In this tutorial, we’ll introduce the seven types of DAC digital filters offered by the ESS ES9038Q2M DAC on the WiiM Ultra. The premium 32-bit/384kHz ESS ES9038Q2M DAC delivers exceptional audio clarity, featuring a THD+N of -116dB and an SNR of 121dB for Line Out. 


These filters allow you to fine-tune the audio output to suit your sound preferences, whether you're aiming for sharp precision, smooth transitions, or minimal artifacts, or to match the characteristics of your audio system.


1. Brick Wall Filter


  • Key Feature: Sharp cut-off above the Nyquist limit with steep roll-off.
  • Benefit: High precision in maintaining the original signal.
  • Suitable Audience: Users seeking maximum accuracy and detail, especially in digital music where precise reproduction is prioritized.


2. Corrected Minimum Phase Fast Roll-off Filter


  • Key Feature: Fast roll-off with reduced pre-ringing and minimal phase distortion.
  • Benefit: Offers a more natural and balanced sound without introducing noticeable artifacts.
  • Suitable Audience: Audiophiles or users focused on high-fidelity playback, who want a balance between accuracy and naturalness.


3. Apodizing Fast Roll-off Filter


  • Key Feature: Eliminates pre-existing ringing from recordings with a fast roll-off.
  • Benefit: Cleans up artifacts from earlier stages, providing a clean and clear sound.
  • Suitable Audience: Users who often listen to recordings with imperfections or compressed files, looking to improve overall sound quality.


4. Minimum Phase Slow Roll-off Filter


  • Key Feature: Slow roll-off with minimized pre-ringing to preserve temporal accuracy.
  • Benefit: Produces a smoother and more natural sound, reminiscent of analog systems.
  • Suitable Audience: Listeners who prefer a warm, soft, and analog-like sound presentation.


5. Minimum Phase Fast Roll-off Filter


  • Key Feature: Fast roll-off with minimized pre-ringing for phase accuracy.
  • Benefit: Balances phase accuracy with faster transitions, offering both precision and natural sound.
  • Suitable Audience: Users who want a balance between the smooth sound of analog systems and the precision of digital systems.


6. Linear Phase Fast Roll-off Filter


  • Key Feature: Steep roll-off while maintaining linear phase accuracy.
  • Benefit: Ensures frequency alignment and timing precision across all frequencies.
  • Suitable Audience: Users seeking the highest accuracy in timing and frequency response, but who can tolerate minor pre-ringing artifacts.


7. Linear Phase Slow Roll-off Filter


  • Key Feature: Gentler roll-off with linear phase characteristics.
  • Benefit: Balances signal accuracy with a smoother, more laid-back sound presentation.
  • Suitable Audience: Listeners who prefer a balance between accuracy and a more relaxed, comfortable sound for casual listening.