Archives for December 2011

What is Ducking In Audio Recording?

December 30, 2011 by Ken 1 Comment

Ducking in audio recording is a technique for allowing a narrator’s voice to be heard clearly and consistently when there is other audio happening at the same time, such as background music. If nothing else, this is a rare example where the term actually describes, in plain English, what it accomplishes. Plus it’s fun to say.

So what does ducking mean anyway?

The way it works is pretty simple. Let’s say you have some background music for either a voice-over project or a video project that will have a narrator, and that this music will play at the same time as the narrator speaks. When the narrator is not speaking, the music should be clear and present – the main thing to listen to. But when the voice comes in, it should take over as the main audio, the background music becoming, well, background audio.
Sure, you can simply turn the music track volume down, but then when the voice goes away the music won’t be loud enough. You’ll have to turn it up again. This cycle will repeat as many times as the narrator stops speaking, which is a lot of work. Ick. I’m all in favor of reducing work. If only there were a way for the audio (or video) program to sense when the narrator is talking and when he/she is not, followed by the program automatically turning the music up when there is no vocal, and down again when there is. Guess what? There is! That’s what ducking is. The audio you want to be the primary thing, like the narrator’s voice, is made prominent because some other audio is “ducking” underneath it at key moments.

So how can I make my program do ducking?

I’ll explain how to do it in Reaper, though the process is going to be the same in any multi-track audio program or video editor. There usually isn’t a tool called “ducking” in these programs since the technique uses a combination of tools working together. The main tool is compression (see our article Should You Use Compression In Audio Recording?), which is a tool that automatically turns audio down by a certain amount, but only when the volume gets loud enough to trigger it.
Usually you insert a compressor effect onto a track to control the audio on that track. So if you have a voice on track 1, and you put a compressor on track 1, the voice will trigger the compressor when its volume goes over a certain level or threshold that you set. Well the big difference with ducking is that the voice is still going to trigger the volume reduction actions of a compressor, but that compressor will be turning down the volume NOT of the voice, but of something else; in this case, a background music track. That means we have to put the compressor on the music track (say, track 2), but make it listen to track 1 for its instructions on when (and how much) to turn down the music. Pretty nifty huh? No? I lost you? Yeah, this kind of thing is much easier to explain with pictures. Take a look at the picture on the right. So it’s just a matter of having at least two tracks, putting a compressor on the one you want to get ducked, and feeding the output of the main audio (the voice) into that compressor.

Ducking in Reaper

In Reaper the first thing to do is put the compressor on the track to be ducked, in this case, track 2 with the music on. Simply click the FX button and choose the built-in compressor called ReaComp. Then close the FX window. You’ll be able to tell that the compressor is loaded up because the FX button will be green.
Next find the I/O (stands for “in/out”) button on the vocal track. See picture on the left. You’re going to click and drag that down to the I/O button on track 2. An I/O window will open with lots of scary-looking stuff on it. Leave everything the way it is except at the bottom where it says “1/2 => 1/2”. Just click the drop-down arrow next to the second “1/2” and change it to “3/4”. See the picture on the right. You have just set it up so that track 1 will send a signal to track 2. The next thing you need to do is click on the FX button in track 2 to open your compressor control. Now it’s time to tell the compressor NOT to listen to the music track for cues as to when to engage, but instead, listen to the voice on track 1. So in the compressor control window (see picture below and to the left). Find where it says “Detector Input” and use the drop-down arrow to change this from the default “Main Input L+R” to “Auxiliary Input L+R“. Now the compressor will change the volume settings of the music based on the fluctuations of the voice track. Pretty neat huh?
Now all you need to do adjust the compressor settings. You can experiment here by listening as you adjust. Start out with a Ratio setting between 4:1 and 6:1 and put the Threshold slider down to about -20 dB. One thing to be sure of before you do any of this is that the overall volume on the music track is already set to where you could hear the voice over it fairly well even without the ducking compressor. If the average volume of the music is so loud that the voice can’t even be heard to start with, ducking won’t help you much.
To make sure things are working properly, close the FX window and play your audio. Click the “S” (stands for “solo“) button on the music track to solo it. It ought to sound very odd, sort of choppy to you. This means it’s working. Now un-solo the music track and listen to how beautifully clear the voice is while the music is still very audible as well.
Use this knowledge for good.
Cheers!

What is Ripple Editing?

December 29, 2011 by Ken 2 Comments

Ripple editing can be a very useful tool in both audio and video editing. But it’s one of those things you don’t want in the “on” position all the time. If you think it’s on and merrily go about editing audio items on your track, you’ll have caused quite a train wreck with your audio clips. Likewise, if you think ripple editing is turned off, and you start deleting or moving items on your track – train wreck.

Definition of a couple of terms

First, let me clarify a thing or two about two terms I’ll be using.
Track: A track is simply a container in audio and video software. It is usually displayed as a sort of swim-lane in horizontal stripes across the screen. You put media “items” into these tracks, where you can move them around (left for earlier in time and right for later in time).
Item: Any audio, video or MIDI file that you place on a track. The big source of potential confusion on this is that while the underlying media is a file (.wav, .mp3, .mid, etc.), once it’s placed into a track, the edits you make do not affect the underlying file. If you insert a wav audio file onto a track, it becomes an item on the track, which is sort of like a copy of file. If you slice that item into 5 pieces, the underlying file is still in one piece, for example. This is typically called non-destructive editing.

So what is ripple editing?

