3Tooth

3Tooth - Bluetooth DAC with Parametric Filtration

Introducing 3Tooth: Your dedicated solution for high-fidelity wireless audio, meticulously engineered to deliver a personalized listening experience.

3Tooth functions as a Bluetooth A2DP Sink, enabling seamless wireless audio streaming from your compatible devices. The incoming audio data is then channeled to a high-quality Digital-to-Analog Converter (DAC) via an I2S connection, where it is processed and prepared for output.

Key Audio Components & Processing:

• Premium DAC Performance: At its core, 3Tooth utilizes the PCM5102A DAC from Texas Instruments. This DAC is specifically designed to achieve excellent dynamic performance and offers improved tolerance to clock jitter. It also provides ultra-low out-of-band noise, effectively reducing EMI and aliasing in downstream audio components.
• Simplified Audio Output: The PCM5102A DAC provides direct 2.1-VRMS ground-centered line-level outputs. This design eliminates the need for external DC blocking capacitors on the output path, simplifying your audio setup.
• Integrated Clocking: An integrated PLL on the PCM5102A DAC removes the requirement for a separate system clock (commonly known as master clock), enabling a simpler 3-wire I2S connection and contributing to reduced system EMI.
• Fixed Audio Format: The 3Tooth system processes audio at a fixed sample rate of 44.1 kHz. The internal Digital Signal Processing (DSP) operates on incoming audio streams as 16-bit signed integer samples.

Advanced Sound Customization with Parametric EQ:

• Three Configurable Filters: 3Tooth features a sophisticated Parametric Equalizer equipped with three distinct Biquad filters. These include a Low Shelf filter, a Peaking filter, and a High Shelf filter.
• Precise Control: Each filter allows for precise adjustment of its frequency, Q (quality factor, adjusts the range of the frequencies affected by the filter), and gain (in dB). This empowers you to finely shape your audio output to match your exact preferences and acoustic environment.
• Flexible DSP Management: You can independently enable or disable individual filters or toggle the entire DSP processing (all filters) on or off for maximum flexibility in sound management.

Intuitive Control & Persistence:

• Global Volume Control: A global volume control is implemented, allowing for easy adjustment of the overall audio output level.
• Automatic Setting Retention: All your customized filter parameters (frequency, Q, gain, and enabled state) and the global volume setting are automatically saved to EEPROM. These settings are then loaded from EEPROM upon startup, ensuring your preferred sound profile is consistently maintained even after power cycling.
• Multiple Control Options:
• Physical Buttons: Convenient physical buttons are available for quick, tactile adjustments. A middle button toggles all filters on/off, while left and right buttons decrease and increase the volume, respectively.

• Serial Command Interface: For more detailed and precise control, a serial command interface is available, operating at 115200 baud. Through this interface, you can:
  • List current settings: View the global volume, DSP status, and all individual filter parameters.
  • Set global volume: Adjust the volume numerically within a range of 0.0 to 1.0 (e.g., set volume 0.5).
  • Enable/Disable all DSP: Control whether all filters are active or bypassed (e.g., set dsp 0 or set dsp 1).
  • Enable/Disable individual filters: Toggle specific filters on or off by their index (e.g., set filter 0 1).
  • Set filter parameters: Precisely set the frequency, Q, or gain for any filter by its index (e.g., set 0 freq 200.0, set 1 Q 1.5, set 2 gain 4.0).

3Tooth delivers a robust wireless audio experience, empowering you with granular control over your sound, all saved for consistent convenience.