---
title: "Helicopter 3 Sound Example"
id: 63150
type: "computer_media"
slug: "helicopter-3-sound-example"
url: "http://localhost/computer_media/helicopter-3-sound-example/"
markdown_url: "http://localhost/computer_media/helicopter-3-sound-example.md"
published_at: "2026-01-30T17:36:44+00:00"
modified_at: "2026-04-03T07:57:58+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/01/helico-3.png"
excerpt: "A compact three-line AY chip sound demo programs the envelope, noise, and mixer registers to recreate a helicopter sound effect."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 2068"
    slug: "ts2068"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts2068/"
model:
  - name: "Timex/Sinclair 2068"
    slug: "ts-2068"
    taxonomy: "model"
    url: "http://localhost/model/ts-2068/"
indiv:
  - name: "Kristian Boisvert"
    slug: "boisvert-kristian"
    taxonomy: "indiv"
    url: "http://localhost/indiv/boisvert-kristian/"
genre:
  - name: "Sound"
    slug: "sound"
    taxonomy: "genre"
    url: "http://localhost/type/sound/"
media_contents:
  - id: 63045
    title: "Byte Power September 1986"
    type: "computer_media"
    url: "http://localhost/computer_media/byte-power-september-1986/"
media_type: "Program"
programmers:
  - name: "Kristian Boisvert"
    slug: "boisvert-kristian"
    taxonomy: "indiv"
    url: "http://localhost/indiv/boisvert-kristian/"
mediadate: "1986"
producer_company:
  - id: 25181
    title: "Byte Power"
    type: "company"
    url: "http://localhost/company/byte-power/"
images:
  - url: "http://localhost/wp-content/uploads/2026/01/helico-3.png"
article_media:
  - id: 63031
    title: "Better Programming"
    type: "article"
    url: "http://localhost/article/better-programming-4/"
media_type_tags: "Sound"
---

# Helicopter 3 Sound Example

This program plays a short musical or sound effect sequence using the SOUND command with multiple channel/register parameters, then waits for a keypress before silencing the sound engine. The SOUND keyword (represented as } in zmakebas source but rendered as SOUND) is a TS2068-specific command that directly controls the AY-3-8910 sound chip registers. The sequence sets registers 8, 7, 6, 12, 13, 0, and 1 in a single compound SOUND statement, configuring envelope and noise parameters typical of a helicopter-like effect, consistent with the “HELICO 3” title. The program is attributed to K. Boisvert and copyrighted 1986 by Byte Power.

***

## Program Structure

The program consists of just three executable lines plus a REM header:

1. `Line 0` — REM block containing the title “HELICO 3”, author credit (K. Boisvert), and copyright notice (©1986 Byte Power).
2. `Line 10` — A compound `SOUND` statement that writes directly to multiple AY-3-8910 registers in one call.
3. `Line 20` — `PAUSE 0`, which halts execution indefinitely until any key is pressed.
4. `Line 30` — `SOUND 13,0`, which silences the envelope by resetting register 13.

## AY-3-8910 Register Usage

The `SOUND` command on the TS2068 maps directly to AY-3-8910 sound chip registers. The compound statement on line 10 sets the following registers:

| Register | Value | Function |
| --- | --- | --- |
| 8 | 16 | Channel A amplitude — value 16 enables envelope-controlled amplitude |
| 7 | 55 | Mixer control — enables noise on channels, disables/enables tones |
| 6 | 20 | Noise period — sets the noise frequency |
| 12 | 3 | Envelope period (fine) — low byte of envelope frequency |
| 13 | 8 | Envelope shape — value 8 selects a sawtooth-rise shape, triggers envelope |
| 0 | 10 | Channel A tone period (fine) |
| 1 | 1 | Channel A tone period (coarse) |

Register 7 value 55 (binary `00110111`) disables tone on channels B and C, enables noise on channel A, and disables noise on B and C, producing a pure noise-envelope blend on channel A characteristic of rotary or mechanical sounds.

## Notable Techniques

- The compound `SOUND` syntax (`SOUND reg,val;reg,val;...`) sets multiple AY registers atomically in a single BASIC statement, minimising timing gaps between register writes.
- `PAUSE 0` at line 20 allows the AY chip to continue sounding asynchronously while the CPU waits, since the AY runs independently of the Z80 once its registers are programmed.
- `SOUND 13,0` at line 30 re-triggers the envelope register with shape 0 (single decay), effectively cutting off the sound after the keypress.

## Source Code

```
 0 REM                                                            HELICO 3                        WRITTEN BY K. BOISVERT          ©1986 BYTE POWER                           
   10 SOUND 8,16;7,55;6,20;12,3;13,8;0,10;1,1
   20 PAUSE 0
   30 SOUND 13,0
```