4-d effect using audio

[anshul1993]

I want to create 4-d effect usng audio. I have little knowledge as im in a learning stage;;

 

[Sceadwian]

You might want to explain what you mean by 4D, as it's difficult enough to get 3D audio!

 

[crutschow]

4D audio appears to be a proprietary audio software for a PC or MAC from GenAudio to enhance the sound. It's unlikely you will find any information on how it actually works. If you want to use it you will need to buy it.

 

[Sceadwian]

It's rather complicated, the outer part of the human ear is hyper critical in positional audio sensing. If you look at the shape of the ear you'll notice the outer edge of the ear starts off at the ear lobe and goes up around the back of the ear gradually starts forming a channel that curves around the upper outter ear and through a second channel and an odd indentiation, that goes into yet a second S channel that directions the sound back into the ear canal along with the main entry way to the ear canal having a distinct shape larger than the outer channels. It forms a physical phase shifting network that causes notches at particular frequencies, but all perfectly relational to other frequencies, the brain can detect these phase notches and that's what gives us the ability to determine how high above or bellow the front or the back of the head an audio source is. The FIRST instinct a person has when they hear something that seems to be important that they get positional information from is they'll cock their head slightly and listen again (cats just move their whole earlobe watch it sometimes it's fascinating) This gives them the ability to determine from the second signal if it's from the front or the back as the slight head position change will be different depending on the foreward or rear facing source of the signal. The ears do point slightly forward though so obviously any signal coming from the back of the head will be weaker, another cue when the head changes position slightly.

Most 3D audio of a truly positional nature is actually recorded from inside the human ear, or a dummy that has a typical human ear shape.

For further study I would recommend using a human ear model with a microphone at it's center as a good basic start. From there you can generate narrow band white noise signals and monitor the phase shift to determine.

Mind you none of this enhances audio per say, it just makes is sound different, it causes our ears to notice, so in a blind study people say the 4D audio sounds better, not because it is, but because it sounds different, even the mildest suggestion of which you think should sound better would lean people towards chosing the more 'complex' sounding of the two signals which would would be the 4D one, but it's just controlled phase noise in the audio.