Conventional stadium PA · long throw
Amplified across the venue
3 ft135 dBat the speaker
330 ft95 dBfar seat
¼ mile81 dBparking lot
0.6 mile75 dBhomes
Long throw vs. near field
Why the neighbors hear the show.
Sound loses about 6 dB every time the distance from its source doubles. A stadium PA has to be loud enough to reach the last seat, so it is still loud when it reaches the parking lot and the homes beyond. VIP starts a couple of feet from each listener, so it only has to be loud enough to cross that short distance, and it fades away within a few rows.
VIP · near field
Delivered at the seat
2.5 ft95 dBat the ears
5 ft89 dBnext row
33 ft72 dB10 rows away
0.6 mile32 dBhomes
Same 95 dB for the fan. Very different night for the neighbors.
Level from one source as it travels away. Each line is set so the listener hears the same 95 dB. Distance is on a log scale, so every step to the right doubles or multiplies the distance.
Stadium PA, 95 dB at a seat 330 ft away
VIP, 95 dB at ears 2.5 ft away
Quiet residential night, 35 to 45 dB
To give a fan the same 95 dB, VIP starts about 40 dB quieter. That is ten thousand times less acoustic power leaving each source.
−6 dB
Every time the distance doubles
Sound from a source spreads over a growing sphere, so its intensity falls with the square of the distance. Two and a half feet to five feet costs 6 dB. Five feet to ten feet costs another 6.
330 ft vs 2.5 ft
The throw sets the starting level
A PA reaching a seat 330 ft away must start about 40 dB louder than the level fans hear. A source 2.5 ft from the ears starts almost at the listening level, because there is so little distance to lose.
Bass travels
Air soaks up the highs, not the lows
Over long distances the air absorbs high frequencies but barely touches bass. That is why neighbors hear the thump of a show. Wind and evening temperature inversions can carry it even farther.
How these numbers are worked out. Free-field inverse-square law (−6 dB per doubling of distance) from a single source, with each source set so the listener hears 95 dB. PA: 95 dB at a seat 100 m (330 ft) away needs about 135 dB at 1 m. VIP: 95 dB at 0.75 m (2.5 ft) needs about 92.5 dB at 1 m. The figures leave out air absorption, wind, ground effects, reflections off the bowl and speaker directivity, so they show the principle rather than a prediction for a specific venue. In a full venue many seat sources play at once and add together, so real-world results depend on system design and the room.
Sources: SFU Handbook for Acoustic Ecology, Inverse-Square Law · Stanford CCRMA, Air Absorption · Institute of Acoustics, Noise control procedure for open-air pop concerts
What it means for your venue
Keep the show. Keep the neighbors.
- Curfews and noise limitsDeliver the full show to fans while far less sound reaches the property line.
- Mixed-use neighborsEntertainment that can sit next to apartments, hotels and offices.
- Open-air stages and stadiumsNo roof to hold the sound in, so where the energy goes matters most.
- A calmer bowlLess stray sound bouncing around means less noise layered over the show.