Certainly a fair statement and it seems on my system the AP1+PP on Input 1 has the most enjoyable sound by a nose versus Input #3 or USB32. As far a music anything that is dynamic - extended range tests my system from popular to classical music. Madonna has been a singer that is hard to reproduce without climbing the walls. Phil Collins is another from very recent memory.
The song included here (Madonna-Cherish from Celebrations (2009) 44.1k/16 flac) is a real test. If you would like to download it and try for yourself just Click on the link, Check the box on the track, select Download, and Save to your drive. For copyright purposes the song has been truncated slightly and included here for demo purposes only.
https://skydrive.live.com/#cid=636DC4E8060D66A1&id=636DC4E8060D66A1%21172
Here are my impressions of the Master 7 Inputs with this tune....
1. AP1+PP Input #1 - Big, deep bass but rhythmically tight with separation of synth bass and kick drum. Nice vocals - rarely anything other than normal sibilance. The notes of the airy synthesizer during the chorus seem to hang in space. Warmer sound compared to the other inputs but very detailed with nice sparkle that is evident in the choruses.
2. AP1+PP Input #3 - Not as much bass it seems as Input #1 but still plenty. Cooler sounding overall. Space narrows. Not bad but not as engaging as Input #1. Some smearing of detail top to bottom.
3. USB32 - Similar to AP1+PP on Input #3 as being cooler sounding with narrower space as compare to Input #1. Some edginess in the vocals with frequently too much breath (sibilance). Not as much clear, distinct inner detail as Input #1.
The differences are slight but can be heard on my setup. I'm not bothered at all by it. I used the USB32 input for months and didn't think anything about it. It's only when you have something else to compare that you notice (or not). I would really be interested in other impressions if someone has a similar setup.