Are you referring to the Original Sound and the High Fidelity Music Mode? The original sound allows you to preserve the sound from your mic without using Zoom’s echo cancellation and audio-enhancing features. The high fidelity music mode not only disables the echo cancellation, but also eliminates the audio compression and raises the audio codec quality.
The high fidelity music mode was introduced in client 5.2.2, while the latest version of SDK is based on the client 5.2.1, so this feature is not yet available in SDK.