[werd]

If by "overhead" you mean higher than the audience listening angle, that is the way everyone does it - at least for the main stereo pair or array, in the case of the infamous Decca Tree. But this angle actually provides more of the rear of the orchestra in the balance. If the micing angle for the main pair was, say, horizontal and low - then you would get string emphasis, because the strings are closest and also acoustically block the middle and rear sections of the orchestra. As it is, zone or spot mics are need to help the middle (second violins and violas and, behind them, woodwinds) and rear of the orchestra.

Nice post 

[eclein]

My setup comes from a corner of my room, my HDTV sits across the corner angle and I have a speaker on either side and a sub to the left of the left speaker a bit and get pretty nice imaging/3d sound/enveloping/(put your particular label here) and I always kinda thought it was the interaction with the angles in my room.

I sit 6-7 ft out in the room at the center position between speakers and with my room being sorta smallish and the sound coming out of the corner area I get nice 2.1 channel wild imaging all the time, put on Peter Gabriel's "UP"  and check it out....LOL...wild

[MLS]

Polk Audio SDA's bring the goods.

[OzarkTom]

I get 3-D ambient sound all the time from 2 channel. No processor needed. Only good tubes, speaker positioning, and room.



Rocket_Ronny

  Now that makes a great sounroom. Every audiophile should have a set-up like that.

[OzarkTom]

Another way is to use Qsound CD's. On the Roger Waters, Amuzed to Death, there is a dog barking way out in right field. If my system is fully burned-in and playing to the fullest, the dog barks at 3 o'clock.
Even if one component is off, the dog will bark from 12-2 o'clock. This is too funny.


Over 60 albums feature QSound processing. Some notable examples include:
 
The Adventures of MC Skat Kat and the Stray Mob by MC Skat Kat (1991)
 Amused to Death by Roger Waters (1992)
 Broken China by Rick Wright (1996)
 The Immaculate Collection by Madonna (1990)
 Dangerous by Michael Jackson (1991)
 Parallels by Fates Warning (1991)
 Pulse by Pink Floyd (1995)
 Power of Love by Luther Vandross (1991)
 The Soul Cages by Sting (1991)
 Spellbound by Paula Abdul (1991)
 Help Yourself by Julian Lennon (1991)
 Whaler by Sophie B. Hawkins (1994)
 Prisoners in Paradise by Europe (1991)

[Rocket_Ronny]

Now that makes a great soundroom. Every audiophile should have a set-up like that.

I only wish the opening behind the speakers was another 2.5' wider on each side. Then majic will happen. Like my old room.





But since we are moving from the sticks to modern life, the present room no longer matters. So when I look at a house listing I always try to see if there is a room aprox. 16' x 26' x 10'. Not too many like that. I also need something in the basement since I listen LOUD>

One thing I found that makes awesome 3D soundstaging is having LOTS of space behind your speakers, spreading your speakers FAR apart, and try playing with listening distances.

I have found having a lot of space behind the speaker, 12', I can spread the speakers farther apart and pull them closer than otherwise since the distance behind the speakers tends to pull back the soundstage.

This arrangement really opens up soundstage, giving a MIND BLOWING - 3D audio experience. As close to surround sound one can get with 2 channel audio. Works for me.

Rocket_Space Cowboy_Ronny

[Duke]

Ah, the old "Hafler Hookup"; my first foray into "surround sound".  I did this many years ago and thought it worked pretty well.

One critical factor in setup is this:  The rear speakers should be at least nine inches further away from the listener's ears than the main speakers.  This way, the first-arrival sounds will come from the main speakers, which is where they should come from for correct image localization.

Floyd Toole reports that a sense of ambience and envelopment is best served by late-arriving energy that comes in not from behind the listener, nor directly from the sides.  Rather, the late-arriving energy is most beneficial when it comes from about 10 o'clock and 2 o'clock.   

[Duke]

sorry double post

[jimdgoulding]

The music isn't merely coming from the two speakers. Sound waves are bouncing off the walls, so some of what you hear is reflected sound. These reflections give the effect of ambient sound.

