Attributive Priority Classing System (APCS) The philosophy behind this "type" designation system is to organize the elements of a band's sonic makeup into a logical system, ordered in a chronological manner. At the foundation, in the '0XX' tier, you'll find the rudiments. A rock / metal band typically employs a four-piece setup and it's prevalence has solidified it as a good standard. *Organic; Something that adheres to the general characteristics of the instrument. A01; Percussion. The entirety of the 'organic' drums occupy this level. A02; Bass. The entirety of the 'organic' bass occupy this level. A03; Guitar. The entirety of the 'organic' guitars occupy this level. A04; Vocals. The entirety of the 'organic' vocals occupy this level. A05; Synth 01. The model displayed above is most adherent to a rock / metal soundscape. While a genre like Hip Hop may retain the first two classes, the order of significance is changed for the remainder. A01; Percussion. A02; Bass. A03; Synth 01. A13; Synth 02. A04; Vocals. If you haven't already observed, 'synth' is being used as an umberella term. It references any synthesized sound. Observe the distinction of 'Synth 02' and how it's assumed the 'A13' tag. Any duplicatory element, instead of tacking on a decimal point, shall be chained in a comprehensive manner such as this. Fleeting idea: Samplers which are simply enhancing in their deployment are assigned to some 04+ designation. If the sampled material is informing of crucial change queues (i.e. lead-in's, non-metronome aided), then it is boosted to the A00 class, the foremost class.