Sorry if this is a complete noob question, but, what's the difference, and how can you hear it?

You could easily do a google search, I found some good interpritations.

Denis

Diminished means flat (half a tone down). Augmented means sharp (half a tone up).

A diminished 5th interval = 6 half tones (power chord with the second finger moved a fret down)
A perfect (or normal) 5th interval = 7 half tones (think root+5th = power chord)
A augmented 5th interval = 8 half tones (power chord with the second finger moved a fret up)

A normal major chord is made up of three note intervals: root, major 3rd, perfect 5th.
A diminished chord is made up of: root, major 3rd, diminished (flat) 5th.

Oh and BTW, augmented and diminished chords generally sound "thin" because they don't cover more than four or five string 99% of the time.

well most chords are derived from scales, so maybe you should understand the scales that make up the chords.
I was going to try to post a lessons on this but hey there are a million sites out there that already have done this and some much better that I could do so I'll give you a link to a cool one i found.
http://www.malletjazz.com/lessons/dim_les1.html

There is a lot to this but it is well worth learning  ..starting out you should understand that there is a half diminished chord (minor 7th flat5) or B,D,F,A  ....root ,minor 3rd,flat5,minor7th..........then you have the full diminished chord  B,D,F,Ab...root, minor 3rd, flat 5,double flat 7)

 whats cool with diminished or augmented chords, is the forms on the guitar stay the same and you can just slide up the neck three frets or 4 frets depending on diminished or augmented.


 half diminished chord form :

-----2-------  then slide up three frets   --------5------ keep on going another three frets ect.
-----1------                                       --------4-----
-----2-----                                        --------5-----
-----1-----                                        --------4----
x---------------------------------------------------------------
x------------------------------------------------------------------

there's  lots of cool things about the diminished scale and chords

Edit I haven't messed with some of this stuff is awhile and had to go back and take a look at it to make sure that I knew what I was talking about ..lol

augmentend scale:  C, D#/Eb, E, G,G#, B,C   or root,augmented 2nd,major 3rd, augmented 4th, augmented 5th, major 7th then root.  augmented chord would be   C,E,G#,

-----0---------  movable up 4 frets repeats itself-  -------4------- up 4 to 10 fret 4th or 8th fret 1st string
-----1-------                                                   --------5------
-----1-------                                                  ---------5-----
-----2-------                                                  ---------6-----
x------------------------------------------------------------------------------
x------------------------------------------------------------------------------      or

------------------------------------------------------------------------------  movable by 4 frets so the next one would be 12 fret
-------1---------------                -------------------------------5-------
-------1--------------                          ----------------------5------
-------2--------------                              ------------------6-----
-------3-------------                                 ----------------7----
-------4------------                                   ---------------8------


There are 4 different Augmented scales after that they are just repeats.....

hope this helps out some

http://forum.bandamp.com/Audio_Review/5094.html

This is one of my songs that has both diminished and augmented chords.

The intro and the chorus have diminished chords and the first bridge has one augmented chord.

This should give you a feel of what the chords sound like.

Denis

Nice info from goat!!

I use them mainly in progression work, with the chromatic scale, it's great fun experimenting with it.

Denis

An augmented note is one that is raised a half-step.
A diminished note is one that is lowered a half-step.
If these are found in a chord then the indicated degree of the scale must be raised or lowered accordingly.

www.nofretguitarlessons.com.au

I'd just use this www.chordacus.com