Revisiting Crossfeed settings...
I discovered that my previous settings could distort with a very small number of songs that have extreme bass at the edges of the sound stage. To be safe with just about any (reasonable) setting, Direct Gain should be no higher than -1.5 dB. (The setting that I had previously posted was just -0.5 dB.) To be absolutely safe and clean, I prefer -2.0 dB as that extra drop of 0.5 dB has no material negative effect.
To do 'same volume' comparisons of the effect of Crossfeed being on and off, you then have to adjust the iPod or amplifier volume by 2 dB accordingly. Otherwise the signal will be louder with Crossfeed off which will make it sound artificially superior. (Louder volumes generally sound more transparent which is also why volume matching is so important when comparing audio equipment).
I have also grown slightly more conservative with my Crossfeed settings, dropping the High-Frequency Attenuation by a further 4 db. This alters the sound a bit less but still provides a very desirable improvement with my ES5 by comparison with leaving Crossfeed off. It find it much less fatiguing. I have been using these new settings for about two weeks, making occasional comparisons to alternatives. I am very happy with them.
Direct Gain: -2.0 dB
Cross Gain: -12 db
High-Frequency Attenuation: -16 dB
High-Frequency Cutoff: 500 Hz
If you want clearly to hear the influence of Crossfeed settings, I recommend Monday, Monday by The Mamas And The Papas. It makes the changes sound a bit extreme - they will sound more subtle with just about any other song - but it allows for useful comparisons of different Crossfeed settings.
Edited by cooperpwc - 9/22/12 at 4:32am
