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Discussion Starter · #1 ·
Please i'm running a system on my Pionner d914 that is as follows:
5.1 philips speaker kit with 8Ω impedance, 100w for the speakers(they are bookshelf type)
2 front mid-sized philips speakers rated 6Ω, 150w.
Is it ok to run this system on the receiver configured for 6Ω what about 8Ω?
Any thing i should look for?
 

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You should be fine. Check the operating manual for whether they have any comments on impedance, but it usually doesn't matter until you go down to 4 ohms.

During the setup the different speakers may have different volumes, but that's easily compensated within the speaker setup settings, by adjusting the volume for each speaker. An SPL meter may come in handy, or a good pair of ears.

If the AV Receiver has an impedence switch, leave it at 8 ohms. The lower impedance setting usually just limits the power output.
 

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Discussion Starter · #3 ·
if i leave the impedance to 8, wont my receiver be forced to deliver more power that its usual to him to the 6 ohms pair of speakers?
 

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If you feel more comfortable setting the AVR to 6 ohms, please do so, but I'm of the understanding that this simply limits the amount of power it can output. For myself, I would ensure that I don't overdrive the AVR and leave it set to 8 ohms, so that the AVR can, if necessary, provide more transient power.

The safer route, however, would be to set it at the lower impedance since that would limit the power output of the AVR.
 

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When you have an imbalance of impedances, there will be an imbalance of power delivered to the speakers (Power is directly proportional to the impedance). You might be able to correct that with the speaker setup or it might prove too much. Also there is a difference of speaker efficiency. Try it out both settings and try to balance it out. Do not worry about the too much power. When you adjust speaker levels from the setting, you also adjusting the power delivered to the speakers. I would say 8 Ohms is preferable if the levels equalize.
 

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Discussion Starter · #6 ·
Thanks for both answers.
I still have one question, if i have a receiver set to 8 ohms and i put 6omhs speakers on it, will it try to provide all the power the speaker is able to receive or it will limit its power because its seted to a 8 ohms(implying lower watt output)?

PS: how can a speaker control how much power the receiver will output, shouldnt the receiver itself control this based solely on the impedance its configured on it?
 

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I believe that an amplifier will put out all the power it's capable of until:

- it clips, potentially damaging itself,
- or a protection circuit kicks in,
- or it blows the speakers

I believe that the (lower) impedence setting on the back of some receivers simply lowers the potential output of the amp, so it's less likely to damage itself, however, as I mentioned before, this may limit amplifier power for (brief) transients, which would not be harmful. Few people drive their amps that hard, especially if they have a subwoofer and have the receiver set to "small" for the speaker setting.

What happens will probably also depend on the individual receiver.
 

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If the impedance is selectable on the receiver you'll need to set it to 8 ohms. My Cerwin Vega speakers are 6 Ohm speakers and on a non-selectable Sony receiver that "required" 8 Ohm speakers the protection circuits would kick in at anything over half volume. Now that I'm running a Sony ES receiver the switch is set to 4 Ohms and I can crank it up all I want.

When impednace is selectable and you set it to value higher than the speakers' impedance the system senses the impedance and will kick into protection mode when the impedance drops below a predefined limit.
 

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In over-simplified terms, power is V*V/R, where V is the output voltage and R is the impedance. So essentially if you use a lower impedance speaker, you will be producing more power. If a receiver is designed for certain power output at certain impedance, and you bypass that by using a lower impedance, you can potentially damage your receiver. Generally, the impedance setting of the receiver plays with the output voltage or gain to protect itself. How this is implemented depends on the receiver, but generally it means you will not be using your receiver to its full capabilities. If you do not crank up the receiver (say you do not go much over %50), you should be fine with 8 Ohm setting and using a 6 Ohms speaker.
To complicate matters more, speaker impedance is not constant over different frequencies.
 

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Yes, I know that, but switching the switch to the lower impedance setting will act to limit the amp's power output - see posts 2, 4 and 7. I believe you may have misinterpreted what I said, or perhaps I wasn't clear enough.
 

