Can We Pair 4 Ohms Speakers With 6 Ohms AVR?

[naren2512]

Hi Friends,

I have already bought my AVR which is Onkyo 608 from the US and was looking for speakers and have liked the PSB Image Bookshelves.

But I noticed that PSB Image Bookshelves have the Impedance as - Niminal Impedence 6 ohms and minimum Impedance 4 ohms.While my AVR has speakers impedance of 6-16 ohms.

Now my questions are :

1) Can I still pair PSB Image bookshelves with Onkyo 608? I mean is it safe to do so?

2) Has anyone tried to pair Onkyo 608 AVR or any other AVR rated 6 ohms or higher with speakers of lesser impedance ? if yes please can you share your experience

3) I read the Onkyo 608 user manual yesterday it says it has speakers impedance of 6-16, but it also says that Asian and European models can support 4 ohms speakers but the North American models cant ( and mine is a later) in reality could it be that the AVR can support 4 ohms but since 4 ohms AVRs have to undergo more serious testings etc hence onkyo AVR says no for 4 ohms for North American models?

Would appreciate any help you can provide with above. Thank you

PS - Am really confused at the moment as I have really liked the speakers so cant look for another set of speakers which have higher impedance and even buying another AVR will be a costly affair

Regards,
Naren

 

[odyssey]

The simple answer is that you dont do such a pairing and looking for a speaker with a minimal impedance of 6 ohms. if you continue with such a pairing, the AVR could heat up, even shut off at higher volume levels due to finding the speaker difficult to drive.

cheers

 

[avidyarthy]

I believe there is no need to worry at all.

My satellite speakers have a nominal impedance of 4 ohm and have an AVR of 6 - 16 ohm capability. In your case, the speakers have a nominal of 6 at least.

I had'nt given this subject a thought when I had purchased. But, there has been no disruption of any kind. The AVR runs cool, does'nt even have a 'feel' of warmth whatsoever.

I generally hear at moderate levels most of the times. Only recently had turned up the volume (to hear the depths) on the Bastogne part of "Band of Brothers" ....... scene depicting bursting of artillery shells in the Ardennes forest. Was scared halfway that the speakers might give away from their supports due to the shock waves created inside the room .... .... still the AVR was running cool.

Onkyos have a thing about getting pretty warm, if not hot ... that is something that you need to recheck with the similar AVR owners.

 

[Ashwanik007]

I also agree with above. Although try to avoid to run on full steam for long durations.

Minimal Impedance 4 ohms
Nominal Impedance 6 ohms

 

[vaibhavyagnik]

voltage = Current x resistance or putting it otherwise, current = voltage/Resistance. Thus if voltage is constant and resistance is lowered, it will result in more current. more the current, more the heat. so there is theoretical risk of heating up of AVR. But looking at practical scenarios,
1. if you dont play at high volumes
2. Assuming that there always be a lit bit head room in electronics and will be able to provide that extra current
3. Measure the resistance of your speakers using a multimeter. determine whether it is still near 6 ohms or has gone less and approaching four.

In any case your AVR will not blow up instantenously if you connect 4 ohm speakers and switch it on. give it a run, say 1-2 hours at your normal listening levels, feel the AVR for heat and get back here to recieve advice on temperature from fellow members who have the same AVR.

 

[ashishkesarwani]

PSB Image series speakers are an easy load to drive, so you don't have to worry on that front. Your Onkyo 608 should be able to handle it with ease even at really high volume. You should also not worry too much about the heat generated by AVRs if we run it with lower impedence speakers as Onkyo are famous for generating a lot of heat as such even during normal operations and even with mediocre speakers.

 

[naren2512]

I believe there is no need to worry at all.

My satellite speakers have a nominal impedance of 4 ohm and have an AVR of 6 - 16 ohm capability. In your case, the speakers have a nominal of 6 at least.

I had'nt given this subject a thought when I had purchased. But, there has been no disruption of any kind. The AVR runs cool, does'nt even have a 'feel' of warmth whatsoever.

