Making Sound Decisions

MIT Lincoln Laboratory has a new exhibit installed in the Museum of Science

If you're walking around the second level of Boston’s Museum of Science and you notice a huge set of headphones, look closer and you’ll find Lincoln Laboratory’s name on it. The exhibit, "A Song in Your Pocket," is a new permanent installation at the museum to commemorate the Laboratory’s 60th anniversary in 2011.

Students and instructors of LLRISE 2012A museum visitor puts the exhibit through its first onsite trial, testing the quality and quantity of the music on a personally-selected song.

The broad goal of this exhibit is to help people understand that engineering decisions involve trade-offs. In this case, the trade-off is between the number of songs that can fit on a digital audio player and the quality of the music. While sitting at the display, a museum visitor can choose from four pre-recorded songs and use onscreen slider bars to adjust two audio processing techniques: number of bits per sample (bit depth) and the number of times per second the music is sampled (sample rate). Results of each engineering choice can then be heard, via audio speakers, and seen, via an oscilloscope-like screen.  Based on these choices, the exhibit also calculates and displays the number of songs that would fit on a nominal digital audio player. By using this exhibit, museum guests of all ages will be able to experience the effect of different audio processing techniques on digital music quality and see the corresponding trade-off with music file size.

Museum of Science Project Manager, Monica Parker-James, said "this type of exhibit is especially interesting to our visitors because it shows how science, technology, engineering and math relate to their everyday lives." Andrea Durham, Museum of Science Director of Exhibit Development and Conservation, was excited to help Lincoln Laboratory establish a presence at the museum. She said "Lincoln Laboratory was very hands-on compared to other organizations we work with. This project was the first of its kind where a sponsor worked side-by-side with us to develop an interactive exhibit component. It was a wonderful collaboration. We look forward to future projects with the Laboratory."

LLRISE 2012 building a radarLeft to right, Ron Parenti, Dale Joachim, Jerry Baum, Gabe Ayers, Pedro Torres-Carrasquillo, and Bill Keicher stand with the finished exhibit after it is newly installed.

The Laboratory team built the software engine that demonstrates the engineering principles that allow digitization of music—such as music frequency content, sampling rate, quantization, and dynamic range—at a level that a middle-school student can appreciate. While ensuring technical accuracy throughout the development process, the team also contributed to many non-technical aspects of the exhibit, such as laying out of the various exhibit elements, wording of instructions, and designing explanatory graphics.  

Bill Keicher (senior staff in the Advanced Lasercom Systems and Operations Group), project leader for this exhibit, indicated "a large number of people at Lincoln Laboratory contributed to this project. Some were only involved in the beginning or end of the project, but each person played an invaluable part in the process, and all twenty-four people were helping out on a strictly volunteer basis."

Keicher explained that developing this exhibit forced staff members to venture into new territories, such as targeting explanations to a middle-school level and demonstrating a sophisticated engineering concept (digital signal processing) in an interactive and highly compressed format.  Jerry Baum (Sensor Technology and System Applications Group), a volunteer throughout the entire two-year process, from early brainstorming to final design choices, added, "the Museum of Science staff told us that a successful exhibit holds a visitor's attention for just two to three minutes." Volunteers noted that they were accustomed to spending that amount of time on just one viewgraph—but not an entire concept.

Keicher said, "Developing this exhibit was similar to what we do here at the Lab when we monitor a contract: we work with them and deliver an end result that has been agreed upon, but that’s where the similarities ended." The scientists on the development team, accustomed to working within specifications from military sponsors, adjusted to a different set of specifications, namely those required for a museum exhibit, like making the exhibit not only educational, but survivable and rugged enough to withstand years of use, and incorporating universal design elements. An additional specification required universal accessibility incorporated as a part of the design. The layout of the physical space, the elements depicted on the display screens, and the placement of the interactive controls were all carefully considered so that the exhibit could be enjoyed by all museum visitors, including those with visual, hearing, or mobility impairments.

Andrew Siegel (Advanced Electro-optical Systems Group), another volunteer for the exhibit development, said that "even at the early stages, the prototype was very good. It provided information in a clear and intuitive manner." Siegel suggested using a thermometer-style scale to display the file size so that guests would better visualize the impact of their choices.

LLRISE 2012 students test their self-built radarsSome of the Laboratory volunteers and Museum of Science employees who made this exhibit a reality pose alongside the exhibit at the official opening.

A key software developer for the project, Jason Biddle, said, "From the start, we had the goal of developing software that would be easy for the museum staff to use and update over time. We developed a modular software framework that allows the Museum of Science to quickly change the user interface and change music selections without having to rewrite or recompile code."

Keicher added, "The Laboratory made a truly significant technical contribution in acting as a sponsor and providing volunteers to help develop this exhibit. The Lincoln volunteer team has learned what the Museum of Science wants in an exhibit as well as how to design, build, and test a technical, interactive museum exhibit. The way is open for future collaborations between Lincoln Laboratory and the Museum of Science to develop future exhibit components."

After almost two years in development, the exhibit officially opened on February 7, 2012, allowing you to practice making a sound decision any time you'd like.

Posted October 2012

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