If you're looking for a reference IEM packing a well extended powerful and fast bass, an articulate midrange and an engaging treble both with accurate tone then at the asking price it's hard to find a better proposition than the Serial. Serial addresses the demanding audiophiles on a budget and it's quite refreshing in a bullish market in the upper tiers. On top of this Serial will scale superbly with more power and an affordable desktop amp is a great option to enjoy all it can offer.
Penon Globe – Golden Globe!
If you’re looking for an IEM with punchy and snappy bass, a transparent midrange with good body and bite and well extended and refined treble delivered smoothly, then I can only recommend the Globe! The Globe is a very strong proposition at its price and keeps up with the best of a strong competition in this segment.
Penon Volt – Electric dreams
If you're looking for flagship performance at a reasonable price and you like full bodied, smooth signature with strong bass foundations, impressive resolution and treble refinement then you'd miss out not adding the Volt to your list. Make sure you have a proper source though to provide enough current to bring the best out of it. And if you have a bigger budget, Totem is a fantastic pairing that brings a more punchy, energetic, focused presentation as well as elite performance that matches much pricier flagships.
Penon Orb – Singing Angel
The Orb is up there with the best in the segment namely ISN H40 and Dunu DK-2001 which is no small feat. If you're looking for an IEM with of the very best bass, a full yet clear articulate midrange and refined treble then it's hard not to recommend the Orb as one of the very best value for money on the market. A no brainer in my opinion!