Ohms? Which is best?

Discussion in 'AV Receivers' started by Jonathan Larson, Mar 31, 2004.

  1. Jonathan Larson

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    For instance, I see 8 ohm speakers then I see 4 ohm speakers, which ones are better or is there a better when it comes to ohms. Can somebody explain this Ohm thing to me.

    Thanks
     
  2. John Garcia

    John Garcia Executive Producer

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    It all depends on what you are looking for and what you plan to drive them with. Low impedance speakers will mean you will want better amplification that can handle the lower impedance load of those speakers. It's not as simple as saying any "4 Ohm speaker is better than any 8 Ohm speaker", it really depends on the speaker design.
     
  3. Cees Alons

    Cees Alons Moderator
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    Jonathan,

    Ohms says how high the voltage (Volts) of your amplifier must be to get a certain current (Amperes) running through that speaker.

    If you compare it to a water tube: a wide tube would have a low Ohms figure, a thinner tube a higher figure. The thinner tube would have a higher resistance to water running, given a certain water pressure.
    Ohms is the resistance to electric current.

    As John said, it's a matter of design. Sometimes they want to use more windings to make up the coil of the speaker driver (and then need less current to get enough movement, so the wire of the coil can be thinner), sometimes a bit less windings (and then the wire must be a bit thicker to let more current through for the same sound pressure).

    Generally, given your amp or receiver, you better stick with the impedance (Ohms) that thing was devised for. The maximum voltage and current an amp can deliver are fixed by its design, so the best use is what they specify. Note, that some amplifiers may have both options (or more).


    Cees
     
  4. CalvinCarr

    CalvinCarr Supporting Actor

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    I noticed on The high end Pioneers they show the rating for 6 ohms.....What size speaker would you use?
     
  5. Cees Alons

    Cees Alons Moderator
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    If the rating is 6 Ohms, I would use 8 Ohms speakers. That way the receiver amps will better "dampen" the speakers (get rid of the unevenness of their frequency response) and it won't be any danger either.
    BTW it would also be relatively safe to connect 4 Ohms speakers to a 6 Ohms amp!

    Note, that the impedance for speakers isn't the same for every frequency (and at all temperatures)!


    Cees
     
  6. Jonathan Larson

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    Hey Cees,

    If I get an 8 ohm receiver, would you recommend using 8 ohm speakers with that receiver?

    Thanks
     
  7. Ted Lee

    Ted Lee Lead Actor

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    here's the less-then-perfect analogy i always use at work.

    if your receiver is designed for 8-ohm speakers, and you hook up 4-ohm speakers ... it's like driving your car (designed to run at 55mph) at 100mph.

    your "opening" up your receiver and making it "work harder" then it's designed to ... causing overheating, possibly wear and tear, etc.
     
  8. Michael R Price

    Michael R Price Screenwriter

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    I wouldn't use that analogy because for "normal" use, 4 ohm speakers are not a real problem. Driving the speakers to very loud volumes would indeed be pushing a receiver past its design limits as Ted says. In other situations it would just cause the receiver to run warm (that's fine) or have slightly degraded sound quality.

    In short, pick any speaker you want (first), regardless of its impedance rating. and then pick a suitable amplifier that works well with them.
     
  9. Cees Alons

    Cees Alons Moderator
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    Jonathan,

    The short answer is "yes". (The long answer is yes too). [​IMG]

    Cees
     

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