15 FEBRUARY 2017
written by Mike
INTRO TO SOUND RECORDING
Today we are going to learn a bit about sound recording.
I want to introduce some basic concepts of capturing audio and some easy tips on sound engineering. For some of you, this will be boring and easy. Remember, everything is built on fundamentals.
Did you do your microphone test yet?
Good. Understanding your recording session is crucial. There will be no smooth sailing without it.
What are you recording?
Is it a live music gig?
Is it some dialogue in a controlled studio environment?
Or maybe you are capturing some interviews outside. Understand it and learn it.
Next step is selecting a right gear. You don’t want to mix up condenser and dynamic microphones during your live recording. Or overdrive the input during the interview. I doubt you will get a second take.
Studio recordings can be easier as you will have more time to experiment. Having said so, I don’t think you will have time to ponder when there is a full orchestra waiting in a recording room. Preparation and planning are essential. Think about techniques of sound recording.
Are we using mid-side? Or A-B?
Extra ambient mic in the corner? How many microphones on your kick drum?
There are many different techniques, and all are up for experimentation. You can have a lot of fun trying out a new thing, but understanding why you want to do it is important too.
First, let’s have a look at few ground rules of live recording.
Start at the source
Get your instrument or amplifier to sound right before setting up the microphone. Tune your guitars, tune your drums. Have a strategy in mind. You don’t want to be working your mixing console to get everything sounding good. You will understand the importance of this point when you are on both sides of the game – recording and editing.
“We’ll fix it in the mix later” it’s easy to say when you are not doing the fixing. I can edit the bad recording, and the mixer will do his/her best. But you know the saying – you can’t polish poop and pretend it’s a diamond? You can always tell.
Be aware of proximity effect
Proximity effect occurs when you place your microphone too close to your sound source e.g. an acoustic guitar. The result will be a
Try to roll off low frequencies at source when it’s possible. Some mics have the option to do so. You can also do it on input track.
Use small number of microphones
Other mics will capture the sound of your source. You need to watch out for potential acoustic gain that decreases by 3dB when the number of microphones doubles. It means that you will have to turn down the volume of the source for every additional mic to avoid feedback.
Because of that, it’s quite tricky to set up a big band on stage. I know you want to mic up every instrument, but sometimes just a good stereo pair will do. I remember once I had to organise a band. It was a world music band with fifteen people, each one of them playing some crazy instrument.
And they all demanded an individual mic. After the initial setup, everything would feedback so much you couldn’t hear them playing. In the end, we muted most of the microphones, they never noticed.
Before I share with you a few general rules of recording, have a look at a couple of quick tips on setting up a studio sound recording session.
Use shock mounts where possible
They will reduce unwanted noise and thumps. Even the smallest vibrations can travel from the floor, through a stand, to a microphone. Try to avoid it. A little rumble is an easy fix in post production. A noise on the dialogue will be more problematic. Ozone Izotope makes great software plugins if you are in need of a quick fix. Izotope DeClicker is one of my favourite tools. Don’t overdo it though as it can change the frequency balance of your recording!
Keep power cables away from audio cables
Mixing them up will more than likely induce some unwanted noise to your recordings. One rule when building a studio is to keep power cables in the ceiling and audio cables on the floor. To be honest, I never worked in a place that had this kind of setup. For most of us, just try not to cross the cables on the floor.
When it comes to vocal recordings, there are few simple techniques to make it painless.
If you want to reduce “pops” and explosive breaths – get a pop shield! The pop shield should be your number one expense. They are cheap, but if you are struggling you can make one with old coat hanger and tights. Old school.
Moving the microphone either closer or further than three inches from the mouth will also help. Three inches from a microphone is the distance where “pops” are most present. With the dynamic mic such as Shure SM7B you can have it near your lips and still shout out loud. With a condenser, you may want to have a bit more distance.
Move the mic around. Above or below lips. Try moving it to the side. Listen if it makes any difference at all. One thing is to keep it consistent, I get a lot of dialogue recordings where the actor goes off mic, mid-sentence. Not helpful.
Another thing that you may come across is sibilance. Sibilance is the effect of nasty, harsh “esssess” that can be quite hard to get rid of later on. Modern techniques would include a de-esser plugin of some sorts or EQ. Don’t use it on your signal input; apply later on as a non-destructive effect. Again, don’t overdo it, it will “squash” the sound a lot. If the recording is bad, you may have to use gain to lower these nasty “essess.” Old school recording engineer once told me about another technique. It may seem quite weird to you. But try it!
Grab a pen or a pencil and tape it to the front of the microphone. Make sure it touches the grill. It will help you to get cleaner recordings.
Watch that input!
Often you will distort your recording by driving the input on your recorder way too high. Remember to keep a healthy balance between microphone placement, sound source volume and the input gain on your console. If you have it too low, you will have a lot of floor noise to clean. Consistency is the key in this situation. Imagine if you have someone shout one line and then whisper the next one. It will be difficult to make these two match each other.
I hope these few tips will be helpful to you. Before we finish up, let’s have a quick look at few general rules of recordings.
3 to 1 rule
3 to 1 rule is a classic rule of thumb that prevents feedback and headaches. The law states that when you are using multiple microphones, the distance between mics should be three times larger than the distance from each microphone to the sound source. For example, if you want to use two mics on your acoustic guitar, and you place them 1ft from it, the distance between the microphones should be 3ft.
It means that the sound captured by the other mic is reduced by at least 12dB and that reduces phasing known as comb filtering. Comb filtering effect or phasing describes a situation where frequencies cancel each other out. Few things can cause this but placing microphones too close to each other is a primary agent of that. The sound level drops around 6dB when the distance doubles from the microphone, and that’s why it is important to be smart in your set up. Other general rules include placing your unidirectional mic towards your sound source. It will minimise the bleed from other sources. Place your microphones away from unwanted sources such as loudspeaker or amplifiers. They will cause massive feedback. It becomes the problem when bands want more feed in their floor speakers.
And they always do.
Switch off your mobile.
You would be surprised how many times I had to edit a mobile interference from high-profile recordings. And it’s almost impossible to do so.
One last thing is to check the phasing. On your input console (or EQ plugin) you should have a Ø switch. It means polarity.
As I said before when you have a lot of mics near each other, for example on a drum kit, it can cause phasing. It is a good practice to invert polarity on each microphone in relationship to the rest of them. You will hear the difference straight away.
Ok, that’s it for today.
Have your cables neat and coiled and you are ready to go!
Remember that sound engineering is a deep topic and in future articles, I will go into more detail about recording instruments, microphones placement, and different techniques. For now, don’t forget that a sound is like a taste. Everyone likes different things.
Don’t be scared to experiment and try out new stuff.
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