I am trying to use DTW to compare pairs of EEG signals over different events. After I computed DTW distance for each event; I noticed that the longer the event is, the larger the DTW distance becomes. I explained this by saying that the longer the event is >> the bigger the distance matrix would be >> the longer the warping path would be >> the bigger the DTW distance would be. Is that correct? and is there an alternative technique, other than DTW, that would not be affected by the length of time series?