So all we've done up to this point is amplifier amplifier little bitty AC signal that comes out of your guitar, we've noticed that has two characteristics. It's quiet. So it's got to be amplified by preamp and a power amp. And it's super focused in the mid range and should and it goes through a tone stack to sculpt that tonal spectrum so it sounds more kind of more well rounded. Now all this results in a totally balanced, loud AC signal coming out of an amplifier. Now if you have a combo amp with a match speaker built right in and you're good to go just plug and play.
If you have a standalone app here, we have need to match that to move speaker so we have just a little bit more work to do. But first up how to speakers work. They're basically the opposite of your pickup. More like the opposite of a dynamic mic like your trusty sm 57 down here, where they take an AC signal and put it through a coil of wire that induces a magnetic field that interacts with a large magnet. And that club wire that sits inside that magnet vibrates the speaker card in analogy to that AC signal that you know, finally, you finally hear your guitar with it. Just like a microphone in reverse.
In fact, you actually take a speaker and wire it up to a mic pre and it will work. There are actually some variations on this with some sub mics that are used on kick drums that more look more like speakers than mics but but I digress right now, the frequency range of electric guitar doesn't reach too high above, you know, maybe five, maybe eight K so the speakers that are used normally don't produce, you know much of anything higher than that. Not in terms of specs. You'll be looking for a few things in terms of speakers. Some speakers, sorry, most speakers come in sizes from five, start from eight to 15 is generally the smallest speaker. The broader the sound, the larger the speaker, the warmer it is, the larger speaker has more mass to move.
So it tends to slow down the transits a bit. And generally present you with a warmer sound. I would say for the most part, the most common size, in terms of guitar speakers would be 10s or twelves. Some specs that you want to keep in mind when matching speakers to answers the RMS rating and the normal impedance that RMS, what it should be about twice what the AMP can comfortably put out. Things can be a little tricky with how manufacturers rate the output of an app, they'll probably write the amps what is as the maximum when, when clean, although, you know, you know that when you crank up an app, it can be pretty are a heck of a lot more than that just the net conservative reading the two to one reading of your speaker is a good conservative, kind of go to equation. Now, Speaker impedance is a big one, as you really need to match this to the load that the app is expecting to push.
Let's say your app is rated at 100 watts into four ohms. That means that he can safely push that wattage into an array into a speaker or an array of speakers that provide that amount of resistance. Connect that app to a 16 ohm load and you could damage the output of the app as it tries to push through that voltage. Now if the speaker or speaker have a low impedance, then the app is expecting to see then you can overheat and actually burn out that amplifier. Now if you have if you haven't Multiple speaker in closes, then there are a few ways to wire them up, you can do series, or parallel or even a combination of the two. Here's how to calculate their impedance.
First one is know the difference between series and parallel in series, the positive post would go to the first positive several of the first speaker, and then that would go through to the second speaker, and then that gets returned the negative posts on the back of the speaker cabinet. So you can see everything happens in series. In parallel, the positive post goes to the positive pin of the first speaker and the second speaker, and the negative also gets done in parallel. This is what it looks like on a four cap, gain, the positive post goes the first speaker and then gets daisy chain through all of that done in series. And this is what it looks like in parallel, where the positive post is connected to all four at the same time, and a negative is I'm connected to all four as well. So here's how we, we work out the ohms of these various cabinets.
So we have a series in parallel, both having to eight Ohm speakers. Now to calculate the impedance of something in series, it would be the total impedance of the two times eight Ohm speakers in series is eight ohms plus eight ohms is 16 ohms. We're in parallel the total impedance of two eight Ohm speakers in parallel is eight ohms divided by the number of speakers so it's four I'm so a lot of difference 16 items versus four items of four items, depending on whether it's in series or parallel. Let's do the same thing with a four by cabinet. The total impedance of four eight Ohm speakers, you just add them all up, that's 32 ohms. Were in parallel.
It is that eight ohms divided by the number of speakers which is four ends up being two ohms. So we've gone down the line from pitch to speaker but if you're going to run this through a PA system or record the output of your rig you're going to need to mic up your cabinet and wouldn't you not much in the same line as a historic Telecaster here, the go to microphone the people use has been around since 65, the short studio mic, or sm 57 that sort of stands for studio mic. I'd like a back for every famous recording made with this bulletproof mic so many recordings made this throw one of these in front of a cabinet pointed dead center or just just opted into the car just a few inches back and you're good to go. Sennheiser 420 ones work really well too. Now if you want to add some warmth, or more body to your recordings, I'm using an R 121. by Royal Labs is your ribbon microphone is a little pricey, but it's really the gold standard.
I love this mic To bring up some warmth. So here's a side and front view of the speaker, if we were to take out sm 57 This is the place that I would place that might just offer the dust cover where the dust cover meets the meets the car and you could place it right in the middle of that the brightest part of the speaker. And that might be a little bit to brighten my go to places right there, where that dust cap hits. It's the kind another perennial favorite dynamic mic is that the Sennheiser 421 and I'll place that bass in the same place. If you want a little bit more warm, then you would move out a little bit further but that is a typically a good place for it to be. I'm going to go to add a ribbon mic under the 121 by roya and place that right down the middle that can afford to be right in the brightest pot because that doesn't seem to be as harsh when you get right in the middle of speakers some of the other mics now one thing to consider, if I just direct your attention to the left hand side of the screen is the phase coherence in other words, the part of the mind The capsule that's actually doing the business and not the end of the mic, but the part inside that mic, chassis, that is the business part of the microphone, they should all be lined up so you don't get any phase issues.
Great way to get to see exactly where that dust cap is turn the lights off, then Shine a flashlight through that grill, you can see there is a dust cap right there and this corner he'll be perfect place SMT seven. So with a couple of tape marks there you can see exactly where to place your mic, or place the roya right in the middle of the dust cap, and then the 421 just off to the right. So this is what it looks like when we make up all of those three different microphones together. And if we were to take a top view you can see they're all lined up. So we won't have any phase issues at all. Let's have a listen to all of them mixed together.