A Speakon connector is designed with a locking system that may be designed for soldered or screw-type connections. Line connectors mate with panel connectors and typically a cable will have identical connectors at both ends. If it is needed to join cables, a coupler can be used. Recently the manufacturer has introduced a new series called STX which includes also male line connectors and female panel connectors. Speakon connectors are designed to be unambiguous in their use in speaker cables. With 1/4" speaker jacks and XLR connections, it is possible for users to erroneously use low-current shielded microphone or instrument cables in a high-current speaker application. Speakon cables are intended solely for use in high current audio applications. Speakon connectors arrange their contacts in two concentric rings, with the inner contacts named +1, +2, etc. and the outer contacts connectors. named −1, −2, etc. The phase convention is that positivevoltage on the + contact causes air to be pushed away from the speaker. Speakon connectors are made in two, four and eight-pole configurations. The two-pole line connector will mate with the four-pole panel connector, connecting to +1 and −1; but the reverse combination will not work. The eight-pole connector is physically larger to accommodate the extra poles. The four-pole connector is the most common at least from the availability of ready-made leads, as it allows for things like bi-amping without two separate cables. Similarly, the eight-pole connector could be used for tri-amping, or quad-amping. Another use for the four-pole cable is to carry two channels of amplified signal from an amplifier to a pair of loudspeakers using a 'combiner' Y-lead connected to the two output channels, and a 'splitter' Y-lead to feed the loudspeakers. The 'combiner' and 'splitter' Y-leads are the same: two two-pole connectors on one end, connected to the ±1 and ±2 pins, respectively, of a four-pole line connector at the other end. Some amplifiers and mixer-amplifiers are configured to do this without the need for a 'combiner'. Also available are 2-pole "combo" receptacles that can also accept 4-pole cables and 1/4″ phone plugs.