
A far more likely reason is that the recording was done in a room with unfavourable dimensions and poor absorption and poor distribution of sound. Why is this so? One possible reason could be a bad guitar with an unwanted resonance due to poor design or workmanship. It's as if this particular string on the guitar is louder than the other strings, in an annoying way. Whenever Roger Waters hits the G-sharp note which is the second note (or step) in the chord, a marked resonance can be heard. The song starts with a picked E-major chord on an acoustic guitar. The tune "If" which was written and performed mainly by Roger Waters and kicks off side two of AHM has an acoustic anomaly.

I'm just having a bit of audio-tech fun for myself. Don't worry I will never discard the originals and always value them as they are. Now I know that some of you might disagree with this tinkering, or even call it sacrilege. I feel sure I can improve the listening experience. The lower strings of the acoustic guitar are also much too resonant and boomy. I am going to repeat that experiment on the song "If" which I think is poorly recorded. The improvement on the boxy sound of the bass and drums is quite astounding. I then filtered the upper bass at 220 Hz as described in my first posting. I have ripped the AHM title track to my PC from the Gold CD using EAC.

I will start looking out for an affordable early Japanese CD. I appreciate the answers above (and look forward to comments to follow).

However, if you read elsewhere what the band think of this album, we must sadly conclude that this aint gonna happen. Having said all that it is truly magnificent and I honestly feel that if a Deluxe Edition of AHM is ever released, this quad mix should be on it in High Resolution format. So the only possibility that remains is that someone has/had access to a four track production master of some sort. I don't know what the source of this could be, but it sounds too good to be a Q8 Cartridge. Someone, somewhere made the quad release available in DVD-Audio format.
