From Jay:
When ZT adds a click to the end of a sound, the sound file needs to be changed to add a fraction of a second of silence to the end of the sound. Here is also some other information for ZT sounds. ZT only supports a certain type of sounds. Any sound for ZT has to be a ".wav" type of file. But ZT does not support all types of ".wav" files. There are certain properties associated with ".wav" files. In MS Windows 11, various properties associated with a ".wav" file can be seen by right-clicking on the ".wav" file, clicking Properties, and clicking the Details tab. The Properties window then shows a number of properties for the sound. The bit rate is not important, but some of other properties deal with efficiency for ZT sounds. The Channels for a sound should be "1 (mono)". ZT uses stereo for its own purpose. When an object is in a zoo and it has a sound, ZT plays the sound differently in the speakers, depending on where the object is on the screen. If the object is on the right side of the screen, ZT plays the sound louder on the right speaker and softer on the left speaker. If the object is on the left side of the screen, ZT plays the sound louder on the left speaker and softer on the right speaker. Since ZT converts mono sounds to stereo in this way, it is best for a sound to have only 1 channel. That will also make a significantly smaller sound file than to have a stereo sound file. For audio sample size, ZT supports both 8 bit and 16 bit. All sounds that come with ZT have both an 8 bit version and a 16 bit version. Theoretically, 16 bit is higher quality. But in practice, I do not notice much difference between the 8 bit version and 16 bit version of the same sound. So I feel it is best to always use 8 bit for a sound for ZT. That will make the sound file significantly smaller than using 16 bit. ZT supports any audio sample rate. All sounds that come with ZT use an audio sample rate of 22 kHz. So if I have a sound that uses a higher audio sample rate, I convert it to 22 kHz so that the sound file is smaller. But occasionally that can make a sound file not sound as good. So I listen to the sound before and after I change the audio sample rate to see if it is acceptable to change the audio sample rate. It is very rare that I use an audio sample rate higher than 22 kHz. If the audio sample rate of a sound file is less than 22 kHz, I leave it at whatever audio sample rate it is using. Although the Properties window does not indicate the loudness of a sound, sometimes that is important. It does not matter if a sound is too loud. When a ZT configuration file refers to a sound, we can use the attenuation setting in the configuration file to say how softly ZT should play the sound. The higher the attenuation setting, the softer ZT plays the sound. An attenuation setting of 0 will cause ZT to play the sound at the volume that is in the sound file. Although it does not matter if a sound is too loud in a sound file, it does matter if a sound is too soft. In that case, the sound file has to be changed to make the sound louder. A sound file might need to be changed for other reasons. Depending on the use of the sound in ZT, the length of the sound may need to be reduced. Sometimes a sound has unwanted clicks to remove. Sometimes a sound has unwanted background noise to reduce. The most important property of a sound is the audio format. ZT only supports the PCM audio format. ZT does not support any other Audio format, such as APCM or MPEG 1. The Properties in Windows XP shows the audio format of a sound. But the Properties in newer MS Windows do not. One program that will show if a ".wav" is using "PCM" is a free and open source program called Detect It Easy. It can be gotten from the following github link:
https://github.com/horsicq/DIE-engine/releases
I have used a number of programs over the years to convert or edit sounds for ZT. The program I currently use is the free and open source program called Audacity, although it can take a while to figure out how to do various things in it. One thing in particular is to always check what folder Audacity is using when exporting a sound, since it is rarely the same place as where the sound is loaded. That program can be downloaded from its web site:
http://audacityteam.org
When a sound is made for ZT, it should be tested in ZT. It is subjective how loud a sound should be in ZT. I put the object with the new sound next to a carousel in the middle of the screen, since ZT plays sounds louder that are in the middle of the screen, and plays them more softly the further something is from the middle of the screen. With the 2 objects next to each other, I listen to see if their sounds seem to have relatively the same volume. If they do not, then I change the sound's attenuation setting in the object's configuration file and test again.