The desktop Mumble client has a noise suppression effect that is applied to the sound you send. If you're translating remotely over Mumble, or just meeting with the team, you may want to enable this.
The settings are at Configure > Settings > Audio Input > Audio Processing. Depending on your microphone, audio setup and ambient noise, different settings may work better.
You can also try the auto-configuration assistant, in Configure > Audio Wizard. This will take you to a few steps to configure your optimal audio settings.