2007/2/9, Ed Kelly <morph_2016@yahoo.co.uk>:
So, if you have a signal at 96dBPD (-4dBFS) and you set it to 90dBPD (-10dbFS), the loudness will be heard to drop by the same amount as when you then set it to 84dBPD (-16dBFS).
... but remember, that ear's frequency response curve is dependent on the level of sound... So the amount is not "the same".