The demonstrative behaves like the adjective.
When attributive, it follows the noun and both take the article.
הַקּוֹל הַזֶּה this voice.
If another adjective is used, the demonstrative follows it, and each adjective agrees with the noun in gender, number, and definiteness.
הַקּוֹל הַטּוֹב הַזֶּה this good voice.