Noise pollution from hazardous sound levels is a common phenomenon that affects both the quality of the listening experience and the health of the audience. It is unlikely that you have ever been at an event that has caused you pain and tinnitus. In order to provide a safe listening environment that protects hearing and to reduce noise pollution at events we need to carry out a site survey regarding homogeneous coverage, even frequency distribution, appropriate directionality and accurate SPL measurements.
Anatomy of the human ear: how does the human ear work?
The hearing system consists of three main parts:
Α. External ear
It includes the flap and the external auditory canal, which collect the sound and direct it to the drum. This area shows a normal amplification of about 10-15 dB at frequencies 2-4 kHz, which explains why the ear is more susceptible to damage within this frequency range when exposed to loud sound.
Β. Middle ear
It consists of the drum and the ossicles (hammer, hammerhead, stirrup) which act as a mechanical amplifier, process the sound and are directly affected by constant exposure to noise.
Γ. Inner ear
The cochlea contains hair cells which are easily destroyed when there is noise pollution at events or loud sound above the permissible limits. Buzzing or temporary hearing loss is a clear indication that hearing is impaired. When hair cells are destroyed, the damage caused is permanent and irreversible.
Legislation and protection measures
THE IA. A5/3010/1985 states that the music level inside shops can reach up to 80 dB(A) and in entertainment centres up to 100 dB(A), provided that the emission to the outside does not cause a nuisance. Quiet hours limit loud music, particularly at night (23:00-07:00).
Permissible operating sound level
- Indoor entertainment venues: 100 dB(A)
- Indoors in shops not considered to be entertainment centres: 80 dB(A)
- Outdoor/neighbourhoods: 50-60 dB(A) at night (depending on the characteristics of the area)
- Workplaces (8-hour exposure): up to 85 dB(A)
Protection measures on noise pollution at events
- Volume adjustment depending on the venue and the audience.
- Direction of speakers to reduce loud sound towards the dwellings.
- Use of delay or other techniques to lower the level to the public.
- Mount the speakers at a 45° room angle with a rubber tread under the speakers to reduce floor vibrations.
- Use earplugs when noise exposure is prolonged and see a doctor in case of severe ringing in the ears.
Control and penalties
In order to reduce noise pollution at events, checks are carried out using a sound meter. If the db exceeds the permissible limits then fines of up to €5,000 are imposed. Of course, excessive sound levels are requested to be reduced immediately and in some cases the music licence is revoked.
Sound Exposure Limits Based on Medical Data
The following data are based on international medical studies on the function of the auditory system and show when noise pollution at events and in our everyday life in general becomes dangerous for the hair cells of the inner ear.
| Level (dB) | Type of measurement | Example | Safe exposure time |
| 30 | A | Quiet room, library | Unlimited |
| 60-70 | A | Normal chat, office | Unlimited |
| 75-85 | A | Full restaurant, cafeteria | Up to 8 hours |
| 80-90 | A | City traffic, lawn mower | 4-8 hours |
| 95–105 | A | Large capacity engine | Up to 1 hour |
| 100–110 | A | Loud TV, chainsaw | 15 minutes – immediate danger |
| 110+ | C | Large concert speakers, airplane | Immediate danger |
| 140–160 | C peak | Gunshots, fireworks | Instantaneous permanent damage |
Notes:
- Type A: (detailed explanation, see section 4)
- Type C: (detailed explanation, see section 4)
- C peak: instantaneous very high pressures, dangerous for permanent damage to hair cells.
- Immediate risk: hearing can be affected even with brief exposure.
- Instant permanent damage: hair cells destruction, irreversible hearing loss.
A-weighting and C-weighting: what they really record
dB(A)
The A-weighting scale simulates human audibility but does not accurately capture low frequencies (bass). However, it is widely used as an official standard in legislation and regulations.
dB(C)
C-weighting captures the full spectrum with an emphasis on low frequencies. Useful for audio professionals, room studies, subwoofers and live applications. Reliable estimation requires measurements at many points due to amplification, cancellations and acoustic variations.
