diff --git a/applecorn.po b/applecorn.po
index 1fdd029..1570116 100644
Binary files a/applecorn.po and b/applecorn.po differ
diff --git a/mainmem.ensq.s b/mainmem.ensq.s
index 4089388..cb1407f 100644
--- a/mainmem.ensq.s
+++ b/mainmem.ensq.s
@@ -121,7 +121,7 @@ ENSQNOTE    PHA
 
 
 * Adjust frequency of note already playing
-* On entry: Y - frequency to set
+* On entry: X - oscillator number 0-3, Y - frequency to set
 * Preserves X & Y
 ENSQFREQ    PHX
             PHY                             ; Gonna need it again
@@ -143,7 +143,7 @@ ENSQFREQ    PHX
 
 
 * Adjust amplitude of note already playing
-* On entry: Y - amplitude to set
+* On entry: X - oscillator number 0-3, Y - amplitude to set
 * Preserves X & Y
 ENSQAMP     PHX
             PHY                             ; Gonna need it again
@@ -155,7 +155,8 @@ ENSQAMP     PHX
             RTS
 
 * Ensoniq interrupt service routine - just calls generic audio ISR
-ENSQISR     JMP   AUDIOISR
+ENSQISR     CLD
+            JMP   AUDIOISR
 
 
 **
diff --git a/mainmem.fsequ.s b/mainmem.fsequ.s
index d3c73b0..c1c4f13 100644
--- a/mainmem.fsequ.s
+++ b/mainmem.fsequ.s
@@ -37,6 +37,7 @@ FBATTR      EQU   FILEBLK+14  ; Attributes
 FBEND       EQU   FILEBLK+14  ; End address for SAVE
 
 * ProDOS MLI command numbers
+ALLOCCMD    EQU   $40
 QUITCMD     EQU   $65
 GTIMECMD    EQU   $82
 CREATCMD    EQU   $C0
diff --git a/mainmem.lists.s b/mainmem.lists.s
index 6df46d4..c7a0b76 100644
--- a/mainmem.lists.s
+++ b/mainmem.lists.s
@@ -110,33 +110,7 @@ QUITPL      HEX   04          ; Number of parameters
             DB    $00
             DW    $0000
 
-
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+ALLOCPL     HEX   02          ; Number of parameters
+            DB    $00         ; Interrupt number returned here
+            DW    $0000       ; Pointer to ISR
 
diff --git a/mainmem.mock.s b/mainmem.mock.s
index 0cf5729..dbc10ac 100644
--- a/mainmem.mock.s
+++ b/mainmem.mock.s
@@ -57,10 +57,13 @@ MOCKINIT    LDA   #$FF                      ; All VIA pins output
             LDA   #MOCK_AY_INACTIVE
             STA   MOCK_6522_ORB2
 
-            LDA   #<MOCKISR                 ; Setup interrupt handler
-            STA   A2IRQV+0                  ; TODO: Should chain existing handler
+            LDA   #<MOCKISR                 ; Set up ISR with ALLOC_INTERRUPT
+            STA   ALLOCPL+2
             LDA   #>MOCKISR
-            STA   A2IRQV+1
+            STA   ALLOCPL+3
+            JSR   MLI
+            DB    ALLOCCMD
+            DW    ALLOCPL
 
             PHP
             SEI
@@ -87,32 +90,47 @@ MOCKSILENT  LDX  #13                        ; Clear all 14 AY-3 regs
 
 
 * Configure a Mockingboard oscillator to play a note
-* On entry: X - oscillator number 0-3 , A - frequency, Y - amplitude
+* On entry: X - oscillator number 0-3, A - frequency, Y - amplitude
 * Preserves all registers
 MOCKNOTE                                    ; TODO
             RTS
 
 
 * Adjust frequency of note already playing
-* On entry: Y - frequency to set
+* On entry: X - oscillator number 0-3, Y - frequency to set
 * Preserves X & Y
-MOCKFREQ                                    ; TODO
-            RTS
-
-
-* Adjust amplitude of note already playing
-* On entry: Y - amplitude to set
-* Preserves X & Y
-MOCKAMP     PHX
-            PHY                             ; Gonna need it again
+MOCKFREQ    PHX
+            PHY
                                             ; TODO
             PLY
             PLX
             RTS
 
 
+* Adjust amplitude of note already playing
+* On entry: X - oscillator number 0-3, Y - amplitude to set
+* Preserves X & Y
+MOCKAMP     PHX
+            PHY
+            CPX   #$00                      ; Noise channel
+            BEQ   :DONE                     ; Has no amplitude
+            TXA                             ; Add 7 to get register
+            CLC
+            ADC   #7
+            TAX
+            TYA                             ; Amplitude 0..127
+            LSR                             ; Divide by 8
+            LSR
+            LSR                             ; Now 0..15
+            JSR   MOCKWRT                   ; Write value to AY-3 register
+            PLY
+            PLX
+:DONE       RTS
+
+
 * Mockingboard interrupt service routine - just calls generic audio ISR
-MOCKISR     JMP   AUDIOISR
+MOCKISR     CLD
+            JMP   AUDIOISR
 
 
 **