Change modes with just one button Due to the BTR15’s ability to work as a Bluetooth receiver and as a USB DAC, we have implemented a PC/BT/PHONE mode button on it. With just a click of a button, you can quickly switch between the three different modes to match your current scenario for listening to high-quality music. Global parametric EQ, be the master of your music The BTR15 features a global parametric equalizer (PEQ). Through FIIO’s self-developed PEQ algorithm and user interface, in any mode* you can choose the exact frequencies to be adjusted along with their gain levels and bandwidth – allowing you to fine-tune the sound to exactly the way you want it. Dual-core upgrade, two modes of high-res audio The upgrades start from the heart of the BTR15, specifically the cores that power it. The BTR15 employs the high-performance combination of the Qualcomm QCC5125 Bluetooth chip = XMOS 16-core XU316 that supports stable high-res audio playback in any mode*, allowing you more ways to immerse yourself in the world of high-quality hi-res music. * MQA Full Decoder for master-quality sound The BTR15 supports MQA Full Decoder, which means the MQA decoding can be achieved in any music app. This allows for high-resolution, master-level sound quality in reasonably sized files well-suited for your mobile device. Double-sided curved glass design With the BTR15, FIIO uses hot-bent curved glass for the first time – embedding it on both the front and the rear of the device. Not only does this make the device easier to hold, but it also gives the BTR15 a more attractive and 3D appearance. Together with the aluminium alloy middle frame, they make the BTR15 a comfortable device to handle – you won’t be able to put it down once you pick it up. Dual outputs gives you flexibility In addition to the standard 3.5mm single-ended headphone output, the BTR15 also comes with the widely-used 4.4mm balanced headphone output – featuring greater contact reliability and durability compared to the 2.5mm balanced out. The dual outputs ensure you can use the BTR15 with more headphones, for more remarkable listening experiences. Independent power supply for the amp, for more explosive power Electricity is the mother of sound. Feiao engineers have carefully designed an independent power supply system for DAC ES9219MQ built-in earmuffs, so that earmuffs no longer share the power supply with DAC and the power supply is purer. In addition, the uniquely designed external power supply has the characteristics of low noise and high current, which increases the balanced output power of BTR15 by 40% to 340mW, and can easily meet the needs of portable use. Parallel output, more power You don’t have to use the 4.4mm balanced output to enjoy the benefits of increased output power. In order to improve the performance of the BTR15 in every aspect, FIIO connected the headphone outputs in parallel to also greatly increase the output power of the 3.5mm single-ended output to better drive low-impedance headphones, allowing you to better unlock their potential. Comprehensive battery protection In order to alleviate concerns about battery health, FIIO engineers have implemented a number of software and hardware measures to comprehensively protect the BTR15’s battery.