Another nubie with a 6ohm verse 8 ohm question

[mtbound10]

I finally got all my components together, and after searching near and far, finally found a entertainment center to accomodate my space and components. Here is the issue....

I need to set up my yamaha 863 to work properly with my EMP ECA4/44 front, surround and center speakers along with my EMP sub. The ECA 4 front speakers and surrounds are all 8 ohms while the ECA 44 center channel speaker is only rated at 6 ohms. In the setup manual if I am reading correctly I can only set the impedance to either 6 ohm minimum or 8 ohm minimum. If I set this to 6 ohm minimum will I be doing a number on the sound quality and or the operation of these speakers. It seems kind of foolish to have to make the system suffer for one center channel speaker???

Sorry for the book, but I did not know a shorter way to explain!!!


I posted this in the Loudspeaker section to but noticed the question posted in here after....

 

[jamie2112]

Your center channel will be fine. Set the yamaha to 8 ohms. The 663 will handle the center channels 6ohm load no sweat.As long as you have the 663 set to 8 ohms you will have no problems. Best of luck..

 

[Rickster71]

Yes, what jamie said.

I would set the receivers impedance switch at 8 ohms. At 6 ohm setting, receiver tend to limit current to speakers via reduced output voltage as to protect itself against lower impedance speaker loads. So performance is compromise in favor of protection. on lower impedance settings.

 

[fmw]

It can be confusing. The switch doesn't do any impedance matching. What it does is reduce the potential output of the amplifiers. It is something like the governor on a truck engine. You can control it just fine without the help of a switch, I would imagine. Also, you aren't likely to need more than a couple of watts to drive the center anyway unless you have an auditorium for a listening room.

 

[jostenmeat]

It can be confusing. The switch doesn't do any impedance matching. What it does is reduce the potential output of the amplifiers. It is something like the governor on a truck engine. You can control it just fine without the help of a switch, I would imagine. Also, you aren't likely to need more than a couple of watts to drive the center anyway unless you have an auditorium for a listening room.

I didn't know that. Thanks. I like the analogy too.

It reminds me of my friend driving with his mom to Colorado from California. Of course, she starts complaining about his speeding, and he replies its impossible to break 85 mph or something due to the governor, to her disbelief. He says "you try it", she drives and realizes the truth, but gets a ticket from the cop, lol.

 

[fmw]

That's a good story. I think the confusion stems from the old tube days when the tuve amps had output transformers. You connected the speakers to the correct tap on the transformers for the impedance of the speakers. Solid state amps don't use output transformers (one of the several reasons they are sonically superior to tube amps.) The lower the impedance, the greater the current draw. So they put a governor on it so you won't be as likely to hurt it if you abuse it. I sometimes wonder if lawyers don't have more influence in product design than engineers.

 

[Rickster71]

So they put a governor on it so you won't be as likely to hurt it if you abuse it. I sometimes wonder if lawyers don't have more influence in product design than engineers.

Absolutely agree!
The switch is there more for UL certification purposes.

 

[chisberry]

I work for a competitor of UL and do safety testing of electrical products, particularly electronics and a/v equipment (I get to play with a lot of high-end stuff that I could never afford, which is cool). Anyway, the safety testing that is done on speakers to ensure that overheating does not occur is based on the manufacturer's max power rating and impedance rating. The higher the max output, the more of a load we put on the speaker, and the lower the impedance rating, the greater the current and more often than not the hotter the equipment gets. Their are cutoffs for how hot different materials on the speaker can get during these tests. I've had times where the manufacturer has raised/lowered their impedance rating based on the temperature testing results. They're obviously a lot happier when they get to lower it!