Hi,
I bought altec lansing ADA 880 (5.1), and my friend said that I have to buy a soundcard that support 6 channels speaker to get the best performance, and then I bought Turtle Beach Santa Cruz. But I have a problem about installation that speaker because from soundcard manual, to get the best performance for 6 channels speaker (surround sound), I must connect the rear speakers (R & L) with R & L out (from the soundcard) and so the front speakers and subwoofer.
But Altec Lansing ADA 880, have a different installation because the front and rear speakers are connected to the subwoofer (not to the soundcard), and from subwoofer there are 2 options to get input from the soundcard, using Analog In or SP/DIF In. Does anyone have any experience about this installation, and maybe there is the best installation (the best sound and performance) for my speaker and soundcard. Thanks

Connect both the analog in and the SPDIF, if possible. I don't know if the Santa Cruz supports digital, but it probably does, so just connect up both and enable digital output in your soundcard utilities.
The subwoofer of a system usually acts as the medium between the speakers and the soundcard.

I'll ehh check if I can find a PDF manual or something first....

Ok, can't find manual. The setup sounds fine though, all 2.1, 4.1 & 5.1 systems require you connect your soundcard to the subwoofer/amplifier/decoder & they are in turn connected to the speakers/subwoofer.

So I'll assume you have the speakers & all attached correctly. What inputs does it feature for the soundcard?? 3 minijack inputs (Front, Rear, Center/Sub), or are the center & sub seperate. You shouldn't need to use the digital input as you'll only get front left/right like that unless the system has a decoder, which it doesn't based on what you said.

thanks friend, for your reply..
I read the speaker manual, and it's said that Analog In is used if the input (from soundcard or whatever) doesn't support digital output. My soundcard support digital output (versa jack type), so I tried to connect the soundcard digital output (1/8 " cable connector) to the speaker SP/DIF In (RCA type) using Y connector.
And.. bummm... it works great, the sound is very very good, the subwoofer, front speakers and the surround speakers sound is very clear. I don't know that this is the right connection, but I like the result. So maybe this is the right one ? (but the Windows volume control isn't working, maybe the digital output always like this? I use the speaker volume control right now)