Sound Machines and Infant Safety
Sound machines can be harmful to babies if used improperly, specifically when played at high volumes or placed too close to the infant, as they are capable of producing sound levels exceeding 85 dB that may cause noise-induced hearing loss. 1
Evidence of Potential Harm
The primary concern with infant sound machines relates to their maximum output capabilities and proximity to the infant's ears:
All 14 tested infant sleep machines produced sound levels exceeding 50 A-weighted dB at 30 cm distance, which surpasses the recommended noise limit for hospital nurseries. 1
Three machines generated output levels greater than 85 A-weighted dB, which—if played for more than 8 hours—exceeds occupational noise exposure limits for adults and risks noise-induced hearing loss. 1
At maximum volume settings, 64.3% of tested devices (9 out of 14) exceeded 85 dBA when placed 10 cm from the measurement point (simulating placement within a crib). 2
No devices exceeded the 85 dBA threshold when placed 30 cm or farther from the infant. 2
Developmental Concerns
Beyond immediate hearing damage, chronic exposure raises additional concerns:
Animal studies demonstrate deleterious effects of continuous moderate-intensity white noise exposure on early development, with human data generally corroborating these findings. 3
White noise machines can reach 91 dB on maximum volume, exceeding National Institute for Occupational Safety and Health guidelines for a 2-hour work shift in adults. 3
The American Academy of Pediatrics recommends maximum sound levels of 45 dB for infants in hospital nurseries, a threshold that all tested machines exceeded at close range. 1
Safe Usage Guidelines
To minimize risk while allowing parents to use these devices, specific operational parameters must be followed:
Never place sound machines inside the crib or within 30 cm of the infant's head. 2
Avoid using maximum volume settings under any circumstances. 2
Position devices at least 100 cm away (across the room on a nightstand) to ensure sound levels remain below harmful thresholds. 2
Limit duration of continuous exposure, as prolonged use compounds risk even at moderate volumes. 3
Important Caveats
A critical distinction exists between harmful noise exposure and potentially beneficial low-intensity sound:
Some evidence suggests low-intensity noise exposure may be beneficial during sleep, though optimal intensity and duration remain undefined. 3
The protective effect of sound masking must be weighed against cumulative noise exposure risk, particularly in vulnerable preterm populations. 4
Current evidence is insufficient to recommend sound machines for SIDS prevention, and these devices may produce false alarms that increase parental anxiety and disrupt sleep. 5
Clinical Implications
For healthy, full-term infants without pre-existing conditions, sound machines are not inherently dangerous but require careful implementation. The risk-benefit calculation shifts dramatically based on volume and distance. Parents should be counseled that these devices, while popular, carry real risks of permanent hearing damage when misused, and that complete silence or very low-level ambient sound is preferable for infant sleep environments. 1, 3
The hearing impairment rate in preterm infants (2-10%) compared to the general pediatric population (0.1%) underscores the vulnerability of developing auditory systems to environmental noise. 4 While this statistic primarily reflects NICU populations, it illustrates the principle that excessive sound exposure during critical developmental periods carries lasting consequences.