Sound

Sound is measured in two different ways: Intensity (how high or low the volume is) and frequency (how high or low the pitch is).  Since most of you guys call us up asking for the biggest, loudest, baddest set of horns we have, well start with intensity. 

The phenomenon of sound is caused by a vibrating object moving particles through a medium (air, water, or a solid object).  Intensity is a measure of how much that vibrating object moves the particles over an area.  Within the sound wave, the displacement of those particles is called the amplitude.  The greater the amplitude of the sound wave, the greater the intensity of the sound.  The greater the intensity, the louder the sound. 

Inside the end cap of each air horn trumpet there is a thin metal diaphragm that vibrates when air passes over it.  If the pressure or volume of air supplied to the diaphragm is increased, the amplitude of the vibration increases which causes that devastating sound weve all grown to love. 

 

The intensity of a sound is measured in decibels.  The decibel scale measures how many times greater the energy output of sound wave is compared to the threshold of hearing.  Threshold of hearing is the intensity at which the human ear can detect sound.  This level of intensity is assigned 0 db on the decibel scale.   As a sound rises on the decibel scale, its energy output (or intensity) increases by an exponent of 10.  For example, a sound that measures at 10 db is 10 times more intense than the threshold of hearing (0 db).  A sound that is 20 db is 100 times more intense than a sound at 0 db.  The same pattern applies as you move up in the decibel scale.  For example, a sound at 90 db is 100 times more intense than a sound at 70 db, and a sound at 100 db is 1,000 times more intense than a sound at 70 db. 

 

Sound Source

Sound Pressure Level

(dB)

threshold of hearing

0

rustle of leaves

10

soft whisper

30

mosquito buzzing

40

average townhouse

50

ordinary conversation

60

busy street

70

power mower

100

threshold of pain

120

rock concert

130

jet engine at 30m

150

rocket engine at 30m

180

 

 

For those of you who dont care about sound waves and the rest of this nonsense, there are two things you should definitely know about the measure of sound. 

  1. Each increase of 3 db on the decibel scale equals a double in the sound intensity
  2. Fun Fact:  A sound that measures 150 db (like the output of most of our air horns) is 1,000,000,000,000,000 times more intense than the human threshold of hearing. 
 

How Loud Are They?

There has been a lot of speculation as to how loud these horns actually are and what variables actually affect the sound levels that the horns reach.  We decided to find out once and for all just how much noise these horns are putting out. 

These horns are too loud to test with normal tools.  We needed a meter that could handle the intensity of the output.  To test these bad boys right we knew just where to go.  We packed up our horns and took them down to T-Rex Audio in Stratford, CT (www.trexcaraudio.com).  If anybody knows loud, its our buddy Manny Alves, the owner and operator of T-Rex.  With over 12 years of expertise in car audio, sound, and security, Manny has been named National SPL Champion four times.  Manny has a SPL meter that is perfect for the job, so he let us use his shop as our testing ground.

T-Rex Audio in Stratford, CT

 

T-Rex Audio Owner Manny Alves with our test rig

 

We started lighting up the meter with our horns and it was insane.  We tested each horn at 100 psi and 150 psi.  One horn got up to almost 157 db!  I hope everyone appreciates the physical pain I went through to get these numbers. 

 

Model DB @ 100 PSI DB @ 150 PSI Sound Clip
99-1 151.3 153.6 Listen
102 146 153.5 Listen
130 148.7 152.9 Listen
141 149.2 150.3 Listen
220 152.7 154.2 Listen
230 150.6 153.3 Listen
230 (With BlastMaster Kit) --- 156.9 Listen
500 149 151.7 Listen
501 149.1 152.2 Listen
502 149.1 152.2 Listen
630 151.8 154.4 Listen
630 (With BlastMaster Kit) --- 157.3 Listen
Pro Series 2 147.3 149.5 Listen
Pro Series 4 141.9 143.7 Listen

 

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