Hi all,
I’ve been working on the Mac mini G4’s sound under Mac OS 9 (MacOS9Lives) and wanted to post where things stand.
Mini Sound Enabler is a system extension that gets the mini’s built-in audio working. It started as Matouš Pikous’s MacMiniAudioFix, which found the amp pins and switched them on at startup. Version 3.0 keeps running after startup. It switches between speaker and headphones on its own, makes alert sounds play, and makes the normal volume slider and the Control Strip work. Muting switches the amps off, so there’s no hiss.
The mini has no audio codec, so there’s no hardware volume, and the amps hang off GPIO pins in the mac-io controller. A timer watches the headphone-detect pin and switches the amps. For volume, the extension stands in for the Sound Manager’s per-channel Frequency Equalizer component and scales each sound buffer on its way through. It’s built with Retro68, and the source comes with a long write-up of what worked and what didn’t.
Testers on Mac OS 9 Lives found these problems in 3.0:
UnexpectedBomb has a separate project for the same machine: a Control Strip module for mute and switching, plus a selectable sound output for volume. Don’t run both at once, since they drive the same amp pins.
Download (3.0): https://github.com/VikSn0w/MiniSoundEnabler/releases/tag/v3.0
Source and technical notes (GPLv3): https://github.com/VikSn0w/MiniSoundEnabler
Reports from other Mac mini G4 owners are welcome, especially from the late 2005 models (1.33 and 1.5 GHz). The disk image includes AudioProbe, a diagnostic app; if something doesn’t work, its log is the most useful thing to post.
I’ve been working on the Mac mini G4’s sound under Mac OS 9 (MacOS9Lives) and wanted to post where things stand.
Mini Sound Enabler is a system extension that gets the mini’s built-in audio working. It started as Matouš Pikous’s MacMiniAudioFix, which found the amp pins and switched them on at startup. Version 3.0 keeps running after startup. It switches between speaker and headphones on its own, makes alert sounds play, and makes the normal volume slider and the Control Strip work. Muting switches the amps off, so there’s no hiss.
The mini has no audio codec, so there’s no hardware volume, and the amps hang off GPIO pins in the mac-io controller. A timer watches the headphone-detect pin and switches the amps. For volume, the extension stands in for the Sound Manager’s per-channel Frequency Equalizer component and scales each sound buffer on its way through. It’s built with Retro68, and the source comes with a long write-up of what worked and what didn’t.
Testers on Mac OS 9 Lives found these problems in 3.0:
- The alert sound can get quieter every time it plays, until it’s silent. That’s a bug in my volume code. For short alert sounds it scaled the sound itself in memory, so each play scaled it again. The fix is to scale a copy.
- Some games crackle (Duke Nukem, for one), while Warcraft II and Doom Legacy play fine. It may be the same bug; I’m waiting on a list of games and AudioProbe logs to know for sure.
- FireWire drives can stop working with the extension installed. The original fix, and 3.0 with it, also forced two pins on, 0x6E and 0x79. The mini’s device tree doesn’t list them as audio pins, and the sound plays with either one off, so the next version leaves them alone.
UnexpectedBomb has a separate project for the same machine: a Control Strip module for mute and switching, plus a selectable sound output for volume. Don’t run both at once, since they drive the same amp pins.
Download (3.0): https://github.com/VikSn0w/MiniSoundEnabler/releases/tag/v3.0
Source and technical notes (GPLv3): https://github.com/VikSn0w/MiniSoundEnabler
Reports from other Mac mini G4 owners are welcome, especially from the late 2005 models (1.33 and 1.5 GHz). The disk image includes AudioProbe, a diagnostic app; if something doesn’t work, its log is the most useful thing to post.
