Bypass capacitor in common emitter input impedance question
Does anyone have a clear source that will describe a good sizing
method for the bypass capacitor if I'm building something to amplify
20Hz-20kHz?

If you are building an amplifier with any half-hearted attempt at a decent level of quality, then you will never use an emitter capacitor like this; you will always put it in series with a resistor so that the gain is properly controlled and not maxed-out at medium to high audio frequencies. Without a resistor in series with the emitter capacitor you will get significant distortion and low input impedance.
So, it comes down to how much gain do you need from your circuit. At the moment, it is ill-defined because the capacitor acts like an AC short and \$r_E\$ is the only definer of gain. Unfortunately \$r_E\$ is highly affected by any collector/emitter current changes and so, it will distort the output signal because as the signal changes, so does \$r_E\$.
\$r_E\$ is also affected by temperature so, gain (albeit badly distorted) will vary as the circuit warms or cools. The low cut-off frequency is also poorly defined with adding a resistor.
Do your self a favour and put 100 ohms in series with the 10 uF capacitor and, to achieve decent low frequency gain control make the 10 uF into a 100 uF capacitor - this will produce a 3 dB point at around 16 Hz and much more compatible to a reasonable audio spectrum.
If you need more gain then use two stages of amplification.