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.

Although the bug appeared in a wide range of Creative products, Creative never officially acknowledged its existence.

Type 1: Illegitimate hanging notes

This variant of the bug manifests itself as "rogue" MIDI notes being generated during MIDI playback. 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.

It occurs in the following games:

Games using the DMX sound system by Paul Radek:

• Doom
• Doom2
• Heretic
• Hexen
• Raptor
• Hocus Pocus

Build engine games

• Duke Nukem 3D
• Blood
• Shadow Warrior (Shareware)

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) - SB 16 CSP
• CT1750 (DSP >4.05) - SB 16 Multi-CD CSP
• CT1770 (DSP >4.05) - SB 16 SCSI-2
• CT2260 - SB 16 Multi-CD OEM
• CT2800 - SB 16 Value OEM
• CT2860 - SB 16 Value OEM
• CT2910 - SB 16 Pro
• CT2940 - SB 16 Value PnP OEM
• CT2950 - SB 16 Value PnP OEM
• CT2980 - SB 16 Value PnP
• CT3600 - SB AWE 32 IDE PnP
• CT3990 - SB AWE 32 IDE PnP

Bugged (Type 2 only)

• CT2230 - SB 16 Multi-CD CSP
• CT2760 - SB AWE 32 Multi-CD
• CT3900 - SB AWE 32 IDE
• CT3980 - SB AWE 32 IDE

Bug-free

• CT1730 - SB 16
• CT1740 (DSP ≤4.05) - SB 16 CSP
• CT1750 (DSP 4.05) - SB 16 Multi-CD CSP
• CT1770 (DSP 4.05) - SB 16 SCSI-2
• AWE64 cards (DSP 4.16)

Cause

...?

External links

• Related thread on the VOGONS forums