency components but in selectively boosting, cutting or reducing them to achieve a desired effect. The process of equalization can be modeled as a process of adding or subtracting a filtered version of the signal from the signal, as shown in Figure 7.40. Adding the filtered version gives a boost to the frequencies selected by the filter, whereas subtracting the filtered output reduces the frequency component amplitudes in the filter’s frequency range. The filter can be a simple highor low-pass filter, which results in a treble or bass tone control, or it can be a band-pass filter to give a bellshaped response curve. The cutoff frequencies of the filters may be either fixed or variable depending on the implementation. In addition, the bandwidths of the band-pass filters and, less commonly, the slopes of the highand low-pass filters can be varied. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2419 (#exemplifies, via linked claim)

Categorization

• XREF: connects to: Inhibitory networks that sharpen spectral peaks can aid listeners with reduced frequency selectivity — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2013; Instrument timbre differences stem from harmonic spectra that shape masking breadth — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 449; Equalizer adjustments at specific frequencies produce predictable perceptual shifts in timbre (+2 more)

Broader Connections

• Equalization selectively boosts or cuts frequencies rather than removing them #exemplifies (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2419