Where ripple editing comes into play is when you have multiple items on a track. See the picture on the left, where I have one track with 8 items in it. Now let’s say I want to slide one of the items (say, the 3rd item from left) to the right just a smidge. This could be because there wasn’t enough blank space (silence) between the blue item before it, and maybe you want it closer to the 4th item, the blue one after it. With ripple editing turned off, you simply left-mouse-click on the item, and drag it to the right. Only THAT item will move and none of the others will.
However, if you did this same thing with ripple editing turned on, not only would the 3rd item from the left move to the right, but every item to the right of it would move by the same amount. The first two items in the track would stay where they were.

Why would you use ripple editing?

Very often, when you have multiple items in a track, you want to maintain the spacing between each item. This would be really hard to do if you had to delete one of the items in the middle of the track without ripple editing. It would leave a huge gap where the deleted item used to be. You’d have to individually drag each of the items, that are on the right of the gap back to the left, one at a time, in order get everything correct again, which would not only be tedious, but the spacing between those items would have to be re-done. But if you have ripple editing turned on when you delete a middle item, all the items to the right immediately shift to the left, not only covering up the gap, but also maintaining the timing relationship between themselves.
Note that this is NOT the same thing as “grouping” all the items on a track, which is another option altogether. When ripple editing, everything you do (if it affects timing – like deleting, moving, lengthening or shortening) to an item affects that item and any item to the right of it, but not the items on the left, the ones that occur earlier in time to the item you are editing. If you group all the items, then every item is affected regardless of whether they are to the left or to the right of the item being edited.
Another useful use of ripple editing is when recording music. Frequently everything is aligned to a tempo grid in the audio software. If you realize that you put too many measures in your introduction (I’ve done this many times) you can easily delete a measure. But without ripple editing, you’ll just end up with a one-bar-long gap of silence in your song after you delete it. With ripple editing turned on, every measure to the right of the deletion will shift to the left, the beginning of the subsequent measure moving nicely into place (assuming you deleted exactly one measure).
This is all very like using a word processor. You type text onto the screen from left to right (in English). If you see a word you want to delete, you can highlight it and hit the “delete” key. What happens? All the text to the right of it shifts back to the left. What it you need to insert some text in the middle of a sentence? You just place your cursor and start typing. What happens to the text to the right? It moves to the right with every keystroke. THAT is just like ripple editing, which is turned on by default in most word/text processors. If you’ve ever turned it off by accident you’ll see how messed up things can get. If you try to insert a word into a sentence, you’ll start deleting everything to the right of it.
Hopefully that makes ripple editing more clear. If you’d like me to put up a video to help clarify it, let me know in the comments below!
Cheers!
Ken

Normalization Myths

December 28, 2011 by Ken Leave a Comment

Normalization is another example of an audio recording concept whose term is both misleading, needlessly confusing.

What Does Normalization Mean?

Basically it means turning up the volume. Well, technically it is “increasing the gain.” But that’s another story you can read about here:
Gain, Volume, Loudness and Levels – What Does It All Mean?). You turn up a selected of a piece of audio until the loudest/tallest peak is as loud as possible without clipping. What’s so hard about that?
Find out more about normalization in our post: Audio Normalization: What Is It And Should I Care?
People normalize their audio to make it as loud as it can be.
But the term “normalization” implies that if you do this to multiple files, they’ll all be the same loudness – at least that is what normalizing something means to me.
But surely anyone can see that this simply is not true. The amount that your audio is turned up depends on how high the highest peak is.
Say you have two recordings of equal average loudness. If one recording had a single very loud peak, like a quick shout, that only about 3 dB lower than max volume, that entire file would only be turned up by 3 dB.
If the loudest part of another recording were not very high, say 10 dB lower than maximum volume, then normalizing that audio would increase the whole file by 10 dB.
See? These files, who had equivalent average loudness prior to normalization now have radically different volumes.
That (the idea that after normalizing multiple audio files, they’ll all be the same loudness) is only one of the normalization myths discussed in this article:
http://www.hometracked.com/2008/04/20/10-myths-about-normalization/

EQ Settings To Start With

December 26, 2011 by Ken Leave a Comment

EQ (equalization) is a very useful concept and tool in audio recording. If you want to brush up on what it is all about, check out our article here: What is Equalization, Usually Called EQ? When first learning how to use EQ, it can be confusing to understand what settings to use for what sounds. It is often very handy to have a a guide that tells you where to start for common sounds, like voices and tons of different instruments. The entry at the below link will give you such a guide. Not only is this a great reference, but it can help you start to learn where on the frequency scale these sounds live, in general, giving you a foundation for understanding how to shape your sounds for the best possible audio.
http://www.audiorecording.me/complete-eq-settings-to-start-when-doing-audio-mixing.html

Cool Audio Stuff – Online White Noise Generator

December 23, 2011 by Ken Leave a Comment

Have you ever been trying to concentrate at your computer when something you hear around you keeps pulling your attention away or distracting you? This happened all the time when I worked in an office made up of cubicles and about 2 dozen other people. Sometimes it happens at home if I can hear the TV or the stereo. I’m easily distracted. But I recently found a very cool thing online that helps drown out all that distracting noise, and it is so simple and fast. Oh, and its totally free. It’s a site called “Simply Noise.” (http://simplynoise.com/) You simply (see what I did there:)) slide the volume control up or down to your correct level and leave that page running in the background while you work. It’s awesome. You actually can choose between white, pink, or brown noise, indicated by, what else, white, pink or brown buttons. Go check it out and discover another use of audio in your life.
Cheers!