Ohm question

Discussion in 'Archived Threads 2001-2004' started by Allen Longcor, Mar 8, 2002.

  1. Allen Longcor

    Allen Longcor Supporting Actor

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    Ok is it important to have the ohms of all your speakers the same? Now here is a situation, lets say you have 8 ohm main speakers and center, but 6 ohm surrounds. If you had a receiver would you just leave it at 8 ohms? Now if you had seperates would you just worry about the amp supplying the power? So for the 6 ohm speaker have the amp supplying the watts in 6 ohms? BUT what if you have a 5 channel amp at 8 ohms. What would you do?
     
  2. Ron Shaw

    Ron Shaw Stunt Coordinator

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    No problem. Your amplifier can put out more power into 6 ohms, but as far as you are concerned, pay no attention because it doesnt matter.
     
  3. jeff lam

    jeff lam Screenwriter

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    Doesn't matter. Just calibrate to the same level. You may find you have to bring down the 6 ohm speakers a bit because they will get more power than the 8 ohm ones.

    Enjoy!
     
  4. Allen Longcor

    Allen Longcor Supporting Actor

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    That was easy lol. THX.
     
  5. Allen Longcor

    Allen Longcor Supporting Actor

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    Actually another question. If you are using a receiver then would you set the ohm switch to 8 ohms????

    Also, for amps can you use say an 8 ohm amp to drive a 6 ohm speaker or would you want to use a 6 ohm amp, assuming you had one for each speaker. But if you had a 5 channel amp at 8ohms would it be ok to use 6 ohm speakers with them?
     
  6. jeff cr

    jeff cr Agent

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    you have the same situation i have. i'm running 8 ohm speakers for the front and 6 ohms for the surrounds. i notice when i turn my reciever up to about 3/4 volume , the amp overloads and shuts down. then i have to turn it back on. i can alleviate this by wiring the surrounds in series but that defeats the purpose. i usually don't listen to stuff that loud anyway.
     
  7. Mark Weber

    Mark Weber Auditioning

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    Let me see if I understand the answer to this question.... If I get 4 ohm mains and 8 ohm rears and center channel, I should not have any problem with a receiver figuring out how many watts to supply each speaker...right?

    Mark
     
  8. ThomasL

    ThomasL Supporting Actor

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    This is how I understand things. ohms are just measuring the amount of resistance on the electrical circuit created between the speakers and the receiver. Speakers that are listed as 8 ohms may not even be showing the receiver an 8 ohm load - that may just be their nominal load. Speakers with less resistance will draw more power from the receiver than ones with a higher resistance given the same amplification level (i.e. volume). So, if you have 8 ohm fronts and 6 ohm surrounds and you crank the volume, you'll reach the point where your receiver reaches maximum power output on the surround channels before the L/R front channels. At this point, it'll probably "trip" and turn off to avoid blowing an internal fuse. Of course, other factors such as the sensitivity of the speakers themselves come into play as well, I believe. I think if you were going to run speakers with different nominal ohm ratings that you just need to be aware of what can happen as you crank the amplification to high levels. Also, check to see if the manufacturer of your amp/receiver lists power ratings for different resistance levels (e.g. 4, 6 and 8 ohm ratings).

    hope this helps,

    --tom
     
  9. Kerry Hackney

    Kerry Hackney Stunt Coordinator

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    Allen, Think of it this way, the lower the impedence of a given speaker the closer that speaker is to a short circuit. A short circuit is one with zero ohms or no resistence. The lower the number goes the more current and voltage the power supply in the amp / receiver has to deliver. And, the more heat it will create as a by product. Less expensive amplifiers have smaller power supplies that can not produce the voltage and current required to drive low loads very hard. At lower volume levels, even cheap amps will drive low impedence down to 4 ohms or so. But, when you want them to crank it up, the amp just can't handle it. One thing to remember is 4 ohm speaker don't play any louder than 8 ohm speakers of the same design. You should be able to calibrate all of the speakers to matching volume regardless of their rating. Also, keep in mind that impedence levels are not static. A speaker that is rated at 6 ohms may have dips below that level. That is why some speakers are said to be harder to drive than others.

    If your amp is going into protection mode then you have to look at upgrading soon if you want to play at that volume. Double check also that your amp has room to breath and isn't in a cabinet or some structure that is compounding the problem.
     

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