Spike Waveforms Hc-2

I'm trying to extract the voltage traces for each spike and am having trouble understanding the format of the .spk files. For example, ec012ec.187.clu.2 has 135288 entries for each of the spikes that are sorted. However, the corresponding .spk has dimension 4x32x270576 (double of 135288). Since the window of data around the spike comes from all 8 electrodes, I was assuming that 2 entries in the 3rd column correspond to the data from one spike? 

Thanks for your help and sorry if this is a very basic question.... my first time going through something like this.