Okay, welcome everybody. We're here today at a London School of sound. And we're going to talk about recording singer songwriter material. So we have an asteroid here from Sweden I believe, who is a who's going to perform for us today, we're going to talk about recording guitars. We're going to talk about a little bit later about recording vocals. And then, of course, we're going to want to end up is when we record a live performance of Astrid playing guitar and singing at the same time.

And of course, we talk about all the issues concerned with that. But we're starting off with with the recording guitar. And I'm going to show you how to add the, of course the choice of microphone is very important. And I'm also going to show you that so that the sound radiating the sound waves radiating of the of the guitar. They, they are by no means uniform. So So one of the first things that we're going to do, we're going to find the right spot where where the microphone sounds at its best.

Alright, so the first thing I'd like to talk about this is the choice of microphone. Now, of course, there's lots and lots of different microphones that we can group them in different ways. And the first thing I want to look at is is dynamic microphones versus capacitor microphones, sometimes also called condenser microphones. Now so so we need to find the right microphone for the job. And the thing is that the big difference between a dynamic microphone and a capacitor microphone is the fact that that's a dynamic microphone that controls struction of the diaphragm is quite heavy. This is because there's a voice coil which is essentially a coil of copper wire that is attached to the diaphragm itself.

And this copper wire is made to vibrate by the sound wave inside a magnetic field. This is how inside a dynamic microphone, the signal is induced. Yeah. Now, there is an issue with that because because this this construction can be quite heavy, relatively heavy. And because this construction is heavy, dynamic microphone response less well to super high frequency super high frequencies that are typically a lot have a lot lower amplitude. And at this, these higher frequencies also Yeah, that contain a lot of important information regarding the Tambra at the signature sound of the guitar.

So we want to capture that. So clearly, a dynamic microphone might not be the best choice. Yeah. Which is why we're going to use a capacitor microphone capacitor. microphones, the diaphragm, because it is not attached to anything. It is essentially one little vibrating plate which is part of a capacitor, it can be made to be much more lightweight.

And because it's much more lightweight, it's going to be much, much more able to accurately respond to the super high frequencies that are also very weak yet contain so much information regarding the Tambora capacitor microphones is what we're going to use for for most acoustic sounds, and certainly, certainly an acoustic guitar. Okay, so the next thing we then need to decide upon now if we understand that a capacitor microphone is probably going to give us the best results, we need to decide on other things like the bowler pattern, the pickup pattern of the microphone, whether it's a cardioid, hyper cardioid, a supercar do the sub cardioid, or indeed an omni. And the other thing is also the size of the diaphragm. So we're so aware. So we need to discuss this further at first. And the thing here is that that's what controls, the pickup pattern of a microphone is the the weather it the sound wave has access to the rear of the diaphragm or not.

Yeah, if you have a microphone whereby the sound wave only has access to one side of the diaphragm, like you can perhaps see with this one you can see with this microphone yet, the sound can get into the front. But you can see there's no openings down the sides here, there's it's not possible for the sound to to get at all to to the rear of the diaphragm, yeah, that means that the rear of the diaphragm is closed off. And indeed, there's a little chamber so a little pressure chamber. And inside that chamber, we sort of captured the nominal air pressure, the pressure that's in this room right now. And we know that sound is changes in pressure changes in Pascal's over time. So that's that if Asterix produces a sound, then these changes in pressure right are going to be compared on one side of the diaphragm with the nominal air pressure which is captured On the other side of the diaphragm, so in a sense, a microphone like that is a super truthful instrument.

Because it's it's, it does exactly what it's supposed to do sound is changes in pressure over time. And the microphone is registering exactly that. It's a pressure meter. Essentially, you can think of it as a barometer. But just like a barometer, yeah. Yeah.

Because the barometer is essentially, the microphone is essentially reading the pressure on the outside of the diaphragm and comparing it to the inside of the diaphragm. And just like with the barometer, it doesn't matter how you have it positioned here. So because it's the normal air pressure is still caught on the inside. It can go anywhere. Yeah, this because of this, that the microphone is essentially, by definition, an omnidirectional microphone. Yeah.

Now, microphones can be made to be directional. If the sound wave has access to the rear of the diaphragm. Yeah, there's a few different examples here. I have a normal microphone. There's no microphone, you can see the sound has access to the front of the diaphragm and through these little slits here, these little, these little thought of fires at the sound is also able to to get to the rear of the diaphragm. It is this principle, what makes a microphone directional?

Yeah. Now, of course, that is a huge big thing, because in many, many cases, directional microphones are required here. live sound is a good example. Sometimes you're in a room whereby the acoustics are not perfect. You can cancel out kind of more or less the acoustics by pointing the microphone more at the sound source. So so the polar pattern ensures that we pick up less of the perhaps not so perfect sounding room, right.

But all this directionality comes at a price. Yeah, the price you pay for directionality is the fact that these microphones all these microphones by the sound has more or less access to the rare and by the way, how easy it is To get to the rear of the diaphragm, or how difficult it is, it is that what controls the difference between the different directional microphones. If you have a microphone, whereby the sound has free access to front and back, that's a proper figure of eight as a clearly directional microphone. As soon as you start to close the rear of a little bit, it becomes more like a hypercar, yours. If you close it off a little bit more still, it becomes a cardioid. If you close it off more still, it becomes a sub cardioid.

And then of course, if you close it off completely, it becomes an omni. Yeah. So now the issue like I said, the issue is that so that all this directionality comes at a price and this price is called the proximity effect. It turns out because the scent the sound has access to front and rear, right? It turns out that only directional microphones as you get closer, yeah. You relatively register more or lower frequencies.

Yeah. Now this can be useful in certain circumstances. freezes on kick drums and rack dorms and floor toms you register a bit more low end, very few people are complaining about that because it gives you more punch. But on a beautiful acoustic instrument like this, yeah, if you have a proximity effect working there, then although it not always has to be bad, but essentially it does change the Tambora and if we're just for a moment assume that ostrich guitar has already a very beautiful sounding guitar, we don't want to mess around with it. And that is exactly what the proximity effects would do. So this is probably why it seems we're in a in a in a really good acoustic space here.

And we're by there's no need to uh, to discriminate against any sort of room reflections because it sounds pretty good in here already to me. Yeah, I think in that case, we're probably the seat up to today will end up using omnidirectional microphones but, but, but I do want to demonstrate the proximity effect. And I also want to make a link with the size of the diaphragm. So So clearly, you have you have different capacitor microphones. have different sized diaphragm small diaphragm large diaphragm. So, now there's multiple differences between the two bitola.

I'll explain what I think are two major major differences between large diaphragm and small diaphragm. A large diaphragm of course, is is is is is bigger and because it's bigger, it's also a little bit heavier, it has a little bit more mass. And because it's more heavy, it's it responds slightly less well to super high frequencies. Yeah, and and it's also a little bit slower, it's a little bit sluggish in our response. And what that does is that most most large large diaphragm microphones as a result, they sound a little bit softer or rounder compared to a small diaphragm microphone. So that's one key difference.

But here is another key difference. And this is the same proximity effect again, because I told you earlier that there's microphones are made to be directional by giving the sound wave excess to the rear of the diaphragm. Now, it is to do B With with the fact that there's a certain time differences is the time difference. That and the phase difference at the first of the same thing. It is this what causes the proximity effects. Now clearly on a large diaphragm microphone, the distance the difference between the front and the rear is larger than a small diaphragm microphone, which is why typically you can expect to have more proximity effect with a large diaphragm microphone and a little bit less with a small diaphragm microphone.

So perhaps we can we can demonstrate it in a little while.