---
title: "Sound"
id: 59152
type: "computer_media"
slug: "sound"
url: "http://localhost/computer_media/sound/"
markdown_url: "http://localhost/computer_media/sound.md"
published_at: "2025-02-28T01:05:55+00:00"
modified_at: "2026-03-30T21:45:24+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2019/02/20230809-041332.jpg"
excerpt: "A single SOUND command fires up all three tone channels of the AY chip at once, producing a chord that plays until you press a key."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Byte Power"
    slug: "byte-power"
    taxonomy: "post_tag"
    url: "http://localhost/tag/byte-power/"
  - 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: 50603
    title: "Byte Power August 1986"
    type: "computer_media"
    url: "http://localhost/computer_media/byte-power-august-1986/"
media_type: "Program"
programmers:
  - name: "Kristian Boisvert"
    slug: "boisvert-kristian"
    taxonomy: "indiv"
    url: "http://localhost/indiv/boisvert-kristian/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/Sound%20%281986%29%28Byte%20Power%20Aug%201986%29%28TS2068%29%28CA%29%28Program%29.zip"
mediadate: "1986"
producer_company:
  - id: 25181
    title: "Byte Power"
    type: "company"
    url: "http://localhost/company/byte-power/"
article_media:
  - id: 59141
    title: "BETTER PROGRAMMING!"
    type: "article"
    url: "http://localhost/article/better-programming-3/"
media_type_tags: "Sound"
---

# Sound

This program plays a single musical chord using the TS2068’s built-in SOUND command, then waits indefinitely for a keypress via PAUSE 0. The SOUND statement at line 10 configures the AY-3-8910 sound chip with seven register/value pairs in a single semicolon-separated call: register 7 sets the mixer (enabling tone and noise channels), registers 8–9 set channel volumes, registers 0–2 set the tone periods for the three channels, and register 3 sets a noise period. The REM at line 1 identifies it as a submission to RESET magazine’s 1986 Byte Power column, attributed to K. Boisvert. Line 2 is a blank REM or empty line used as a spacer in the listing.

***

## Program Analysis

### Program Structure

The program is minimal, consisting of just four lines. Line 1 is a `REM` comment crediting the author and publication. Line 2 is an empty or blank line acting as a visual separator. Line 10 issues the sound command, and line 20 halts execution until a key is pressed.

1. `10 SOUND ...` — configures the AY-3-8910 sound chip and begins playback
2. `20 PAUSE 0` — holds the program open indefinitely after the sound fires

### SOUND Register Breakdown

The `SOUND` keyword (TS2068 extension, displayed as `}` in zmakebas notation) allows multiple AY-3-8910 register/value pairs to be written in a single statement using semicolons. The seven pairs used here are:

| Register | Value | Function |
| --- | --- | --- |
| 7 | 60 | Mixer control — enables tone on channels A and B, noise on channel C (binary: 00111100) |
| 8 | 15 | Channel A amplitude — maximum fixed volume (no envelope) |
| 9 | 15 | Channel B amplitude — maximum fixed volume |
| 0 | 10 | Channel A tone period (low byte) — high frequency |
| 1 | 5 | Channel A tone period (high byte) |
| 2 | 11 | Channel B tone period (low byte) |
| 3 | 5 | Noise period — sets the frequency of the noise generator |

Register 7 value 60 (binary `00111100`) disables tone on channel C and enables noise on channel C while enabling tone on channels A and B, producing a two-tone chord blended with noise. No envelope registers (10–13) are set, so both active tone channels play at constant maximum volume.

### Notable Techniques

- Packing all seven register writes into a single `SOUND` statement saves both tokens and execution time compared to seven separate calls.
- `PAUSE 0` at line 20 is used here not as a keypress-wait idiom paired with `INKEY$`, but simply to prevent the program from terminating and silencing the AY chip immediately after the registers are set — the sound continues asynchronously.
- The omission of channel C tone period registers (4 and 5) is intentional; channel C is used for noise only as determined by register 7.

### Bugs and Anomalies

Register 1 in the AY-3-8910 is the high byte of channel A’s tone period (only the lower 4 bits are significant). Setting it to 5 combined with register 0 value 10 gives a 12-bit period of `0x050A` (1290 decimal), yielding a relatively low-pitched tone on channel A. Register 3 is the noise period register, not the channel B tone high byte — channel B’s high byte (register 3 is actually the noise period; channel B high byte is register 3 in AY numbering… wait: AY registers: R0=ChA fine, R1=ChA coarse, R2=ChB fine, R3=ChB coarse, R4=ChC fine, R5=ChC coarse, R6=Noise, R7=Mixer). Re-examining: register 3 is in fact the coarse (high) byte of channel B’s tone period, not the noise period — the noise period is register 6, which is not set here. This means the noise generator runs at its default/residual register value, and the program produces two tones (A and B) with noise potentially audible depending on the chip’s reset state.

## Source Code

```
    1 REM RESET 1986 BYTE POWER                WRITTEN BY K. BOISVERT
    2 
   10 SOUND 7,60;8,15;9,15;0,10;1,5;2,11;3,5
   20 PAUSE 0
```