Early B., true but ambient sounds of the recording venue are in many recordings.  Lots of classical music recorded on location, for example.  If one's speakers are out a ways from the walls you will be hearing more of the venue and less of your room.  Wall treatments are useful in this regard, also.

[Russell Dawkins]

Floyd Toole reports that a sense of ambience and envelopment is best served by late-arriving energy that comes in not from behind the listener, nor directly from the sides.  Rather, the late-arriving energy is most beneficial when it comes from about 10 o'clock and 2 o'clock.

This is the first I've heard of this. It seems counter-intuitive, in that the standard speaker position for either two channel or 5 channel reproduction is taken as ±30º for the L & R or LF & RF speakers. 10 and 2 o'clock would have the ambiance speakers at ±60º - just 30º further from center than the L&R mains? The 5.1 standard goes on to specify ±110º for the rear surrounds.
Just curious.

[Letitroll98]

Another way is to use Qsound CD's.

Over 60 albums feature QSound processing. Some notable examples include:
 

The Soul Cages by Sting (1991)
 

The one that I own and the very thing I was referring to in my post awhile back.  Other than the Roger Waters CD, I'm not sure I would appreciate the other selections you noted.  And while I do enjoy listening to this CD and I like the "special effects", I can't help thinking it's just a bit too phasey sounding in the front stage area.  Good for pop albums, but not something I'd go for in small acoustic groups or classical music.  However this is from one recording, I could change my mind if I had more examples.     

[saisunil]

In addition to room placement and room acoustics, I'd say software plays a huge part.
MA Recordings have done such a good job at capturing the space and is the easiest way to hear it in your system to more or less degree depending on your system.

I have been listening to some of the CDs I go from MA from the ny audio show - they are amazing sounding indeed. Highly recommend ...

Amazing sense of space or 3D ...

[dB Cooper]

Deriving the ambient sounds of a recording by using a a pair of rear speakers has been around since 1970. The passive 4-channel matrix system was popularized by Dynaco's co-founder David Hafler. The Dynaco QD-1 Quadapter enabled a bit of control over the rear channel.



Try it, nothing will blow up. I must have used this system for stereo at one time but it was more of a novelty than a useful setup.

Wayne

Most likely not- although you could run into trouble if using low-impedance speakers, or an amp with poor performance into low impedance loads. The link provided with the diagram advises of the problem but gets the reason partially wrong- it's not simply a volume problem, it's an impedance problem, as the rears are essentially in parallel with the main drivers when carrying the difference information. 'Back in the day', a friend took his 45 wpc Pioneer amp to a party where this setup had been put together. I was on my way to the party when I met my friend coming the other way looking for me- his amp had blown up after a very short time. I turned around and got my 40/40 Dyna integrated (party was only two blocks from my house) and dropped it into the exact same speaker setup, where it proceeded to rock the room for the duration.    (Thank you Dynaco!)

I understand Wayne's opinion but partially disagree- with the right recording (meaning,for the most part, live recordings) - properly adjusted, this setup cold be quite convincing. With studio recordings, not so much, although on certain recordings some amusing effects could sometimes be had, the bumblebee flying around the room on Ummagumma for example.

I used to have it set up in about a 12x20ish room with the mains along the short wall and a single rear, with an L-pad, on a bookshelf high in the middle of the rear wall. I found this to be better than the 4-corner arrangement (which was a sop to marketing imo). If you use the 2-rears arrangement, be aware the rears must be connected out of phase with each other to be in phase electrically. This is shown in the Hafler/Dyna hookup diagrams.

[Saturn94]

The one that I own and the very thing I was referring to in my post awhile back.  Other than the Roger Waters CD, I'm not sure I would appreciate the other selections you noted.  And while I do enjoy listening to this CD and I like the "special effects", I can't help thinking it's just a bit too phasey sounding in the front stage area.  Good for pop albums, but not something I'd go for in small acoustic groups or classical music.  However this is from one recording, I could change my mind if I had more examples.   

Like you, I also enjoy the "special effects" in pop music, but not so much for classical.

[werd]

It might be helpful to point out the oppsosite of 3d ambient playback. The dreaded U playback shape. Just a bunch of congestion with no air.