I own a pair of AVI9 RS's (the latest versions) as well as the AVI 10" sub.
Loudness is definitely not an issue with or without the sub. I have played them loud (loud enough for my lounge / kitchen open plan room (11meters / 3 meters (played at one end of the room)) without any issue.
Vocals and treble are also not an issue – with house / techno / minimal electro all the detailed clicks, whoosh’s etc... sound amazing.
Bass on house / techno / minimal electro also sounds very impressive – mainly due to the sub. I have no idea how loud the sub goes, but it is very powerful.
There is more of an issue if you like hip hop. For a very specific e.g: Kendrick Lamar M.a.a.d City. For anyone that knows this song, there is a very particular B-Line that comes in. The AVI’s (including the sub) don’t do a good job of picking this up. The lower mids / upper bass, even with the sub and even with all the speaker cones vibrating a lot, just aren’t projected. Other songs on his album do sound good though.
Otherwise, FLAC / .wav’s for classical, jazz (& the genre’s mentioned above) sound very good. Oh and I play my Samsung 46” LED through them and TV and film all sound very good (especially with the sub).
A word of warning with the AVI’s: the quality of the music played through the DAC has to be high, as the crystal clear tweeters will pick up all the noise. I’ve started to abandon some old songs I have on my PC already.