These musicians do not flinch from the open-hearted simplicity of the Adagio, slightly marred through irritating breaths, while the emotional zig-zag of the closing Allegro reflects, perhaps, something of the composer's own inner turmoils.
The great G major Quartet, Schubert's last, was famously rejected by his publishers and did not appear until 23 years after his death. It is so tempting to hear an angry, ailing man in the opening movement with its jagged rhythms and massive, almost orchestral, eruptions.
The musicians bring all this out, perfectly caught by producer Martin Sauer, the man responsible for Isabelle Faust and Claudio Abbado's recent Beethoven and Berg outing.
The vast 20-minute stretch of Schubert's Allegro is tautly sustained, and so is the subsequent Andante, taking us from sweet serenade to terrifyingly intense soul-baring.
It all comes to a head in the Finale, a fevered Tarantella, eternally torn between major and minor. And it is here that the players, more than ever, capture the special genius of Franz Schubert.
Schubert: String Quartets (Harmonia Mundi, through Ode Records)
Verdict: Spanish Quartet injects passion and pathos into cherished Viennese classics.