Mixing speakers in a 5.1 setup

[McBainUK]

Looking for advice from the audio hardware people out there!

I have a sub and 2 front speakers from a Altec Lansing ACS56 system, specs:
-Satellite power: 4 X 8.75 watts
-Subwoffer power: 35 watss
-Total audio power: 70 watts
-Speaker response: 30Hz-20Khz. Crossover Frequency 105Hz
-Interface: 2 analog inputs for 3D positional audio, 1 S/PDIF input for PCM digital audio

I have all 6 speakers from a Creative Labs Inspire p580 system, specs:
-Satellite Power: 6 Watts RMS per channel-Subwoofer Power: 17 Watts RMS
-Frequency Response: 40Hz ~ 20kHz

And now for the questions:

1. Are the Creative satellites compatible with the Altec sub and output? I would like to use them for the rear left/right speakers. They physically plug in ok and sound comes out but I wonder if they would blow if the volume was maxed out?
   
2. Most of my sources (TV, recordings, MP3 music) are stereo so would just come out of the (better) Altec speakers and sub but when I watch a DVD it would mean 5.1 output on a 4.1 system. Would the be much of a difference between a 5.1 system and a 4.1 system when it comes to surround sound on DVD?
   

I'm not sure if this is the best forum to post these questions on (maybe avforums would be better?) but it's the most friendliest and (for me) trustworthy

[gEd]

1. What matters is that the impedance of the speakers are the same (such as 4,8,10 ohm)
if the sub is designed to power 4 x speakers, I would assume that means 4 x speakers of the same impedance as those supplied with the sub. The power rating is mostly irrelavent.

2. never had more than 2.1 but AFAIK, the centre speaker locks the dialogue to the screen so that the voices appear to emminate from the screen, leaving the spatial sounds and effects to wizz around the speakers. i.e. without the centre speaker, the voices may appear to be floating around the room.

the cyberlink audio filter has options to create virtual/pseudo centre and surround speakers.

but it's the most friendliest and (for me) trustworthy

if you send me £50 via paypal, I can send you some more details...

[McBainUK]

So impedance is how you tell if speakers are compatiable, will have to find the the specs somewhere.

Where can you get the Cyberlink audio decoder from, I installed the "DVD powerpack" that came with my graphics card but it didn't add an audio decoder to GB-PVR, only the video/sp decoder. I quite like the video decoder, would be nice to try out the 'matching' audio decoder

but it's the most friendliest and (for me) trustworthy
if you send me £50 via paypal, I can send you some more details...

I don't use paypall but if you let me know your real name, address and bank details I'll wire the money over straight away

[Fatman_do]

Right, impedance is a more crucial factor, if you mix speakers. You end up overdriving one set to get the others to a reasonable level. Really I wouldn't be terribly concerned unless you pump the volume to highest levels.

[Fatman_do]

I would guess these PC speaker systems are pretty much the same spec. Usually the difference is when you mix high cost and cheap speakers (in over simplified terms).

[McBainUK]

The Altec is listed as 10 kOhm but I can't find the specs for the Creative. I think originally they were about the same price range.

[pBS]

typical rule of thumb is 8 ohm for home speakers, and 4 ohm for car speakers, tho hi-end systems can be anything....[Bose uses 2 ohm! but needs matching amp]
10 ohms will be only very slightly quieter than same speaker at 8 ohms..

only need half the power to make half the ohms same level..
meaning, 10Wx8ohm = 5Wx4ohm = same loudness

only have to watch out for using too little ohm speakers with amps that can't handle that low, can blow amp after long periods of use..[won't blow right away, just gets 'crunchy' over time]

[gEd]

the point is that if a 'speakers impedance is too low, it could draw more current from the amp then the amp can handle.

The creatives will probably be just fine. In fact you might want to try using just the creative speakers, you might get a more consistent sound that with mixing them up.

[gEd]

Where can you get the Cyberlink audio decoder from, I installed the "DVD powerpack" that came with my graphics card but it didn't add an audio decoder to GB-PVR, only the video/sp decoder. I quite like the video decoder, would be nice to try out the 'matching' audio decoder

from powerdvd v8