The Fosi Audio StepSense C3 Gaming Audio DAC & Headphone Amplifier combines AI-powered footstep enhancement, hardware-level 7.1 virtual surround sound, and high-resolution audio processing for competitive gaming and immersive entertainment. Featuring an XMOS XU316 processor, Cirrus Logic CS43131 DAC, and dual TPA6120 headphone amplifiers, the C3 supports PCM up to 32-bit/384kHz and DSD256 with up to 320mW per channel of headphone power. With AI microphone noise reduction, customizable EQ presets, and USB-C, optical, coaxial, and RCA connectivity, the C3 delivers an adaptable desktop audio solution for gamers and music enthusiasts.
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Fosi Audio StepSense C3 Gaming Audio DAC & Headphone Amplifier

Take your gaming audio to the next level with the Fosi Audio StepSense C3 Gaming Audio DAC & Headphone Amplifier, an intelligent desktop audio solution designed for competitive gaming, immersive entertainment, and high-resolution music listening. Featuring Fosi Audio's proprietary StepSense AI technology, the C3 analyzes in-game audio in real time to identify and enhance critical sounds such as enemy footsteps by 3–9dB with just 10ms of processing latency. Unlike traditional EQ adjustments that boost entire frequency ranges, StepSense intelligently emphasizes footsteps without unnecessarily amplifying gunfire, explosions, or other background effects, helping players identify enemy locations and react with greater confidence.

Built with audiophile-grade components, the C3 combines an XMOS XU316 USB audio processor, Cirrus Logic CS43131 DAC, and dual Texas Instruments TPA6120 headphone amplifier chips to deliver detailed, low-distortion sound with accurate imaging and excellent clarity. Supporting high-resolution PCM audio up to 32-bit/384kHz and native DSD256 through USB Audio Class 2.0, the C3 is equally capable of handling demanding music collections and immersive gaming soundtracks. Its 3.5mm headphone output delivers at least 320mW per channel into 32 ohms, while hardware-level 7.1 virtual surround processing creates a more expansive, directional listening experience with compatible multichannel games and movies.

Designed for seamless integration into modern gaming setups, the StepSense C3 features USB-C, optical, and coaxial digital inputs, a dedicated 3.5mm microphone input, and stereo RCA outputs for connecting powered speakers or external amplifiers. AI-powered microphone noise reduction suppresses distracting keyboard clicks, fan noise, and other environmental sounds by up to 40dB for clearer communication during gaming, streaming, and voice calls. Independent headphone and microphone volume controls, one-touch microphone muting, and sidetone monitoring provide convenient control over your gaming audio.

The Fosi Audio C3 also offers customizable parametric EQ, game-specific sound presets, and a browser-based control interface that lets you adjust audio settings without installing traditional desktop software. Its compact aluminum alloy chassis features an ergonomic 5-degree angled design with tactile buttons and sliders for quick adjustments during gameplay. Compatible with Windows PCs, Macs, PlayStation 5, Nintendo Switch, and a wide range of wired headsets and desktop audio systems, the C3 combines competitive gaming enhancements with high-fidelity audio performance in one versatile desktop device.

