L-1 Acoustic Emissions

The measurement of Acoustic Emissions serves many purposes. It makes a qualitative comparison of the L-1 design with others possible. It allows a determination of what exactly is causing the emissions as well as which emissions are the most intense. It helps in the determination of which emissions can be decreased. It helps in the selection of materials that absorb acoustic energy, as well as in finding the best places to install these materials.
 

Specifications
Acoustic
Airspeed
Efficiency

These measurements are published so that potential buyers of the design can compare our machine to that of our competition, as well as helping to determine its compatibility with a proposed site. An important thing to remember is that our prototype machine is still in it's basic configuration. Nothing has been done thus far to reduce noise emissions even though quite a bit can be done. Yet the design is very quiet compared to competing designs, especially for an outdoor type.

Click below to look at acoustic measurements taken at the named locations:

Chart Explanation
The charts show the intensity of sound at different frequencies (pitches). The horizontal scale shows the audio frequency in Hertz (Cycles Per Second) with low frequencies such as thunder to the left, and high frequencies such as the crack of a whip to the right. The vertical scale shows the intensity of the noise in decibels(db). Decibels (db) are the standard unit for audio intensity. A db is the minimum difference a person can detect. The legend to the right of the chart shows the RPMs for a specific line, and the total db reading from the meter for that measurement. The meter has three scales. The low scale is used for the ambient readings, while a higher scale is used for louder noise. A zero measurement means that reading was below the minimum of that scale.
The following links to unrelated web sites are provided for your convenience. They will help you understand these measurement units:
Decibels:
http://www.coolmath.com/decibels1.htm
http://www.lhh.org/noise/decibel.htm
Frequencies:
http://www.dplay.com/tutorial/freqpaint.html

For most of these tests we are using a Phonic PAA2 Personal Audio Assistant. You can click the model name/number above to go to the manufacturers site to read about this sound meter. There is also a wealth of information on the internet if you simply search for "Phonic PAA2". You can read a review on page 32 of the December 2003 issue of Pro Audio Review.

If you have any doubts about these measurements, you are welcomed to come make your own with your own equipment.

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