---
title: "MIDI versus digital audio"
subject: "Multimedia System"
chapter: 2
key: "semester_8/multimedia_system:midi-vs-digital-audio"
source: https://www.bctengineer.com/q/semester_8/multimedia_system/midi-vs-digital-audio
site: BCT Engineering
---

# MIDI versus digital audio

Multimedia System · Chapter 2: Sound / Audio System

- Asked in: 2074 Bhadra, 5 marks; 2072 Asoj, 4 marks; 2073 Bhadra, 5 marks (asked 3 times)
- Video: [Audio vs MIDI: What's The Difference?](https://www.youtube.com/watch?v=gQeAhooG2cc) — EDMProd
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_8/multimedia_system/midi-vs-digital-audio
- Whole chapter: https://www.bctengineer.com/md/semester_8/multimedia_system/chapter-2

## Question

Differentiate between MIDI and digital audio (WAV).

## Short answer

MIDI stores musical instructions (notes, instruments) and is very small, but sound varies by playback device and cannot store vocals. Digital audio (WAV) stores sampled waveform, is large (about 10 MB per minute at CD quality), and sounds identical everywhere.

## Answer

**MIDI** (Musical Instrument Digital Interface) is a protocol that stores music as a list of instructions (which note, how long, which instrument, how loud) that a synthesiser plays back. **Digital audio** (for example WAV) stores the actual sound wave as numeric samples taken from an analogue signal.

| Point | MIDI | Digital audio (WAV) |
|---|---|---|
| What is stored | Commands/events such as note on, note off, velocity, instrument | Samples of the sound waveform (PCM) |
| File size | Very small (a few KB per minute) | Large (about 10 MB per minute at CD quality) |
| Sound produced by | Synthesiser or sound bank of the playback device | The recorded sound itself |
| Sound consistency | Varies with the playback device | Same on every device |
| Can it store speech or vocals | No | Yes, any sound |
| Editing | Easy: change notes, tempo, instruments without quality loss | Harder: editing the waveform, quality may fall |
| Recording | Needs a MIDI keyboard or sequencer | Needs a microphone and ADC |
| Typical use | Music composition, game background music, ringtones | Speech, effects, music CDs, voice recording |
| Quality control | Depends on synthesiser | Depends on sampling rate and bit depth |
| File extension | .mid | .wav |

#### Example

A 3-minute song as MIDI may be about 30 KB, while the same song as 44.1 kHz, 16-bit stereo WAV is about 31.8 MB (1,411,200 bits/s x 180 s / 8). But the MIDI song can sound different on a phone and on a good sound card, and cannot contain the singer's voice.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does a MIDI file store?
   A. Samples of the sound waveform
   B. Instructions such as which note, how long, which instrument and how loud
   C. The singer's recorded voice
   D. Compressed MP3 data
   Answer: B. MIDI stores events and commands that a synthesiser plays back, not the sound itself. (Key point: What MIDI stores)

2. Why is a MIDI file much smaller than a WAV file of the same song?
   A. MIDI uses a higher sampling rate
   B. MIDI removes the music's melody
   C. MIDI stores only a few commands, not waveform samples
   D. MIDI uses lossy compression of samples
   Answer: C. MIDI holds note commands (KB per minute) while WAV holds numeric samples (about 10 MB per minute at CD quality). (Key point: File size difference)

3. Which statement is correct about playback of MIDI and WAV?
   A. MIDI sounds the same on all devices; WAV varies
   B. Both vary with the device
   C. WAV sounds the same on every device; MIDI varies with the synthesiser
   D. Both are identical on all devices
   Answer: C. WAV is the recorded sound itself, whereas MIDI output depends on the playback device's synthesiser. (Key point: Sound consistency)

## Related in Multimedia System

- [Audio quality versus file size](https://www.bctengineer.com/question.md?key=semester_8%2Fmultimedia_system%3Aquality-vs-file-size) — Multimedia System, chapter 2

## Related in other subjects

- [Analog versus digital measurement system](https://www.bctengineer.com/question.md?key=semester_4%2Finstrumentation_i%3Aanalog-vs-digital-measurement) — Instrumentation I, chapter 1
- [Short note: Analog vs digital mux hierarchy](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aanalog-vs-digital-mux-hierarchy) — Data Communication, chapter 6
- [Digital vs analog spread spectrum](https://www.bctengineer.com/question.md?key=semester_5%2Fdata_communication%3Aspread-spectrum-digital-vs-analog) — Data Communication, chapter 6
- [Image space versus object space methods](https://www.bctengineer.com/question.md?key=semester_5%2Fcomputer_graphics%3Aimage-space-vs-object-space) — Computer Graphics, chapter 7, asked 9×