A sub-audible sound source emitting a continuous wave of frequency \(f_0 = 20 \text{ Hz}\) moves to the right at a constant speed of \(v_s = 170 \text{ m/s}\) through still air, where the speed of sound is \(v = 340 \text{ m/s}\). Observer 1 is stationary and positioned directly ahead of the source along its line of motion. Observer 2 is stationary and positioned at an angle of \(60^\circ\) relative to the line of motion, as shown in the diagram. Which of the following correctly gives the frequency \(f_1\) measured by Observer 1 and compares the wave speed \(v_1\) measured by Observer 1 to the wave speed \(v_2\) measured by Observer 2?