With your questions and our answers, we are moving in a certain direction.
We had to re-jig the features/announcements. So here you go.
Super Duper Feature 1.6
3D Holographic for Headphones(i)/Speakers(ii)
Section i: Background to 3D Holographic for Headphones
Recordings are by and large, made for speakers. By definition, when listening on headphones, you get the "Kylie sensation."
Put politely, this really irks the human brain as it is not "normal."
Explanation
Human hearing needs a "mix" of left and right. Not purely left in left and right in right. There are numerous solutions available such as JRMC that use Digital Signal Processing (DSP).
There are two drawbacks:
1. The signal is no longer Bit-Perfect.
2. Simple crossfeed does not fully address what the human hearing is missing.
How 3D for Headphones benefits the listener
Solution: The iFi solution for some time has been 3D Holographic for Headphones.
This is an Analogue Signal Processing circuit (ASP) that retains the integrity of the audio signal getting the sound back out of the head + gives the sense forward spaciousness. More akin to this.
More reading here:
http://ifi-audio.com/wp-content/uploads/data/3DHolographic.pdf
Section ii: Background to 3D Holographic for Speakers
Recordings are usually carried out in "free space." Slight problem here because when we listen, we listen with ears either side of a head (no funny quips). While upper and middle frequencies are received well, low frequencies are not as they are blocked by the head, this is called the "acoustic shadow."
Alan Blumlein, the "father of stereo" is someone few people in audio have heard of, but he is revered in pro audio circles. Alan Blumlein lived a short but very eventful life and due to his early death at the age of 38 in a Wellington bomber crash during WWII in 1942, his prolific work on recordings and radar (among other works) never truly received the recognition they deserved as his death was hushed up by the government (time of war).
This is a fascinating read:

(not excessively technical but interesting anecdotes throughout).
But we digress. AMR/iFi is not the first to point this out as there have been past solutions.
Explanation
The thorny issue of “stereo sound perception” is well-documented in the recording field. The following are a few well-known examples but all these approaches are fundamentally limited due to a paucity of such recordings made using these components:
1.
Faulkner Microphone Array[1]: Tony Faulkner[2]; one of the most well-known British recording engineers developed this recording solution which drew upon Alan Blumlein’s work.
Source:
www.evi.com
2.
Binaural recordings[3]: As the human head “listens” with ears located either side of a physical head, the Neumann K-100 microphone for commercial dummy head microphone mimics this for professional binaural recordings. This approach is aimed squarely at headphone playback.
Source:
http://www.kallbinauralaudio.com
3.
Jecklin Disk[4]: was invented by Jürg Jecklin a former Swiss recording sound engineer and chief of Swiss radio who is now teaching at the University for Music and Performing Arts in Vienna. His solution documented in his technical paper[5] is a descendant of the baffled microphone technique initially described by
Alan Blumlein in his 1931 patent. A more recent refinement of this design is the Schneider Disk[6].
Source:
http://www.indecentmusic.com/img/blog/drum-mics/overheads-jecklin-ew.jpg
[1]
http//www.sengpielaudio.com/TonyFaulknerPhasedArray01Engl.pdf
[2]
http://www.analogplanet.com/content/veteran-recording-engineer-tony-faulkner-goes-back-analog-0
[3]
http://en.wikipedia.org/wiki/Binaural_recording
[4]
http://en.wikipedia.org/wiki/Jecklin_Disk
[5]
http://www.mdw.ac.at/I101/iea/tm/scripts/jecklin/tt03mikrofon.pdf
[6]
http://www.core-sound.com/jecklin/1.php
There are numerous others such as the EMI Shuffler[7].
[7]
http://www.phaedrus-audio.com/stereosonic.pdf
How 3D for Speakers benefits the listener
The micro iDSD's 3D HolographicSound® System for Speakers (as used in the iTUBE) is an “outside of the box” solution as it resolves this fundamental issue once and for all - for ALL recordings during the playback process.
Hifi speakers implemented well, typically always convey upper frequencies well with accurate tones and placement is easily “perceived”. Low frequencies are less well-defined and perception of their location is not as good as with higher frequency instruments.
The 3D Holographic Sound® setting with simply puts the bass back where it belongs, leaving the rest untouched. Like this:
More reading here:
http://ifi-audio.com/wp-content/uploads/data/iTubeTechpaper2_3DHolographic.pdf
On the micro iDSD to use each of these totally different circuits:
i. 3D for Headphones can be engaged through the 6.3mm jack.
ii. 3D for Speakers can be engaged through the RCA outputs.
Thanks.