Question about ohm's

[i81two]

I am not a big technical genius when it comes to stereos so I hope this question doesn't sound stupid.

I have a Yamaha RX-V590 and a pair of Klipsch 3.5. I bought these new about 15 years ago and they are great together. Sound is good at all levels.

I picked up a pair of Cerwin Vega AT-12 for a house party I had to get some noise out side.

Well, after about 8 hours of the Dead my receiver shut down from what I believe to be overheating.

I have done a little research and apparently the Yamaha and Klipsch's run at 8 ohms, and the Cerwins from what believe to be correct run at 6 ohms.

Remember that im just a dumb bricklayer. Is this setup bad for my receiver or Klipsch's or is there some other way to set this up ?

Thanks

 

[ImcLoud]

I would imagine that running any component to thermal shut down wouldn't be good as a common practice...

That is an older AVR rated for 8 ohms, if I remember correctly. I wouldnt go crazy running it at high levels for long periods of time with the proper rated speakers...

If you are looking to make noise, maybe pick up a pair or even a single Mackie TH 15A TH15A Thump 15" Powered PA Loudspeaker | eBay you can find them for under 250 each shipped and they are loud.. just plug in you ipood or phone or what ever and it has its own amplifier built in... just plug in power and a source, and you have a party...

 

[i81two]

Did you mean to say without the proper rated speakers ? If not, I don't understand. I turn this stereo up loud for long periods of time with no problem. Would 50' of 12 awg speaker wire running to both of the 6 ohm CV's also be a problem.

Im not looking to spend any more $$ I just don't want to do damage to my existing setup. Though it may be old it does serve it purpose well. I just want to have some backup speakers that I can keep in the garage and pull out and hook up quickly for parties. That is why I bought these CV's for $80. I will sell them and get some 8 ohm speakers if that would be the answer.

Thanks for the input

 

[Pyrrho]

Impedance is a complex subject:

Electrical characteristics of dynamic loudspeakers - Wikipedia, the free encyclopedia

However, if we have accurately rated speakers, we can simplify the whole matter and just pretend that the speaker really is one impedance at all frequencies.

You were running both pairs of speakers at once, right? So you still have the issue of running two pairs of speakers at once, and since virtually all receivers wire the speakers in parallel, you have a combined effect in accordance with:

I = 1/(1/I1 + 1/I2 + 1/I3...)

Where I is the resulting impedance, and I1 is the impedance of the first speaker, I2 is the impedance of the second speaker, etc.

So, assuming that the impedances you have are accurate (which is a risky assumption, as many manufacturers lie and rate them higher than what they actually are), 6 and 8 ohms, we plug them in for:

I = 1/(1/6 + 1/8)

We need common denominators to add fractions, so we convert:

I = 1/({[1/6] * [4/4]} + {[1/8] * [3/3]})

(Note that 4/4 = 1 and 3/3 = 1, so this is not changing the actual value.)

I = 1/(4/24 + 3/24)

I = 1/(7/24)

I = 24/7

I = 3.4 (approximately)

That is a low impedance for a receiver to deal with, particularly when playing loudly for a long period of time. Do not run both pairs of speakers at once with that receiver.

I imagine if you had looked carefully at the writing on the back of your receiver near the speaker terminals, they would tell you not to run such speakers at the same time.

 

[Adam]

Welcome to the forum!

Everything else being equal, a lower-impedance (smaller ohm rating) speaker will draw more current from an amplifier than will a higher-impedance speaker. The more current, the more heat will need to be dissipated by the amp circuitry. The amp section in your receiver was designed to handle some given amount of current draw, based on some assumed average volume level and 8-ohm speakers (or 16-ohm...see below). You can run 6-ohm speakers on it, but if you play those speakers loudly for a long time, then it's not unlikely that it's thermal protection circuitry will engage because the components are getting too hot.

A couple of things came to mind when I read your post:
(1) Klipsch are normally really efficient speakers, meaning that they'll play louder than less efficient speakers given the same power input. I don't know how the Cerwins compare (but I know that they play loud, so they are probably pretty efficient). If the Cerwins are less efficient, then you would have been running the receiver harder to get them loud.
(2) If you had both the Klipsch and the Cerwins playing, then that would have put a bigger strain on your receiver in regards to current draw - bigger than it's rated for. So, having it overheat wouldn't be unexpected. While that receiver is rated for 8 ohms/speaker when you are running one pair of main speakers, it's rated for 16 ohms/speaker if you are running two pairs of main speakers (according to the manual and the label on the back of the unit).

At lower volumes, I wouldn't be afraid of running those two pairs of speakers, but I would at first be feeling how hot it was getting before I kept using it that way. At higher volumes, I personally wouldn't feel comfortable running two pairs of speakers on it. That said, you got a good eight hours out of it. I'm assuming that the receiver turned back on later after it had cooled down - correct?

 

[Pyrrho]

Did you mean to say without the proper rated speakers ? If not, I don't understand. I turn this stereo up loud for long periods of time with no problem. Would 50' of 12 awg speaker wire running to both of the 6 ohm CV's also be a problem.

Im not looking to spend any more $$ I just don't want to do damage to my existing setup. Though it may be old it does serve it purpose well. I just want to have some backup speakers that I can keep in the garage and pull out and hook up quickly for parties. That is why I bought these CV's for $80. I will sell them and get some 8 ohm speakers if that would be the answer.

