diff --git a/applecorn.po b/applecorn.po
index 4f1b0e5..13f6c6c 100644
Binary files a/applecorn.po and b/applecorn.po differ
diff --git a/mainmem.audio.s b/mainmem.audio.s
index e0e0cf0..c5c88b6 100644
--- a/mainmem.audio.s
+++ b/mainmem.audio.s
@@ -732,7 +732,6 @@ ADSRPHASE   STX   OSCNUM
 :S1         TYA                             ; Change/step -> A
             CLC
             ADC   CURRAMP,X                 ; Add change to current amp
-*            BCS   :CLAMP                    ; If overflow, clamp to target
             CMP   :TARGET                   ; Compare with target
             BCS   :CLAMP                    ; If target < sum, clamp to target
             BRA   :UPDATE                   
@@ -743,7 +742,7 @@ ADSRPHASE   STX   OSCNUM
 :S2         TYA                             ; Change/step -> A
             CLC
             ADC   CURRAMP,X                 ; Add change to current amp
-            BCS   :CLAMP                    ; If overflow, clamp to target
+            BCS   :CLAMP                    ; If overflow (-ve), clamp to target
             CMP   :TARGET                   ; Compare with target
             BCC   :CLAMP                    ; If target >= sum, clamp to target
             BRA   :UPDATE                   
diff --git a/mainmem.ensq.s b/mainmem.ensq.s
index 8c2968c..806d757 100644
--- a/mainmem.ensq.s
+++ b/mainmem.ensq.s
@@ -2,6 +2,7 @@
 * (c) Bobbi 2022 GPLv3
 *
 * Ensoniq DOC Driver for Apple IIGS.
+* Simulates Hitachi SN76489 sound generator chip found in BBC Micro.
 *
 
 * Ensoniq control registers
@@ -145,7 +146,13 @@ ENSQNOTE    PHA
             CPX   #$00
             BEQ   :NOISE                    ; Oscillator 0 is noise channel
 
-            PHA                             ; Stash orig freq
+            CPX   #$01                      ; Oscillator 1 controls noise freq
+            BNE   :S0                       ; Not 1? Skip
+            CMP   #$00                      ; If frequency is zero ..
+            BEQ   :S0                       ; .. skip
+            STA   :CH1NOTE                  ; Store frequency for noise gen
+
+:S0         PHA                             ; Stash orig freq
             TAY
             LDA   EFREQLOW,Y
             TAY                             ; Frequency value LS byte
@@ -232,6 +239,7 @@ ENSQNOTE    PHA
 :NOISENOTE  DB    149                       ; BBC Micro note P=0 or 4
             DB    101                       ; BBC Micro note P=1 or 5
             DB    53                        ; BBC Micro note P=2 or 6
+:CH1NOTE    DB    00                        ; Note on channel 1
 
 
 * Adjust frequency of note already playing
diff --git a/mame_applecorn b/mame_applecorn
old mode 100644
new mode 100755