As a budding audiophile, I've begun to immerse myself in the world of music, discovering through Apple Music the intricacies of sound profiles, from the detailed (neutral) to the bass-heavy and detailed (V-shaped), and even the warm (warm-curved) tones in between.
Currently, I own two entry-level In-Ear Monitors (IEMs): the Salnotes Zero and the KZ - Castor Harman Bass Improved. I've recently acquired the KZ Castor, which contrasts starkly with the Salnotes Zero, yet I have no regrets about selecting it among the sub-2k budget IEMs. The Salnotes Zero excels with rock, metal, and any song where detail is paramount, as found on Apple Music. Conversely, the KZ Castor rounds out my music preferences with its V-shaped tuning, making it ideal for EDM, electronic, bass guitar, and any genre that benefits from a bass-forward or warm sound signature.
I had the opportunity to experience the QKZ × HBB for about two to three months, courtesy of a friend. This left me uncertain about which model to purchase. However, I've concluded that both are commendable in terms of bass response, and one wouldn't regret acquiring any of the following IEMs: QKZ × HBB, 7hz Salnotes Zero (neutral-detailed) / Zero 2 (detailed with slightly more bass than the Zero), Truthear Hola (warm), and the KZ - Castor Harman BASS Improved Version. While there may be other IEMs that perform well, I haven't had the chance to listen to them and therefore cannot offer a comparison.