Impedance – Speaker Cabinet WiringThere are a number of important technical issues relating to the matching of speakers to amplifiers, and to the wiring of multiple speaker systems (eg 2 x 12″, 4 x 12″, etc.). Impedance – Cabinet Wiring The impedance of a speaker is basically a measurement of how hard the amplifier will have to work to drive that speaker. The impedance is measured in Ohms and is marked on the back of most speakers. The impedance of the speaker(s) installed in an amplifier or cabinet will be quoted in the operating instructions (If you have them). It is essential, particularly in the case of tube (valve) amplifiers that the impedance or ‘load’ presented to the amplifier is correct; otherwise this can damage the amplifier. Many tube amplifiers are set up with multiple ‘taps’, eg. 8 and 16 Ohms. In such cases, it is important that the impedance of the speaker system matches the impedance value set on the amplifier. Most transistor amplifiers are designed to drive 8 Ohm loads. Although the impedance matching is not as critical as with tube amplifiers, the impedance of the speaker(s) should be at least equal to the minimum impedance of the amplifier. The majority of guitar speakers are available in a choice of 8 and 16 Ohm impedances. However, the way in which multiple speakers are wired (in a 4 x 12″ cabinet for instance) determines the overall impedance of the speaker system. Hence wiring is critical. There are basically two ways of wiring multiple speakers: Series and Parallel.Here are diagrams of the most typical wiring configurations. Power Rating If multiples of identical speakers are used in a combo or cabinet, the overall power rating is calculated by multiplying the individual speaker rating by the number of speakers in the cab, eg: 4 x 25 watts = 100 watts. However, when speakers are mixed, the lower rating is used to make the calculation, as both speakers draw the same power from the amp. For example, in the case of one 60 watt speaker and one 25 watt speaker in the same cab, the effective power rating is calculated as follows: 1 x 25 watts + 1 x 25 watts = 50 watts total. It is not critical to match the power handling of a speaker system precisely with the power output of the amplifier. But as a general rule, the power rating of the speaker(s) should be at least equal to that of the amplifier. Phase / Polarity All guitar speakers have just two connectors, one marked positive (+) and the other negative (-). If one speaker is wired the wrong way around in a multiple speaker configuration, it will not damage the amplifier. However, it will be ‘pushing’ when the other speakers are ‘pulling’, resulting in the cancellation of some frequencies in the overall sound. It is therefore important that the correct wire goes to the correct terminal. Credit: Extroverts Anonymous Want more? For further in-depth information on speaker impedance and wiring visit the Sound City page. 300Guitars Shop My shop is located at 1 Executive Dr Unit L Toms River, NJ 08755 Please feel free to email me if you have any questions or are in need of some tech work. Monday: 10am - 5pm Tuesday: 10am - 5pm Wednesday: Closed Thursday: 10am - 5pm Friday: 10am - 5pm Saturday 10am - 2pm. (I am in every other Saturday). I am also an Eminence, Mercury Magnetics, Mojo Musical Supply dealer. I do all the tech work myself so you deal directly with me. I am a one man shop and my hours can vary so please contact me to confirm that I will be open. Email me: email@example.com Call or text me: 848-218-0362 Shipping Info for all repair work: Please ship all repairs to: 1 Executive Dr Unit L Toms River, NJ 08755 I am currently offering all phases of guitar work which includes: Set-ups Fret dressing Re-fretting New hand cut custom bone nuts & saddles Electronics work And amplifier work which includes: Basic maintenance Bias adjustment Repairs and restorations Modifications And more.... Testimonials: David Nicholas - The 20watt amp is sounding fantastic! Delivered the goods at the gig and I'm finding cool tones all over the place with it. Love the cab w Emenince Tonkerlites too- perfect for my sounds! Makes the 12 string sound like a grand piano! Peter Lacis - I had an audition for something recently that was all about Led Zeppelin I -- my custom Pennalizer BLEW THE MINDS of the guys I was playing with. They couldn't believe the sounds coming out of that amp. That album was never in my mind when I came up with the idea....so that's yet another testament to the amazing work that you do. Scott Goldberg - I am very satisfied with the set-up, and the fast turn around. With the "lower" action it feels easier to play. I will definitely spread the word.