Surround Sound From Stereo

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Introduction: Surround Sound From Stereo

About: Electronics expert

This instructable describes how I converted stereo into surround sound using my decoder and two satellite speakers. The goal is to extend "home theater" surround sound experience to any place with quality and simplicity. Works great with all stereo equipment including TVs.

You will need the following items to convert stereo into surround sound:
1 Surround Sound Decoder Kit
2 Satellite speakers (4 - 8 Ohm, about 3 Watt nominal power). Almost any type of speaker works: Computer speakers, satellite speakers, small speakers, big speakers, etc.
Cables to connect satellite speakers
Pliers, cutters, and heat gun to strip and terminate cables

Step 1: Choose Place for Satellite Speakers and Prepare Cables

The satellite speakers should create a trapezoid, rectangle or square shape with the front speakers. Two short cables are needed to connect amplifier output with the decoder and two long cables are needed to connect satellite speakers to decoder.

Step 2: Terminate Cables

Strip 3/8 of insulation from the ends of all cables. Place cable end on the snap-on terminal, allowing 1/8 of insulation to reside within terminals tail. Fix cables end in place by squeezing the terminals tail around cables insulation. Squeeze terminals neck around wire with pliers. Bend excess wire toward the terminals tail. Attach terminals to all cable ends going to decoder. Mark cable ends with heat shrink tubes. Place red tube on + or red wire. Place white tube on - or black wire. Apply hot air to shrink the tubes. Snap-on terminals and heat-shrink tubes are included in the kit.

Step 3: Final Connection

Snap terminals to decoder using directions on the label. Connect other ends of cables to amplifier and satellite speakers, maintaining proper polarity for all connections.

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    28 Discussions

    To anyone reading this instructable for the first time,this is a HAFLER setup,dressed up as an elaborate "decoder".The same results can be achieved (for free) by connecting one or two speakers across the + terminals of your amp as described all over the internet.

    An active version with centre and sub outs can be found here-http://sound.whsites.net/project18.htm

    And as part of a complete system here -

    http://sound.whsites.net/project26.htm

    The center channel can be created by simply running a wire from the + terminal of the 2 front speakers to the terminals of the center channel speaker. The same could also be done for the rear speakers. This causes only a slight reduction in volume.

    This is cool! What about center channel?

    Got chance to hook up ABC surround sound to High-end system, everyone was impressed. No digital system can beat it up for linearity.

    13 replies

    What do you mean? Digital systems are inherently more linear than analog; besides that, the sound you hear is analog, whether or not the processing equipment is digital.

    Spurious free dynamic range of digital to analog converter the major linearity limitation for digital processing (guess why there is significant price difference between digital systems). Passive ABC decoder will over-perform any active analog/digital one.   

    "Spurious free dynamic range..."??? Do you make this up as you go along?

    My apologies... I didn't make myself clear.  "Spurious free dynamic range" is a valid term when dealing with the fidelity of an analog to digital conversion (not DAC as RRC suggests).  It has absolutely nothing to do with this particular circuit.  There is nothing "digital" about it, and using the term here is a smoke screen. 

     Let me remind that conversation was started from digital linearity versus ABC (passive) linearity. There is a significant difference between performing surround sound math using digital circuitry and analog (particularly passive), in case of digital processing it is much harder maintain linearity. 
    DAC also has linearity issues, output signal contains steps producing very rich spectrum falling into audible region. Steps unfortunately is not equal creating even more harmonics (spurs).  

    This is a basic concept of digital audio processing, study it to understand or just enjoy.

     Passive means all additions and subtractions are performed using passive (resistors) components.  

    Yes, I know what "passive" means, and I know what "decoder" means; but I cannot find anywhere that there is a type of decoder that's passive and known as an "ABC" variant.

    Others following this discussion: run a Google search for "abc passive decoder", "passive abc decoder", or "abc decoder circuit". The quotes are needed for it to search for the phrase (rather than just containing all three on the same page).

    I still can't find any, which leads me further to believe that this is simply a Hafler circuit (or some variant thereof) in a box, and thus incapable of "decoding" anything apart from the difference of the left and right channels.

    To RRC: So, how do I make a sound play on the one of the rear speakers, but not any of the other three, via this Instructable?

    You should use different language and search engine for ABC surround sound.

    Hafler circuit is incapable of decoding more than left/right difference since it does not have weighting.

    You can get discrete sound from rear speaker by proper encoding. Encoding method is beyond this instructable. 

    I have shared simple quality surround sound from stereo method, this instructable is good for someone handy to connect wires, while another instructable is good for someone willing to build from schematic.  

    Sorry, but this is "pseudo" surround sound.  If you want to see how the really works, look for the article titled "Simulated Surround Sound".

    2 replies

    This is true 360 degree surround sound system with appopreate recording.
    It acts as 180 degree surround sound for regular stereo and x.1 formats.  

    No sir, it is not "true 360 degree" sound.  That requires at least one and preferably two discrete signals for the rear channels.  With your setup, some component of the left and/or right signal will always exist in the other channels.  At best, this device will widen the stereo field, but it can never derive a discrete sound source from the existing two channels of audio.