sound to noise ratio?

[dirtysouth05 10+ year member]

Can someone please verify exactly what the s/n ratio on an amp means. The higher in db it is the better?

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[thch 10+ year member]

Can someone please verify exactly what the s/n ratio on an amp means. The higher in db it is the better?

signal to noise ratio is pretty defined in itself. it is the highest signal to noise ratio possible.

basically the universe is not perfect. some unrulely electrons will move around and make their own signal.

the amp will play that signal.

the amp also plays your musical signal.

under good conditions, the power in the music signal will be X times greater then the power in the noise.

X is expressed in dB. 60dB = 1,000,000 times more signal then noise power -- a 100W amp with a SNR of 60dB would put out 100W of signal, and 100 microWatts of noise. 80dB is 100,000,000x. 100dB is 10,000,000,000x difference in power.

cd's are limited to just over 95dB for "real snr".

People have realized that some noise is more noticeable then others. people have a hard time hearing noise at 20hz or 20,000hz, but hear noise easily at 2000hz. so a curve was made. this is A-weighting. it means the number has been adjusted to show the difference in signal to noise as seen by the typical ear.

this is also used in modern CD mastering. it is actually possible to get a much higher A-weighted SNR then the normal SNR limit by "noise shaping".

SNR also defines the "dynamic range" or the ratio of the largests signal that can be played to the smallest signal possible.

note that if the music is at a quite point, the effective SNR may fall.

 

[squeak9798 5,000+ posts]

Just to add....most modern amplifiers will have a SNR ratio high enough that using it as a comparison (Amp A > Amp B because it has a higher SNR) is pretty meaningless. Most any amplifier will have a signal to noise ratio that is high enough that it won't make an audible difference in your system.