While the Replica app primarily focuses on mirroring your iOS device's screen to Chromecast, it's worth noting that the audio output may still come from your iPhone or iPad's built-in speakers. If you want to enjoy a more immersive audio experience, consider connecting your iOS device to external speakers or a soundbar.
You can achieve this by using a Bluetooth connection or an audio cable (such as a 3.5mm auxiliary cable or a Lightning to HDMI adapter with audio output). By doing so, the sound will be routed through the connected speakers, enhancing the audio quality and making it more enjoyable, especially when watching videos or listening to music.