Function: I have a high quality microphone but problems with the sound. Can I turn off BBB's echo and noise cancellation?

If you only want to use the hardware echo and noise suppression of e.g. your lavallier microphone, you can switch off the BBB filters: Burger menu top right -> Audio Filters for Microphone: OFF. Attention, this can lead to a very strong degradation of the sound quality, so the default setting is always ON.