The decibel is defined by ratio of power. Double pressure or voltage represents 6 dB. 10 dB SPL roughly relates to a change of perceived loudness at 1 kHz by a factor of 2, but represents 10x power and ~3.16 the pressure.Units of dB SPL and dBV reference a ratio compared to a certain value, generally 20 micropascals and 1 Volt rms. Reminiscent of JJ Johnston's old tube/transistor amp comparison. The story starts before 20 minutes in.
10/1/16 at 10:58am