Hardly a man is now alive who remembers when the Budapest Quartet was comprised exclusively of Hungarians, and not too many can recall the days when the Tokyo String Quartet was an all-Japanese ensemble. But this reviewer goes back a very long way with the Tokyo, all the way back to summer evenings at Yale music school in the mid-1970s – I have been listening to violist Kazuhide Isomura perform with various partners for more than 30 years now.

I, among others, have recently pointed out that there was something amiss in the Tokyo Quartet. The group has now begun to address the problem, asking relatively new first violinist Mikhail Kopelman to step down in favor of Canadian Martin Beaver. The issue was primarily a stylistic one: Mr. Kopelman’s effusive Slavic brio was a bit much for this once smoothly blended but reserved ensemble. Certainly the sound of the group is nowhere near as unified as in its heyday; one wonders how many degrees of separation the quartet can withstand (cellist Clive Greensmith is also rather new) and still keep any sense of identity. As Jerry Seinfeld once said about the era of free agency in sports, we root only for the team jersey now, not for the players.

Wednesday night the new and different quartet appeared at the Kaplan Penthouse on Lincoln Center Plaza, the latest attraction of the Mostly Mozart Festival’s “A Little Night Music” series of soirées. The atmosphere was cabaret style, with round tables in the center and bar stools on the sides. Complimentary wine and water were served. Except for the occasional clinking of glasses and snippets of conversation, the music progressed relatively undisturbed, although there is more street noise on the 10th floor than I had realized. The crowd was reasonably well behaved, allaying my fears when first observing the layout of the room that a heckler might at any point spoil the moment.

The hour-long concert began with Mozart, specifically the quartet K. 575, known as the “Prussian” since it was written for amateur cellist Frederick William II. Once the music started, the room took on the feel of a catered wedding dinner, complete with lit candles on every table and along the windowsills. The piece is a great one, but is ultimately a prime example of tafelmusik written for a nobleman’s pleasure. The relaxed and convivial atmosphere at Kaplan was probably much closer to that of the original performances, but it still takes some adjustment to hear this type of profundity outside of the concert hall.

Though past iterations of the Tokyo achieved high levels of performance, its years at the pinnacle of chamber groups are probably now forever behind it. It is difficult to compete with the roseate memories created by oneself, but the occasional technical gaffe and the somewhat tired phrasing of this performance argued strongly that there is a palpable deterioration in the ensemble as a whole. Mr. Beaver has a decent tone, though not a particularly rich one, and he has that bad habit of lingering just a nanosecond too long on his strings, creating unwanted overtonal chaos, especially when his mates have already chimed in with their next utterances.

Also performed on Wednesday night was the more famous of the two string quartets by Bedrich Smetana subtitled “From My Life.” The depth of feeling these gentlemen obviously have for this piece seemed to ignite both intensity and sloppiness. The highly dramatic viola statement was filled with angst and fire, and we were off on a wild journey of reminiscence. This was full-blooded narrative to be sure, but it was also related with a certain light touch that can otherwise be infused with a tad too much Sturm und Drang.

Beethoven, of course, comes to mind when listening to the mature works of the deaf Smetana, but in addition to the rage against nature there is also the quiet reflection in tranquility that only those rare few of us who truly live in our own little world can muster. I would hope that when the composer listened to this wonderful composition in his own mind, he heard a version as genuine as this one – without the miscues, of course.

Much credit needs to go to the planners of Mostly Mozart for experimenting with this type of creative, adventurous seating. Next week I will venture to the heights of the back of the orchestra, sitting behind the players to experience the possible future of acoustics at Avery Fisher. Oh, one more thing. Wouldn’t you think that even the most disorganized of New Yorkers could be on time for a 10:30 concert? Amazingly, there were still latecomers to seat at this recital.