The TWS600 are the first true wireless in-ear monitors designed by Hifiman.
The meaning of “true wireless” is that, while normally a Bluetooth earphone has wire connecting the left and right channels (and, frequently, the segment housing the wire also contains the BT receiver), the TWS600 have no wire and they can be connected independently to the smartphone (or other source).
Inside each earpiece, there is an independent BT receiver, DAC/amp circuitry and battery.
The TWS600 come with a dock system that works both as a carrying case, battery charger, power bank. It’s very portable and conveniente, and drmatically increases the battery life of the TWS600 during long trips: while the TWS600 battery life lasts about 5 hours of continuous usage (they are offically rated to last 5.5h), putting them in the dock for charging, will let thme last over 30 hours more (wthout connecting to wall electricity).
The TWS600 come with a reasonably wide selection of eartips: triflangs, and differently sized biflanges, but no foam tips. Generally, foam tips are the most comfortable, but with dynamic driver IEMs (such as the TWS600), my favourite eartips for sound are large biflanges, which manage to strike the best balance of details and low end.
The TWS600 are based on Hifiman RE600 dynamic driver, and mainly tuned towards a spacious, detailed sound. treble and one of their stronger points is the open presentation and high level of detail.
The music flw clearly across the spectrum, the bass is clean and fast, although lacking some depth and impact. The sense of space is quite good (especially for the price range), as well as the soundstage size, courtesy of the RE600 drivers.
The mids are a bit recessed, giving the perception of certain sounds being farther away from the listener and allowing the treble to shine further. The treble focus, as often happens with bright earphones, translates in energy that maintains the sense of pacing and engagement.
Rich sections in the never sound confused, although there the overall sense of clarity and detail is a bitinferior to that of the RE600.
Despite the focus on the middle treble, the TWS600 are quite smooth and not sibilant, probably thanks to the dynamic driver technology.
The TWS600 sound very good with with electronic music, full bodied music and music with high production values, but for other stuff (such as old music, poorly produced rock, low fi stuff, old jazz recordings) they would benefit from equalization centered in the midrange (3-6 dB), especially around 500-2000 Hz, which would make vocals closer and meatier, adding presence and some volume to them.
These are a very interesting product, especially technology-wise, given their ability to run independently (each playing in mono, or together in stereo), and for the price range they manage to pack many advantages: clear sound quality, isolation, good battery life, zero wires at all.
The differences between the TWS600 and the RE600 could be caused by the bluetooth tehcnology and the implied constraints (such as power saving in the behaviour of the earpiece), compared to those provided by the usage of an external amp wired headphones (such dac / amp circuitry present inside smartphones / digital audio players).
Still, for the price, they pack a lot of desirable qualities for a wireless earphone, and Hifiman has also cleverly managed the average battery life (another “sacrifice” coming with wireless earphones), thanks to the inclusion of the dock, which does triple duty of being a snug carrying case, charger and also power bank.