External SPDIF Connection

Outside the computer, the SPDIF connection can be made between other digital devices, such as professional CD players, Mini Discs, DVD players and Home Theater receivers.

The edge of the SPDIF connection lies in its immunity from electromagnetic interference (i. e., noise), as it is digital. Thus, this is the best connection type available. So, if your DVD player has SPDIF outputs and your home theater receiver has SPDIF inputs, the best way to connect them ir thru SPDIF connection.

Unfortunately the vast majority of users aren't aware of this, and still use analog connection (RCA cables) when connecting digital audio equipments or while connecting these equipments to their PC. If your computer has external SPDIF connectors, your can also connect such devices to your PC digitally, avoiding the use of analog connection, which generates noise.

There are two kinds of SPDIF connections: optical (set up by optical fiber) and coaxial (set up by coaxial cable). On Figure 5 we show the optical fiber used in optical SPDIF connections (the best connection available) and on the other pictures you can see many examples of digital audio devices that have SPDIF inputs and outputs.

Figure 5: Optical fiber Used in optical SPDIF Connections.

Figure 6: Rear of a Mini Disc deck, you can see from left to right one coaxial SPDIF input, two optical SPDIF inputs, one coaxial SPDIF output and one optical SPDIF output.

The optical SPDIF connector is usually protected by a cover, that must be removed when you want to install the optical fiber. On Figure 6 you can see that the inputs are protected by this cover, while we removed it from the optical output.

Figure 7: Coaxial SPDIF output on a professional CD player (Pioneer CDJ-100S). In this case, to use this output, the switch labeled "digital out" should be on "on" position.

Figure 8: Optical and coaxial SPDIF outputs on a DVD player (Sony DVP-NS575P).

Figure 9: Optical and coaxial SPDIF inputs on a home theater receiver (Sony STR-K750P).

So, using the above products, we can say that the best way to connect the DVD player from Figure 8 to the home theater receiver from Figure 9 it thru optical SPDIF connection using an optical fiber. If you want to record some musics from your Pioneer CDJ100S (Figure 7) on a Mini Disc (Figure 6), the best connection is done thru coaxial SPDIF (since this CD player doesn't have optical SPDIF).

This same idea can be applied to PCs. For instance, if you want to record your Mini Discs to MP3 or Wav files in your computer, connect the SPDIF output from the Mini Disc deck to your PC SPDIF input. If you want to connect your PC to an external amplifier to enjoy the full experience a game can deliver you, you should connect the SPDIF output from your PC to the SPDIF input on your home theater receiver. This connection you allow you to fully enjoy the 5.1 audio (also known as 6-channel audio). We will explain this further on the next page.

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