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Which Soundcard 6: Does having on-board DSP make a difference?

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Which Soundcard 6: Does having on-board DSP make a difference?

PostPosted: Sat Dec 16, 2000 10:49 am
by Martin Walker
All soundcards use Digital Signal Processing for their basic audio features, but with the more powerful DSP chips used by many modern soundcards, manufacturers can provide onboard effects, hardware mixing, sampling, or other features beyond standard audio recording and playback. Generic DSP chips also have the potential to be reprogrammed, allowing new features to be added at a later date via driver software, but you should always make your choice based on what features are available now, and then you can’t be disappointed.

The most common DSP feature is built-in effects, and using these instead of DirectShow plug-ins can remove a huge overhead from your PC processor. This will either allow a less powerful PC to be used, or more simultaneous audio channels to be managed by your software.

Although the effects available on low-cost consumer soundcards (£50-200) sometimes have rough and ready quality, many are still surprisingly good. In the mid-price (£200-500) there are various soundcards that offer four or five effect busses with a huge range of quality effects to choose from. At the high end, professional cards like the
Lexicon Studio include an industry standard PCM-90 reverb unit.

DSP chips can also mix multiple streams of digital audio (and often add effects to them individually). Although the user can access these channels individually from within a
MIDI+Audio sequencer (using multichannel drivers), the hardware cost is kept down by using digital mixing (again using some DSP power). Once mixed together, they can emerge from a single stereo analogue output on the card, which avoids the need for additional expensive D/A converters.

Others (such as the SoundBlaster Live!, the now discontinued Emu APS, and Creamware’s PowerSampler) provide the equivalent of a built-in sampler which runs alongside the hard disk based tracks.

If you want a self-contained system, with everything inside your PC, this sort of all-in-one card is ideal. The only disadvantage is that you are unlikely to be able to use their internal effects on other external MIDI gear, unless you re-record these as audio tracks.