From b96dabbe98fe6c37841e54bf20e1b8f4475af940 Mon Sep 17 00:00:00 2001
From: TomW <TomW@localhost>
Date: Sun, 28 Sep 2014 11:33:08 +0100
Subject: [PATCH] Silence PC speaker output at very high frequencies - fixes
 Lemmings and other games that use high frequency as "speaker off".

---
 src/pit.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/pit.c b/src/pit.c
index ccb12c4..8b3b340 100644
--- a/src/pit.c
+++ b/src/pit.c
@@ -527,7 +527,12 @@ void pit_refresh_timer_at(int new_out, int old_out)
 
 void pit_speaker_timer(int new_out, int old_out)
 {
-        speakon = ppispeakon = new_out;
+        int l = pit.l[2] ? pit.l[2] : 0x10000;
+        if (l < 25)
+                speakon = 0;
+        else
+                speakon = new_out;
+        ppispeakon = new_out;
 }