diff --git a/lib/ft4/ft4_downsample.f90 b/lib/ft4/ft4_downsample.f90
index 8fb7c5d1d..ff0595629 100644
--- a/lib/ft4/ft4_downsample.f90
+++ b/lib/ft4/ft4_downsample.f90
@@ -40,8 +40,8 @@ subroutine ft4_downsample(iwave,newdata,f0,c)
    c1=0.
    c1(0)=cx(i0)
    do i=1,NFFT2/2
-   if(i0+i.le.NMAX/2) c1(i)=cx(i0+i)
-   if(i0-i.ge.0) c1(NFFT2-i)=cx(i0-i)
+      if(i0+i.le.NMAX/2) c1(i)=cx(i0+i)
+      if(i0-i.ge.0) c1(NFFT2-i)=cx(i0-i)
    enddo
    c1=c1*window/NFFT2
    call four2a(c1,NFFT2,1,1,1)            !c2c FFT back to time domain