Does having 4 ohm & 8 ohm speakers together cause problems?

[Joe B #7]

Hi - For quite some time, I have been running an integrated stereo amp mainly to play vinyl records. I am a vinyl junky, and play records a few hours each day. My last amp, a Marantz 1060, had to be repaired, and again is not working after a year of heavy use. I primarily listen in my living room, but also have a set of outdoor speakers and will often play both sets of speakers. Both sets of speakers are properly wired with good "monster" brand speaker wire. Somebody told me that since my "ohms" are different on my indoor & outdoor speakers it could be causing problems with the amp. My indoor speakers are 4 ohm KEF Tower speakers and sound great. My outdoor speakers are Infinity and sound pretty good too. However, I just looked and the Infinity outdoor speakers are 8 ohm... Could having both 4 ohm and 8 ohm speakers running simultaneously be creating a problem??? I just ordered a used amp online - an Onkyo TX-8511. It is a simple 2 channel amp with less than 0.08% thd, and had good reviews, and I found a good deal so I bought it to replace my Marantz (which I probably still will have repaired). One feature on the amp says it has a "switch" to switch between 4 ohm and 8 ohm. Should I set the switch to 4 ohm or 8 ohm on this Onkyo amp? Also, am I creating a problem by having 8 ohm speakers outdoors that could be easily fixed by having 4 ohm outdoor speakers? I don't mind buying replacement 4 ohm outdoor speakers (to match with the 4 ohm indoor speakers) if that is what is creating a problem. I do not really want to put 8 ohm speakers indoors (because I love the sound of my KEF speakers). I guess I don't understand what "ohm" means when it comes to running 2 sets of speakers. Any help would be greatly appreciated. Thanks so much!

 

[TLS Guy]

Hi - For quite some time, I have been running an integrated stereo amp mainly to play vinyl records. I am a vinyl junky, and play records a few hours each day. My last amp, a Marantz 1060, had to be repaired, and again is not working after a year of heavy use. I primarily listen in my living room, but also have a set of outdoor speakers and will often play both sets of speakers. Both sets of speakers are properly wired with good "monster" brand speaker wire. Somebody told me that since my "ohms" are different on my indoor & outdoor speakers it could be causing problems with the amp. My indoor speakers are 4 ohm KEF Tower speakers and sound great. My outdoor speakers are Infinity and sound pretty good too. However, I just looked and the Infinity outdoor speakers are 8 ohm... Could having both 4 ohm and 8 ohm speakers running simultaneously be creating a problem??? I just ordered a used amp online - an Onkyo TX-8511. It is a simple 2 channel amp with less than 0.08% thd, and had good reviews, and I found a good deal so I bought it to replace my Marantz (which I probably still will have repaired). One feature on the amp says it has a "switch" to switch between 4 ohm and 8 ohm. Should I set the switch to 4 ohm or 8 ohm on this Onkyo amp? Also, am I creating a problem by having 8 ohm speakers outdoors that could be easily fixed by having 4 ohm outdoor speakers? I don't mind buying replacement 4 ohm outdoor speakers (to match with the 4 ohm indoor speakers) if that is what is creating a problem. I do not really want to put 8 ohm speakers indoors (because I love the sound of my KEF speakers). I guess I don't understand what "ohm" means when it comes to running 2 sets of speakers. Any help would be greatly appreciated. Thanks so much!

Having the outdoor speakers four ohm will make it worse. Then the amp will have a 2 ohm load! What you have now is 1/load = 1/8 + 1/4. So 1/load = 3/8. So your load is 2.7 ohms which is far too low, and will blow pretty much any amp. You need a four ohm load or close.

You could only run two sets of 8 ohm speakers. Even then it would be risky as most speakers are less then 8 ohms even if they say they are 8 ohms.

Onkyo amps are not very robust and that load will blow it fast.

You could use an impedance compensated switcher, but that will compromise audio quality and you would not want to run your KEFs through it which you would have to do.

