Jazz club: to most, the phrase evokes a smoky room with dim white-blue light glaring onto a stage, reflecting subtly off of a deep golden saxophone as it wails over chord changes. But Firehouse 12, a small music bar at Crown and Church streets, offers something different. Here, the audience can watch live jazz in a studio, in many cases as it is being recorded for an album.

The performance area is a small stage surrounded by about 50 chairs in a half circle. Although this setup sacrifices some intimacy in comparison with the more traditional jazz club — the plain white walls, for example, make the environment feel sterile — it also engenders a deep connection between the audience and the performers. Everyone sits on the same level as the stage, and every sound — from the deep string bass to the warm splash of a ride cymbal to the offbeat foot tapping of an audience member — is an organic part of the performance.

Last Friday’s performance featured the Steve Lantner Trio, a free-form jazz combo with piano, bass and drums. All three players displayed tremendous technical facility through modal and sometimes atonal solos. Their sound, however, was probably too avant-garde to be accessible to the average listener, and even an experienced jazz player might have found this atonal, ambient sound uncomfortable.

Lantner, the pianist, draws upon jazz tradition in emulating the great stride pianist Fats Waller, modifying this older style into his own. However, much of Lantner’s soloing was disjunctive and incoherent. His playing was almost completely linear, as he ran parallel octaves for most of his solos; this tendency rendered his playing even more difficult to comprehend. Some left-hand comping would have been helpful in establishing the form and tonality of each tune for the audience, but chords were almost non-existent in this performance. This linear style, while interesting, becomes confusing and monotonous for the listener very quickly.

While this particular style might not sound appealing, Firehouse 12 hosts many different styles and configurations of jazz combos and bands. As part of their Fourth Annual Fall Jazz Series, Firehouse 12 will feature a different live jazz performance every Friday night at 8:30 and 10:00, and each new group will bring different styles, players and instrumentation.

“It’s a great opportunity,” said Steve Lantner after his trio’s performance. “There are way more bands than there are venues, so it’s nice when you can book a place like this.”

Lantner’s free-form style is not necessarily representative of future performances of the Fall Jazz Series, and this venue is a convenient and welcoming spot for anyone — from the casual listener to the serious musician — to enjoy jazz.

For Nick Lloyd, the series’ organizer, jazz and improvised music are pure forms of human expression.

“Jazz is unique among other forms of music in its reliance on improvisation and its openness to immediate musical communication: It lives or dies on the success of the interplay between the performing musicians, and that makes it relevant to the very moment you experience as a listener,” Lloyd wrote in an e-mail. “For me as a presenter, it’s a pleasure to be able to put on these shows and give interested listeners the opportunity to engage with this process every week.”

Next Friday, the Fall Jazz Series will feature the quartet Conference Call.