Hi Avidyarthy,

This is helpful, can you advise since when you have been using this speaker + AVR combi ?

voltage = Current x resistance or putting it otherwise, current = voltage/Resistance. Thus if voltage is constant and resistance is lowered, it will result in more current. more the current, more the heat. so there is theoretical risk of heating up of AVR. But looking at practical scenarios,
1. if you dont play at high volumes
2. Assuming that there always be a lit bit head room in electronics and will be able to provide that extra current
3. Measure the resistance of your speakers using a multimeter. determine whether it is still near 6 ohms or has gone less and approaching four.

In any case your AVR will not blow up instantenously if you connect 4 ohm speakers and switch it on. give it a run, say 1-2 hours at your normal listening levels, feel the AVR for heat and get back here to recieve advice on temperature from fellow members who have the same AVR.

Good advise, thanks ! but i was wondering that it may be difficult to confirm / measure the minimul impedance of the speakers using multimeter becuase their nominal impedance 6 ohms and the speakers may touch min impedance of 4 ohms only in frequencies lower than proabbly 120 hz or so.

PSB Image series speakers are an easy load to drive, so you don't have to worry on that front. Your Onkyo 608 should be able to handle it with ease even at really high volume. You should also not worry too much about the heat generated by AVRs if we run it with lower impedence speakers as Onkyo are famous for generating a lot of heat as such even during normal operations and even with mediocre speakers.

Ashish,

I was just hoping that you will come with some good advise and save me from either selling Onkyo 608 or from the idea of having to buy some other speakers and you did exactly that

Your reply is very helpful and encouraging... thanks a ton !!

 

[avidyarthy]

Hi Avidyarthy,

This is helpful, can you advise since when you have been using this speaker + AVR combi ?

.................. since Feb 2010

 

[naren2512]

3) I read the Onkyo 608 user manual yesterday it says it has speakers impedance of 6-16, but it also says that Asian and European models can support 4 ohms speakers but the North American models cant ( and mine is a later) in reality could it be that the AVR can support 4 ohms but since 4 ohms AVRs have to undergo more serious testings etc hence onkyo AVR says no for 4 ohms for North American models?

Friends, any thoughts on above?

Can it be true that the amplifier section of the same model being sold in two different regions / countries is different?

or it could be just to avoid the additional / serious testing required to be done for AVRS claiming to be 4 ohms ( i read abt this testing some where and i think its called something like ULC or ULS testing )

 

[prankey]

There is ABSOLUTELY no need for worrying about. Speakers normally mention NOMINAL IMPEDANCE like Amps and if this pair mentions minimum impedance, thats an EXCESS SPEC meaning if another speaker suggests nominal impedance as 6 ohm and no mention of minimum impedance, we can NEVER ASSUME that is the MINIMUM IMPEDANCE. Infact, in ANY speaker minimum impedance at a particular frequency can go VERY LOW (<1 ohm) or very high (more than 16 ohms) especially on a cheap, poorly designed speakers.

Equation of VA vs "resistance" do not entirely apply here. There is a difference between impedance and resistance - Resistance remain almost constant when any voltage or current is applied, however impedance sometimes change SIGNIFICANTLY with frequency response of speakers and crossover network.

Sometimes, even when speaker says nominal impedance as 6 ohm, tests may result in something else and almost every speaker has different characteristics including frequency response and impedance. Not to mention, cables and crossover networks all have tolerable difference in these characteristics. So, the only way to test these speakers is to run them extensively on the respective amp.

Talking of EXCESS CURRENT, every amp is capable of producing current to a LIMIT. Hence if you pair the amp with a lower impedance load (speakers), it may DISTORT the sound reproduced by those speakers as the voltage curve will get reduced during high current drain. Similarly if you pair it with higher impedance load, it may not be able to produce its rated power output as the VOLTAGE CHARACTERISTIC is practically constant and higher impedance will restrict the current output. SO IMPEDANCE MATCHING is more to do with the sound quality and power output and less to worry about the damage on the amp. I have been using lower impedance speakers with ABSOLUTELY NO DAMAGE or OVERHEATING of the AVR or ANY OTHER AMP for that matter for my entire lifetime.

 

[spirovious]

Well .no worry as its nominal imp is 6ohms.If you see MS avant BS model,it has same features like minimum imp 4 ohm & max 8.So I have not read any such thread in HFV as MS causing any problem to AVR(may I be wrong).I have taken Demo of them with Yamaha AVRs.

secondly it has good sensitivity upto 89 db(MS has around 90),so I dont think it will drain Onkyo 608 with moderate sound levels.
http://www.psbspeakers.com/products/Image-Series/Image-B5-Bookshelf

Lastly Onkyo has good powersupply with high current output than similar priced Denon/Yamaha AVR.

