Archive: DIY Custom Audio DSP (like miniDSP)

From 24th-Alchamist in Minnesota:

"Built an audio signal processing device that I use in my car."

Features:

• Analog outputs: Four independent WM8524 24-bit stereo DACs (e.g. sub, midbass, midrange, tweets). 2 Vrms ground-centered output (no DC blocking caps).
• Digital Outputs: Four independent optical S/PDIF outputs (CS8406 to TOTX147). (Future plans are to use these instead of analog).
• Inputs:
  • Digital: Two S/PDIF optical -- one from H/U, one direct from CD changer (TORX147 to CS8416 S/PDIF receiver to CS8421 ASRC).
  • Analog: one "AUX" analog input (e.g. for handheld device) using CS5351.
  • Optional: a third S/PDIF input if needed in the future.
• Power: "12 volt" from car with remote turn-on/off.
• Control: Digital volume up/down and digital source select. (Possibly more in the future if needed).
• ADAU1442 Computing Highlights:
  • 3584 instructions per sample at 48 kHz.
  • 56-bit processing.
  • 8k data RAM (up to 170 ms delay at 48 kHz).
  • IIR and FIR filters, EQ and more; easy implementation with GUI software (see below).
• ADAU1442 Usability:
  • Self-boot from EEPROM (no microcontroller required).
  • Analog Devices SigmaStudio drag-n-drop graphical user interface is so nice to use.
  • Analog sampled a ADAU1401 evaluation board which allows for real-time EQ and A/B testing with a laptop.

Read more