Toe-in aimed at the listener compensates off-center phantom drift only at mid-to-high frequencies

Evidence

In the early days of stereo Hugh Brittain, recognized for introducing metal cone loudspeakers while he was at GEC in England, promoted the idea of aiming the loudspeakers so that their axes crossed in front of the listener. His name became associated with that arrangement. Knowing that loudspeakers are somewhat directional, especially at high frequencies, the idea was that as one moved away from center the more distant loudspeaker would get louder and the nearer one would be reduced in level, thereby achieving a crude amplitude panning to compensate for the delay error (time/intensity trading); the phantom image would be perceived to move less. Obviously, with typical cone/dome loudspeakers it only works at mid-to-high frequencies and the off-axis behavior of loudspeakers is unpredictable; sound quality is at risk. Added to this, the time/amplitude trading ratio is different for sounds of different spectral and temporal structure and images tend to break up. So, it is not a solution. — Toole, Floyd E, Sound reproduction- the acoustics and…, 428

Categorization

Category: Factual Claims

• XREF: Connects to the author’s caveat that time/intensity trading ratios vary by spectral-temporal structure — a mechanism echoed in broader psychoacoustic localization literature.

Related

• Toe-in loudspeaker aiming failed to stabilize phantom center imagery off-axis (similarity 0.91)
• Panning between two speakers recreates a phantom source positioned by interaural phase shift (similarity 0.84)
• Stereo phantom center images have a spectrum dip near 2 kHz from interaural crosstalk (similarity 0.82)
• Phantom center images reduce speech intelligibility due to interaural crosstalk (similarity 0.82)
• Headphones lack the phantom-center 2 kHz comb notch present in loudspeaker stereo (similarity 0.81)
• Phantom center image sound quality is inherently compromised even in the sweet spot (similarity 0.79)
• Equal-level stereo speakers create a phantom image midway between them (similarity 0.79)
• High-frequency interaural phase differences are ambiguous about azimuth location (similarity 0.79)
• Stereo loudspeakers create directional illusion through summed phase shifts mimicking time delays (similarity 0.79)

Broader Connections

• High-frequency interaural phase differences are ambiguous about azimuth location #complicates (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1467
• Panning between two speakers recreates a phantom source positioned by interaural phase shift #expands (0.78) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2200