I've seen this term used, but I must say I do not have a clue what it means. Does it mean you'll sound like a psyco with an acoustic? What does it mean?

Psychoacoustics - is the scientific study of sound perception. More specifically, it is the branch of science studying the psychological and physiological responses associated with sound (including speech and music).
 
Psychoacoustic plugins use algorithms to trick the brain into thinking a sound is in a specific location, usually in 3D space (without using surround processing). I used to have a plugin called SpinDelays that used psychoacoustics to trick the brain into hearing the delays spin around your head. Sounded pretty cool, to be honest. The HAAS effect is another example of psychacoustic theory.
 
Regards,
Dan
 

Anything where we use physics to fool the ear/brain is psycho-acoustics.  Stereo imagery in itself is psycho-acoustics.  
Another plugin example would be Waves Maxx Bass technology where the harmonics, rather than the fundamental are boosted to fool you into believing the bass is fuller on smaller systems.  
 
Noise shaping in dither is another psycho-acoustic phenomenon.  It pushes the noise to the frequencies where the human ear is less sensitive.   Similarly, A weighting measurements are a way to measure system or microphone noise based on how it would be perceived by the human ear, rather than linearly. 

i use the phrase "clown fookery' (with the PROPER spelling and pronunciation) for all 'phsycoacoustic' effects.
(coined from another forum....)
 

 
that said, i DO use waves MaxxBass, love that plug.
 
 
i would say, beware of messing with ANYTHING that changes phase of anything.
especially on the high end.
 
 

It's also an over-used marketing catchphrase, which has eroded its meaning. Be wary of any marketing text that uses "psycho-acoustic" without further explanation.
 
An excellent book on the subject is called "This is Your Brain on Music". I forget the author's name.

In the 1990's Roger Waters trumped a form of Pyschacoustic plug-ins called Q-Sound for his album Amused To Death-great album by the way and it worked but it's a bit of trickery really.
 
Ben

I like playing with those kinds of plug ins, even if they never make it into any music. I downloaded an app with binaural rhythms.These work similar to psycoacoustic sounds,actually I think it works on a similar concept, but the rhythms are at low frequencies and are designed to relax by playing different patterns in each ear. These are supposed to put your brain into a different rested state depending on the rhythm and how deep you want to go.
 
When I tried it I didn't know what to expect. I went to bed with it playing in my headphones hoping that it might relax me a little. Instead my tinnitus got 100% worse. It felt like someone had a high pitched gong going off in my head. It gave me a migraine headache. So much for relaxing to the beats.
 
I have a theory that tinnitus might be partially caused by an irregularity in the part of the brain that reconciles bilocation between both ears. The binaural beats made it go absolutely haywire because they seemed to throw that part of the brain off, further adding to the problem.
 

Binaural rhythms actually messes with the way your brain is programmed :-)  Depending on who to you talk to? I could use some "or a lot" of this music...

I guess it depends on the folks you listen to...sometimes these rhythms are combined with shrooms inside a sweaty TeePee and maybe passing a peace pipe around.People looking to find another zone besides the one we're in now....then there's the scientific explanation that the beats are relaxing because the brain zones out on the rhythm..ok that's not really scientific but you get the idea.. I was going for the relaxing part of that. You can find binaural beats with the sounds of streams,birds and other relaxing meditative things mixed in...seems to be helpful to a lot of people. Maybe I used the wrong technique...many of those beats are in the sub base regions...maybe my brain didn't like that. I'm not sure.
 
I'd be willing to try it again if I have some Tylenol close by. Maybe I need a different binaural drummer:) It might help to further prove my theory.

I requested a binaural enema? Two ex-cons came in and raped me... I should have been more specific :-(