This means C2 should be 8.4µF, but I didn’t have one so I used a 4.7µF and 3.3µF in series for a total of 8µF.
You want those in parallel for them to add. The series combination (which I see in the breadboard pic, not just the text) is only 2µF, making your high-pass frequency a little over 10kHz.
You want those in parallel for them to add. The series combination (which I see in the breadboard pic, not just the text) is only 2µF, making your high-pass frequency a little over 10kHz.
Whoops! You’re right! Will do.