Parallel connecting an Onkyo receiver?

[Ess El Emm]

I have an Onkyo TX-8211 receiver which is a 4 channel stereo receiver. The receiver states on the back that it is stable down to 4 ohms if only using two of the four channels. If using all four channels, it is only stable to 8 ohms. Unfortunately, the only speakers I have right now are 8 ohms, and I have no desire to run two pairs of speakers with it at the same time.

While I don't think it's officially supported in the owner's manual, is there a high risk of damage to the amp if I enable both sets of outputs, and run both left outputs into one speaker, and both right outputs into another? So, not really bridging the amp down to mono or anything, but just rather running both left channels to one (8 ohm) speaker, and both right channels to one (8 ohm) speaker?

 

[whoaru99]

It's a stereo receiver. Paralleling the the A and B speaker outputs gains nothing as they both come from the same two amp channels.

 

[Ess El Emm]

Oh, I see. So, essentially it's only a two channel amp stable to 4 ohms with a place to plug in two more speakers to the same amp output, at which point you would still be at 4 ohms per channel with a set of four 8 ohm speakers.

Thanks. Guess it's time to find some 4 ohm speakers.

 

[Sir.Byrd]

Why would you need to find 4 ohm speakers?
What exactly is the problem?

 

[Ess El Emm]

I just wanted to make sure I was using the amp to its full capacity. It's fine for now, but obviously if I had a set of 4 ohm speakers it would be a little more efficient than running 8 ohms on an amp that could handle 4.

 

[bobaloniny]

Well, I think the only appreciable difference would be making the amp run hotter. I have a few amps that are stable down to 2, but I let them have an easy life and run 8 on them. I certainly doubt that the increase in wpc would be appreciated as normal listening is around a watt or so. Just my take on it.

 

[terra1]

Oh, I see. So, essentially it's only a two channel amp stable to 4 ohms with a place to plug in two more speakers to the same amp output, at which point you would still be at 4 ohms per channel with a set of four 8 ohm speakers.

Thanks. Guess it's time to find some 4 ohm speakers.

You don't need 4 ohm speakers.

If you have 8 ohm speakers you are fine. You have no problem.

Download the manual from the Onkyo site.

One pair of speakers if 4 ohms: It sounds like what it is saying is if you have speakers rated at 4 ohms you can only connect one pair of speakers at a time. Connect to A or B but not both. Minimum of 4 ohms means they cannot be rated less than 4 ohms. Do not DO NOT connect two pair of 4 ohms speakers. Do not connect a pair of 4 ohm speakers with a pair of 8 ohm speakers.

Two pair of speakers: If you have speakers rated at 8 ohms you can hook up to two pair of 8 ohms speakers. A+ B.

You of course can hook up just one pair of 8 ohm speakers.

 

[Snow]

I just wanted to make sure I was using the amp to its full capacity. It's fine for now, but obviously if I had a set of 4 ohm speakers it would be a little more efficient than running 8 ohms on an amp that could handle 4.

Actually its far easier on any amp to use 8 ohm speakers than 4 ohm speakers, by running a harder load it will create more heat and more heat = shorter life span of your amp.


REGARDS JIM

 

[Ess El Emm]

I understand that it's always acceptable to use a set of speakers higher than the lowest acceptable impedance. My only reason behind using 4 ohm speakers would be for the added efficiency that a lower impedance would provide compared to 8 ohms.

Also, technically, wouldn't a lower impedance set of speakers cause an amplifier to work less and produce less heat for a given sound output? Now, clearly an amplifier set to the same volume level would work harder and produce more heat with a lower impedance load.

But given two identical speakers, one with a 4 ohm coil and one with 8, the 4 ohm speaker would be more efficient and produce more sound at any given volume level, resulting in the amp volume actually being turned down to achieve the same level of sound as the 8 ohm speaker.

Edit: Actually, thinking it through some more, it is probably pretty much a wash either way. Sure you may be able to turn the volume on an amp lower to achieve the same sound output with a higher efficiency speaker, but the lower resistance of that speaker will also result in higher current through the speaker circuit. So, while the voltage produced by the amp may be lower at a lower volume level, the current will be higher, resulting in the same overall wattage.

 

[bowtie427ss]

the 4 ohm speaker would be more efficient and produce more sound at any given volume level,

No, it won't. The 4 ohm speaker may be more SENSITIVE at any given volume setting. The load on your amp will be doubled each time speaker impedance is halved.

There is a STICKY here, in Vintage Solid State i think, "Why 4 Ohm Loads Stress Your Amplifier", i'd urge you to read it as many times as necessary to get a good understanding.

http://www.audiokarma.org/forums/showthread.php?t=60386

Just my .02...........

 

[Ess El Emm]

Yeah, I'm realizing that now. Sure the speaker would be louder at any given volume knob position, but the lower impedance is also causing the amperage in the circuit to increase, so it's a tradeoff.

 

[Snow]

Yeah, I'm realizing that now. Sure the speaker would be louder at any given volume knob position, but the lower impedance is also causing the amperage in the circuit to increase, so it's a tradeoff.

Speaker sensitivity is going to play a part in how hard your amp is going to work also to achieve the same volume. If you had a speaker that was 8 ohm rated but was 84db at 1 watt it would work your amp harder to achieve 110 db then lets say a speaker that was 4 ohms but was rated at 104 db at 1 watt and in fact most amps wouldndt have the power to achieve 110 db with a 84db rating nor would most speakers be able to take the power required, but a 4 watt amp could with a 104db rated speaker.

REGARDS JIM

 

[bman22]

As an owner of the TX-8211, I can tell you its not a huge fan of 4 ohm loads, but it will handle them just fine if need be. I do think you should keep running it on the 8 ohm load though, as its probably far better at that. I was using it to drive some pretty demanding speakers (The Kappa 7s) for quite a while though, and it did a pretty decent job.

 

[Sir.Byrd]

Just because a speaker is 4 ohms does not mean that it is necessarily more sensitive than a speaker that is 8 ohms.

 

[dbayyz]

I would like to find a service manual for onkyo tx-sv727. also when hooked up to computer it doesnt have digital, what r the best options-both computerhookups and stereo? Mine is currently hooked up to Cerwin Vega Mx 250's (4onm).

 

[mulester7]

.....those who I hear saying don't heat up the amps with 4 ohm loads, I suspect have never heard two like speakers paralleled on each side of a 2-channel amp....makes for some great 4-corner....more punch top to bottom, but especially noticed from the lows....the "realism" meter goes up a few pegs....a 4ohm load of bullets is being fired at two 8-ohm speakers which stand together as a 4ohm load....sounds better to me on everything.....

.....if you're worried about more heat from the amp sections, get a small plastic fan from Wal-Mart involved running on low....they come in crazy colors, but you can spray paint them whatever color you want....I suggest using them face down on the top vents.....