CD ROM FAQ Audio

Information in this page updated: 07 Jan 96


8. Audio

All mentioned CD-ROM drives support some kind of Audio-CD-Player operation(3.5mm outlet on the front). Some even can be set to work only in this mode and they do not require a host computer for this. You just have to connect the audio outlets on the rear with your Stereo Set or extra Speakers. There is lots of software that emulates a CD-Player on your Amiga. Most commercial drivers have one, but the best are found in the PD area (YACDP 1.2, Jukebox 2.x; both are shareware). Some drives do not support curtain features. So first check the users guide and see what features are supported by your drive and by the software player. (e.g. NEC drives do not support all audio mixer features!)

8.1 Amiga-Audio and CD-AUDIO

Only A4000(T) and the A3000T have internal pin connectors for the audio of the CD-ROM drive. Amiga-sounds and CD-ROM audio are mixed internally. The proportion of amiga/cd-rom tends to the amiga side, so sound f/x can be heard even if cd-sound is playing (for games, multimedia etc.)

All other amiga models have to mix the audio externally. Please do not just combine both left and right channels. This is not a very clever move. Both the amiga and the drive circuits can be damaged (and PAULAs are very hard to get in these times :-)

On the serial port (on the A2000 on the internal port also) there is a pin called AUDIO-IN. Please do not use this pin! It's initially built for the sound of a modem(!) and just mono mixed to the left channel. Just like the AUDIO-OUT pin which is builr for the output of sound through a modem and comes only from the right channel.

So if you want to mix amiga-sound f/x with CD-ROM audio from your drive, use the following schematic to build a little mixer. It works for several people right now, but nether me or the author take any responsibility for damage to your hardware.


                        R1,2 = Stereopoti 50kOhm linear
                        _____
        left    O------[_____]------O   left
                          ^
        Amiga      +------+             CD-ROM
                   |    _____
        right   O--|---[_____]------O   right
                   |      ^
                   |      |
                   X¹     X²    R3,4 Stereopoti 50kOhm log.
                   |      |     _____
                   |      +----[_____]--+--O    GND
                   |              ^     |
                   |      +-------+     |
                   |      |     _____   |
                   +------|----[_____]--+
                          |       ^
                          |       |
                          |       |
                right     O¹      O²    left
                        to amplifier

        R1,2 := Balance amiga-sound and CD-ROM-Audio
        R3,4 := Volume (not really nescessary! The signals
                O¹, O² for the amplifier can come from
                X¹, X² also!)
GND is just connected between the devices. This may also solve some peoples (including myself) grounding and resonance problems. If the volume drops to much you can reduce the 50kOhm a little (stay above 20kOhm).

8.2 Digital Audio?

See chapter 3.2 for a list of CD-ROMs that support CDDAviaSCSI or CDDAviaIDE.

The following programs enable you to read CDDA over the SCSI bus. At this writing there is no program known to me that can do the trick for the few IDE drives.

 Program        FileSystem      Drive
 -----------------------------------------------------------------
 JukeBox 2.x    (optional)      all drives
 YACDP 1.2                      Toshiba, Sony/APPLE
 SCSIUtil                       Toshiba, Sony/APPLE
 CDDA                           Toshiba, Sony/APPLE
                AsimWare 3.4    SCSI-2, Toshiba, Sony/APPLE

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