The 1051 Dual Four-Channel Mixer module is a "split" eight-channel mixer for audio or CV signals with a number of unique features. Each of its channels includes a separate out, so it can be used an attenuator or mixer, and in addition to the master 1-8 out, it also includes outputs for channels 1-4 and 5-8 for added flexibility. This module does not actually exist for the original ARP 2500. The original instrument relied on a combination of mixing through it matrix switches and multiple filter inputs, but we created the 1051 module, because we often found ourselves wishing for a dedicated mix module.