[rubberneck]

Originally Posted by cszakolczai

Ok well heres the rumor
A buddy of mine has a friend who owns a para ordnance handgun. My buddy was able to put a couple of rounds through it, he says that it was so loud he couldn't hear. This I can understand, but than the kid whos handgun it was said that the noise is about the same as a suppressed M4. This I just can't take myself to believe. My friend told me to get some proof that the M4 was quieter so I am coming to you guys. Whats the real truth here?
Chris

The guy who owns the Paraord is an idiot. I copied this from Surefire's website:

Sound Science Made Simple.
The design went through several iterations as the sophisticated Danish sound machine told Dueck and Smith precisely what baffle arrangements worked better than others. Sound reduction, he found, was also dependent on atmospheric conditions. "We'd get one reading one day and another the next. Barometric pressure, temperature and humidity were all having an effect," Dueck said. "We had to test a given design a number of times under different conditions to get a meaningful reading."
After finalizing on the optimum design, the noise attenuation was rated at between 27 and 30 decibels (dB), reducing the sound of a 5.56mm to a handclap from an ear-splitting crack.

To appreciate how significant a reduction 30 dB represents, we need to understand how sound is measured. Most noise sources are measured in terms of intensity, or strength of the sound field. The standard unit of measure is 1 dB which is the amount of sound that is barely audible to the average human.

The decibel scale is logarithmic, meaning that each unit is 10 times that of the preceding one. For example, a noise source measuring 70 dB is 10 times as loud as a source measuring 60 dB and 100 times as loud as a source reading 50 dB.

A barely audible whisper measures 10 dB and a speeding express train rates 100 dB, although the train generates 10 billion times as much sound energy. This misleading difference can also be seen in earthquakes using the Richter scale, which is a logarithmic scale like the decibel scale. A magnitude of 5.3 on the Richter scale is a moderate earthquake, while a devastatingly strong earthquake has a magnitude of 6.3. Thus, like sound, a small difference in value actually means a great difference in intensity. "Reducing a gunshot by 30 dB makes it 1,000 times quieter. To put it another way, the sound of the action cycling - just the bolt clattering back and forth - is louder than the round firing," Dueck explained.

"Even a 14-inch barreled M4 can be safely fired indoors without damaging your hearing," the director of the Suppressor Division added. "This is a very significant tactical advantage."