Depending on the total number of channels (i.e., either 6 or 8,) that you would like to use you have two choices: a single-cable digital interconnection or a multi-cable-bundle analog interconnection. Because you’re using an Audigy 2 card* the digital connection would provide better audio quality however you would be limited to 5.1-channel (e.g., AC-3,) audio. *(With an Audigy 2 card your audio quality will almost certainly benefit by choosing the interconnection method that ultimately minimizes the amount of processing done on the Audigy 2 card, i.e., using the coaxial S/PDIF connection.)
The alternative to a digital connection—and your only option if you want to use all 8 audio channels—is to use Creative’s Sound Blaster Home Theater Cable multi-cable bundle to connect the Audigy 2 card to your HT-R550B A/V receiver in the analog domain.
The next step is to purchase (if you haven’t already done so,) the appropriate cable - either a 75Ω coaxial cable fitted with an RCA connector at each end or Creative’s “Sound Blaster Home Theater Cable.” (Please follow the links below if you’re interested in high quality digital audio cables; though any well-made 75Ω coaxial cable should be sufficient.)
To use the digital connection connect the 75Ω coaxial cable from the audio card’s Digital I/O jack (DIGITAL_IO) to one of the orange color-coded coaxial S/PDIF DIGITAL IN connectors on the back of the HT-R550B A/V receiver. Be sure to configure the settings on both your computer and Onkyo A/V receiver for proper 5.1-channel operation.
Conversely, if you choose to utilize all 8 audio channels then you must connect the Sound Blaster Home Theater Cable from your Audigy 2 card, as indicated in the Creative documentation, to the L and R: FRONT, SURROUND, and SURR BACK, analog audio inputs as well as the single-channel CENTER and SUBWOOFER analog audio inputs on the rear of your HT-R550B A/V receiver. Again, be sure to configure the settings on both your computer and Onkyo A/V receiver for proper 6.1- or 7.1-channel surround sound operation.
For what it’s worth Creative’s Audigy 2 cards are far from the best choice these days when it comes to providing “maximum [audio] quality.” Nearly any of the new sound cards on the market, including Creative’s X-Fi cards, will perform much better than the unpopular Audigy 2 cards.
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Sound Blaster Home Theater Cable
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Digital Audio Cables at Blue Jeans Cable
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Digital Audio Cable Price List
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