Thanks for the input

Getting a second pair of 8 ohm speakers is likely not the answer. With two pairs of 8 ohm speakers, you would present a 4 ohm load to your receiver (use the formula above if you wish to calculate the matter for yourself). The answer is, you need an ąmplifier that is capable of driving low impedances, or you need a second ąmplifier for the second pair of speakers. Or just listen to one pair at a time. Anything else, and you are likely to damage your receiver.

 

[i81two]

So Yamaha puts all these spots to plug in speakers but its not good to do so ? Or are they there more for surround sound speakers ?

I am bummed and will probably chub up some $$ for a new receiver and put this one in my garage or another room with some surround sound.

Bottom line is, I want to run 4 speakers when I want to. Will the different ohms of the two brands be a problem with every receiver I would buy.

 

[Adam]

Hi. The difference in ohms between the two brands is not a general problem. The most likely reason that running two pairs of speakers is an issue on your receiver is that both sets of main speaker terminals are probably wired to the same amplifier circuit. You will want to make sure that anything that you buy (if you decide to buy something) can handle running both pairs at once, though.

However, there might be another solution. I say "might" because I don't see what I have in mind specifically mentioned in the manual, but there are things that are close. You could hook the Cerwins up to the rear speaker terminals (yes, those are rated to 8 ohms, but just don't blast it) and try the different DSP modes to see if any of them mimic four-channel stereo. If any are close, you might be able to tweak the delay settings to have it sound good (which might not be too tough if you have one pair inside and the other pair outside).

That receiver also allows you to connect an external amplifier, so you could also try getting an inexpensive one and hook up the Cerwins to that.

 

[Pyrrho]

So Yamaha puts all these spots to plug in speakers but its not good to do so ? Or are they there more for surround sound speakers ?

The surround speakers are run off of a different ąmp, and so they may be considered separately. With the main A and B speakers, they are run off the same ąmp, and so they must be factored together. Given the fact that 16 ohm speakers are pretty rare these days, having a second terminal is basically allowing you to hook up two sets of speakers at the same time, but not allowing you to listen to both at the same time (at least not most speakers, particularly at high volume for an extended period of time). This could be useful if you have one pair of speakers in one room, and another pair of speakers in another room, and you switch on whichever speakers are appropriate for the room that you are going to be in, and have the ones off for the room that you will not be in.

I am bummed and will probably chub up some $$ for a new receiver and put this one in my garage or another room with some surround sound.

Most receivers are not set up for low impedance speakers. If your receiver has preąmp outputs (which, from looking at the manual that I downloaded from Yamaha's web site, it does), your best bet is to buy a separate power ąmp that can handle low impedances, or simply another ąmp to drive one set of speakers if hooking up something to the preąmp/line level main/front output does not disable the internal main ąmp.

I did not read the whole manual, though you might wish to do so before deciding what to buy. Or, you can do a very simple test, and simply plug a wire into the preąmp outputs, with the other end connected to nothing, and see if it shuts off the main speakers. If not, then you just need an amplifier capable of dealing with one set of the speakers at a time rather than low impedances. You would then hook up one set of speakers to the Yamaha you have, and the other to whatever ąmp/receiver you buy, preferably with a volume control, so that you can set the balance any way you like between both sets of speakers.

If you need something to drive them all, a professional power ąmp is probably the cheapest way to get lots of power for low impedances, but make sure that whatever you get has the right sort of connections that you can use.

Bottom line is, I want to run 4 speakers when I want to. Will the different ohms of the two brands be a problem with every receiver I would buy.

Not necessarily, but I recommend buying a separate ąmp instead to deal with your issue.

And it isn't a problem that they are different impedances; the problem is, the combined impedance is too low for your receiver to handle at high volume for long periods of time.

 

[i81two]

So when there is speaker A and speaker B buttons there is a chance that they are still on the same amp circuit ?

That's why I thought the receiver has 2 sides. To handle 2 sets of speakers.

 

[Pyrrho]

So when there is speaker A and speaker B buttons there is a chance that they are still on the same amp circuit ?

That's why I thought the receiver has 2 sides. To handle 2 sets of speakers.

Not only is there a chance that they will be the same ąmp circuit; it is a virtual certainty that they will be on the same ąmp circuit, no matter what receiver you buy.


Edited to add:

That is why I recommend buying a separate ąmp in my post above.

 

[Pyrrho]

Now, the short and simple response for what to do, that will *probably* work well and be cheap. Go on Craigslist or some such thing and find a receiver that seems like it could handle driving one set of speakers as loud as you will ever want it. Go check it out and make sure it works okay. Buy it, bring it home, and use standard RCA connectors to hook up the Front right and left output (near the speaker terminals, but NOT the speaker terminals) of your Yamaha to the newly purchased receiver via a line level input (most likely, any input except NOT Phono). Hook up one set of speakers to it, and one set to your Yamaha. Turn it on, and adjust the volume on the newly purchased receiver to get the speakers hooked up to it to be the relative volume you want between the two sets of speakers (the same, if you want the same volume from both), then you use the volume control on your Yamaha to adjust the volume of all of the speakers together at that point. You never need to again adjust any controls on the newly purchased receiver as long as no one else touches the controls on it, and as long as you want the relative volume between the speakers to remain the same.

You could also buy a new receiver, integrated ąmp, or power ąmp (as long as it has volume or level control), and hook it up as described above, if you cannot find a good used unit cheaply. Here is something that would be very cheap new that would probably work okay:

Amazon.com: Sherwood RX-4105 100 Watt Stereo Receiver (Black): Electronics

Again, I want to remind you to check first to make sure that hooking up a wire to the line output of your Yamaha does not automatically shut off your main speakers. If it does shut that off, then you cannot do things this way.