The M18i Max is built around Questyle's proprietary Current Mode amplification, a globally patented technology (PCT Patent No. US9,614,483B2) that resolves the classic tradeoff between size, power, and performance in portable audio. Two independent SiP modules house four groups of selected "current mode" amplifiers, delivering both robust driving power and delicate tonality, while holding distortion to just 0.0002%. Paired with TOREX's precision power management system, the M18i Max delivers flagship performance without sacrificing efficiency, pushing the boundaries of what a portable device can do.

At the heart of the M18i Max sits the selected flagship ESS Combo DAC ES9219Q ×2, arranged in a dual DAC mono decoding design paired with Questyle's TTA (Three-Tier Architecture) decoding framework, a configuration comparable to desktop equipment. The result is decoding capability up to PCM 384kHz (16/24/32bit) and DSD256, delivered with a noise floor of -130dB and full command over dual 3.5mm single-ended and 4.4mm balanced outputs, backed by a peak output current of 1.5A and switchable HIGH/STD gain.

Seamless switching, lossless enjoyment. The M18i Max supports both USBDAC and lossless Bluetooth operation, giving you the flexibility to match your source. On the wireless side, Qualcomm's latest Snapdragon Sound™ technology and Bluetooth 5.4 bring support for AAC, SBC, aptX, aptX HD, aptX Adaptive, LDAC (24bit/96kHz), and the latest LE Audio, so compatible source devices can enjoy true wireless, lossless audio.

An Infineon flagship microphone with call noise reduction keeps voice calls clear and steady, even on the move, so conversations stay clear from start to finish.

Questyle Lab put the M18i Max through extensive testing and targeted optimization for everyday use across devices. It's fully compatible with iOS, HarmonyOS, and Android 5.0+, supports Windows 10 (version 1803 or later, no drivers required) and macOS (Lightning connection requires the Kuangshi LTCO2 adapter), and is even compatible with PSP gaming consoles. It's also Apple MFi certified, connecting seamlessly into the Heiuco ecosystem for iPhone and iPad users.

Design follows Bauhaus's core philosophy: function first, less is more. A pure black matte metal body pairs with an always visible display built into the full screen, while all buttons and ports are neatly tucked to the side, free of unnecessary decoration. Layered, exposed internal circuit boards contrast with the refined CNC anodized aluminum alloy exterior, a design that shows off its own craftsmanship while striking a perfect balance of form and function for audiophiles who care about both sound and texture.

An 1800mAh battery delivers up to 12 hours of playback over Bluetooth or 8 hours via USB, with smart charging across two ports for effortless charge and play convenience.