 

[ShaQ.Blogs]

voltage = Current x resistance or putting it otherwise, current = voltage/Resistance. Thus if voltage is constant and resistance is lowered, it will result in more current. more the current, more the heat. so there is theoretical risk of heating up of AVR. But looking at practical scenarios,

If only it was that simple with reactive loads

2. Assuming that there always be a lit bit head room in electronics and will be able to provide that extra current
3. Measure the resistance of your speakers using a multimeter. determine whether it is still near 6 ohms or has gone less and approaching four.

Utter Nonsense!!
Why dont you buy an LG or Philips amp and use it with your speakers??

This is a reactive load! Not a resistive load. So anyone who reads 2 & 3, just simplly disregard the 2 statements. If it was that simple, why on earth would anyone end up blowing tweeters (which is a resuly of mismatched amps to speakers)

2. Assuming that there always be a lit bit head room in electronics and will be able to provide that extra current

Assume . This is highly relative to the speakers in question!!!

In any case your AVR will not blow up instantenously if you connect 4 ohm speakers and switch it on. give it a run, say 1-2 hours at your normal listening levels,

Nonsense Galore!! Why dont you try this with your money??? And then come back to us and tell us what the result was so we can then .... :clapping: :yahoo:

Yeah!! You speaker definitely knows what 1 - 2 hours is! In fact it has a rolex timer in it!!

feel the AVR for heat and get back here to recieve advice on temperature from fellow members who have the same AVR.

Do you know that all AVR's get hot? Do you know that different AVR's get heated to a different extent? Do you know with different loads heat is different? So does different volumes, different environment...different ventilation.
Forget about u giving advice...How on earth do you genius measure hot?

Edited:
The first posts nailed it exactly right!!
Volume knob, be super careful with it. For this particular pair, -10 to -15dB from reference levels shd be your limit.

 

[doors666]

Do you know that all AVR's get hot? Do you know that different AVR's get heated to a different extent? Do you know with different loads heat is different? So does different volumes, different environment...different ventilation.
Forget about u giving advice...How on earth do you genius measure hot?

Didnt he mention it You feel it.:lol:

Guys, please dont give advice if you are not sure. Atleast put a caveat stating you are not sure. Atleast the other person can choose to further investigate. When you give wrong advice while sounding very confident, people might believe you. At the very least, you will get hammered by others.hyeah:

 

[ShaQ.Blogs]

There is ABSOLUTELY no need for worrying about.

There is need to worry. Just because your drove fast all your life and didnt ever meet with an accident, dosen't mean he wont when he does the same.

Speakers normally mention NOMINAL IMPEDANCE like Amps and if this pair mentions minimum impedance, thats an EXCESS SPEC meaning if another speaker suggests nominal impedance as 6 ohm and no mention of minimum impedance, we can NEVER ASSUME that is the MINIMUM IMPEDANCE. Infact, in ANY speaker minimum impedance at a particular frequency can go VERY LOW (<1 ohm) or very high (more than 16 ohms) especially on a cheap, poorly designed speakers.

Equation of VA vs "resistance" do not entirely apply here. There is a difference between impedance and resistance - Resistance remain almost constant when any voltage or current is applied, however impedance sometimes change SIGNIFICANTLY with frequency response of speakers and crossover network.

Sometimes, even when speaker says nominal impedance as 6 ohm, tests may result in something else and almost every speaker has different characteristics including frequency response and impedance. Not to mention, cables and crossover networks all have tolerable difference in these characteristics. So, the only way to test these speakers is to run them extensively on the respective amp.

Talking of EXCESS CURRENT, every amp is capable of producing current to a LIMIT. Hence if you pair the amp with a lower impedance load (speakers), it may DISTORT the sound reproduced by those speakers as the voltage curve will get reduced during high current drain. Similarly if you pair it with higher impedance load, it may not be able to produce its rated power output as the VOLTAGE CHARACTERISTIC is practically constant and higher impedance will restrict the current output. SO IMPEDANCE MATCHING is more to do with the sound quality and power output and less to worry about the damage on the amp. I have been using lower impedance speakers with ABSOLUTELY NO DAMAGE or OVERHEATING of the AVR or ANY OTHER AMP for that matter for my entire lifetime.

