I have no electronics knowledge at all. I've tried to read up on impedence but none of it makes sense. Here's my setup. I just want to know if I should be concerned about the mix. I'm also looking to buy a Denon 888 and wonder if there is any concern due to the varying impedences here.

Center: 12 ohms nominal, 8 ohm minimum (Energy)
Fronts: 4 ohm (Paradigm)
Surrounds: 8 ohms nominal, 6 ohm minimum (Energy)
Sub: 8 ohm (Velodyne)

If the mix is bad, and I think it might be, what is the effect? Will the whole system sound better if I replace something here?

which Paradigms are 4Ohms?

Ideally, the center and front should be matched (brand and range)

most importantly, what is the Denon rated at? receivers are 6 or 8Ohms normally, which would be a worry if you were going to drive 4Ohm speakers loud. It could cause the amplifier to run out of juice and clip (and severe clipping could fry your tweeters)

Paradigm 9 SE Mk II's. They are an older model but there is nothing wrong with them.

From the Denon 888 spec sheet.
Rated output *THD figures are power amp stage values.
Front 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)
Center 100 W (8 ohms, 20Hz - 20kHz)
135 W (6 ohms, 1kHz)
Surround 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)
Surround back 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)

"Help with impedence" Viagra?

Paradigm 9 SE Mk II's. They are an older model but there is nothing wrong with them.

From the Denon 888 spec sheet.
Rated output *THD figures are power amp stage values.
Front 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)
Center 100 W (8 ohms, 20Hz - 20kHz)
135 W (6 ohms, 1kHz)
Surround 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)
Surround back 100 W + 100 W (8 ohms, 20Hz - 20kHz)
135 W + 135 W (6 ohms, 1kHz)

No, you're looking at the wrong spec table. That info is telling you your receiver's power ratings for each channel and what load and frequency bands in which they were driven at the rated power. They do that power at 6 ohms to make people say "WOW look at the wattage!". Look in manual where it instructs you how to hook your speakers up to your receiver. It is there they will usually tell you the minimum impedance that a channel can handle. I'm 100% positive that your Denon can handle a 4 ohm load on the front two speakers. It will not cause your receiver to run out of power early and fry your speakers like Sirius is suggesting. If the receiver can't handle the load it will shut itself down on protection to keep from overheating. The Denon should have no problems with this. At best it will run a little hotter. As for amplifier clipping, it can happen with ANY speaker with ANY impedance, not just 4 ohm and you should always turn your stuff down if you hear any kind of distortion no matter what the impedance.

Sorry to thead-jack, but the topic is similar.

The question: If you have speakers with adjustable db levels, which also change the impedance of the speakers, should you change them from the neutral settings (+- 0 dbs)(6 Ohms) to (I think, -3dbs)(8 Ohms) so the imedances on all of the speakers match?

Background: I have SpeakerCraft AIM8-Three's as the Left and Right, with the matching box center channel and other SpeakerCraft ceiling speakers for Surrounds. The Center and Surrounds are 8 Ohms, and the Left and Right are 6 Ohms, but as mentioned I can change it to match.

TIA,

Tony

Ok, I don't know where this school of thought came from that impedance must be the same on all your speakers or else your system will blow up, so let me clear all this up. Chances are that if all your speakers don't have the same impedance, they are mismatched already by brand or series so yes they will sound different. Impedance does not change the way a speaker sounds or even how sensitive it is unless it is a driver db cut switch like mentioned above. For the most consistent sound quality speakers should be the same brand and same series. If you mix different brands and series, you will get major sound differences not because of the difference in impedance, but because it's a totally different speaker. If your receiver has any problems with the impedance being too low, IT WILL TELL YOU! It will not blow up or start smoking. Any decent receiver will either shut down completely like my Yamaha does, or shut the speakers down for a few seconds as a warning to turn it down like my Onkyo did. Old school stereo receivers might smoke if overloaded because they didn't have such protection features.

Thanks Mr. Audio. As for the "school of thought" ...it's not necessarily what I've learned, but what I havn't. Consider me an utter newbie, trying to understand and piece together information here. It is a little overwhelming. Probably like my Mom felt when she was trying to learn things on a computer, and being afraid to drag and drop an icon, because she was afraid that she might "break" something. I tried to explain to her that nothing bad was going to happen, but when you are working with unfamiliar, expensive technology, you will tend to err on the safe side, or asking too many "stupid" questions.

So then, if I understand your advice, if the speakers within the same series and brand have different impedances, I probably should leave them that way.

Thanks Mr. Audio. As for the "school of thought" ...it's not necessarily what I've learned, but what I havn't. Consider me an utter newbie, trying to understand and piece together information here. It is a little overwhelming. Probably like my Mom felt when she was trying to learn things on a computer, and being afraid to drag and drop an icon, because she was afraid that she might "break" something. I tried to explain to her that nothing bad was going to happen, but when you are working with unfamiliar, expensive technology, you will tend to err on the safe side, or asking too many "stupid" questions.

So then, if I understand your advice, if the speakers within the same series and brand have different impedances, I probably should leave them that way.

I'm sorry if I came off too abrasive. I thought I was seeing the start of an epidemic. Sirius starts warning against parts being fried in an attempt to answer a simple question about impedance and then you came in with your question. I was starting to think that people were being told that this impedance thing is more of an issue than it really is. I was just trying to put it to rest quickly if that was the case. Newbies are aloud to ask stupid questions. The questions that aren't allowed are questions like this one:

"Tonight I am buying the following Speakers for a 5.1 Setup:

Front Speakers: eD A6-6T6 Towers
Center Channel: eD A6-6T6
Surround Speakers: eD A6-5T5
Sub Woofer: eD A3-300


I am still looking for a Deal on a Onkyo 705. Once I find one I will pull the trigger on that as well.

My room is 18x19.


Am I doing anything Wrong????"