More ohms or less ohms

R

Roscoe187

Audiophyte
I have a yamaha rx 2700 that runs 8 ohms.
now is it worse for the amp if i have 16 ohm speakers
or is it worse if i have 4 ohm speakers?
plus if its not correct for the amp wouldnt the amp just have a safety overload and just switch off?


Should i just pull the speakers out and connect them Parallel so thay are 8ohms?

thanks.
 
M

markw

Audioholic Overlord
The higher the speaker impedance presented to the amp, the less the amp has to work.

You take it from there.
 
Adam

Adam

Audioholic Jedi
Welcome to the forum!

For starters, your receiver can handle 4-ohm speakers when used as the front speakers.
RX-V2700 Owner's Manual said:
4 ohm speakers can be also used as the front speakers...
For general info, I'll add a bit to what Mark said (which is correct). 16-ohm speakers will present an easier load. 4-ohm speakers will result in a higher current draw from an amp, and some amps do have protection circuitry to shut down if they need to.
 
P

PENG

Audioholic Slumlord
Your receiver will deliver less power to the 16 ohms speakers so just make sure the sensitivity of the speakers are high enough to make up for the lower available power.
 
M

Moonlight

Audioholic Intern
Hi (noob question)
Rather than start a new thread I will ask here.
I have a chunky 70's 60W per ch Sansui amp and have 2 8ohm b/shelfspeakers attached to system A. I recently purchased a centre speaker which is 6ohm.
I realize this is not ideal, but can I connect it to say the left side of system B and run both A&B. I have tried it and the power protector flashes and takes about 3 mins of turning it off and on before it turns on reluctantly. Is this damaging the amp or speakers and should I connect another speaker to the r/s of system B to even it up? Would it need to be 6ohm also or doesn't it matter? All of my other speakers are 8ohm. The 6 is a Jensen.

Thanks in advance :)
 
Lordoftherings

Lordoftherings

Banned
Impedance matters.

First, 16-ohms speakers are almost inexistant for in-home speakers.
And the vast majority of speakers on the market have inpedance that varies from approximatively 4 ohms to 20 ohms more or less, with a nominal average of about 6 to 9 ohms with a minimum impedance of about 4 ohms (dips at certain frequencies of the audio spectrum).

The speaker's manufacturers have to build the majority of their speakers to accomodate the majority of receiver's and amp's manufacturers.

The speakers that are from lower impedance are generally the high end ones that cost more money. And the more powerful a receiver or power amp, the more capable generally they are able to handle a bigger choice of speakers, irrelevant of their designers or their minimum impedances.

As for your last question about running two set of speakers, in your particular case, you should not do it.
Because when you do so, your receiver or integrated amp will see an impedance that is twice less than the average sum of your two different set of speaker's impedance.
For example, let's presume that your speakers A are a 8 ohms minimal, but with a minimum of 5 ohms (lower dips).
And your second set of speakers B, are a 6-ohm minimal impedance, but with a minimum of 3 ohms at certain frequencies.
So take the minimum of speakers A (5 ohms), and add that to the minimum of speakers B (3 ohms), you get 8 ohms.
Now, divide 8 ohms by two, to give you the average of your two set of speakers, and you now get 4 ohms, which is now the minimum average of your two set of speakers.
Now, if you play them (A +B) together, your receiver or integrated amp will see twice as less than this figure, which is 4 ohms divided by two = 2 ohms.
There is no way that your old Sansui amp or even your Yamaha RX-V2700 can do that, it will trip their protective amp circuitry.
You need a very powerful amp to handle 2-ohm loads.

And even if you take their nominal impedances (which is always a bit lower than specified), you'll get 8 ohms (A), plus 6 ohms (B), equals 14 ohms, which you divide by two for the nominal average, so equals now 7 ohms.
Then your receiver or integrated amp (when running both set of speakers at the same time), see half of this number, which is 3.5 ohms nominal impedance, withouth considering the true minimum.

That's just the way it works.

