The coarse tune gives you a range from just under 1 Hz (~A-5) to 3100 Hz (~G7) on its own, so feeding in more via fixed resistors is kind of pointless. A bit more here (including chart!):
(ok, in the stripboard layout the pot is a variable resistor, not a voltage divider, so the low end will differ unless you ground the other pin; see here for a discussion about that.)