I agree with most of what you said. This is exactly right. But,....

SO IMPEDANCE MATCHING is more to do with the sound quality and power output and less to worry about the damage on the amp. I have been using lower impedance speakers with ABSOLUTELY NO DAMAGE or OVERHEATING of the AVR or ANY OTHER AMP for that matter for my entire lifetime.

This is where the problem starts...and sound gets distorted. Fine!
But, just because you did not blow your tweeter, does not mean he wont! Just because your speakers didnt suck the life out of your amp, dosent mean his wont. It dosent mean that it will either.
The problem here is, how do you know how much 'distortion' his tweeter can handle...or more technically excess of power!!
You might have been lucky, dosent mean he will. He can be adventurous like you and experiment..., and then let us know the test result on his expensive pair of speakers.
Or he can match it right.
Or he can be careful with the volume knb!!

Your speaker manufacturer might have given the speaker a tweeter, with a better thermal capacity than what the specs mentioned...but this need not be!!

This is why when you need pair an amp right with the speakers in question, and then you need not worry! :licklips:

 

[ShaQ.Blogs]

To the OP

You shd note one very important point. I am highly certain about this. (Just not 100%. Could be manufacturer dependent. Unlikely though.)
Your warranty will not cover it, if the tweeter blows in this scenario!!

to ... odyssey
Can you confirm on this? Or any other knowledgeable dealer/distributor

 

[ShaQ.Blogs]

Didnt he mention it You feel it.:lol:

Guys, please dont give advice if you are not sure. Atleast put a caveat stating you are not sure. Atleast the other person can choose to further investigate. When you give wrong advice while sounding very confident, people might believe you. At the very least, you will get hammered by others.hyeah:

Duh! I hope you dont mind it if I call you Einstein.

Please read..
How do you (Einstein) know how much heat is too much heat for the AVR??? You don't know this period!!!

You might feel that it was more hot, relative to god knows what.
Unfortunately, for electronics, it is defined by thermal limits & manufacturers specs to a point. (and not by how you feel the AVR all over)
More heat than what it was designed for, will reduce the life of the product!! How much reduction could be hours or days or weeks or years or could be instantaneous. Too many factors and variables here. You could, well, feel free to experiment with yours!!
So one tries to abide by some rules - if one may call it rules (for which *one needs* a decent electronics background). More importantly, one dosent do certain things with their product. This pairing is that certain thing one dont want to experiment with! Of course, since you are Einstein, you can go ahead!

If after listening to advice from clowns like you who come and laugh, and if the OP goes and tries this stuff and ends up blowing his tweeter (oh, and I think... he paid for his speakers with his money) ...and this particular scenario will void his warranty claim. One look at the tweeter & they will tell him to take a hike.
Maybe since you seem to know better, you could help him out. Again!!!

 

[prankey]

There is need to worry. Just because your drove fast all your life and didnt ever meet with an accident, dosen't mean he wont when he does the same.

He do NOT need to worry about as he will be using a branded speaker pair of 6 ohm nominal impedance with another branded Amp which SUPPORT 6 ohm nominal impedance! Rest, real world results do NOT have anything to do with these specs which can change in different scenario. You are UNNECESSARILY trying to scare the OP that just because a 6 Ohm speaker has minimum impedance written as 4 Ohm, he SHOULD be WORRIED! Dude, you are out of your mind, did you fight with your spouse before writing these posts?

I have done enough "engineering" to talk in these terms. Infact ALL the AVRs manufactured in the last 10 years have overload and short circuit protection built in which will shut the amp in such situation automatically. So its VIRTUALLY IMPOSSIBLE to blow these AVRs. Hope you know this.

This is where the problem starts...and sound gets distorted. Fine!
But, just because you did not blow your tweeter, does not mean he wont! Just because your speakers didnt suck the life out of your amp, dosent mean his wont. It dosent mean that it will either.
The problem here is, how do you know how much 'distortion' his tweeter can handle...or more technically excess of power!!
You might have been lucky, dosent mean he will. He can be adventurous like you and experiment..., and then let us know the test result on his expensive pair of speakers.
Or he can match it right.
Or he can be careful with the volume knb!!

