OK, here's the ultimate volume boost trick for digis.

[pixel]

Code: Select all

    ; Stop channels.
    lda #$7e
    sta $900a
    sta $900b
    sta $900c
    sta $900d

    ; Let channels rest until LSFRs are empty.
    ; Some extra explaining why that takes so long
    ; would be nice.
    ldy #0
l:  dey
    bne -l

    ; Start alto channel at highest frequency of
    ; ~8659Hz, which is 128 CPU cycles.
    lda #$fe
    sta $900b

    ; Waste 56 cycles.
    ; 2+10*5+4
    ldy #11     ; 2
l:  dey         ; 2
    bne -l      ; 3

    ; Waste missing 2 cycles.
    nop         ; 2

    ; Start soprano channel at same frequency as alto.
    ; Takes 6 cycles. Then it's exactly half a wave
    ; (64 cycles) apart from the alto.
    ; Complain to my weed dealer if I'm wrong.                                                                                                                
    lda #$fd    ; 2
    sta $900c   ; 4

    rts

Sounds REALLY good on a real machine with tube.

[nanoflite]

Nice trick! The sample playback itself is handled by the volume register I assume? While this trick tries to make the average sound output as high as possible on average?

[pixel]

Nice trick! The sample playback itself is handled by the volume register I assume? While this trick tries to make the average sound output as high as possible on average?

Yep, it's still the volume register. I guess it gets as loud as it can get.