Please submit the following answers in class on Tuesday, Feb. 14.

• For the crossover network with two speakers (LP and HP filters), answer questions 1a, 1b, and 1c. You do not have to submit any Bode plots, but provide brief written answers to the questions.
  What happens if you reverse the polarity on the output voltage of one of the filters (corresponding to swapping the wires to the speakers)? With B = 0, how does this change the gain of the total system at 1,000 rad/sec? Submit a Bode plot of the total response for this case with B = 0.
• For the crossover network with three speakers (LP, BP, and HP filters), answer questions 2a-2e. Specify your choice for B that provides the "flattest" gain, the corresponding filter cutoff frequencies, and explain how you obtained values for L and C for each filter to achieve the design. Then provide the Bode plots from filter_RLC.m showing that your L and C values achieve a desirable total frequency response. Explain how adding the mid-range speaker (and BP filter) improves the response compared with the design that uses only LP and HP filters. (Or, does the mid-range improve the total response? Explain whether you think adding the mid-range speaker improves or degrades the total response.)
• Extra Credit: See if you can obtain a flatter total response with other filter designs. For example:
  • Try reversing the polarity on the output of the BP filter. Does it produce a flatter total response?
  • Can you get an even flatter total response by reducing the passband gain of the BP filter to a value less than 1 (in addition to reversing the polarity on the BP output)? How can the circuit of the BP filter be modified to achieve this reduced gain?
  • In the Matlab scripts that were provided, the LP filter cutoff frequency is equal to the lower cutoff frequency of the BP filter, and the HP filter cutoff frequency is equal to the upper cutoff frequency of the BP filter. What if you remove these constraints? Try setting the LP and HP cutoff frequencies equal to 1,000 rad/sec, then adjust the BP filter bandwidth until you get the flattest total response. (You can get a perfectly flat response, without reversing any polarities at the filter outputs!)

Chapter 8: Problems 8.4 and 8.8 (a and b only).