Electronics Overview - DSP - DAC

The Electronics Overview

We add this section to help new users get a better idea of what they are paying for when they shell out their hard earned audio dollars.  While chips might look similar they can vary drastically in price and performance.  Let’s lift the hood on this card and see what we have.

DSP – SoundCore3D
 

The new SoundCore 3D DSP was released by Creative to replace the aging X-fi Processors.  This new chip is a quad core unit but very little information is actually available on internal architecture and signal routing. Although this chip does offer built in converters seen on other products, on this card the built in converters are not used.  The chip offers the obligatory EAX and OpenAL support along with new algorithms from THX.  The card also supports Dolby Digital Live and DTS-Connect but those are usually software based compression routines.

The ZXR contains 2 SoundCore processors, utilizing one for the base card features and the second is strictly for handling recording functions.

Digital to Analog Converters (DAC’s)

If we look along the copper shielding we can see three stereo DAC chips.  The PCM 1798’s being used for the rear channels and the Center/Sub channel, labeled U20 and U22. The PCM 1794, labeled U18 is being used for the headphone / Front-line outputs. Let’s take a closer look at these converters.

DAC – PCM1794

The PCM 1796 DAC is a high end component, offering a very high dynamic range of 127dB @ 2V RMS and THD+N of 0.0004% these chips are used a great deal in the AV industry in higher end receivers. PCM 1794 Specification Sheet “http://www.ti.com/lit/ds/sles080c/sles080c.pdf”

DAC - PCM -1798

The PCM 1798 converter offers a high dynamic range of 123dB and a THD+N rating of 0.0005%.  As with the above converters these are usually seen in high end consumer grade A/V gear. It is great to see a design where higher end DAC’s are used for all channels not just for the front lineoutputs.

PCM 1798 Specification Sheet “http://www.ti.com/lit/ds/symlink/pcm1798.pdf”

ADC - PCM 4220

This is a high performance Analog to digital converter, offering input quality of 123dB and THD+N of 108dB.  The Creative designers added some recording muscle to this beast to cover those bases as it seems more and more people are getting into home recording.  It is also great to have a quality microphone input for VOIP, in game communication and video.