Is 2.3v compared with 2.0v significant?
A simple calculation then.
Originally Posted by STHLS5
What we are saying is that the louder CD player is a number of decibels (dBs) louder than the quieter one. How significant is 2.3v output compared with 2.0v? Audiology and psychoacoustics works in decibels not volts so we need to convert from volts to dBs.
We can calculate that decibel difference. First, dBs are simply a shorthand way of comparing A with B. Or C with D. Or X with K. dBs are a compariative measurement. Unlike kgs and seconds and amperes dBs do not exist as single entities: there must be a pair of things to make a comparison. dBs is nothing more than a nice neat way of expressing a ratio, one number divided by another number.
So, using the inbuilt Windows calculator set to (view) scientific mode, we enter the following ....
a) 2.3 divided by 2.0
b) The answer is 1.15
c) Then we press the Log button; the display says 0.060697.... (don't need to know why)
d) Then we press (*) times then type 20 then = (don't need to know why)
e) The result is that 2.3v relative to 2.0v is a gain of 1.21dB
We know from audiology text books and/or personal experience that a loudness difference of about 1.0dB is just enough for the careful listener to detect a very small difference in loudness, which the human brain will interpret as a difference in sound quality (specifically, sound spectrum). In the same way we can say that, if a tweeter unit is about 1dB louder than another nominally identical unit off the same production line, it might just sound a shade brighter to the trained, careful listener.
So yes, I don't doubt that as a careful dedicated listener you will experience a sonic difference between these players simply due to a difference in their output voltage. Let me guess: the louder one is the more expensive one? If I was designing a CD player that the marketing dept. wanted to sound 'full bodied and involving' under uncalibrated listening tests as you have described, I would make it play significantly lounder than a competitor unit .... not 2.3v rms but perhaps 3v, 3.5dB louder than the 2v player. That would give an obvious difference (in perceived sonic character) to even the most casual, dissinterested cloth-eared listener.
Alan A. Shaw
Harbeth Audio UK