We capture the pictures on our film scanner, but lifting audio off 8mm films can be quite tricky. We have several options, including using Heurtier sound projectors. The audio files are then synced up with the picture.
If you want, here are PDF copies of the instruction books you can download.
These projectors have survived well. The film transport mechanism remains solid and the film speed across the audio heads very steady. Considering the limitations of the recordings, which are now 50 years old or more, the quality we can achieve is surprisingly good.
Finding 8mm sound projectors that work well, that don’t chew up film and provide decent audio is not easy and this perhaps is another reason to digitise film. Although a premium brand half a century ago, unfortunately many very old 8mm Eumig projectors now cannot run at a steady speed. Multi-standard projectors sound good in theory but will often make damaged film worse, particularly if they only move the film with a claw mechanism.
Audio on Super 8 is easy by comparison.