Errors of the DEEP tracker were exceptionally low, but the comparison with the remaining three trackers is not fair, since the test set was much smaller for DEEP (see section 4) and DEEP was trained to VTR-TIMIT and therefore has an advantage.
most of these earlier studies are in agreement that the quality of formant trackers' results can be improved by adjusting the parameters of the algorithm to the given task, i.e.