How-to Experience 3-D Ambient Sound from Stereo
On the sleeve-notes to one of Brian Eno's albums (sorry, can't remember which one), I remember reading how he came across an easy trick to achieve an "all-round ambient-type" sound from a stereo recording by wiring a third rear speaker into a stereo amplifier - Brian Eno, for those who don't know, is regarded as the grandfather of ambient sound.
First, blah blah blah... don't blame me, k?
Having said that, I used to have my own stereo system wired-up in the way I'll describe, with no problems at all.
... and yes, it does sound amazing!
OK, you need a third speaker - preferably one that is smaller than your two main front speakers. The reason - from what I remember Eno writing - is that you don't want so much bass. He even suggested an old car-speaker - but don't stress too much, I just used any ole speaker TBH.
The rear speaker should be sited to the rear of your listening position (see above diagram).
Wiring the Speaker to the Amplifier
This is the crucial bit, and possibly the fiddly bit too, depending on your speaker connections.
Run cable from the rear-speaker to your amplifier and separate the positive and negative wires.
Note: I'm assuming the pos and neg wires are stripped. If they're connected to a jackplug or whatever, you'll probably need to cut it off and separate the pos and neg wires. I can't see from here, so how am I supposed to know!.
Now shove, say, the positive wire into the positive output of the right-channel of your amplifier - that's right, jam it in with your front, right-speaker connection (somehow), go on!
Now do the same with the negative wire (rear speaker), into the positive of the left channel output of the amp.
Now stick on your fave Rod Stewart record, dim the lights, and take your seat for a "3-dimensional" sound experience.
So what's happening?
Well I don't think even Brian Eno knew for sure when he wrote of the trick, but what we both think is happening is that you are basically taking the central mono sound, and placing (some of) it behind you.
The effect of this is to move any panning sounds right around your body, rather than just from left-to-right in front of you.
That's a simple explanation. The experience however, is something else: sounds are perceived in front, above and behind your head; the room is "full" of sound - ambient sound, or surround sound if you prefer.
It really is quite extraordinary.
Don't forget, the mono centre sound is largely used for bass and kick, which I mention to reinforce the reason given for the choice of rear speaker, ie., a more "trebley" speaker to the rear works best.
So there you go. If you don't yet have a fancy surround-sound system, this is a good alternative if you fancy experimenting.
Oh yeah, don't forget the disclaimer!