When a receiver like Yamaha or any other receiver, has two set of front speakers (A & B), it's for using a second set of speakers to another zone, but without the two set playing at the same time (main zone at once, zone 2 at once by disabling main zone speakers).

To be quite honest with you, I damaged quite a few amps and speakers just playing both pairs at the same time (I admit it, I did my part of foolish things).

There are several reviews and articles talking and describing these amplifiers behaviors when face with situations like these. Even here at Audioholics, you have some good articles discussing this very own subject. Also at Secrets of Home Theater and High Fidelity web site.

I hope that my explanation was clear enough for you to understand what happens in your situation, and that in the future, you will not drive two set of speakers at the same time.
* For a mutichannel surround receiver, it's different, each channel is powered by it's own discrete power transistor amps. But even then, when all 7 channels are going, your receiver that is rated at 100 watts per channel, will often delivers only a fraction of that number, let's say about 35 watts or so.
Of course, a bigger receiver will be able to perhaps get that same ratings of 100 watts per channel, at about 70 watts when all 7 channels are driven together, and only temporary, not constantly. These examples are average, for informative purpose only.

Regards,

Bob
 
M

Moonlight

Audioholic Intern
Thanks Bob - I will most certainly take your advice and only run one pair of speakers.
Cheers :)
 
P

PENG

Audioholic Slumlord
let's presume that your speakers A are a 8 ohms minimal, but with a minimum of 5 ohms (lower dips).
And your second set of speakers B, are a 6-ohm minimal impedance, but with a minimum of 3 ohms at certain frequencies.
So take the minimum of speakers A (5 ohms), and add that to the minimum of speakers B (3 ohms), you get 8 ohms.
Now, divide 8 ohms by two, to give you the average of your two set of speakers, and you now get 4 ohms
Your math is incorrect. If you parallel a 5 ohm load with a 3 ohm load, the equivalent impedance is:

Req = (R1*R2/R1+R2) = 15/8=1.875 ohms. That is significantly lower than 4 ohms. Like you said, don't do it!
 
speakerman39

speakerman39

Audioholic Overlord
Your math is incorrect. If you parallel a 5 ohm load with a 3 ohm load, the equivalent impedance is:

Req = (R1*R2/R1+R2) = 15/8=1.875 ohms. That is significantly lower than 4 ohms. Like you said, don't do it!
Very true not to mention that the 3-ohm load would result in more power. This in turn, will create a lot of cancellation in the time domain. That type of configuration would not sound very good either. Of course, nothing is ever exact. ;):);)



Cheers,

Phil
 
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Lordoftherings

Lordoftherings

Banned
Bravo! You just win a free vacation, all expenses paid.

Your math is incorrect. If you parallel a 5 ohm load with a 3 ohm load, the equivalent impedance is:

Req = (R1*R2/R1+R2) = 15/8=1.875 ohms. That is significantly lower than 4 ohms. Like you said, don't do it!
I knew that, I did work on my post to try fixing few things, and after a while, I get tired and I knew that I still have work to do on it, but in my lapse of focus and wanting to watch the blu-ray of "Gran Torino", I scooped it by skipping it (my post).
But I knew right from the bat, that a smart as* will find the error on my math, and correct it accordingly. And who is that smart as*? Seems that,... you are! ;)
And that makes you the final nail in the coffin, as to really not use two pair of speakers driving at the same time, when running "parallelly".

Is that makes you a pedantic individual? Sure it does. ;)
And without people like you, the world would be a worse place to live. :)

To wrap it up, I'm not as smart as you, but I knew that I can count on people like you. :D

P.S. Is "parallelly" a word? If yes, is this the correct spelling?
If not, then just switch it for "in parallel", like: "when connected in parallel".
 
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Adam

Adam

Audioholic Jedi
But I knew right from the bat, that a smart as* will find the error on my math, and correct it accordingly.
In other words, you don't mind giving incorrect advice to people who come here for help. Noted. You shouldn't rely on others here to read all of your responses and fix them.

