This post is part of a 6 part course on Sermon Podcasting. If you would like to see the whole course go to the Course Intro Page.
So, let’s talk about improving the sound of your recording. Let’s start with gain staging which I call the almost cure-all for audio issues. Let’s look at some examples of bad and good gain staging.
Gain Staging Example 1
A generic example of bad and good gain staging is shown below. In the bad gain staging example, you have a source and you’re dealing with it at a low level. Moving to the right shows your source along with the noise in a system (all systems have noise in them of one type or another and as these examples progress you’ll see how that is true). Then at the next gain stage when you boost the audio to the usable level you boost the noise along with it and you get something like the result on the right. As you can see the noise got a lot louder.
A good gain staging example is, you have a source and you’re dealing with it at a healthy level (a good volume), as shown above. Moving to the right shows there’s still the same amount of noise in the system. On the far right shows that when you boost your audio to the usable level the noise floor went up but is still low enough to be usable.
Gain Staging Example 2
Okay, so let’s go to another example. Bad gain staging an example would be, you have a mixer output (everything in your mixer is being summed together and it’s coming out the output). Well inside that mixer there’s electrical noise along with some other noise and it’s about at the level in “initial sound” below. The audio that you’re dealing with all mixed together is at the level in ‘Mixer” below. When you hit the amplifier and you amplify all that to a level for your speakers to output, you’re amplifying all that noise floor also and you get a noisy signal. As you can see in the “Amp” box below.
A good gain staging an example of that would be you’re mixing your audio together at a higher level. You have that same noise floor inside the mixer. Then when you boost it at your amplifier stage you end up with a signal looks like in the example above with a little bit of noise and a lot of good signal.
Is this making sense now?
Gain Staging Example 3
Okay, so let’s look at one out in the physical world. Maybe it’ll click even a little bit better. Let’s say you have a microphone and the person’s not using good microphone technique and holding the mic down by their waist. To get them to a decent level you are going to be forced to boost the signal. This will also boost the air conditioner noise, people talking, coughing, etc.
If good mic technique is used and it is close to the speaker/singer’s mouth. The audio is coming in at a good level. We have the same room noise that we had in the previous example but, when we boost all this to a usable level the room noise hardly goes up so we have a good clean clear signal.
So, I’m going to stop real quick and talk about good microphone technique and what good microphone technique is. Good microphone technique is having the microphone close to your mouth having it pointing at your mouth if it is a directional microphone. Closer to the source the better as long as you’re not eating the microphone. Pretend like the microphone is a flashlight. You have to point it at the source you want if it’s a directional microphone and most handheld mics are. A lot of lapel microphones are omnidirectional which means they pick up all around. If you can get away from using one of those and train your users to use directional mics properly you will be better off.
Bad microphone technique is bad gain staging because you’re getting a small signal and a lot of room noise. You have to boost the signal and boost the room noise along with it to get a usable signal.
Gain Staging Example 4
Let’s do one more example of bad gain staging with a microphone. A person talking or singing so loud into the microphone and you get a mixer input that’s peaking. Then on the channel fader you try to turn it down to get it to a usable level but, that distortion never comes out once it hits the top and starts distorting. That signal will be distorted no matter what you do at a later stage.
Good gain staging would be to turn the input down on the mixer to accommodate the loud signal. Then at the channel fader you don’t have to boost it or attenuate it, and you have a good usable source.
Finding and Fixing Hum, Buzz, and Hiss
Okay, in this section, we’re going to talk about hum, buzz, hiss, and distortion. The key to fixing noise in your recording is finding the offender and dealing with it. Hopefully, at this point, you’ve corrected any gain, staging issues, and all the offenders have gotten a lot less offensive.
What you want to do is get to where you can hear the sound, the offending sound, the hum, the buzz of the hiss. Whatever you have, get to where you can hear it. One good way to do this is to plug some headphones into your computer that your recording from.
If you’re using the Closer Sharing sermon recorder the “monitor” button allows you to listen to what you’re recording. One thing to know about this is if you’re sending the computer audio to your soundboard to a channel that is being sent back into the recorder. If you hit this button you’re going to create a nasty feedback loop. So the channel that you’re sending your computer audio to on the mixing board, you need to mute that before you engage monitoring. Closer Sharing isn’t the only one that has this feature. I’m sure you can do this in Garage Band, Audacity, and other recorders.
So, once you can hear that offending sound while you’re listening, start going through your board and muting channels one by one. When you hear that offending sound go away or get better. That’s the channel you need to work on. You might get through all the channels and not find anything that gets better or finding the buzz it all. Then you want to move on to things connected to your system, whether it be your computer or your mixer. One likely offender is a projector. That’s a device that hook two your system in any way. It could also be a CD player, a DVD player, a tape deck, or any device that is hooked to your system can be a source of buzz. What you want to do is one by one, unplug these things from your system or from your computer. If the buzz doesn’t get better, go ahead and plug them back in and move on to the next item. You’ll eventually, using this process of elimination, figure out what the offending item is. Once you found the offending device, the first thing I would suggest you do is to unplug the device from the wall and see if the buzz goes away. If it does, it’s most likely you have a ground loop, and this is caused by a device that is hooked to the same system that takes a different path to ground. So, what you can do to fix it is get a device called a Hum-X, and this will plug into your wall and then you plug your device into it. It will safely lift the ground without the buzz. If you have found the offending device and it turns out not to be a ground issue, and I would suggest starting to check cables, checking connections, swapping cable’s out and see if you can get rid of the buzz. If after all this, you still have a buzzing you’re recording, I would suggest going to an audio interface like I suggested in the last lesson.
This particular one here is, a Focusrite Scarlett Solo, and I like it because it will accept a line level balanced input. There are a lot of similar units on the market.
If you have any questions about this particular lesson or suggestions on how I can improve it don’t hesitate to comment below. I’ll do my best to help you out. Thanks for checking this out and we’ll see you in the next lesson.