Thomastik-Infeld JS23 Nickel Flat Wound 4th string (D) .023, Single

I'm an Indian classical musician who plays the 'chitravina' - an Indian classical Hawaiian guitar-like acoustic instrument that I've always been on the hunt for good bass strings for. It's played with a slide, and the music is full of intra-tonal swings, oscillations, and glides, so I prefer flats for minimal string noise.

The issues I've faced with with other strings are either they're too boomy/shrill with low sustain (D'Addario flats), or they don't have not enough presence and don't last long due to the high string tensions on my instrument (some Indian-made filament-wound strings). I tune this 4th to C# on an instrument with a few inches longer speaking length than a guitar.

These strings are very different.. They're lighter than anything I've tried - less taut at the same gauges, and sounding less shrill and less boomy. There is a 'bendy' quality to the sound, giving the slides and oscillations more character. The tone is warm with a hint of rasp, perhaps a bit like the violin family. And string noise remains quite minimal, not as low as the Indian filament-wound ('double-wound') strings, but negligible enough.

They have also lasted well, at least the past few months I've had them, and I play at a very high string tension (this 4th is tuned to C# on an instrument whose speaking length is a few inches longer than a guitar's).

Overall, I'm quite enjoying these strings, and despite the price, at least for my instrument and music, I feel they offer something much beyond anything else I've tried so far.