i am getting a home theater system (onkyo ht-s6200), i also want to get a set of floor standing speakers (sony ss-f6000). the standing speakers are 8 ohms and the receiver is a 6 ohm set. would this matchup create a problem or not?
You can change the ohm range on each channel in the Onkyo setup. Just click the menu button on your receiver remote and adjust each channel manually.
The ohm rating of all your speakers should be the same as the receiver can output at one setting only.
More than likely the speakers on your old Sony home theater in a box will not sound good and will burn out at higher volume. Those home theater in a box do not provide you good quality speakers at all. I would recommend you replace the speakers with a name brand like Definitive Technology, Energy, Focal, Infinity, JBL, Klipsch, Mirage or Polk audio to name a few. The sub woofer might not be compatible with your new receiver. You might look at an Onkyo HT-S model, it is a separate receiver and a set of speakers. Hope this will help you out.
The other answer notwithstanding; it won't make any difference. If you are replacing 6 ohm speakers with 8, that is a minuscule difference, and actually will make the receiver work easier. Speaker impedances are NOT consistent; they vary (with frequency) from less than 1/2 the rating to 3 times the rating. That is why they say Nominal impedance. You may need to correct levels, which your receiver may or may not have the ability to do. Check to see if there is a level set-up in the menu of the receiver. Other than that, you will be fine. You shouldn't go lower in ohms (say, a 4 ohm set) than the speakers supplied with the unit, although it may or may not bother the receiver because of that pesky variable impedance that all speakers have Good luck!
From reading the two specifications pages for your products (linked below) it looks like you amp can handle speaker impedances from 6-16 ohms, but its rated output in watts drops, the higher the speaker impedance. For your 8 ohm speakers the output will drop to 100 watts from 130 watts for your current speakers. That means there will be a minimal decrease in output, because the amp faces more load, but it is still well within the capabilities of your amp. If you were to decrease the ohm load of your speakers, you could have a problem because the speakers would draw more power from your amp than in it capable of delivering, causing it to blow a fuse.
