Updated Audio modes demystified (markdown)

Audio-modes-demystified.md

@@ -135,7 +135,7 @@ All versions of Popn use DirectSound.
 
 Uses Exclusive WASAPI.
 
-# Spice audio hook
+# Spice audio hook for WASAPI
 
 ## Low latency audio mode for DSound and Shared Mode WASAPI
 
@@ -224,6 +224,18 @@ Spice only hooks some of Windows volume APIs, which should cover most games. If
 
 For most games, there are also patches that can be applied.
 
+## WASAPI Stereo Downmix
+
+Some games require surround sound setup. For example, FutureTomTom wants 4 channels, and GitaDora Arena Cabinet requires a 7.1 setup. If you turn on `-downmix` option, you can play these games with just a stereo system; spice will lie to the game engine that surround system is available, internally perform a downmix to stereo, and output to your audio device with just two channels.
+
+## WASAPI Exclusive Mode Resampling
+
+Allows you to upsample / downsample exclusive mode streams. This can be useful if your audio device doesn't support the sample rate that the game wants (e.g., you have 48kHz-only device but SDVX wants 44kHz). Note that this only works for exclusive mode, not shared.
+
+## WASAPI Exclusive Buffer Size
+
+Allows you to modify the buffer size. This can be used if the buffer size requested by the game engine is too low (e.g., SDVX requests 3 ms) and causing static noise in your speakers. You should start with 10 (10 milliseconds) and slowly increase it; higher values are safer, but will add more latency.
+
 # Other audio hooks and hacks
 
 [REAL](https://github.com/miniant-git/REAL) was used in the past to minimize DSound and shared mode WASAPI latency, but it is longer needed as the feature has been integrated into spice2x as of 2023-11-23 (see `Audio latency reduction for DSound and Shared Mode WASAPI` section above).