Hafler free surround sound safety question

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by goodguys, May 31, 2018.

  1. goodguys

    goodguys
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    Just been reading about the famous hafler circuit to get 4-channel surround sound from a 2-channel amp. This is the description:

    Then I ran a single wire from the right-positive post on the power-amp to the positive post on the right rear speaker. Then (2) a single wire from its negative post to the negative post on the left rear speaker. Then (3) I completed the circuit with a single wire from the left rear's postive post back to the left-positive post on the power-amp.

    In shorthand: R+ to R+, R- to L-, L+ to L+.

    That's the famous Hafler Circuit, given to the world by the famous designer David Hafler (and picked up and made into millions of dollars by Mr Dolby). The effect is subtle; it "warms up" the acoustic feel of the room. It isn't time-delay reverb, just an out-of-phase 'difference' between left and right, which itself is neither left nor right.



    What I want to know is if it is safe for the amp as there is a mention of low impedance dips and dangers

    Any thoughts?
     
  2. Dolus

    Dolus
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    I did exactly that back in the 90's with a stereo amp and two canon V100 speakers.

    To simplify the wiring and obtain what the instructions say, you just connect the speakers as normal to the amp with two core speaker cable and at the amp end disconnect the two black wires and join them together.

    My amp like many of the time supported two sets of speakers A, B or A+B. The rear speakers will be just as loud as the front speakers but it is an interesting effect. I never suffered any problems doing it.
     

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