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Instead of starting another thread, I would like to ask a related question. My current system is an HTIB by LG. The speakers are rated 4 Ohms and the Subwoofer 3 Ohms. I would like to upgrade the AVR but keep the speakers. Most of the units that are available from Onkyo, Pioneer and Sony recommends 8 Ohms. Does that mean that my current speakers cannot be used ?

Thanks.
 

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There are some AVRs that are rated as low as 2 ohms, however, the speakers from the HTiB are probably not that great, so you could consider an upgrade of the speakers along with the upgrade of the AVR.

You could also use almost any AVR, provided you don't try to drive it too hard.
 

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Thanks. I was looking at a unit from either Onkyo TX-SR505 or Pioneer VSX-517-KS . I wanted to upgrade my system in two stages as I can't afford to go all the way at the moment. My LG has only one digital audio input (Opt) and I thought an AVR with at least two Opt. Inputs will help. I have the OPPO connected to the only OPT IN and the Rogers Box is linked with a pair of white and red analogue cables. I read somewhere that any 5.1 or surround sound programmes from the TV will no work because the audio from the Rogers Box is not a digital one. Any advice will be appreciated.
 

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I read somewhere that any 5.1 or surround sound programmes from the TV will no work because the audio from the Rogers Box is not a digital one. Any advice will be appreciated.
See the following thread:

http://www.digitalhome.ca/forum/showthread.php?t=17870

You need a digital audio connection from the SA8300HD to the AVR and you will have DD5.1 on channels/programmes that are DD5.1
 

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Discussion Starter · #16 ·
On the speaker impedance, many of the receivers you mentioned can be configured to 6 ohms, so dont worry about the 8 ohms too much.
Regarding the speakers you have i wouldnt use it because you can overdrive your amp with them.
 

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Speaker impedence is the last thing I would ever worry about when buying speakers. The impedenvce will vary considerably over the frequency range anyway.
 

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Thanks for the wealth of info. The ideal solution is a replacement of the AVR and my current speakers. I have decided to add a Toslink Switch to my current system that will provide the capability to connect the two optical inputs (OPPO and Rogers Box) to the LG AVR. From another thread I found a switch from Tiger Direct that will even work with the Harmony Remote. I wish I had reseached this forum well prior to my buying the HTIB. But I guess you get what you pay for.
 

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Impedance Warning!

This is fairly old thread but it seems like there is a misunderstanding of how impedance should be dealt with when trying to match speakers and receivers.

Some mistakes could be costly and therefore the reason of this reply.

1. Most HTIB (I am not talking about mix and match HTIBs) uses 2 ohms speakers and are not suitable for use with AVRs that are sold separately as most of them are rated 4, 6 or 8 ohms.

2. When you are using a speaker and your AVR can not match the impedance of the speaker, you should always set your AVR to lower impedance than the speaker impedance NEVER THE OTHER WAY AROUND!

3. R = Resistance and is measured in ohms and Z = Impedance and is also measured in ohms but they are very different as R always remains constant(the same value) however, Z reacts totally differently as it is a coil and the impedance value will change with the amount of current going through it (your 2 ohms might be seen as a short when current changes its value).

To make it short, if you set your AVR for higher ohm rating than your speakers, this will overload your output and some chances of blowing the output or shorten its life! Yes, the lower the impedance and the more power out to the speaker but the more strain you put to the output. In the days of transistors, this wasn’t as bad as there was a transistor for each output but with today’s technology (ICs), when one output is blown, it means replacing all outputs that are confined within the same IC. This can be pretty costly mistake as often it will not limit it self to the IC! Other surrounding components such as resistors will also give but more important, there could be damage to the PCB itself!

Please take the advice seriously; the rule should be that if it is not possible to match receiver and speaker impedance, set your receiver to lower impedance than your speaker! «Simply see it this way: Lower impedance will be seen by your receiver as a short and a short means blowing something up!

NOTE: As a repair shop owner, most of the receivers and amplifiers I repaired where blown outputs and most of the times, the owner had either used speakers with lower impedance or had used speakers hooked-up in parallel which would lower the impedance and caused the output to overheat and blow-up! :(:confused::mad::eek: Yes, you will probably go through those feelings if this happens!
 
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