Is that makes you a pedantic individual? Sure it does. ;)
"Pedantic" is typically given a negative connotation. I'm glad that Peng gave the right answer.

This isn't the first time that you've stated incorrect information, but that happens. The fact that you think it's fine to knowingly post incorrect information is disconcerting, though.
 
Lordoftherings

Lordoftherings

Banned
Explanation.

In other words, you don't mind giving incorrect advice to people who come here for help. Noted. You shouldn't rely on others here to read all of your responses and fix them.

"Pedantic" is typically given a negative connotation. I'm glad that Peng gave the right answer.

This isn't the first time that you've stated incorrect information, but that happens. The fact that you think it's fine to knowingly post incorrect information is disconcerting, though.
Oh Adam, Adam, so serious! Can't read between the lines? Didn't see a sense of humor on there? Over 900 posts, do you think there is one that I give wrong advice by purpose? Do you realy believe that I will be giving incorrect information willingly without minding? Do you also believe that I rely on others to fix my mistakes? Well, that last one, I'll say no, but it can happen that I do need help.

The word "pedantic" was used in my post with the utmost respect, in a very positive sense. You interpreted it to your own benefit for degrading me. You felt for something that you don't even fully comprehend. How could you go to the other way of a compliment?
Of course, just like you, I'm glad that Peng did correct me, because it's true that I was off in my math. But was this offensive to anyone? To you? Or is it because my response to Peng post? Of course, you have to chew each word with the negative side of it.
True, I ain't perfect, but I surely try my best.

And it won't be the last. And are you nuts? Do you really think that what you're saying is my true way of thinking? I thought that you were smarter than that. ;)


Let's be honest here Adam, if someone see a mistake from my part, he'll correct it, just like Peng did, no fuss.
If I see someone making a mistake, I just do as Peng did, no fuss.

The problem as I see it now, is that my response was not totally understood in the true sense, so you decided to give it your own interpretation. No problem, now you know that I was humoristic in it. You just know me a little better now.

And for you to remind me about past incorrect informations without saying which ones or correcting them (if they were not), is a low blow that tell a sad side of you.

I suggest that you relax, and say what you have to say with a straight face, but in a positive manner, so we can get on the right foot, if you know what I mean. There is no use to keep animosity between us. Let's be constructive here, and not let incidents accumulate till they explode right in your face, that it's too late to repair the damage.
And if you want to keep sour feelings towards me, don't share them with me the way you do, be a gentleman and PM me about your problem.

And before making a judgement, be sure that you understand the meaning of people's words in their right context.

I think that you are a great guy that help a lot of people, and I will rather stay friend with you than feeling wrongfully accused.

If you, or anyone else felt offended by my response to Peng, or any prior incorrect informations from my part, I sincerely apologise, but I can assure you that it was not in any way whatsoever my intention.

I realise that sometimes, because we can only see what we type, it can be hard to read the sense of humor from some people, and that we can be easily influenced by giving a quick judgement, based on wrong emotional impact and interpretation, but we have to keep our heads up, and concentrate a bit more for a better understanding. And communication with total respect is always the best method.

You did bring in me some emotional feelings of anger, but now I'm over with it, because I do understand where you coming from, and for that I apologise that I was not more serious in my posting.
I can assure you at 120% that I always try my best to help by giving the best informations at my disponibility, and that helping people is my true passion and reward.
Yes, like you said it yourself, it happens that sometimes our informations are somewhat not the most accurate, but it is human nature, and we are not at war here, like if our lifes depends of it.
You got something to say, say it, don't let it accumulate in the back of your head, because it will eventually give you a headache.
Shoot it up in the air, just like you were bending at maximum strength a bow to shoot an arrow up in the sky to your highest capability.

Adam, I got high esteem of you, but I feel a bit misunderstood now. I hope that with this post, I reestablished a bit more confidence from you.

