Equal temperament beats stay within the 5% critical bandwidth so consonance survives

Evidence

Music can be played in all keys when equal tempered tuning is used, as all semitones and tones have identical frequency ratios. However, no interval is in tune in relation to the intervals between adjacent members of the natural harmonic series (see Figure 3.3); therefore, none is perfectly consonant. However, intervals of the equal tempered scale can still be considered in terms of their consonance and dissonance, because although harmonics of pairs of notes that are in unison for pure intervals (see Tables 3.6 to 3.12) are not identical in equal temperament, the difference is within the 5% critical bandwidth criterion for consonance. Beats (see Figure 2.6) will exist between some harmonics in equal tempered chords that are not present in their pure counterparts. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1045

Categorization

• XREF: Connects the critical bandwidth criterion from earlier psychoacoustics chapters to why tempered chords still read as consonant.
• DEEPTHINKING: Elegant reconciliation: equal temperament sacrifices pure intonation, yet consonance persists because residual beats fall within the critical bandwidth already established as the consonance threshold.