Hit us with that comparison of the two...
I'm at the place where my speakers are now the weak link in my system and so I am only getting a bit of what I suspect is there.
The soundstage is fuller, meaning that there is less missing space between the speaker edges and center image. The JBLs I have are excellent at imaging. The singer is dead center and in well mastered music the speakers disappear. However, when the mix is expansive and really pushes the sound to the very edges of the speaker boundaries I can hear left speaker, dip/gap, center image, dip/gap, right speaker. The Duo has done a good job of nearly eliminating those dip/gap spaces. Again, in better speakers I'm sure that gap would simply be gone.
Another thing I notice is better edging of sounds. By edging I don't mean "sharp" edges, but more "defined" edges. I feel as if the sounds are more "present" without sounding blended into other sounds. What this has lead to is more layers of sounds being heard. It isn't that if I switch back to the 20/20 I don't hear most of those sounds...but I have to focus on hearing them more. Whereas with the Duo I keep experiencing "wow, I haven't heard/noticed that before" without losing the sounds that I was normally hearing in the mix with the 20/20. An example of this is Dua Lipa's
Future Nostalgia. The mix on this album has lots of information and the soundstage goes well beyond speaker edges. There was just so much more information I noticed when listening to the Duo. I thought maybe it was just confirmation bias going on, but when I went back to the 20/20 I
could hear those things but I they just weren't as
present.
Another thing I noticed is increased perceived sound decay. Which again just has to be a function of the increased definition of sounds I mentioned above. Meaning, the information on the recording hasn't changed so if I am hearing more decay it has to be that the Duo is simply revealing more of the tail end of the notes than I heard with the 20/20. I noticed this first while listening to Melody Gardot's
Currency of Man. Notes just seemed to hang in space longer. It was really cool.
So, would I recommend someone jump from the $2200 20/20 to the $4000 Duo? Probably not unless they got a great deal on one like I did. Is there improvement? Absolutely! Am I enjoying that improvement? Damn right! Will I get even more impact with better speakers? Yeah. But, I spent the money on the preamp instead. Perhaps I would have been smarter to go with the better speakers first. But, where I currently live I can't buy and use the speakers I want as my neighbors would call the cops. So, I decided to bet on the future impact the Duo's will have over the 20/20 on those next speakers when I am living in a place they will "fit".
In the mean time I have no complaints. I still gained definite improvement at an excellent price and the expectation of even bigger impact in the future.