Hanging note bug
The so-called hanging note bug is a hardware bug on certain models of the Creative Sound Blaster 16 and Sound Blaster AWE32 series of sound cards. The bug only occurs when affected cards are utilized for digital sound effects and MIDI music simultaneously, but it happens on any MIDI device regardless if connected to the internal Wave Blaster connector or externally through the game port.
Contents
Type 1: Illegitimate hanging notes
This variant of the bug happens in games which use the DMX sound system programmed by Paul Radek:
- Doom
- Doom2
- Heretic
- Hexen
- Raptor
- Hocus Pocus
It manifests itself as MIDI notes being generated randomly. Since these notes are not part of the soundtrack, they are not stopped and hang for a long time. Also, these 'illegitimate' notes tend to be high-pitched, which makes this variant of the bug a rather annoying experience.
Type 2: Legitimate hanging notes
This type of the bug has been witnessed in many games, but occurs very rarely. In this case, the hanging notes are part of the soundtrack, but for some reason the "Note off" command is missed.
Affected cards
Affected are all Sound Blaster models with DSP revisions 4.11, 4.12 and 4.13.
Type 1 doesn't occur on cards with a CT1747 bus interface.
Bugged (Type 1 and 2)
- CT1740 (DSP >4.05)
- CT1750 (DSP >4.05)
- CT1770 (DSP >4.05)
- CT2260
- CT2800
- CT2860
- CT2910
- CT2940
- CT2950
- CT2980
- CT3600
- CT3990
Bugged (Type 2 only)
- CT2230
- CT2760
- CT3900
- CT3980
Bug-free
- CT1730
- CT1740 (DSP ≤4.05)
- CT1750 (DSP 4.05)
- CT1770 (DSP 4.05)
- AWE64 cards (DSP 4.16)
Cause
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