That is why MAX/MIN measurements are as important as the average (Leq).
Acoustic diagram
The acoustic diagram shows how we perceive different frequencies according to their intensity. The horizontal axis shows the frequency of sound in Hz and the vertical axis shows the sound pressure level in decibels (dB). The curves we see in the diagram are called equal-loudness contours and the unit of measurement of loudness is the phon.
For example, 60 phon is the intensity perceived by the human ear at 1000 Hz, at 60 dB SPL. To perceive sound at 100 Hz as the same intensity (60 phon), it takes about 80 dB SPL.
Interesting conclusions can be drawn from the diagram:
- Mid frequencies (2-5 kHz): here the ear is more sensitive, which makes speech and singing sound clear even at low volume.
- Low frequencies (<100 Hz): low frequency sounds need more energy to be perceived.
- When the intensity increases: Low frequencies become progressively more audible, while high frequencies are not so amplified. The acoustic curve “flattens”, i.e. the differences between low and high frequencies decrease.
The acoustic diagram helps so that depending on the level of the sound volume:
- We direct the energy of the sound correctly in the space.
- All instruments and voices are clearly audible, with no exaggerated low or high frequencies.
- The listener hears the sound as faithfully as possible to the actual source.
Space study to avoid noise pollution at events
Designing a venue is a key step to avoid noise pollution at events, to protect the public’s hearing and to avoid exceeding sound limits in catering areas. This study involves homogeneous coverage, uniform frequency distribution, appropriate directivity and accurate SPL measurements.
Homogeneous coverage
Homogeneous coverage is achieved by:
- The appropriate choice of speakers depending on the size of the room (e.g. line array for large rooms),
- Proper placement of speakers (2.5-4 m for small/medium spaces, 5-12 m for large line arrays). In very small spaces the volume is adjusted appropriately to protect the audience’s hearing,
- The correct distance and angle between speakers so that there are no excessive levels at near or far points; and
- The use of delay speakers, where necessary, to ensure that the sound reaches all zones at the same time with a constant volume.
Uniform frequency distribution
The uniform frequency distribution is ensured by:
- Adjusting the speakers so that each zone of the room can hear all frequencies well,
- Pay attention to the speaker phase, for a clean stereo image and to avoid cancellations,
- The distribution of energy so that each region hears all frequencies in balance, reducing the risk of hearing loss.
Appropriate directionality
Directionality is controlled by:
- The horizontal angles 60-120° are adjusted according to the width of the room for uniform coverage of the audience.
- The 10-40° vertical angles are adjusted to limit the energy to the ceilings and the floor, reducing noise pollution in the surrounding areas.
Accurate SPL measurements
Accurate SPL measurements are necessary to monitor the sound level and ensure that it remains within safe limits:
- We measure where the listeners are located, usually 1.2-1.5 m high, 5-15 m from the main speakers,
- We adjust the system to keep the overall SPL measurement low without affecting quality, protecting hearing and reducing sound problems at events.
Delay Speakers
Delay speakers are adjusted in milliseconds so that sound from the main source and delay bands reach listeners simultaneously, ensuring constant volume without echo and excessive energy up front, protecting hearing, avoiding sound problems at events.
This design and proper installation achieves a safe, clean and balanced sound environment where music reaches every listener evenly, while reducing noise pollution at events and health risks to the audience.
7. Conclusion: The Art and Science of Sound in Every Event
Any event with a strong presence requires careful acoustic planning. Our team conducts a detailed site survey, evaluating speaker directivity, coverage homogeneity, and system frequency response to deliver clean, balanced acoustics without overload or sonic hotspots.
With the combined application of scientific knowledge and professional experience, every event is transformed into an exciting acoustic experience, where every detail is perceived, ensuring hearing protection.
Contact us for a personalized study at your venue and bring out the acoustic effect of your next event at the highest level of quality.
