I can share my experience so far for what it's worth. I can't say how the 3600 compares to a sealed sub for music since I haven't had one in my room, but I can tell you that I am listening to more music these days than movies if that tells you anything.
The 3600 replaced a SVS 12/2 Ultra and I use PSA along with 3 PB13 Ultras. One of the first things I noticed was that the 3600 worked noticeably better with my PB13s as far as the general SQ goes. For music, I run pretty much a flat curve, but the subs running a bit hot (I adjust the level on a disc by disc basis)
I also just recently upgraded my speakers to a full PSA setup (210s up front and 110s in the rear for a 7.1 setup) which is a big factor in all the music I have been listening to lately. Just like the PSA speakers, I have found the 3600 and PB13s to be VERY revealing of the source material as I am hearing little details, both good and bad, that get lost in my car or other lesser type system. When you get an impeccably recorded and mixed low end like in the Talking Heads DVD-A Speaking in Tongues ( for example), it is a jaw dropping experience as the 3600 hits fast and hard....I think I used the term "hits like a sledgehammer"
in the PSA speaker thread the other day after listening to this disc.
Another example is a 192/24 FLAC Dead show I have from 1990 where Branford Marsalis plays with the band. There is a song (if your not familiar with the Dead) called "Eyes of the World" in this show that is known among heads as one of the all time best versions and a true live improv musical masterpiece. Point being that I have listened to this version of this song literally hundreds of times since it first happened in 1990 and it wasn't until hearing it on the PSA speakers/sub (along with the PB13s) that I realized what a huge part the bass guitar (Phil Lesh) played in this over 16 minute jazzy musical conversation. I had always heard this version as a conversation between Garcia and Branford as they played off eachother communicating musically with the rest of the band acting as support. Hearing it on the PSA gear showed that the bass was nearly as big a communicator as the guitar and saxophone as the 3 musicians are clearly all playing off eachother. It actually floored me because I know this version (I thought) so intimately considering how many times I have heard it in the last 26 years. I felt as if I finally heard the full impact of the song and the subs played a major part in this.
Just in the last week I have been floored with a number of musical experiences as far as the bass goes. First being the Talking Heads disc already mentioned. The second was the new Roger Waters The Wall blu ray which has some great bass moments (for a concert) throughout. The last 4 or 5 songs in particular starting with "Run Like Hell" showcased some great musical bass that was tight and punchy along with some effects bass thrown in that had me and my GF in awe with our jaws hanging open!
The other disc that floored us was U2 Rattle and Hum from the song "Bad" on. Bad in particular has 2 sections where the bass kicks in super low (for rock music) and extremely loud to the point that it pressurizes the room and creates these waves of bass
that wash over you in a shuttering, vision blurring type effect that is absolutely a mind blower! Again, I have heard this track countless times inymy HT over the years and while it has always been impressive and hit hard it was clearly at the next level.
I have listened to a wide range of music otherwise on cd, sacd, DVD-A and blu ray audio since getting the 3600 and anything impeccably recorded and mixed is amazing. Everything from Bob Dylan, Rap, Dream Theater, Metallica, Floyd, Opeth, Porcupine Tree, Flaming Lips, Big Band Music, The Dead, Talking Heads, Phish, Widespread Panic, etc.....these speakers/sub seem to handle everything well to one degree or another which I couldn't say the same with my JBLs.
I'm rambling, but point is I have been VERY impressed with the 3600 and PSA speakers for music. I actually can't stop buying multichannel music discs! Just bought 5 more Talking Heads albums on DVD-A which are on the way and can't wait to hear them. Hope that helps somewhat and sorry my thoughts are a bit scattered.