Your best bet is to use a pre amp and two power amps, or get a receiver with preouts and use the zone 2 outs.

What you are doing now will not work.

 

[Joe B #7]

Thank you. I am totally clueless and lost on ohms I guess... Why do amps have speaker a and speaker b selectors then? I think I do have another set of 8 ohm indoor speakers I could use. Would a speaker splitter box help if I hooked both indoor & outdoor into that, then plug it into the speaker A only on the amp? I appreciate you getting back to me. I would really like to run 2 sets of speakers, and I am lost on a simple way to do this without harming my amp...

 

[TLS Guy]

Thank you. I am totally clueless and lost on ohms I guess... Why do amps have speaker a and speaker b selectors then? I think I do have another set of 8 ohm indoor speakers I could use. Would a speaker splitter box help if I hooked both indoor & outdoor into that, then plug it into the speaker A only on the amp? I appreciate you getting back to me. I would really like to run 2 sets of speakers, and I am lost on a simple way to do this without harming my amp...

A lot of people make that mistake. That A/B switch puts the speakers in parallel when using both speakers. Speakers should not be run together. It is a hangover from years gone by when speakers were 16 or 8 ohms at least. Now all speakers are nearer four ohms, even if they say they are 8 ohms. This is because speaker drivers have got smaller and cabinets narrower. This means that what is known as baffle step loss starts at a higher frequency. Compensating for this results in lower impedance where the power is.

A speaker switch that is impedance compensated (most are not) would stop your amp blowing up but will downgrade your sound. Those sort of devices are for background ceiling speaker systems and such.

I would not advise trying to solve this by changing speakers.

To do this properly requires a power amp for each set of speakers. That is what you need to, and should do.

 

[Joe B #7]

Would these help?

https://www.amazon.com/s/?_encoding=UTF8&camp=1789&creative=390957&field-keywords=speaker selector&linkCode=ur2&rh=n:172282,k:speaker selector&tag=geothegregee-20&url=search-alias=electronics

 

[TLS Guy]

Would these help?

https://www.amazon.com/s/?_encoding=UTF8&camp=1789&creative=390957&field-keywords=speaker selector&linkCode=ur2&rh=n:172282,k:speaker selector&tag=geothegregee-20&url=search-alias=electronics

NO!

Just understand you can NOT play two sets of speakers together without using two power amps.

You do not want to use an impedance compensated switcher unless you want to loose a lot of quality you have paid for.

You need to change your electronics and not mess with switchers.

The other option is to NEVER play both sets of speakers at the same time.

 

[Joe B #7]

OK - thank you for your help. I just don't know how to have 2 separate amps set up, and be able to run my music to both of them at the same time since all of my music components only have one RCA audio output on them. Is there a pre-amp that would allow me to connect my music into 2 separate amplifiers at the same time? Sorry, but I am very confused. I have just been using an integrated amp for all of these years into both speakers A & B. Apparently I have been making a big mistake. I still guess I don't understand how ohms work. I wish it was simpler and could just hook up 2 sets of speakers. Your help is greatly appreciated.

 

[Joe B #7]

I just saw your other post. Again thank you. Any suggestions on reasonably priced equipment (a pre-amp I guess) that would allow me to connect my turntable and other audio components into 2 separate amps so I could fix this problem??? It would be nice to be able to have separate volume control on indoor and outdoor speakers.

 

[TLS Guy]

I just saw your other post. Again thank you. Any suggestions on reasonably priced equipment (a pre-amp I guess) that would allow me to connect my turntable and other audio components into 2 separate amps so I could fix this problem??? It would be nice to be able to have separate volume control on indoor and outdoor speakers.

Any preamp can be connected to two power amps. You just connect them form the output of the preamp with Y cords. It is simple.

Your other option is to get a receiver that has a powered zone 2. Just be aware that a lot of receivers only output analog sources and not digital ones from zone 2. So choose your unit with care.

To control the output to the two sets of speakers, would mean getting at least one of the power amps with volume controls, or making a DIY volume control unit to one of the power amps.