3. Issue Claim 1 recites, a “first position of said switch coupling a full frequency range audio signal” to the speakers. AI’s product includes a switch where a first position of said switch couples a mid/low pass filtered audio signal to a speaker subset. Claim construction of the term “full frequency” is to be litigated. AI should win because “full frequency” should be construed as flat frequency response for full range operation. PO should win because “full frequency” should be construed as frequencies in a signal before applying the high pass filter.

4. Patentee’s device This diagram shows the patented device and the signal inputs to the switch

5. Allegedly infringing product This diagram shows the accused infringer’s device and the signal inputs to the switch

6. Alleged infringer’s improvement The alleged infringer’s product introduces tweeters designed to produce high frequencies, typically from around 2,000 hertz to 20,000 hertz. The addition of tweeters allows for more faithful representation of high range frequencies.

7. Bode plot for a first-order highpass filter This shows the effect of a highpass filter on an audio signal

8. Bode plot for a first-order lowpass filter This shows the effect of a lowpass filter on an audio signal