Difference between revisions of "Hanging note bug"

Revision as of 11:53, 4 March 2013

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.

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

...?

External links

Related thread on the VOGONS forums