Step 1: Use the formula for resonance frequency.
The resonance frequency for an LCR circuit is given by:
\[
f_0 = \frac{1}{2 \pi \sqrt{LC}}
\]
Step 2: Modify the formula with the change in capacitance.
If the capacitance \( C \) is made 4 times larger, the new resonance frequency becomes:
\[
f_{\text{new}} = \frac{f_0}{2}
\]
Final Answer:
\[
\boxed{\frac{f_0}{2}}
\]