  We analyse an eleven-orbit inspiral of a non-spinning black-hole binary with
mass ratio q=M1/M2=4. The numerically obtained gravitational waveforms are
compared with post-Newtonian (PN) predictions including several sub-dominant
multipoles up to multipolar indices (l=5,m=5). We find that (i) numerical and
post-Newtonian predictions of the phase of the (2,2) mode accumulate a phase
difference of about 0.35 rad at the PN cut off frequency 0.1 for the Taylor T1
approximant when numerical and PN waveforms are matched over a window in the
early inspiral phase; (ii) in contrast to previous studies of equal-mass and
specific spinning binaries, we find the Taylor T4 approximant to agree less
well with numerical results, provided the latter are extrapolated to infinite
extraction radius; (iii) extrapolation of gravitational waveforms to infinite
extraction radius is particularly important for subdominant multipoles with l
unequal m; (iv) 3PN terms in post-Newtonian multipole expansions significantly
improve the agreement with numerical predictions for sub-dominant multipoles.
