Impedance Matching Speaker Cabinets | Too Afraid To Ask

welcome to cs guitars the science of loud matching impedance between your amplifier and speaker cabinet is a very important thing to do i think most people are well aware of that at this point however some of the rules and reasons behind what you can and can't do are still a bit ambiguous to the common user this question popped up recently in the cs guitars discord which incidentally is a great place to have your technical questions answered and asked specifically about the speaker outputs on the back of an orange terror amplifier and which and how many cabinets can be connected to it this is a great example of a very general question as many amplifiers only label the impedances without any further information and if you don't remember your high school physics lessons it can be very easy to make a mistake when choosing which cabinets to plug in so we're going to talk about impedance and how to correctly connect cabinets so that you can no longer be too afraid to ask before we get into actually connecting anything it might be a good idea to find out what this impedance thing is anyway you're probably familiar with the concept of electrical resistance which is the opposition a component or circuit has to direct current and is measured in ohms with a greek letter omega as its unit symbol however the kind of signals that are generated by our guitar pickups and are amplified by our amplifiers are in dc these are ac signals and that literally makes things more complex simple resistance fails to cover completely how an ac signal is opposed by a circuit resistance is still part of that opposition a static magnitude element which is measurable and easily denoted on the amplifier chassis but it's not the whole story there's also a very important phase element to the opposition of ac made up from capacitive and inductive elements within the circuit which are a little intangible i'll spare you the mathematics which describes this and simply state the phase element is frequency dependent that is it changes depending on what type of signal it's trying to oppose it's not a static value but one that interacts with the signal and is constantly in flux this electrical opposition to ac which combines both the resistive magnitude and the complex phase is called impedance and that's what we're trying to match between our amplifier and speaker cabinet because the impedance of the amplifier's output changes with the frequency of the signal being amplified it needs to be connected to a speaker load which can change and react in the same way this develops a delicate three-way dance between the signal power amplifier and speaker each invoking a reaction on the other the amplifier and speaker talk to each other pushing back and forth as their impedance changes with the frequency of the signal failure to match the impedance can be damaging at worst and inefficient at best mismatching the speaker cabinet can result in a loss of power efficiency and restrict that dynamic interplay between the elements the amplifier is expecting to see a specific impedance load to function at its best and not doing so doesn't really provide any advantages to the user people will try to talk about a safe mismatch where their equipment won't be damaged but any mismatch simply means that the equipment won't be giving its optimal performance therefore it always makes most sense to match the nominal impedance let's get back to this amplifier then as you can see there are three speaker connections on the back one 16 ohm and two eight ohm connections now how many of these could we use at once for example could we use all three of them at the one time the answer to that is no all of these connections tap off from the same output transformer within the amplifier 16 ohms is the impedance of the full transformer secondary coil tap that in the middle and we get access to eight ohms of it so for our connections here if we connect to the 16 ohm socket with a 16 ohm cabinet of course to match the impedances then we've used the entire transformer and this is the only cabinet that can be connected in this arrangement similarly if you have an 8 ohm cabinet and you connect it to either one of the atom connections on the amplifier then we will have used the entire 8 ohm tap on the transformer and that's the only cabinet that can be connected in this arrangement but there are two 8 ohm connections here why can't we connect two atom cabinets at the same time the reason that we can't is because these two eight ohm connections are wired in parallel to the atom tap on the transformer meaning that whatever is connected to one other or both of these connections must display to the amplifier as eight ohms this is where remembering your high school physics comes in this is day one electronics class stuff for resistances or the measurable magnitude of impedances wired in series they sum thusly however for resistances wired and parallel they sum like this it's the latter we need to consider as our atom connections are paralleled to the atom tap let's let the left side of the equation be what the amplifier is expecting to see and the right side of the equation being the impedances of the cabinets we're going to connect both sides need to match when we're connecting a single 8 ohm cabinet the solution is trivial of course this is the answer the atom tap is seeing an atom load no surprises there but i wonder if you can guess what would happen if we connected two atom cabinets to the parallel connections now we can see what the problem is two eight ohm loads in parallel equates to a total four ohm load the amplifier is seeing four ohms when it's expecting to see eight now you're probably ahead of me here and i've already figured this out but what happens if we connect two 16 ohm cabinets to those eight ohm connections it's a perfect match two 16 ohm cabinets in parallel equates down to a total load of 8 ohms matching precisely what the amplifier expects to see across those two atom connections this is all information that you will find in your amplifier's instruction manual which i'm willing to bet you have never read and some companies will expect you to know this especially if those companies have been around for long enough that when they started making amplifiers everybody did know this but other companies don't leave it to chance my angle savage makes it quite clear what loads and how many cabinets can be connected to each set of outputs and this even has a 4 ohm tap on the transformer so that you can connect to 8 ohm cabinets in this arrangement now inevitably the question is going to come but colin is this only for valve amps and the answer to that is yes kind of this is most vitally important for valve amplifiers as the output stage requires an output transformer and that's where all this complex impedance interaction stuff is happening solid state amplifiers lack the output valves and lack the output transformer and a little more accepting of what loads they're willing to see you'll quite often see them labeled along the lines of 8 ohms minimum which means what it says you can use anything 8 ohms or above but that doesn't mean you should dismiss this information entirely if you own a solid state amplifier power efficiency is still dependent on matching impedance even if there isn't a dynamic interplay with an output transformer that you could risk damaging so you'll still get best performance if you match the impedances hopefully that's cleared up what the hell this impedance thing is why it's so important and how you can safely and efficiently connect cabinets to your amplifier if you've got a question of your own that you would normally be too afraid to ask please do leave it in the comments section below or in the dedicated tata channel in the cs guitars discord perhaps it'll become the topic of a future video don't forget to click all those buttons you're supposed to to make this video viable to the ever-changing whims of the youtube algorithm that's all for now keep it loud and stay safe forest is always impedance

Channel: CSGuitars

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Keywords: CSGuitars, Colin, all the gain, guitcon, scotland, victory, pickups, science, will it shred, whats the difference, studio, recording, guitar, amplifier, pedal, scottish, metal, cs guitar, cs guitars, collin, impedance, ohms, safe mismatch, how many, speaker, speaker cabinet, cabinets, cabs, boxes

Id: pFhClJDeNYk

Length: 8min 22sec (502 seconds)

Published: Fri Jan 29 2021