4ohm, vs 6 ohm vs 8 ohm

Discussion in 'Archived Threads 2001-2004' started by Greg Kolinski, Oct 25, 2002.

  1. Greg Kolinski

    Greg Kolinski Second Unit

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    Kind of a newbie question[​IMG] I have an Onkyo txsr-600 receiver,am currently using a M&K center channel 4 ohm,and for fronts older Accoustic research AR-510's also 4 ohm.The receiver power rating is at 6 and 8 ohms,I know I'll be working the receiver harder with the lower resistance speakers but it shouldn't hurt it ,right?? I've used these AR speakers on 3 JVC receivers over the last 10 years and never had a problem with them,so I would think I would not need to worry with a better grade of equipment.
    Question 2...... Why is there such a difference in speaker ohm rating's?? I've noticed that some of the higher end speakers are more prone to be 4 ohm.?? Why is this?
    thanks
    Greg Kolinski
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    No, it wont hurt anything.

    In fact, your speakers actually CHANGE their impedence nearly every second. It swings from about 2 ohms to about 30 depending upon what sounds it is currently making.

    (Low frequency sounds - 2-4 ohms, high frequency sound 20-30 ohms)

    The impedence rating of your speakers is called the "Nominal" impedence. It's kind of an average value. Some speakers have a lower value, some a higher value.

    Yes, the higher-end speakers tend to be 4 ohm nominal. These speakers take more power, but are designed to be more accurate/sensistive to small changes in the sound. This tends to require more power.

    Hope this helps.
     
  3. Greg Kolinski

    Greg Kolinski Second Unit

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    thanks Bob ,cleared it up for me!!!!!!I just got home from Rat Shack.......SPL meter and Video essentials in hand[​IMG]
     
  4. Allan Jayne

    Allan Jayne Cinematographer

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    If the receiver has a choice of amplifier output impedances, you should match the speakers whenever possible but if you can't, it is better to choose a published, or nominal, amplifier impedance less than the published speaker impedance. For example if the speakers are 8 ohm, you can use a 4 or 6 ohm amplifier with no problem, but using 4 ohm speakers and an 8 ohm amp output, you have to be careful not to go to maximum loudness. Otherwise you can burn out the output amp stages in the receiver.
    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  5. Greg Kolinski

    Greg Kolinski Second Unit

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    I dont often go full volume ,and I would think that if the JVC's lived for 10 years tha Onkyo should do OK.Reciever is rated @ 6 or 8 ohms in the specs.Either way ,Im kinda stuck,cant go out and buy a new rciever,and would spend a lot to get speakers as good as these old AR's.I got out the manual for the 600,it mentions "Dynamic power output

    2*215W @ 3 ohms, if it mentions 3 ohms for anything ,I would feel safe at 4 ohms @ medium volumn??
     
  6. Debbie K

    Debbie K Extra

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    Also a newbie here. We also have the TX-SR600 and are exchanging it today hoping the replacement will resolve a hollow sounding center channel. Voices are not very clear, kind of muffled sounding. Tried swapping the center and right front speakers of the Onkyo HT-S500 speaker set with no change. Posting because I noticed when disconnecting everything that the back of the receiver does have printed above the speaker connections: "Caution: Speaker Impedance 6 Ohms Min/Speaker". Does this then not matter?

    Debbie's husband Neil posting
     
  7. Allan Jayne

    Allan Jayne Cinematographer

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    Hollow sounding center channel -- Are there any adjustments you can make specifically to that channel without affectimng other channels, for example phasing using switches or knobs? You can also try changing the phase by switching the two wires behind the speaker, but if the center channel sounds hollow with all the other speakers turned way down, switching the wires is probably not the problem.
     
  8. Debbie K

    Debbie K Extra

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    Neil again, Yes, we tried all available adjustments. Verified the + to + on the wiring. Switching speakers made no difference, nor does just the TV fed directly into the receiver, and just listening to the center channel, or any other channel with others set lower db. We are about to return the Onkyo to one store, buy it at another so we have the full 30 day return again. The next step would probably be swapping the speakers for (shudder) somewhat more expensive ones. Budget is already blown anyway [​IMG]
     
  9. Greg Kolinski

    Greg Kolinski Second Unit

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    Reguarding Debbie K's post......

    ohhhh,I looked and ,damn there is a warning 6 ohm min speakers.........so what do I do,take the reciever back??? or spend twice that amount on new front speakers???Or is this only really a problem @ high volume settings??

    A badly confused

    Greg
     
  10. Greg Kolinski

    Greg Kolinski Second Unit

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    IM BACK[​IMG] Ok been doing some research,seeing how low frequencies draw the most power,will setting all my speakers to "SMALL"in the receiver set up menu allow me to safely use the 4 ohm speakers on my Onkyo that states no less than 6 ohms??
    My head is really starting to hurt[​IMG]
     
  11. Iver

    Iver Second Unit

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  12. Greg Kolinski

    Greg Kolinski Second Unit

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    solved the problem,called Onkyo, and they said no way on the 4 ohm speakers.So I returned it and got a HK ARV520[​IMG]
     
  13. Bob McElfresh

    Bob McElfresh Producer

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  14. Greg Kolinski

    Greg Kolinski Second Unit

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    YEP ,never actually ran into a problem ,but all my front channel speakers were 4 ohms,but as pointed out ,and found by me the dreaded "6 ohm min" plate on the rear,and Onkyo said dont do it.It probobly would have been ok,but I just didnt feel like worrying all the time if "this will be the one to crater the receiver"[​IMG] Looked at the HK sight,and on their FAQ it had one about 4 ohm speakers,and HK says no problem[​IMG] .Circut City wanted $799 ,I showed em some internet prices and they came down to $649,so I went home with an HK 520.So far I really kicks Butt[​IMG]
    appriciate everyones help
    Greg
     

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