From c2ebe39f4a99302f83c969df65d5bd105234cadc Mon Sep 17 00:00:00 2001
From: jsiegle <joshs@alleninstitute.org>
Date: Thu, 18 Sep 2014 14:34:19 -0700
Subject: [PATCH] Finally! The noise gate does what it's supposed to
---
Source/Processors/AudioNode.cpp | 18 ++++++++----------
Source/Processors/AudioNode.h | 2 +-
2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/Source/Processors/AudioNode.cpp b/Source/Processors/AudioNode.cpp
index 0d274f5a5..a804995f4 100755
--- a/Source/Processors/AudioNode.cpp
+++ b/Source/Processors/AudioNode.cpp
@@ -142,7 +142,7 @@ void AudioNode::setParameter(int parameterIndex, float newValue)
{
// noiseGateLevel level
- Expander.setThreshold(newValue); // in microVolts
+ expander.setThreshold(newValue); // in microVolts
}
else if (parameterIndex == 100)
@@ -359,9 +359,7 @@ void AudioNode::process(AudioSampleBuffer& buffer,
}
// Simple implementation of a "noise gate" on audio output
- // Modified from http://musicdsp.org/archive.php?classid=1#272:
-
- Expander.process(buffer.getWritePointer(0), // left channel
+ expander.process(buffer.getWritePointer(0), // left channel
buffer.getWritePointer(1), // right channel
buffer.getNumSamples());
@@ -381,14 +379,14 @@ void AudioNode::process(AudioSampleBuffer& buffer,
Expander::Expander()
{
threshold = 1.f;
- attack = release = envelope_decay = 0.f;
output = 1.f;
- transfer_A = 0.f;
- transfer_B = 1.f;
-
env = 0.f;
gain = 1.f;
+
+ setAttack(1.0f);
+ setRelease(1.0f);
+ setRatio(1.2); // ratio > 1.0 will decrease gain below threshold
}
void Expander::setThreshold(float value)
@@ -432,13 +430,13 @@ void Expander::process(float* leftChan, float* rightChan, int numSamples)
env = det >= env ? det : det + envelope_decay*(env-det);
- transfer_gain = env > threshold ? pow(env, transfer_A) * transfer_B : output;
+ transfer_gain = env < threshold ? pow(env, transfer_A) * transfer_B : output;
gain = transfer_gain < gain ?
transfer_gain + attack * (gain - transfer_gain) :
transfer_gain + release * (gain - transfer_gain);
- leftChan[i] = leftChan[i] * gain;
+ leftChan[i] = leftChan[i] * gain;
rightChan[i] = rightChan[i] * gain;
}
}
\ No newline at end of file
diff --git a/Source/Processors/AudioNode.h b/Source/Processors/AudioNode.h
index f153208be..cec80c82b 100755
--- a/Source/Processors/AudioNode.h
+++ b/Source/Processors/AudioNode.h
@@ -139,7 +139,7 @@ private:
bool bufferSwap;
- Compressor compressor;
+ Expander expander;
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(AudioNode);
--
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