Your speaker manufacturer might have given the speaker a tweeter, with a better thermal capacity than what the specs mentioned...but this need not be!!

This is why when you need pair an amp right with the speakers in question, and then you need not worry! :licklips:

Why are we discussing blowing of tweeters here? Even if you pair a 1 ohm speaker to a 8 ohm amp, it may never happen unless there is excessive clipping or power applied. And if such clipping happens, irrespective of IMPEDANCE, speakers including tweeters are BOUND to be blown.

If in this speaker pair, tweeters usually have 6 ohms or higher impedance, and instead woofers tend to drag their impedance towards 4 ohms or less, and the tweeters still get blown due to excessive clipping/spikes or distortion, how would you want us to INTERPRET your statement?

Again, you are wrong that OP will NOT get the warranty as he is pairing a 6 ohm nominal impedance speakers to a 6 ohm capable Amp. So there is NO WAY the manufacturer do not honor the warranty claims. Any 6 ohm speaker will usually have 4 ohms or LESS minimum impedance. That does not make them DANGEROUS to DRIVE as it is AS PER DESIGN!!:clapping:

 

[prankey]

Edited:
The first posts nailed it exactly right!!
Volume knob, be super careful with it. For this particular pair, -10 to -15dB from reference levels shd be your limit.

Like you talk of measuring heat, on what ground are you talking of these volume levels? There could be variable input levels which may not be enough to give full load power even at 0dB. If the OP take your advice as you are a PROVEN, SEASONED ADVISOR here, he may never get maximum power output from his speakers. Speaker's impedance and volume levels have NO CORRELATION whatsoever. If the speakers can not support that high volumes, irrespective of their impedance, they are bound to get damaged. Speaker's voice coils and their insulation has more to do with them going bust than a damn specification of impedance and power output which may not even be TRUE! Same applies to the amp's capacity, quality and protection mechanism. These components do not declare themselves dead if there is an impedance mismatch (IRRESPECTIVE of VOLUME LEVELS).

Usually, there is a prominent CHIRPY sound which comes from speakers and tweeters before they go bust, till the time you are getting reasonably distortion free sound,there is no reason speakers can go bad at those volume levels.

Gist - If the maximum power output of the speakers at 6 Ohm matches that of the Amp at 6 ohm, there is NO WAY you could draw such co-relation of volume levels! Also, you would again want to ride my head on this, however - typically a speaker having nominal load capacity of even half the maximum rated capacity of an amp work without an issue, EVER. Infact, the manufacturers USUALLY pair lower capacity speakers with higher (sometimes much higher) capacity amps while giving FULL WARRANTY COVERAGE. A classic example is the Onkyo HT range with speaker package.

 

[vaibhavyagnik]

i may be wrong shaqs but prankey just showed you how it is done!! way to go prankey!!

 

[jls001]

Impedance matching is desirable because physics says that the maximum transfer of power from source (amp or AVR) happens to the load (speaker) when impedance of source and load are same (Maximum Power Transfer Theorem in electrical circuit theory). At exact match, the power transferred is 50% max theoretically. And since no real-life electrical circuit is 100% efficient, power transfer from amp to speaker in real life is alway <50%.

Now coming to the impedance rating of the speaker, the nominal impedance of 4, 6 or 8 ohms or whatever is only the nominal impedance and not the exact impedance. Impedance varies wildly with frequency. See the attached impedance versus freq and phase curve for the $65,000 Vivid Audio G1 Giya speaker to have an idea of how it varies across the freq band (from Stereophile's review). The danger comes when the impedance mismatch causes uncontrolled oscillation and both source and load can be damaged.


Irrespective of other people's experiences, it is safest to use a speaker matched to your source. Even OEMs recommend that. If nothing else, the likelihood of transferring the maximum power is highest when you stick with matched nominal impedance.

And guys, let's refrain from calling names! Members responding to posts do so with knowledge and experience they have at hand, and those may differ from your own knowledge and experience, but I do believe the intention of every responder is to answer the original query in the best way they can. The onus lies with the OP to filter the chaff from the wheat as no advice can be deemed 100% accurate (including this one!). Peace
Joshua