Week-04

Overview

This week introduces sample-based instrument creation using Decent Sampler, a free and powerful sampler plugin. We’ll learn the fundamentals of sample mapping, XML structure, and building a traditional instrument from recorded samples. This skill enables you to create custom instruments for your compositions and distribute them freely.

Learning Objectives

By the end of this session, students will be able to:

• Explain the basic architecture of sample-based instruments
• Write and edit Decent Sampler XML preset files
• Map samples across the keyboard with appropriate zones
• Create a basic playable instrument from recorded samples

Topics Covered

Sample Instrument Fundamentals

What is a Sampler?

• Sample playback vs. synthesis
• Memory vs. CPU considerations
• When to use samples vs. synthesis
• Popular sampler formats (Kontakt, SFZ, Decent Sampler)

Sample Organization

• Naming conventions for samples
• Velocity layers
• Round-robin variations
• Key ranges and zones

Introduction to Decent Sampler

Why Decent Sampler?

• Free and cross-platform
• Simple XML-based format
• Easy distribution
• Sufficient for many use cases

Interface Overview

• UI elements and controls
• Loading instruments
• Basic playback

XML Structure Basics

Preset File Structure

<?xml version="1.0" encoding="UTF-8"?>
<DecentSampler>
  <ui>
    <!-- UI elements go here -->
  </ui>
  <groups>
    <group>
      <sample path="samples/C3.wav" rootNote="60" loNote="58" hiNote="62"/>
      <!-- More samples -->
    </group>
  </groups>
</DecentSampler>

Key Elements

• <DecentSampler> - Root element
• <ui> - Interface controls
• <groups> - Sample organization
• <sample> - Individual sample definitions

Sample Mapping

Basic Mapping Parameters

• path - File location
• rootNote - The original pitch of the sample
• loNote / hiNote - Key range
• loVel / hiVel - Velocity range
• volume - Sample volume adjustment

Mapping Strategies

• Chromatic sampling (every note)
• Interval sampling (every 3rd, 4th, etc.)
• Range-based mapping
• Velocity layer organization

Recording Samples

Preparation

• Consistent recording environment
• Proper gain staging
• Multiple velocity layers
• Clean edits (start/end points)

Processing Considerations

• Normalization (per sample vs. group)
• Fade handling
• Loop points (for sustained sounds)
• Sample rate and bit depth

Resources

• Decent Sampler Plugin
• Decent Sampler Developer Documentation
• Decent Sampler CCC_Tongue-Drum
• Kontakt Building the CCC-C Piano

In-Class Activity

Building Your First Sample Instrument

Part 1: Sample Preparation (20 min)

Using provided samples (or record your own):

1. Organize samples in a logical folder structure
2. Name samples consistently: InstrumentName_Note_Velocity.wav
   • Example: Piano_C3_mf.wav, Piano_C3_f.wav
3. Verify all samples are:
   • Same sample rate (48kHz preferred)
   • Same bit depth (24-bit)
   • Cleanly trimmed

Part 2: Basic XML Setup (25 min)

Create your first Decent Sampler preset:

1. Create a new folder for your instrument
2. Create preset.dspreset file
3. Start with this template:

<?xml version="1.0" encoding="UTF-8"?>
<DecentSampler>
  <ui width="812" height="375">
    <tab name="main">
      <labeled-knob x="20" y="20" width="90" label="Volume"
        type="float" minValue="0" maxValue="1" value="0.8">
        <binding type="amp" level="instrument" parameter="AMP_VOLUME"/>
      </labeled-knob>
    </tab>
  </ui>
  <groups>
    <group>
      <!-- Add your samples here -->
    </group>
  </groups>
</DecentSampler>

4. Add your first sample mapping

Part 3: Complete Mapping (30 min)

Map all samples across the keyboard:

1. Add each sample with appropriate parameters:

<sample path="samples/Piano_C3_mf.wav"
        rootNote="60"
        loNote="58"
        hiNote="62"
        loVel="1"
        hiVel="100"/>

2. Adjust loNote and hiNote to create zones
3. Test in Decent Sampler:
   • Load your preset
   • Play across the keyboard
   • Listen for pitch shifting artifacts
   • Adjust zone boundaries as needed

Part 4: Basic Refinement (15 min)

1. Adjust individual sample volumes if needed (volume attribute)
2. Add basic ADSR envelope:

<group attack="0.01" decay="0.5" sustain="0.8" release="0.3">

3. Test and adjust envelope to taste
4. Save your work

Deliverable: Working Decent Sampler preset with at least 5 mapped samples.

Preview: Next week we’ll add velocity layers, round-robin, and effects!