Maybe the sound quality differences between the 60 and 90 are more to do with the 60 being flawed? Just looking at the measurements of each over at ASR and the 60 did not perform well.
Relatively speaking, yes, that's why
@Cos and I would have preferred that he compared the 90 to the 70, that measured a lot better. Still the AVM60's measurements seem to indicate sufficient transparency, going by generally accepted distortions threshold. So given that the difference seem so audible in Theo's test session with consistent results among 3 people, I have to guess that it might have been IMD and/or jitter.
Even IMD, the 60 didn't too too bad, but then we all know IMD is less forgiving so the 60's might just be high enough to make it audibly bad when compared to the pristine performance of the 90.
On AVSF, those compared the 90 to the 70, the majority heard enough difference to opt for the 70, but none that I know of had compared the two like Theo did, and in my own unscientific comparison in the dealers, I walked away with the 70 so I guess if it is a case of 90 vs 70, the results might not have been as dramatic.
Having said that, just for kicks, read a few posts on AVSF when one posted his comparison between the AV10, and AVM90: Note: Theo likely have read this poster's and I bet even he would have some skepticism, but as the poster forewarned "For equal double blind testing folks, this review isn’t for you – please look elsewhere.", so there is no point commenting on such a review, just read it for fun, curiosity, or whatever, otherwise ignore it and you might expect "over the top" kind of things in such reviews...
I am citing this particular one, because it is a comparison between two that based on ASR, and Audioholics.com's measurements, are so similar, practically identical in some cases, so go figure!
Marantz AV10 vs Anthem AV90 | Page 13 | AVS Forum
He made clear of the following:
All serious die-hard music listening was done in 2-channel only. No sound modes, no extra EQ, no extra channels, no outboard subwoofers (the 7001’s have built in subs so they are fairly full range).
I did not do double blind testing with level matching and a switcher. I did try to level match as close as possible, but each unit was tested separately at different times. I ran the Marantz for about 2 weeks, then the Anthem for about 2 weeks, then the Marantz / Anthem back and forth for 2 days, twice each. For equal double blind testing folks, this review isn’t for you – please look elsewhere.
Nothing is night and day, or life changing, or holy crap dramatic. Anyone who says that has bionic super ears. But the differences ARE very clear for sure.
All judgements here are for 2 channel MUSIC listening.
Comparisons…….
As another much more qualified forum member stated, the 90 has a 3D type sound quality. In comparison, the 10 is more 2D.
The 90 floats music out into the room, while the 10 is more flat inside the speakers.
With the 90, if you close your eyes, it’s hard to tell where exactly in space where the sound is coming from. With the 10 the sound is definitely coming from each speaker.
The 10 is extremely detailed and defined. Each and every pluck can be heard separately. The 90 is also very detailed, but it’s more “free” and loose.
The 90 is wide and loose, while the 10 is tight and restricted.
The 10 has a perceived quieter noise floor. It’s dead quiet. I didn’t perceive this on the 90.
The 10 has an actual lower “ear” noise floor in my system. With my ear on each speaker, I could hear some hiss and hum from the 90. I got none from the 10.
The 90 presentation has soul and emotion. The 10 is, in comparison, flat and lacks that “something” that makes it human.
The 90 sounds fluently “real” while the 10 sounds more decisively “robotic” or clinical.