Tactile vibration raises perceived loudness and lowers preferred bass levels

Evidence

The loudness of a sound presented via headphones is perceived to be higher in the presence of a simultaneous tactile vibration produced with a whole-body shaker. The change in loudness corresponds to a change in level of about 1 dB (Merchel et al., 2009). In bass reproduction, the preferred level of acoustic sound is lower if a shaker is also used to reproduce low frequencies (Simon et al., 2009). Interestingly, this auditory–tactile loudness interaction does not depend significantly on the power of the vibration (Merchel et al., 2009). — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1826

Categorization

• CANDY: A fun fact: adding a vibrating shaker makes audio seem louder regardless of how strong the shake is.
• ADDENDUM: Directly relevant to the trees-as-infrastructure article’s broader theme? Not really — but it is a clean acoustic-application data point for the reader’s stated goal.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1826
• XREF: connects to: Small bass-level changes strongly alter perceived spectral balance; Headphone bass boosts may compensate for missing haptic sensation from loudspeakers — Toole, Floyd E, Sound reproduction- the acoustics and…, 1863; Loudness perception involves central mechanisms beyond cochlear vibration (+4 more)

Broader Connections

• Tactile vibration accompanies most real sound and fuses with it unconsciously #expands (0.80)
• Perceived loudness does not map one-to-one onto acoustic amplitude #expands (0.72) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 616
• Volume changes alter perceived frequency balance, not just loudness #expands (0.70)
• Adding lower-frequency sound can decrease perceived sharpness #complicates (0.70) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1350