Super Duper Features 1.2.
Different Strokes for Different Folks (Filters for different formats)
Background
Ringing (in electronics): "artefacts" that appear as spurious signals ("rings") near sharp transitions (transients) in a signal.
Visually, they appear as "rings" near edges; audibly, they appear as "echos" near transients
BEFORE the transient = Pre-Ringing
AFTER the transient = Post-Ringing.
"Ringing" arises in recordings and DAC chipsets. There is a wealth of information on the Net.
Technical Explanation
In the micro iDSD, when playing back PCM and DSD it has the following filters that reduce/eliminate such types of ringing:
DSD: Extreme/Extended/Standard filters
PCM: Bit-Prefect/Minimum-Phase/Standard filters
DXD: Bit-Perfect
Further, from our point of view, measurements and listening are not necessarily identical.
Generally, we recommend "Standard" for measurements (such as when hooked-up to test equipment) and the other filters for listening. But always try them out, on-the-fly.
Filters will be discussed more in-depth in a future Software Team's Notes.
How this benefits the listener
Audio is ultimately subjective. Hence we always try offer customer options to adjust the sound to suit what they like and the headphones speakers of choice.
The different filters come with our recommendations under each format but there is no such thing as "best" and we leave the customer to make the "last mile" selection.
Where applicable, we recommend trying Bit-Perfect first: for listening, at AMR/iFi this is what we use most.