In the General Settings window of the AXR4T you can choose between conversion modes: ‘Linear’ or ‘Short Delay’. Is there any technical data or technical explanation for these modes?
Intuitively I have to compare them to Linear Phase vs zero latency EQ’s. The short delay mode seems more punchy in the lows and brighter in the highs. I just don’t understand why EQ processes would be applicable to conversion modes. But that might just be my limited knowledge on the subject.
Are there any other users that can confirm the differences in sonic properties between the modes? Or are there any developers that can give some technical information?
@Simsalablim, I had to reach out to development for an explanation myself, and I hope that this is still of interest…
“The ‘Conversion Mode’ switches the built-in digital filters of the ADC and the DAC. We selected these digital filter modes after listening and examining as a team during the development of AXR4. Technically, the “Linear Phase” mode is characterized by a steep filter and a linear phase, and the “Short Delay” mode is characterized by a non-linear phase with shorter delay. However, since the evaluation of audio quality depends on the listener and the audio source, it cannot easily be described which mode has what kind of “audio” characteristics or which mode is good/bad. Therefore, except for the delay, we would like users to choose the Conversion Mode according to their application and preference.”
A linear phase filter means that all frequencies are delayed by the same amount of time., or the phase response graph would be flat. Some people claim they can hear “pre-ringing” in linear phase filters, but I think that depends upon how the filter is implemented. If you are working at a high sample rate, e.g., 96K or higher then even if the filter produces that effect I don’t think you would hear it. However, some people prefer minimum phase filters where some frequencies are slightly delayed w.r.t others, e.g., the fundamental of a complex tone would not be delayed but the successive harmonics could be shifted in time by varying amounts depending upon their frequency.
What I hear with the AXR4(T) is linear phase mode gives the stereo image of well recorded material more depth or sounds more 3D. It also sounds a bit more clean/transparent compared to “short delay”. With the “Short Delay” setting (which maybe is minimum phase ?) some frequencies or parts of the mix sound more up front in the stereo image. It’s almost like a tiny bit of compression and transients don’t quite sound as clean or sharp to me. Some people might say that the frequencies are smeared where the filter is not linear phase. You could also say it’s easier to hear what is going on in the mix when everything is more “up front” with the “short delay” setting at the expense of clarity. Ideally, your mix should sound good with either setting because there are both linear phase and minimal phase converter designs out there. I have found the “Short delay” makes the AXR4T sound more other converters in A/B tests which I presume means the other converters are not linear phase.
Just out of curiosity, can you mix the 2 modes within the same project, or is it fundamental to project / interface settings in some way?
E.g, lets say for drum tracking you like Linear conversion mode, but for guitar tracking you prefer short delay. Can you mix it up as you like with all rendered audio tracks playing nicely together in the same project once recorded, irrespective of whether they were recorded in linear or short delay?
Thanks in advance
