High-resolution measurement and Q-matched filters are required for effective EQ
Evidence
Figure 14.31 illustrates what happens when measurements on a subwoofer in a room lack the resolution to reveal the problem in sufficient detail, and when the equalizer lacks the resolution to address the resonance. It is evident that high-resolution (1/20-octave in this case) measurements were necessary to reveal the true nature of the resonance and that matching the Q of the resonance with the parametric equalizer had a significant beneficial effect on the reduction of time-domain ringing. Excessive smoothing of room curves disguises the true nature of the resonance and prevents a maximally effective equalization. For similar reasons, a graphic-type equalizer with fixed filters, is not effective. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1633
Categorization
Category: Causal Relationships
- XREF: Directly relevant to practical subwoofer setup; a causal requirement linking measurement resolution to equalization efficacy — core to the reader’s goal of applying psychoacoustics to real systems.
- QUESTION: What measurement resolution is empirically sufficient for typical home rooms — is 1/20-octave always needed?
Related
- High-resolution measurement and matched Q are required for effective modal EQ. (similarity 0.95)
- Meaningful frequency-response specs require high resolution and narrow tolerance. (similarity 0.82)
- Equalization only corrects sound at the measured position, not the physical resonance (similarity 0.81)
- Modal decay times below 80 Hz are achievable with parametric equalization (similarity 0.81)
- Equalizing only the low-Q resonance substantially improves subjective loudspeaker ratings. (similarity 0.81)
- Equalization and mode cancellation both reduce bass resonance ringing despite different mechanisms (similarity 0.80)
- Room reflections cannot be corrected by electronic equalization (similarity 0.80)
- Lower Q spreads resonances wider in frequency but shortens time-domain ringing (similarity 0.80)
- Subwoofers must be equalized together, not individually, to sound right (similarity 0.80)
- Low-Q subwoofer resonances are audible mainly as spectral balance shifts (similarity 0.80)
- Tone-control adjustments are easily heard because low-Q resonance thresholds are tiny (similarity 0.79)
- Resonance detection thresholds rise with higher Q and lower frequency (similarity 0.79)
- Most loudspeakers need equalization to correct low-frequency room resonances (similarity 0.79)
- Audible resonance decay thresholds rise sharply as frequency decreases (similarity 0.79)
- Resonance Q reductions below about 16 are subjectively imperceptible (similarity 0.79)