Hello, I've ordered a GK 410 SBX today but i'm confused what type of connecting cable to use between my head and the cab. I have a hartke 3500 head which I'll be using with the GK SBX cab. I read this on the GK site and got confused, please someone help HMS - Horn Management System (Horn Bi-Amp) Bass players have always liked the growl they get from slight overdrive. In GK amps this comes partly from the boost circuits and partly from the power amp. The problem is that growl sounds great through woofers and horrible through horns. In the typical full range system with a passive crossover, there is no way to get growl and keep the definition that the horn provides. With GKs Horn Management System, an internal active crossover splits the signal between the main amp which drives the woofer, and a separate 50 watt amp which drives the horn. Both signals are sent through a single four-conductor Speakon cable into a GK HMS compatible cabinet like the 410SBX. This way, we can send an overdriven signal to the woofer while keeping the horn crystal clear. This requires a GK HMS compatible cabinet like the 410SBX and a four-conductor Speakon cable, which is provided with the cabinet. Note: Standard Speakon cables are two-conductor and will not support the separate horn signal. Replacement cables may be ordered from GK. DO NOT USE THE FOUR-CONDUCTOR SPEAKON CABLE WITH A NON-GK HEAD OR CABINET. Set to Bi-amp when using the supplied four-conductor Speakon cable. Set to Full Range when using a two-conductor Speakon or ¼ speaker cable.