|
mark | Hi hawk, You mentioned on another post "The signal to noise ration of the 4300 is only 92 db, but in the 5300 it is 105 db, which works out to about 4 times less noise in the 5300" Please roughly explain the calculation for this. I really appreciate your time Mark |
|
Derek | The db scale is logarithmic because that't how we hear. Converting linear numbers to logrithmic numbers takes some calculation see http://www.phys.unsw.edu.au/~jw/dB.html. The difference between 92db and 105db is actually about 20 times less noise. Every 3db is about double. So the difference between 92 and 98 db (6db) is about 4 times less noise. Every 10db is about 10 times less. So 20db is about 100 times less noise. I arived at "20x" above by adding 10db to 92 and arived at 102. So we are at least 10x quieter. Now, we stil have a difference of 3db and since 3db will provide 2x the quieting, 2x10=20. Hope that helps. |
|
John A. | Derek, That is a great link. Thanks. I see "double" is an increase of 3.0103 dB, to four decimal places. So "about" is correct there. But for 10 dB, 20 dB etc. the factor is exactly 10, 100, etc. A signal-to-noise ration (S/N) of 100 dB means the signal has 10,000,000,000 times the power of the noise. This "power" is sound pressure level, not volume, which is subjective. The dB scale is adopted because it corresponds roughly with the way we hear; most people would experience a 10 dB increase in sound pressure level as a doubling in volume of sound. Your "20 x" is correct (19.952 x). But noise 92 dB below the signal is inaudible to start with, and so decreasing its power to one twentieth has no real meaning in terms of loudness. Therefore the difference between S/N ratios of 92 dB and 105 dB is not a practical consideration when buying an amp. Perhaps this was your point, and I am just being slow. |
|
mark | "Your "20 x" is correct (19.952 x). But noise 92 dB below the signal is inaudible to start with, and so decreasing its power to one twentieth has no real meaning in terms of loudness. Therefore the difference between S/N ratios of 92 dB and 105 dB is not a practical consideration when buying an amp. Perhaps this was your point, and I am just being slow. " So will it sound cleaner or not? (not louder) Cheers |