Disclaimer: This IEM was donated from an user at SEEKO.co.kr, named 궁금중. I should appreciate him for the contribution.
In September of 2012, upon releasing their high-end cellphone, Optimus G, LG also introduced an IEM called HSS-F450, which was better known as Quadbeat. Manufactured by iSound of South Korea, Quadbeat was designed by Y.H. Na, a senior manager of the core technology lab, mobile communications division at LG. As a stock IEM of Optimus G, the MSRP of Quadbeat was set at around 20 USD, which was quite affordable.
And as Goldenears.net further provided its frequency response certification, the publicity of the IEM just sky-rocketed, with some even claiming that the Quadbeat's electroacoustic performance is on par with or better than Ultimate Ears Triple.Fi 10 Pro. (And my take on the claim is here) The Korean public's demand well-exceeded the manufacturer's supply, and Quadbeat was considered an absolute steal.
CON: 5~6 kHz peaks are little too harsh, and stock sleeves are absolutely horrible as they simply crumble upon even a slight pressure, causing leak. On top of that, bulkiness of the housing makes the IEM unusable by the users with small ears.
ON SECOND THOUGHT #4: Does $20 Quadbeat really outperform Triple.Fi 10 Pro, of which the original MSRP was set at $399? Here's my take on the claim, and the overall analysis data indicate that while Quadbeat does better job in some aspects, Triple.Fi 10 Pro simply does better job in reproducing higher fidelity. So the answer is NO.