Karbosguide.com - Module 7c2.

PC sound - continued


The contents:

  • The sound card - an adapter
  • Newer sound cards
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  • The sound card - an adapter

    In the previous module, we saw the principles of PC sound. Let us here look at the sound card, which is an adapter card.

    The sound card used to be a ISA card (using the old ISA interface). Here you see the original Sound Blaster AWE64 Gold card:

    The connectors may look different on different sound cards, but as an example: In the back of the AWE64 Gold card you find connectors to:

  • Microphone input, a jack
  • Line input, a jack
  • Two phone jacks for active speakers
  • A DB15 jack for MIDI or joystick.

    Most sound cards typically have a 2 Watt amplifier built-in. It can push a set of earphones. An exception is the SB Gold card, where the amplifier is eliminated. It has no practical significance, since you probably want to attach it to a pair of active speakers.

    The new sound cards

    For many years PC sound has been totally dominated by the Sound Blaster card. All sound cards had to be compatible with Sound Blaster, or it would not sell. Obviously that is due to the numerous game programs, which require a SB compatible sound card.

    The new sound cards break away from the Sound Blaster compatbility. This break involves many facets. Below I will describe some of the tendencies in the sound technology.

    Sound over the PCI bus

    New sound cards use the PCI bus. The SB compatibility used to require the old ISA bus, but this has been overcome. Creative Labs produce fine PCI-based SoundBlaster cards. With PCI you gain these advantages:

  • The IRQ problems disappear.
  • Signal/noise ratio can be improved with 5 dB.
  • There is sufficient bandwidth (capacity for data transmission).
  • The sound card workload for the CPU is less.
  • We can drop the ISA bus, which takes up unnecessary space on the PC system board.

    The problem in moving the sound to the PCI bus involved the existing software. First of all the old DOS games, which expected and demanded the Sound Blaster card with its well-known IRQ- and DMA numbers. The games did not work with the new cards, unless special solutions were implemented. However, the impact of this problem is gone. No more ISA-based sound cards are in production, and all games use the new standards for Windows sound.

    Onboard sound chips

    Many motherboard include sound card functions. This is i fine thing, if you only need sound for ordinary use. The quality is not as good as the sound from a $80-$100 sound card, but for many users it is fine!

    On-board audio is found within some chip sets. For instance you find it in the much used VIA KT133 chip set for AMD processors. Here the VT82C686B south bridge I/O-controller holds built-in AC97 digital audio functions:

    A Windows report on this:

    Onboard sound chips is an in-expensive an simple via to incorporate sound facilities in your PC.


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    Learn more
    Read Module 6a about file systems

    Read about chip sets on the motherboard in module 2d

    Read Module 4d about super diskette and MO drives

    Read module 5a about expansion cards, where we evaluate the I/O buses from the port side

    Read module 5b about AGP

    Read module 7a about monitors, and 7b on graphics card

    Also see: Module 7d - about digital music: MP3s, MODs etc.

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