Specifications

• Brand: Fosi Audio
• Model: StepSense C3
• Product Type: Gaming sound card, digital-to-analog converter, and headphone amplifier
• USB Audio Processor: XMOS XU316
• DAC Chip: Cirrus Logic CS43131
• Headphone Amplifier Chips: Dual Texas Instruments TPA6120
• AI Audio Processing: StepSense AI footstep detection and enhancement
• Footstep Enhancement: 3–9dB
• StepSense Processing Latency: Approximately 10ms
• AI Processing: On-device hardware processing without relying on host computer CPU resources
• Optimized Gaming Profiles: Includes PUBG and Counter-Strike 2 profiles, with additional optimization supported through updates
• Spatial Audio: Hardware-level 7.1 virtual surround sound for compatible 5.1 and 7.1 multichannel sources
• Audio Modes: AI FPS, 7.1 Virtual Surround, Parametric EQ, and Bypass
• Audio Mode Limitations: AI FPS and 7.1 Virtual Surround require UAC 1.0; AI FPS, 7.1 Virtual Surround, and PEQ cannot operate simultaneously
• USB Audio Modes: USB Audio Class 1.0 and USB Audio Class 2.0
• UAC 2.0 Audio Resolution: PCM up to 32-bit/384kHz and DSD256
• UAC 1.0 Audio Resolution: PCM up to 16-bit/48kHz
• Optical Input Resolution: PCM up to 24-bit/192kHz
• Coaxial Input Resolution: PCM up to 24-bit/192kHz
• Digital Inputs: USB-C, optical (TOSLINK), coaxial
• Microphone Input: 3.5mm microphone jack
• Headphone Output: 3.5mm single-ended
• Line Output: Stereo RCA
• Simultaneous Outputs: 3.5mm headphone and RCA outputs operate in parallel and cannot be independently enabled or disabled
• Supported Headphone Impedance: 16–300 ohms
• Headphone Output Power: At least 320mW + 320mW at 32 ohms, THD+N below 1%
• Headphone Output Signal-to-Noise Ratio: 123dB (A-weighted)
• Headphone Output THD+N: 0.0004% (A-weighted)
• Headphone Output Dynamic Range: 123dB
• Headphone Output Noise Floor: 3µV or less (A-weighted)
• Headphone Output Frequency Response: 20Hz–20kHz (±0.06dB)
• RCA Line Output Level: At least 2Vrms
• RCA Signal-to-Noise Ratio: 124dB (A-weighted)
• RCA THD+N: 0.0005% (A-weighted)
• RCA Dynamic Range: 124dB
• RCA Noise Floor: 3µV or less (A-weighted)
• RCA Frequency Response: 20Hz–20kHz (±0.06dB)
• Microphone Noise Reduction: AI-powered noise suppression up to 40dB
• Noise Reduction Control: Dedicated rear-panel toggle; available in UAC 1.0 mode
• Noise Reduction Latency: May add up to 50ms of microphone communication latency
• Microphone Controls: Independent microphone volume, one-touch mute, and sidetone monitoring in UAC 1.0 mode
• Headset Compatibility: Supports compatible wired 3.5mm gaming headsets using the included microphone/headphone splitter cable
• Equalization: Customizable multiband parametric EQ with presets and shareable sound profiles
• PEQ Compatibility: UAC 1.0, UAC 2.0, optical, and coaxial input modes
• Bypass Mode: Disables internal EQ and sound effects for unprocessed audio playback
• Control Interface: Browser-based Fosi Audio companion app
• Web App: https://cc.fosiaudio.com
• Web App Compatibility: Windows and macOS computers
• Physical Controls: Power/input selection, UAC mode selection, sound mode selection, headphone volume, microphone volume, microphone mute/monitoring, and AI noise reduction toggle
• Status Indicators: LED indicators for input, audio format, UAC settings, sound modes, and microphone functions
• Computer Compatibility: Windows 7, 8, 8.1, 10, 11, macOS 10.6 or later, and Linux
• Gaming Console Compatibility: PlayStation 5 and Nintendo Switch through compatible UAC 1.0 USB audio connections
• Driver Requirements: Standard audio playback is generally plug-and-play on compatible systems; DSD playback may require additional drivers or software configuration
• Firmware Updates: USB-C firmware updates through the Fosi Audio web application
• Power Input: DC 5V via USB-C
• Power Source: USB bus-powered
• Chassis Material: Aluminum alloy
• Design: Compact desktop enclosure with 5-degree angled control surface
• Warranty: 24-month limited manufacturer warranty
• EAN: 6976136961284
• Included Accessories: USB-A/C to USB-C cable, 3.5mm Y-splitter cable, and user manual

