Perhaps I am a bit embarrassed to say as I own HQPlayer but here it goes…. As my DAC has its own built in FIR filter(Finite Impulse Response (FIR) symetrical Flat phase and group delay), by using HQPlayer am I adding an additional filter on top of the filter that my DAC uses?
Also as DAC has a FPGA how would it interact with HQPlayer’s filters?
It’s much easier to answer these questions if you state the DAC model
Otherwise it’s all a big mystery.
It’s a Jeff Rowland Aeris DAC. Thank you
In some cases yes, in some cases replacing part of, in other cases no. Some DACs allow inputs that will bypass the internal digital filters, and in some cases also the internal modulators as well.
In your case, most likely you end up replacing one or two stages of internal 3-stage filter, and leaving just the final one. Typical DAC chip has three stages, here example of 44.1k rate family:
44.1 → 88.2 → 176.4 → 352.8
where arrow is built-in digital filter. Typically the next stage is about one half in length too. This keeps internal DSP load constant in relation to the master clock, for such synchronous DSP processors. When you for example input 88.2k instead of 44.1k, the first filter stage just falls off and you have two stages remaining.
With your DAC, USB input seems to be limited to 96 kHz (maybe due to old style synchronous USB Audio Class 1 interface?). And you get higher rate support through S/PDIF. So I’d recommend to use some high quality bit-perfect S/PDIF interface (coaxial or optical) and sen your DAC always 192k data from HQPlayer. This leaves just one filter stage active in your DAC.
Sonically the first conversion stage is most critical.
Awesome! Thank you for your insight on this. And indeed, I have it fed through SPDIF. Cheers!
Sorry one more question! Based on the DAC, any suggestions as to the type of filters you would recommend to try based on the latest version of HQ Player?
It is mostly up to your music genre and listening preferences. I’d recommend to try at least three different ones:
Also when using S/PDIF, remember to set “DAC Bits” to 24. And I’d recommend to get started with TPDF or Gauss1 dither.