8 Ohm receiver and 4 Ohm speakers...

Discussion in 'GENERAL AV Discussions' started by ShootingBlanks, Jan 24, 2007.

  1. ShootingBlanks Enthusiast

    ShootingBlanks
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    I am replacing my audio system. I currently have a really crappy out-of-the-box dvd/receiver/5-piece-speaker set from Panasonic that's 4 ohms. All the new stuff I bought is 8 ohm. Here's my problem...

    ...the new receiver arrives in the mail tomorrow. The speakers are backordered and won't be in for a couple weeks. Admittedly lacking patience, I'd love to get the receiver hooked up now, and then just replace the speakers when they come in. But, isn't that a bad mismatch to have a 8 ohm receiver with 4 ohm speakers? What would happen?

    It will only be for a week or two, and if I don't juice the system too loud or anything, will it be okay? Or is the "volume" irrelevant, and it's all electrical mumbo-jumbo that would mess up the speakers and blow them no matter what volume? (cuz I'm not throwing out my old system - just giving it to my dad - so I don't want to break it!)...

    Thanks!...
  2. AVRat Audioholic Ninja

    AVRat
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    You might be OK, besides it's the receiver that will be damaged, not the speakers. If the receiver becomes overloaded, it will go into protection mode and shutdown.
  3. skizzerflake Audioholic Field Marshall

    skizzerflake
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    It's pretty rare that any receiver or amp you buy wouldn't be able to handle 4 ohm speakers, in fact most amps will produce somewhat more power into 4 ohms. It doesn't matter how long you do it, minutes or weeks.
  4. emorphien Audioholic General

    emorphien
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    Hopefully, or it could clip and damage the speakers.


    What receiver did you buy? Some companies have better reputations for handling 4 ohms than others.

    At 4 ohms, the receiver will require twice the current vs 8 ohm, which is where heat can become a problem and can also cause clipping.
  5. ShootingBlanks Enthusiast

    ShootingBlanks
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  6. JVC Banned

    JVC
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    You should be ok, as long as you don't listen at very high volumes, for a long period of time............... :)
    JVC,
  7. ShootingBlanks Enthusiast

    ShootingBlanks
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    I'm more concerned with the RECEIVER getting messed up, as opposed to the speakers. If the speakers got messed up, it's not a huge deal. But I'd be pretty upset it the receiver blew...

    ...so, which item would break? The receiver or the speakers? Thanks, everyone for the input!
  8. jcPanny Audioholic Ninja

    jcPanny
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    Receiver settings

    To be safe you could set the receiver in its 4-6 ohm speaker mode so it will limit the power to the HTIB speakers. With this setting engagued, the receiver should be fine. I have a similar Yamaha receiver driving a pair of 4-ohm Onix Refrence 1's without problems at moderate volumes. 5-7 4-ohm speakers are obviously a more difficult load than 2 of them.
  9. Ampdog Audioholic

    Ampdog
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    ShootingBlanks,

    You have been reassured by now, but just let me confirm with some reasons. Unless you play at ear-splitting levels, nothing is going to happen. In any normal music the average/peak ratio of energy is fairly low. By that I mean that if turned up to where peaks will start clipping, the average energy going out will still be about 25% of the amplifier capability. You will probably stop increasing volume to below such a level, because peaks clipping will begin to assert by distortion every time a peak is hit - you should thus hear that you are then overloading. (Hope this is understandable.)

    Thus the amplifier is unlikely to overheat at only twice the normal (8 ohm) current, only now and then. Further, though this is not a large factor, speaker impedances are not constant with frequency. The value is higher over much of the frequency range.

    Hope this is clear.
  10. Nuglets Full Audioholic

    Nuglets
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    HAHAHA, nice name...ShootingBlanks...:D :D :D :D
  11. zumbo Audioholic Spartan

    zumbo
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    It will be fine. I wouldn't mess with the receivers ohm setting.

    Don't test it out to see what it will do. Listen at a level that would be considered normal to most.

    Don't place the receiver it a confined area. Make sure it has room to breath. (top, back, and sides)

    I would suggest setting the crossover as a way to limit the work load on the receiver.

    What is the FR of the current center channel speaker?

    What is the FR of the current sub?

    Just guessing, I would think 100Hz would be a good place to start.
  12. ShootingBlanks Enthusiast

    ShootingBlanks
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    Thanks for all of the informative posts, everyone...

    I actually randomly got my speakers early (today), and hooked them up. I used the YPAO (autio setup), and it put the crossover at 200Hz. That seems really high, right?...

    As I went to manually lower it on the receiver's setup menu, the lower it got, the quieter the bass got. When it was at like 80Hz, I coul barely hear the bass. I dunno - maybe I'm doing something wrong. I set it at like 120Hz or something, I think, so I dunno if that's "right", but it sounds fine...

    ...to be honest, I don't even know what that crossover setting means.

    There's a crossover dial on my actual sub as well, and in the receiver's manual, it said that before doing the auto setup to turn the sub's crossover dial as high as it would go. So, right now that dial is juiced to it's max (and, again, I don't know what any of that means/does, but I just did it cuz that's what the receiver's manual said)...

    Anyway, thanks again everyone for all the informative posts!...
  13. jcPanny Audioholic Ninja

    jcPanny
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    Crossover settings

    Shoot,
    The crossover setting on your receiver determines which frequencies go to your main speakers and which go to the subwoofer. For your satellite speakers, the 120 Hz setting sound reasonable. The satellites will play 120 Hz to 2 kHz and the sub will play 120 Hz and below.

    By setting the crossover knob on the sub to the Max, you are letting the receiver set the crossover and "disabling" the crossover on the sub.
  14. ShootingBlanks Enthusiast

    ShootingBlanks
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    Cool - thanks again, everyone...

    ...got everything set up, and it all sounds good!

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