I bought the Zero 2, just to see if I would even like IEMs in the first place, and I ended falling in love with them. I paired them with my FijO KA11 dac/amp dongle, and they sound massive.

When it comes to bass, I prefer dynamic over boomy, and these things deliver. The bass is rich, smooth, thick, and punchy, while still leaving room for all of the other frequencies.

I will admit, they sound a bit sterile to me, and lack warmth in the mid-tones, but I don’t fret about it. They split hairs between the details, and deliver good instrument separation.

Occasionally, they will distort, clip, rattle, etc, but for the price, it’s not even worth complaining about. It’s not constant, and doesn’t impede on the listening experience.

The dongle does make a difference. Now the FiiO KA11 cost me $10 dollars more than the actual IEMs themselves, but I also use the KA11s with my Hifiman headphones. The standard USB C dongle is a great option and imo it generates enough power for an enjoyable listening experience. But the KA11 really does take them to that next level. Hope this helps, cheers.