What It's Great At

• AI-Powered Footstep Detection: Proprietary StepSense technology identifies and enhances enemy footsteps by 3–9dB with approximately 10ms processing latency, helping competitive FPS players recognize important positional audio cues.
• Immersive 7.1 Virtual Surround Sound: Hardware-based spatial processing converts compatible multichannel game and movie audio into an expansive two-channel listening experience with improved directional awareness.
• High-Resolution Gaming and Music Audio: The combination of XMOS XU316 processing, a Cirrus Logic CS43131 DAC, and dual TPA6120 amplifier chips delivers detailed audio with support for PCM up to 32-bit/384kHz and DSD256.
• Clearer Gaming Communication: AI-powered microphone noise reduction suppresses unwanted background sounds by up to 40dB, while independent microphone volume, mute, and monitoring controls keep communication convenient.
• Customizable Sound Profiles: Browser-based parametric EQ and selectable sound modes let players adjust their listening experience for competitive gaming, movies, or high-fidelity music playback.
• Flexible Desktop and Console Connectivity: USB-C, optical, coaxial, dedicated microphone input, headphone output, and RCA connections provide versatile compatibility with computers, supported gaming consoles, wired headphones, and powered speakers.

FAQ Section

Q: What is the Fosi Audio StepSense C3 used for?
A: The Fosi Audio StepSense C3 is a gaming DAC, headphone amplifier, and external sound card designed to improve audio clarity, directional awareness, and communication during gameplay. It also functions as a high-resolution desktop DAC for music listening and connects to compatible headphones, gaming headsets, and powered speakers.

Q: How does StepSense AI footstep enhancement work?
A: StepSense uses a dedicated on-device AI algorithm to recognize and enhance footsteps in supported FPS games. It boosts detected footsteps by 3–9dB with approximately 10ms processing latency, helping players hear subtle movement without broadly increasing the volume of explosions, gunfire, or ambient effects. StepSense requires UAC 1.0 mode.

Q: Does the Fosi Audio C3 support 7.1 surround sound?
A: Yes. The C3 supports hardware-level 7.1 virtual surround processing that converts compatible 5.1 and 7.1 multichannel audio into a spatial two-channel headphone experience. This feature operates in UAC 1.0 mode with supported multichannel content and is not applied to ordinary stereo sources.

Q: Can I use the Fosi Audio C3 with a PlayStation 5 or Nintendo Switch?
A: Yes. The C3 supports compatible PlayStation 5 and Nintendo Switch USB audio connections using UAC 1.0 mode. This mode provides 16-bit/48kHz audio and supports microphone communication with a properly connected compatible headset.

Q: Does the Fosi Audio C3 improve microphone quality?
A: Yes. The C3 features AI-powered microphone noise reduction designed to suppress background sounds such as keyboard clicks and computer fan noise by up to 40dB. It also includes independent microphone volume, mute, and sidetone monitoring functions in UAC 1.0 mode.

Q: Can I use the Fosi Audio C3 for high-resolution music listening?
A: Absolutely. In UAC 2.0 mode, the C3 supports PCM audio up to 32-bit/384kHz and DSD256. For music listening, users can select Bypass mode to disable audio processing or adjust the parametric EQ to customize the sound.

Q: Can I connect powered speakers to the Fosi Audio C3?
A: Yes. The C3 includes stereo RCA line outputs for connecting powered speakers, integrated amplifiers, and other compatible audio equipment. The headphone and RCA outputs operate simultaneously rather than offering independent output selection.

Q: Do I need to install software to customize the Fosi Audio C3?
A: No traditional desktop application installation is required for the main sound customization features. Connect the C3 to a compatible Windows or macOS computer and visit https://cc.fosiaudio.com to access the browser-based interface, select sound profiles, adjust parametric EQ settings, and manage supported firmware updates. Certain DSD playback configurations may require additional audio drivers or software.