In professional mixing, one of the most insidious obstacles is the change in sound perception as a function of listening volume<\/strong>. What we perceive as 'balanced' at a certain sound pressure level can be unbalanced, switched off or overloaded<\/strong> to another. This is not subjective suggestion, but a documented and quantifiable effect, described in detail by the Fletcher and Munson isophonic curves<\/strong>now standardised in the ISO 226:2003 protocol<\/strong>.<\/p>\n The isophonic curves show how the hearing threshold of the human ear varies with frequency and loudness<\/strong>. At low listening volumes (e.g. 60 dB SPL), much higher pressures are needed at the deep bass (30-100 Hz)<\/strong> so that they are perceived with the same intensity as the average frequencies<\/strong> (around 1,000 Hz). This imbalance gradually decreases as the listening volume increases<\/strong>to become almost negligible around the 80-90 dB SPL<\/strong>.<\/p>\n That is why the reference volume for professional mixing<\/strong> is 'historically' fixed at 85 dB SPL<\/strong>at this level, the human ear offers a sufficiently linear frequency response, with a good compromise between tonal fidelity and auditory security<\/strong>.<\/p>\n Here, with quantitative data, how sound perception changes<\/strong> at varying volume compared to the standard reference of 85 dB SPL.<\/p>\n +1-2 dB at 100 Hz<\/strong><\/p>\n<\/li>\n +8 dB at 50 Hz<\/strong><\/p>\n<\/li>\n +10 dB at 30 Hz<\/strong><\/p>\n<\/li>\n -2\/-3 dB at 3.5 kHz<\/strong> (medium-high)<\/p>\n<\/li>\n -3\/-4 dB in the super-high frequencies (above 10 kHz)<\/strong><\/p>\n<\/li>\n Increased sensation of reverberation depth<\/p>\n<\/li>\n Increased perception of background noise<\/strong> (humming, rustling)<\/p>\n<\/li>\n Subjective reduction of harmonic distortions<\/strong><\/p>\n<\/li>\n<\/ul>\n -4\/-5 dB at 100 Hz<\/strong><\/p>\n<\/li>\n -7\/-8 dB at 50 Hz<\/strong><\/p>\n<\/li>\n -9\/-10 dB at 30 Hz<\/strong><\/p>\n<\/li>\n Medium-high and high frequencies almost unchanged<\/strong><\/p>\n<\/li>\n Reduction of environmental perception and reverberation<\/strong><\/p>\n<\/li>\n Greater evidence of unmasked distortions<\/strong><\/p>\n<\/li>\n<\/ul>\n -18 dB at 30 Hz<\/strong> compared to 85 dB SPL<\/p>\n<\/li>\n -28 dB at 30 Hz<\/strong> compared to 110 dB SPL To ensure a mix translatable to all listening systems<\/strong> - from headphones to disco subwoofers - it is essential to test your work at multiple sound pressure levels<\/strong>.<\/p>\n Warning: theprolonged exposure above 85 dB SPL<\/strong> involves significant auditory risks. How logical, the finalisation sound pressure<\/strong> should take into account the listening habits of the target audience:<\/p>\n Each mix, however, must be also tested at different volumes<\/strong> from the preferred one to ensure cross-platform compatibility (hi-fi, car, headphones, etc.).<\/p>\n Listening at different volumes is useful in all stages of work<\/strong>:<\/p>\n In phase preliminary<\/strong>to assess the tonal quality of the isolated element<\/p>\n<\/li>\n In the process of mixing<\/strong>to check consistency between instruments<\/p>\n<\/li>\n In the process of finalisation<\/strong>to simulate real listening conditions<\/p>\n<\/li>\n<\/ul>\n Particular attention should be paid to:<\/p>\n Elements a low extension<\/strong> (kick, bass, timpani)<\/p>\n<\/li>\n Tools bright or shiny<\/strong> (voices, brass, high strings)<\/p>\n<\/li>\n<\/ul>\n Every sound professional is exposed to intense and prolonged acoustic stimuli<\/strong>. It is essential to adopt a listening routine that safeguard the integrity of the auditory system<\/strong>avoiding both continuous exposure to high volumes and sudden peaks.<\/p>\n Source: NIOSH and OSHA guidelines To achieve a consistent, translatable and professional mix:<\/p>\n Establish 85 dB SPL as primary reference<\/strong><\/p>\n<\/li>\n Work daily at 70 dB to reduce hearing fatigue<\/strong><\/p>\n<\/li>\n Check each mix at 60 dB and 105 dB for consistency<\/strong><\/p>\n<\/li>\n![\"\"](\"https:\/\/alessandrofois.com\/wp-content\/uploads\/2025\/06\/20-1.jpg\")
<\/p>\nThe basic principle: variation in auditory sensitivity at different frequencies<\/h2>\n
Comparative analysis: what happens when changing the listening volume?<\/h2>\n
85 dB SPL to 110 dB SPL transition<\/h4>\n
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85 dB SPL to 60 dB SPL transition<\/h4>\n
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Extreme example: listening at 45 dB SPL<\/h4>\n
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(values derived from reading of ISO 226 curves, 1000 Hz scale as reference<\/em>)<\/p>\n<\/li>\n<\/ul>\nSetting the right reference volumes for the mix<\/h2>\n
\u2705 Recommended volumes for sound work<\/h3>\n
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\n \nContext<\/th>\n SPL level<\/th>\n Recommended use<\/th>\n<\/tr>\n<\/thead>\n \n 85 dB SPL<\/strong><\/td>\n Standard tone reference<\/td>\n Testing and finalisation<\/td>\n<\/tr>\n \n 70 dB SPL<\/strong><\/td>\n Work volume<\/td>\n Safe daily routine<\/td>\n<\/tr>\n \n 60-65 dB SPL<\/strong><\/td>\n Soft listening<\/td>\n Checking equilibrium at low pressure<\/td>\n<\/tr>\n \n 105-110 dB SPL<\/strong><\/td>\n High-impact volume<\/td>\n Occasional testing for high-dynamic music<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n
Working daily at 70 dB SPL reduces fatigue and protects the auditory system in the long term.<\/p>\nFinalisation volume by music genre<\/h3>\n
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\n \nGenre<\/th>\n AVERAGE finalisation volume<\/th>\n<\/tr>\n<\/thead>\n \n Dance \/ EDM<\/td>\n 100-105 dB SPL<\/td>\n<\/tr>\n \n Rock \/ Pop<\/td>\n 80-90 dB SPL<\/td>\n<\/tr>\n \n Classical Music<\/td>\n 75-95 dB SPL (occasional maximum peaks up to 105 dB)<\/td>\n<\/tr>\n \n New Age \/ Ambient<\/td>\n 60-80 dB SPL<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Critical listening and volume variability<\/h3>\n
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\nHearing safety: every sound engineer's priority<\/h2>\n
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\n \nSPL<\/th>\n Recommended maximum exposure<\/th>\n<\/tr>\n<\/thead>\n \n 85 dB<\/td>\n 8 hours<\/td>\n<\/tr>\n \n 90 dB<\/td>\n 2 hours<\/td>\n<\/tr>\n \n 100 dB<\/td>\n 15 minutes<\/td>\n<\/tr>\n \n 110 dB<\/td>\n <1 minute<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n ![\"\"](\"https:\/\/alessandrofois.com\/wp-content\/uploads\/2025\/06\/21-1.jpg\")
<\/em><\/p>\nOperational conclusions<\/h2>\n
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