[JimBob1971]

Hi,

I read a post on here recently that made me wonder whether the best sound quality from an iPhone (and other portables) is achieved using low volume, or high volume (and an attenuator to make it listenable through IEMs). The person is question thought that best SQ was always attained at top volume, as digital compression (?) was evident otherwise.

Anyone able to shed any light on which is likely to be the best?

 

[Stuee]

As I understand things, it is better to use an analogue volume control as reducing the volume digitally can introduce distortion as the sample values have to be recalculated to achieve the desired amplitude, and often the numbers 'don't go' exactly, which is where the distortion occurs.
Thus it is usually better to use a digital device at maximum volume (or zero digital attenuation) and attenuate in analogue - hence the reason everybody prefers to use the fixed output dock connector, which bypasses the volume control altogether = zero distortion.

Phew!

EDIT: Here's a link you should check out

 

[JimBob1971]

Great reply. Thanks!