From bc7b6954cc294b1b26e5ef3409e39e6443ff120d Mon Sep 17 00:00:00 2001
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Date: Mon, 9 Nov 2015 23:02:29 +0100
Subject: [PATCH] Move the limiter after the compressor; since it is not the
 prettiest limiter out there, this seems to give better results. Again tuned
 by ear.

---
 mixer.cpp        | 25 ++++++++++++-------------
 ui_mainwindow.ui | 16 ++++++++--------
 2 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/mixer.cpp b/mixer.cpp
index 8ccd7fa..0e362f0 100644
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -578,9 +578,19 @@ void Mixer::process_audio_one_frame()
 
 //	float limiter_att, compressor_att;
 
-	// Then a limiter at +0 dB (so, -14 dBFS) to take out the worst peaks only.
+	// The real compressor.
+	if (compressor_enabled) {
+		float threshold = pow(10.0f, compressor_threshold_dbfs / 20.0f);
+		float ratio = 20.0f;
+		float attack_time = 0.005f;
+		float release_time = 0.040f;
+		float makeup_gain = 2.0f;  // +6 dB.
+		compressor.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
+//		compressor_att = compressor.get_attenuation();
+	}
+
+	// Finally a limiter at -4 dB (so, -10 dBFS) to take out the worst peaks only.
 	// Note that since ratio is not infinite, we could go slightly higher than this.
-	// Probably more tuning is warranted here.
 	if (limiter_enabled) {
 		float threshold = pow(10.0f, limiter_threshold_dbfs / 20.0f);
 		float ratio = 30.0f;
@@ -591,17 +601,6 @@ void Mixer::process_audio_one_frame()
 //		limiter_att = limiter.get_attenuation();
 	}
 
-	// Finally, the real compressor.
-	if (compressor_enabled) {
-		float threshold = pow(10.0f, compressor_threshold_dbfs / 20.0f);
-		float ratio = 20.0f;
-		float attack_time = 0.005f;
-		float release_time = 0.040f;
-		float makeup_gain = 2.0f;  // +6 dB.
-		compressor.process(samples_out.data(), samples_out.size() / 2, threshold, ratio, attack_time, release_time, makeup_gain);
-//		compressor_att = compressor.get_attenuation();
-	}
-
 //	printf("limiter=%+5.1f  compressor=%+5.1f\n", 20.0*log10(limiter_att), 20.0*log10(compressor_att));
 
 	// Upsample 4x to find interpolated peak.
diff --git a/ui_mainwindow.ui b/ui_mainwindow.ui
index be10d9b..858771e 100644
--- a/ui_mainwindow.ui
+++ b/ui_mainwindow.ui
@@ -508,7 +508,7 @@
           </property>
          </widget>
         </item>
-        <item row="3" column="2">
+        <item row="3" column="3">
          <widget class="QCheckBox" name="limiter_enabled">
           <property name="text">
            <string>Enabled</string>
@@ -518,7 +518,7 @@
           </property>
          </widget>
         </item>
-        <item row="1" column="2">
+        <item row="1" column="3">
          <widget class="QDial" name="limiter_threshold_knob">
           <property name="minimumSize">
            <size>
@@ -549,7 +549,7 @@
           </property>
          </widget>
         </item>
-        <item row="0" column="2">
+        <item row="0" column="3">
          <widget class="QLabel" name="limiter_threshold_label">
           <property name="text">
            <string>Limiter threshold</string>
@@ -559,7 +559,7 @@
           </property>
          </widget>
         </item>
-        <item row="2" column="2">
+        <item row="2" column="3">
          <widget class="QLabel" name="limiter_threshold_db_display">
           <property name="text">
            <string>-14.0 dB</string>
@@ -569,7 +569,7 @@
           </property>
          </widget>
         </item>
-        <item row="1" column="3">
+        <item row="1" column="2">
          <widget class="QDial" name="compressor_threshold_knob">
           <property name="minimumSize">
            <size>
@@ -600,14 +600,14 @@
           </property>
          </widget>
         </item>
-        <item row="0" column="3">
+        <item row="0" column="2">
          <widget class="QLabel" name="compressor_threshold_label">
           <property name="text">
            <string>Compr. threshold</string>
           </property>
          </widget>
         </item>
-        <item row="2" column="3">
+        <item row="2" column="2">
          <widget class="QLabel" name="compressor_threshold_db_display">
           <property name="text">
            <string>-26.0 dB</string>
@@ -617,7 +617,7 @@
           </property>
          </widget>
         </item>
-        <item row="3" column="3">
+        <item row="3" column="2">
          <widget class="QCheckBox" name="compressor_enabled">
           <property name="text">
            <string>Enabled</string>
-- 
2.39.2