Lm3915 Calculator -

[ V_\textth,n = V_\textRLO \times 10^(n-1)/10 \times \fracV_\textRHIV_\textRLO \times 10^9/10 ]

Desired input at pin 5 for LED10 = 5.0 V (peak). Actual peak input = 1.414 V. Thus, we need gain , not attenuation. Instead, set RHI lower: Use a voltage divider from Vref to set RHI = 1.5 V (peak). Then: LM3915 Calculator

RLO = 0 V (ground). RHI = 5.0 V (to reference). But now the highest LED triggers at ( V_\textin \approx 5.0 ) V peak? That’s far above 1.414 V. So we must attenuate input. we need gain