All tracks are non-DRM (evil stuff that DRM), driving into a load of 4 ohm speakers. Test will be repeated with supplied earphones and Sennheiser 64 ohm earphones. Album is Bat Out of Hell with a few bonus tracks.
As can be seen the low impedance speakers cause heavy battery drain (why not a higher impedance buffer amp at the front? - strange Logitech hey?).
Increasing bitrate makes no noticeable difference to battery life. However, the drain of the speakers will mask small changes hard to find. (9% battery use for each MP3 set, 16% for Vorbis)
Format: MP3
Bit rate: 128
VBR/CBR: VBR
Time played: 3976 (66:16)
Battery % Before: 100%
Battery % After: 91%
Format: MP3
Bit rate: 192
VBR/CBR: VBR
Time played: 3976 (66:16)
Battery % Before: 91%
Battery % After: 82%
Format: Ogg Vorbis
Bit rate: 192
VBR/CBR: VBR
Time played: 3976 (66:16)
Battery % Before: 82%
Battery % After: 66%
