Echo Cancellation & Vibration Simulation for Smart Speakers

It is important for a smart home device, especially a smart speaker that plays music simultaneously, to recognize commands from hosts' voices. When talking to people on the Internet, the capability of echo cancellation allows smooth communications. 

We can build the simulation model to predict the situation and then give solutions to prevent it in the early design stage. Figure 1 shows a smart speaker that is designed with four array microphones.

Figure 1 shows a smart speaker design with four array microphones.

 

The simulation results indicate significant vibrations at 71Hz, which will impact the receiving quality of the microphones. Figure 2 shows the initial result of the simulation (the area of red color has the highest displacements (vibrations), and blue is the opposite.

Figure 2 shows the initial result of the simulation; the red color indicates high displacement, and the blue indicates low.

 

KS suggests two solutions to deal with the situation. The first one is to modify the plastic walls to stiffer materials directly. The example here is to use ABSPC to replace the original ABS for all devices’ plastic walls. Figure 3 shows the simulation results; the vibrations are efficiently suppressed.

In Figure 3, the simulation results show the vibrations are efficiently suppressed.

 

Another solution is to add ribs to strengthen the stiffness of the walls. Figure 4 shows where the ribs are added.

Figure 4 shows where the ribs are added

 

Simulating the model after adding the ribs, the result shown in Figure 5 indicates that the vibrations are suppressed and unable to reach the microphones.

Figure 5, shows the simulation results after adding the ribs

Using proper tools to predict design issues and solve them as early as possible during development can save time and costs and strengthen the power of competition.