furnace/papers/doc/7-systems/qsound.md

# Capcom QSound (DL-1425)

this chip was used in Capcom's CP System Dash, CP System II and ZN arcade PCBs.

it supports 16 PCM channels and uses the patented (now expired) QSound stereo expansion algorithm, as the name implies.

because the chip lacks sample interpolation, it is recommended that you try to play samples at around 24038 Hz to avoid aliasing. this is especially important for e.g. cymbals.

the QSound chip also has a small echo buffer, somewhat similar to the SNES, although with a very basic (and non-adjustable) filter. it is however possible to adjust the feedback and length of the echo buffer (the initial values can be set in the "configure chip" option in the file menu or the chip manager).

there are also 3 ADPCM channels, however they cannot be used in Furnace yet. they have been reserved in case this feature is added later. ADPCM samples are limited to 8012 Hz.

# effects

- `10xx`: set echo feedback level.
  - this effect will apply to all channels.
- `11xx`: set echo level.
- `12xx`: toggle QSound algorithm (on by default).
- `3xxx`: set the length of the echo delay buffer.
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00			`# Capcom QSound (DL-1425)`

lots of doc updates 2022-10-16 05:53:05 +00:00			`this chip was used in Capcom's CP System Dash, CP System II and ZN arcade PCBs.`
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00
lots of doc updates 2022-10-16 05:53:05 +00:00			`it supports 16 PCM channels and uses the patented (now expired) QSound stereo expansion algorithm, as the name implies.`
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00
lots of doc updates 2022-10-16 05:53:05 +00:00			`because the chip lacks sample interpolation, it is recommended that you try to play samples at around 24038 Hz to avoid aliasing. this is especially important for e.g. cymbals.`
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00
lots of doc updates 2022-10-16 05:53:05 +00:00			`the QSound chip also has a small echo buffer, somewhat similar to the SNES, although with a very basic (and non-adjustable) filter. it is however possible to adjust the feedback and length of the echo buffer (the initial values can be set in the "configure chip" option in the file menu or the chip manager).`
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00
lots of doc updates 2022-10-16 05:53:05 +00:00			`there are also 3 ADPCM channels, however they cannot be used in Furnace yet. they have been reserved in case this feature is added later. ADPCM samples are limited to 8012 Hz.`
Add 3xxx effect to set echo delay buffer length. Add documentation 2022-02-22 20:16:46 +00:00
			`# effects`

QSound: implement panning macro - PLEASE READ the panning strategy for QSound has changed! it's now 08xy where x is left and y is right (muting is not possible though!) this makes it consistent with other chips, plus QSound's pan range was 32 anyway in order to toggle the QSound effect use effect 12xx 2022-04-29 04:58:11 +00:00			- `10xx`: set echo feedback level.
			`- this effect will apply to all channels.`
			- `11xx`: set echo level.
			- `12xx`: toggle QSound algorithm (on by default).
			- `3xxx`: set the length of the echo delay buffer.