# How to apply gain correctly to the sampler?

**URL:** <https://forum.juce.com/t/how-to-apply-gain-correctly-to-the-sampler/48108>\
**Category:** Audio Plugins\
**Created:** [October 4, 2021, 5:55pm UTC](https://forum.juce.com/t/how-to-apply-gain-correctly-to-the-sampler/48108 "2021-10-04T17:55:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dotinspiredby](https://avatars.discourse-cdn.com/v4/letter/d/ebca7d/32.png) [@dotinspiredby](https://forum.juce.com/u/dotinspiredby)\
**Post date:** [October 4, 2021, 5:55pm UTC](https://forum.juce.com/t/how-to-apply-gain-correctly-to-the-sampler/48108/1 "2021-10-04T17:55:47Z")

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Hello, everyone! As a Juce beginner I would like to ask you about one thing I’ve been trying to figure out for quite a bit of time, but unfortunately without any proper result.

Based on the tutorials about building Sampler on the YouTube (TheAudioProgrammer channel), I decided to add a gain to the sampler for myself.  
Here are the parameter characteristics:  
“GAIN”, “Gain”, juce::NormalisableRange { -40.0f, 0.2f, 0.1f }, 0.1f, “dB”.

in case 1: when I just get the gain parameter from AudioProcessorValueTreeState and apply it straightly to the given buffer in PluginProcessor.cpp in processBlock function, I get nothing in effect, here’s code:

void SamplerAudioProcessor::processBlock (juce::AudioBuffer& buffer, juce::MidiBuffer& midiMessages)  
{  
…  
buffer.applyGain(juce::Decibels::decibelsToGain(getCurrentGain())); //without ramp, just to make it  
//simple  
mSampler.renderNextBlock(buffer, midiMessages, 0, buffer.getNumSamples());  
}

in case 2: when I try to apply gain by accessing the buffer getAudioData() of the uploaded sound file to the sampler, as a result I get terrible sound explosion (apparently the sounds gets madly loud) and afterwards I don’t hear the sound at all:

void SamplerAudioProcessor::updateGain()  
{  
auto gain = mAPVTS.getRawParameterValue(“GAIN”)-\>load();  
for (int i = 0; i \< mSampler.getNumSounds(); ++i)  
{  
if (auto sound = dynamic\_castjuce::SamplerSound\*(mSampler.getSound(i).get()))  
{  
auto samplerBuffer = sound-\>getAudioData();  
samplerBuffer-\>applyGain(juce::Decibels::decibelsToGain(gain));  
}  
}  
}  
plus the call of this function in processBlock…

I guess that in case 2 my mistake is that I edit the data irrevocably, thus I don’t fully understand why the code from case 1 doesn’t work… But I might be totally off, due to probable lack of understanding.

Mainly I don’t know what is is the volume set by default once I upload the file to the sampler itself…

I would be sooooo happy, if someone could help me with any tip!  
Thanks for reading and for your attention!  
Katya:)

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<div class="post-metadata">

**Author:** ![xenakios](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/xenakios/32/4047_2.png) [@xenakios](https://forum.juce.com/u/xenakios)\
**Post date:** [October 4, 2021, 6:06pm UTC](https://forum.juce.com/t/how-to-apply-gain-correctly-to-the-sampler/48108/2 "2021-10-04T18:06:19Z")

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In your case 1, you are doing the calls in the wrong order, you should first call the renderNextBlock of the synth/sampler, and then apply the gain.

In your case 2, you seem to be causing an accumulating gain change on the audio buffers used by the sampler. I would avoid even trying to do something like that.

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<div class="post-metadata">

**Author:** ![dotinspiredby](https://avatars.discourse-cdn.com/v4/letter/d/ebca7d/32.png) [@dotinspiredby](https://forum.juce.com/u/dotinspiredby)\
**Post date:** [October 4, 2021, 6:47pm UTC](https://forum.juce.com/t/how-to-apply-gain-correctly-to-the-sampler/48108/3 "2021-10-04T18:47:16Z")

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Oh thank you so much!! Now it works:)