True regards,

Bob
 
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P

PENG

Audioholic Slumlord
I am embarassed, but I thank you both for reading my post. I must also tell you that I respect you guys for being straight shooters.
 
Adam

Adam

Audioholic Jedi
It was this part here that got me:
I knew that, I did work on my post to try fixing few things, and after a while, I get tired and I knew that I still have work to do on it, but in my lapse of focus and wanting to watch the blu-ray of "Gran Torino", I scooped it by skipping it (my post).
But I knew right from the bat, that a smart as* will find the error on my math, and correct it accordingly.
I read that as meaning that you knew that you had incorrect information in your post, but that you'd rather get back to your movie than either correct it or delete it. My apologies if I interpreted that incorrectly. I don't dislike you, Bob. You strike me as a good guy.

You and Peng clearly got the humor of your post, and my apologies for taking it the wrong way.
 
M

Moonlight

Audioholic Intern
ohms

Thanks to each poster for your input.

Although 100% accuracy is the aim, for my purpose anyway (can't speak for OP) the info lordoftherings offered was sufficient and appreciated. I agree that if info is not completely accurate, which can easily happen, other knowledgable posters can post to add or correct it, as was the case here.
Once again, thanks to each of you :)
 
Lordoftherings

Lordoftherings

Banned
The truth behind the humor.

Actually Adam, that last quote that you use from my post here just above, was not totally accurate. :(

I kind of fabricated it for a smooth exit, with a low life explanation from my unknown correct mathematical formula at that time.
But I did honestly work on the ditto post, like I said, and spent quite a bit of time on it too, to come up with the best that I knew at that time. And I did not know that I was not entirely correct, but I did honestly feel that something was missing. But I could not exactly pinpoint what.
And I really appreciated Peng response for coming with the right math formula.

I'm sorry for having use such a "low" response back to Peng. But it was done 100% with a sense of humor, and was not intended in anyway to upset any member.

What is very positive in all of that, is your reaction to my ditto post. With your reaction, you forced me to reveal the truth, which I'm glad for, because it makes things in their true light, without my sense of humor obscuring it.

I hope now that you feel much better, as I do.

I did learn a good lesson from this, and I will apply it on my future postings.
Because, after all, it's only fair for all members, and not just one.

Sincerely with my best regards,

Bob
 
Vallenato

Vallenato

Audioholic Intern
I have a yamaha rx 2700 that runs 8 ohms.
now is it worse for the amp if i have 16 ohm speakers
or is it worse if i have 4 ohm speakers?
plus if its not correct for the amp wouldnt the amp just have a safety overload and just switch off?
Should i just pull the speakers out and connect them Parallel so thay are 8ohms?
thanks.
Hi Roscoe. I was in your situation and after Read and read I found One Option to connect many speakers to the A/V receiver or Amp."Speakers Selectors Device". I have Sony A/V STRDG520 (impediance 8-16 Ohms)connected to Sima SSW-4(speaker selector) with 2 pairs of speakers 4 and 8 Omhs each one and also one pair of Tweeters 4 omhs and the sound is Fine.
I attach the Features of the Sima, but you can find several others brands in the Market
Speaker Selectors At a Glance:
Dual Protection Circuits protect unit
from excessive power/volume overload.
ƒ. Automatic PolySwitches turn off unit
when overload or excessive volume is
detected, and then reset within a short
time once the overload is removed or
volume is reduced.
ƒ. Impedance Protection allows a single
amplifier to safely power several pairs of
speakers.

Features and Technical Information
ƒ. Listen to one, all or any combination of speakers at one time
ƒ. Designed for use with amplifiers up to 100 watts per channel
ƒ. Accepts up to 14 gauge speaker wire
ƒ. Flat frequency response from 20 Hz to 20 kHz for full range sound
ƒ. Left and right “commons” are isolated to work with all types of amplifiers
ƒ. Unique circuitry protects amplifier or receiver as well as unit and
speakers from excessive power/volume
ƒ. Supports speakers from 4 to 16 ohm impedance
Good Luck;)
 

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