4-8 ohm speakers on a 6 ohm AV receiver?

Discussion in 'Home Cinema Speakers' started by OotzybOotzy, Apr 16, 2016.

  1. OotzybOotzy

    OotzybOotzy
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    I apologize if this is in the wrong place as this is my first post.

    I have 2 questions which I would appreciate an answer from anyone who knows..

    I have Mordaunt short Mezzo range speakers which are 4-8 ohms
    I just purchased a Sony STRDN1060 receiver. The thing is I never realized initially that this receiver actually has an impedance of 6 Ohms. As far as I understood it is the ohms you have to watch out for not the wattage in regards to damaging your equipment. I have already asked richer sounds this question and I Was told my speakers and receiver should be ok together..but I would like a second opinion.

    Well as far as I know 6 ohms drains more power than 8 ohms, which in turn, 6 ohms is actually louder than 8 ohms, correct me if I am wrong?
    Also from what I heard never have a lower number of ohms on your speakers than you do on your receiver...again correct me if I am wrong.

    The first question is, if I use my 4- 8 ohm speakers on my 6 ohm receiver, the fact that my speakers start from the number"4", does this mean that I will drain my receiver because my speakers start from 4 ohms. My receiver being 6 ohms, will my "4" -8 ohm speakers drain too much power from my receiver? As 4 ohms is more powerful than 6 ohms?..trying my best to explain this as clearly as possible hehe!

    The second question, as I said as far as I am aware that 6 ohms is louder than 8 ohms...the fact that I have a 6 ohm receiver, will I automatically get the 6 ohm sound from my speakers which have an impedance of 4-8?

    Thank you,
     
  2. noiseboy72

    noiseboy72
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    In almost all respects you are correct, you should not connect a 4 ohm speaker to an 8 ohm amplifier and yes, a 4 ohm speaker will sound louder than an 8 ohm speaker with the amplifier set at the same level. Some of your other statements are a little confused though, but I understand what you mean.

    However, there are complications. Impedance is a dynamic figure and changes with frequency. This is why some speaker manufacturers state a range of values.

    In this case however, the speakers are suitable for an amplifier capable of driving speakers in the range of 4-8 Ohms, so you amp will be absolutely fine. In fact, Sony only state 6 ohms instead of 4 ohms as it would otherwise fall foul of a US law relating to power output and voltage swing, requiring them make other alterations to the amp to meet the rules.
     
  3. OotzybOotzy

    OotzybOotzy
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    Thanks very much, I thought that it would be ok. I just wasn't entirely sure if the speakers were rated 4-8 ohms whether the 4 would be too much power for a 6 ohm receiver...but as long as itis ok that is all that matters.
     
  4. BlueWizard

    BlueWizard
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    There are no 6 ohm Amps, there are only amps that are rated at 6 ohms with the intent of inflating the apparent power.

    Now there are 4 ohm capable amps. That is, amps that are capable of driving 4 ohm speakers. Sony typically are rated at 6 ohms, meaning you can not have speakers with less than 6 ohm ratings.

    However, 4-8 ohm rating gets a bit tricky. The impedance of a speaker is nominal or something of an average. A typical 8 ohm speaker will drop down to about 6 ohms and rise up to 60 ohms or more.

    A 4-8 ohm is generally 8 ohms, but at one frequency or small frequency range it drops near 4 ohms. But again, across the spectrum it is ...more or less... 8 ohms.

    How well this will work with any give amp depends on the amp. Sony are not noted for liking low impedance speakers, but again, it likely only drops that low are one low frequency, so it is hard to predict.

    If you use these speakers with a Sony amp, then you must make sure that the amp is properly ventilated. Low impedance speakers, mean higher current, and higher current means more heat, more heat means more risk of the amp shutting down. So, good ventilation is important. You might even need assisted ventilation, meaning you might need to add a fan to increase the airflow and therefore the cooling inside the amp.

    Likely you would be OK, but again, you do not want to restrict the ventilation to the amp by placing it in a closed cabinet or placing things on top of the amp.

    My amp was in a very tight cabinet that was originally made for a VCR, so I put a couple of 12v computer fans on it. That amp had a switched outlet on the back of the amp, which was handy because, when the amp came on, the fans also automatically came on.

    The fans were 12v, but I ran them slower with 9v to keep the quieter, but I still had more than enough ventilation. At one point I used only one fan, but I had other fans laying around so I eventually moved to the TWO fans shown in the Photo.

    You can also see that these are very small thin fans - about 60mm x 60mm x 10mm. Very cheap too.

    [​IMG]

    The fans in my case are directly above the heat sinks.

    Again, if the amp is out in the open, ventilation is probably fine. But in a tight space, you might want to consider this.

    Steve/bluewizard
     

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