Audiophilepure

https://www.headfonia.com/io-audio-cielo-review

The bass range is not as elevated as some of the other IEMs in the kilobuck bracket, but it is far from flat. While the overall bass quantity is modest rather than dominant, the low extension is great, and the control is excellent. There is also a subtle mid-bass lift, which I appreciate, that helps the fundamentals of the timbre and the naturalness of the midrange.

Many Chi-Fi manufacturers have been dialing down the 150-300Hz region to introduce extra air to the presentation, but IO Audio did not follow that trend here. That decision gives the Cielo a more natural foundation and prevents the midbass and the midrange from sounding dry or overly clinical.

Overall, the Cielo’s bass is tight, nimble, and tonally rich. It reaches low when the recording demands it, but the quantity remains strictly controlled. This is not an IEM that adds excessive bass weight to every track you play. Instead, it gives you a clean, fast, and disciplined low-end response that serves the recording rather than completely reshaping it.