Originally published at: http://mycroft.ai/blog/making-some-noise-an-update-on-mark-ii/
Let’s make some noise! Here is a little behind the scenes look at how we designed our loudspeaker enclosure for the Mark II. We talked about trying different shapes and enclosure designs in an earlier post, but we have since continued to refine the enclosure through iteration. We have been collaborating with Chris Ostrander, our Audio Engineering consultant, to come up with these different configurations.
We have tested multiple speaker drivers in combination with either ported enclosures or passive radiators. In the photo, you can see the designs with a port have a small triangle shaped hole located low in the enclosure. This is attached to a tube that runs along the inside of the enclosure. Ports are used to enhance the reproduction of low frequencies (BASS).
The alternative design uses what is called a passive radiator, these resemble normal speaker drivers but lack a voice coil and a magnet assembly, therefore they aren’t powered. The passive radiators resonate to increase the lower frequency response when the speaker system is working. You may have seen this design in a bluetooth speaker or computer speakers because it is very effective in small enclosures. If you see the passive radiators moving you know it’s working well. To drive all of our concepts we are using a development board from our chosen amplifer manufacturer Rohm. This board allows us to simulate the same system that will be integrated into the main PCB of Mark II.
You may have noticed that we used a few different colors for our prototype prints. These are PLA prints off of our Oni FDM 3D printer. The print quality is great for prototyping functional prototypes. However for appearance level prototype we use our Form 2 by Formlabs. We are doing our best to find creative ways to give the Mark II a boost in the audio department. For next year’s bbq or summer activities you’ll be able to listen to your favorite playlist on Mark II.