Except for New York, there is no city where I would rather hear music than Vienna, the undisputed capital of the classical music world for more than 200 years. But it is not always easy to find the time to get away, so this weekend I attended three concerts here in town that featured five works that are at the apex of Viennese music.

The Morgan Library hosted a fascinating evening titled “Double Take” on Thursday. The work offered was arguably the greatest piano sonata of all, the Sonata in B Flat Major, D960, of Franz Schubert, and it was played twice, by different performers, on two very different instruments.

Robert Levin offered the work on a fortepiano. This exquisite instrument is not a replica but rather an original made by Conrad Graf in 1830. It is exactly the same as the one that Schubert would have employed, parallel strings with no overlapping, 6 1/2 octaves of range, and four pedals. Hearing such a profound sonata on this jewel was an exceptional experience.

Mr. Levin cautioned that the evening was about the distinctness of the musicians’ sounds, rather than the performances or their quality, but a word on his playing is in order. Perhaps not the cleanest exponent of the pianist’s art, Mr. Levin is a superb communicator and worked very hard at pacing his phrases and even individual notes for maximum effect. His mysterious, time-bending and haunting realization of the Andante sostenuto was arrestingly moving.

Clearly Schubert heard this work differently than we do today. There is little or no vibration in these strings and overall there exists a quietude missing in the modern Steinway. As Mr. Levin pointed out, the fortepiano was meant to speak, the pianoforte to sing. Notes are dampened in a manner now forgotten, and boisterousness is achieved through the now-defunct bassoon pedal. Emanuel Ax once said that if you know where you are in a Schubert sonata, you are playing it wrong. Like wandering the back alleys of Venice, the whole point is to become thoroughly and magically lost. The fortepiano version heard with modern ears helps to foster that illusion of timelessness.

After intermission, Claude Frank came out to play the same piece on a modern Steinway. He talked briefly about Schubert’s songwriting abilities and pointed out the elongated nature of his melodic writing. In performance, he skillfully spun that golden web of song in an unhurried and sensually lyrical realization. He too was somewhat equivocal in his accuracy, but had a firm grasp of the architecture of the work, the first movement so much longer than any of the other three that metronomic time loses all meaning. This was a solid performance in a more familiar manner.

So how do the two versions compare? Well, the experiment was rather flawed, since the two performers had very distinct ideas about phrasing and structure. A better scientific method would have been for Mr. Levin to play both halves of the program so that the audience could hear a more consistent interpretation, necessarily altered by environmental conditions. This, however, might be too wrenching for the performer psychologically as well as physically. But this evening was in itself transformative, and any occasion when this incredible work is on the program, even if but once, becomes a special one.

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Every now and then, the Austrian Cultural Forum presents concerts of great promise. On Friday, it hosted three song cycles by Gustav Mahler in the little theater.

The musicians were mezzosoprano Hermine Haselboeck and pianist Russell Ryan, and, in addition, the performance featured the light shows of Viennese artist Victoria Coeln, who creates environments of light that she has dubbed “chromotopes” and then videotapes them. They were projected above Ms. Haselboeck on a large movie screen. For better or worse, it was just like being in modern Vienna.

The musicians began with the “Kindertotenlieder” (“Songs on the Death of Children”) and the visuals consisted of — you guessed it — Austrian children singing in a somewhat shadowy manner. When the work was over, the woman directly in back of me said to her companion, “Not exactly ‘The Sound of Music.'” At least the extramusical activities were in soft focus and thus minimally invasive.

Ms. Haselboeck delivered a competent but rather guarded performance. Each note seemed deliberate, calculated. The emotional approach was a gingerly one. High notes tended to be sharp, but in general pitch was under control. Since the room is so tiny and Ms. Haselboeck employed a microphone, it was extremely difficult to evaluate this voice and its potential. Mr. Ryan was prone to fat-fingering and was not terribly supportive. The “Kindertotenlieder” are set to texts by Friedrich Rückert, a professor of Asian literature, and the singer and pianist also offered the other five songs based on Rückert’s texts, which can be sung in any order, known simply as the Rückertlieder.

The best performance was that of the “Lieder eines fahrenden Gesellen” (“Songs of a Wayfarer”). Ms. Haselboeck was more animated in her characterizations and even hit some high emotional points. In “Ging heut’ morgen über’s Feld” (“This Morning I Went Across the Field”), her final intonation of the line stating that her happiness will never, never come was lump-in-the-throat good. Still, some more mercurial mood changes would have helped tremendously. Ms. Haselboeck seemed hesitant to let herself go, but she will never reach the center of songs like these without surrendering to abandon.

Mahler’s Symphony No.1 quotes from this song and also recalls another Wayfarer song, “Die zwei blauen Augen von meinem Schatz” (“The Two Blue Eyes of My Beloved”). In this song the protagonist encounters a lime tree (Lindenbaum) “where I first found peace in sleep.” Any informed music lover would have easily recognized that this is indeed the Lindenbaum of Schubert’s great song cycle “Winterreise” (“A Winter’s Journey”), where the hero “would have found rest.” This particular song (actually entitled “Der Lindenbaum”) from the cycle is one of the prime examples of Romantic insertion into music of the phenomenon of memory. Mahler juxtaposes the rhythms of the Trauermarsch with the melody of his lied to leave one with the impression, identical with that of the Schubert, that the hero’s resting place under the Linden tree is in fact his grave.