> From what I can gather, discrete sound emulation might not sound like the real thing > despite being a direct 1:1 emulation of the discrete logic, because there could be > all sorts of additional variables from the analog sound playback and amplification > equipment that aren't factored in. Did I get that right?
Pretty much, yeah. In a lot of cases, I expect MAME emulates the analog circuitry of the sound generation portion of the PCB, but not always every last bit of discrete analog circuitry between that part and the speakers in the cabinet.
Then, as you mention, there's the amplifier in the arcade machine itself, and any environmental effects like the speakers tending to have more bass due to being a bit bigger than your average compiler speaker, and the resonance of the cabinet itself. Things a dedicated audio programmer could spend months working on replicating, none of which really have to do with emulating the arcade game, and most of which (I imagine) go away if you drop a PC into an actual cabinet.
EDIT: Then there's the very real fact that analog components tend to drift with multiple factors, including both age and ambient temperature. Early analog synthesizers like the Moog Modular were notoriously difficult to keep in tune for the latter reason, and would even drift noticeably out of tune over the course of a single day. MAME is based on an idealized model that uses the exact component values found in the schematic and verified against component markings on a real board (since schematics can be wrong). You can verify this yourself by looking up different videos of actual Donkey Kong cabinets and observing the variance in sounds.
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