Join Larry Jordan for an in-depth discussion in this video Audio terminology, part of Soundtrack Pro 2 Essential Training.
Before we launch the application and get lost in the interface there are six audio terms I'd like to define. The first is Frequency. Frequency is measured in cycles and this determines the pitch of a sound. Where low frequencies are low pitched, high frequencies are high pitched. For instance a base guitar centers around the lower frequencies where a piccolo centers around the high frequencies. Unless it's a pure tone, every instrument has lots of different frequencies associated with them, but they do tend to clump in particular areas and we can take advantage of that in our mixing process.
The next term came from computers, it's called Sample Rate, and this is measured in samples per second and it determines the frequency response, the range form the lowest frequency to the highest frequency to the particular sample rate for support. For those who love math, if you take the sample rate and divide it by 2 that determines the maximum frequency that that sample rate will support. It's called the Nyquist Theorem. Bit depth: Bit depth determines the dynamic range of a clip, the distance between the softest and the loudest portion of a clip.
If there is no dynamic range, if it's all the same loudness, that's like Metallica. If it's an orchestra, then there's going to be a lot of dynamic range between the solo flute playing and the entire orchestra playing. Bit depth determines how great a dynamic range we can have and I'll talk about more in just a second. Levels is another term for the volume of a clip. Cross-fades are dissolves between audio clips except we don't call them dissolves; we call them Cross-fades. And Envelopes are keyframe lines, that's where we set keyframes, but they're not called keyframe lines.
That would be too easy, instead we call them Envelopes, even though they don't get mailed anywhere. Let's take a closer look at Sample Rate though. We actually have lot of different sample rates to choose from. Here's a table that illustrates four of the common ones. 22,050 Hz. Hz is the abbreviation for hertz and a hertz is simply a cycle. 32,000 Hz, 44,100 Hz and 48,000 Hz. Because the Nyquist Theorem says that if you take the sample rate divided by 2, that means that a 22,050 Hz which is often called 22 KHz, the lowest frequency is 20 cycles.
This is well below human speech and at the bottom end of the human hearing. The highest frequency is 11,025 and it's a really good frequency for speech because it easily contains the frequency range of human speech. 32,000 Hz which is often abbreviated at 32 KHz is good for 20-16 thousand and many consumer-grade cameras record at this level because the file sizes are smaller. Audio CD's use 44,100. Again the bottom end of 20 cycles doesn't change but the highest frequency is 22,050, and this is the standard recording sample rate for audio CD's.
Most professional cameras and DVD video have a sample rate of 48,000 Hz, which again is abbreviated at 48 kHz, the lowest frequency is 20 and the highest frequency is 24,000, and just to give you a comparison, human hearing goes from 20 to 20,000. Assuming that you are 18 -- for the rest of this training we are going to assume everybody has perfect hearing, and we are all 18. I like that idea. Higher sample rates create bigger files but they also have higher quality because they more accurately represent all the different frequencies that we listen to.
When in doubt, notice that little asterisk there. Setting your sample rate to 48 kHz is always a good safe choice. Just as we have sample rates that we can select from, we also have bit depth, and there are three bit depths that Final Cut and Soundtrack support. There is 8-bit, 16-bit and 24-bit. Bit depth controls the dynamic range of your audio. Here for instance, with 8-bit sound we have 256 steps between absolute silence and absolute as loud as it can be.
This would express itself as a dynamic range of 0dB to -96dB, and it's useful for the Internet, and broadcast television tends to use this. 16-bit sound gives us 65,000 steps. It gives us a dynamic range of 0 to -124 and it's used in audio CDs and all video recording. 24-bit gives us audio levels well over 16 million, a dynamic range of about 143dB and it's principally used in theatrical releases but also DVD audio.
That is not the audio for a video DVD but the specific format called DVD audio. The smaller the bit-depth, the smaller the file, and when in doubt set your audio files to 48 KHz and 16-bit depth, that's always safe and it's always a really, really good quality. Well, let's just take a second and digress. You see this audio level thing. It took me a long time to get my brain wrapped around this, but think of it this way. Think of yourselves building a house. You pour the concrete for the first floor. That first floor is not going to be move,. You frame the house and you put the second floor and the second floor is not going to move.
If I only have one step that takes me from the first floor to second floor, it gets really hard to move easily between those two floors. If I add 12 steps between it gets easier to move. If I add 20 steps in between that gets even easier to move gradually, smoothly up from one floor to the next. Now, the first floor position doesn't change and the top floor position doesn't change. All I am doing is I am altering the steps between the first and second floor. That's what the bit depth is doing. It's not changing the location of dead silence and it's not changing the location of as loud as it can be, it's simply giving me a greater range of steps as I move from total silence to as loud as it can be.
That's what the bit depth that is controlling. Now, there is one more concept that I want to get across during this definition and that's a difference between a waveform and the spectrum, and Soundtrack supports both. Final Cut, for instance, only works with waveforms. A waveform shows the amplitude, the volume of the clip, and where the amplitude, the waveform is wider the sound is louder. Here for instance, we've got pulses, which vary in width, but the loudest pulse is the widest one. That is to say wide from top to bottom.
Soundtrack also supports the display of frequencies contained by a clip, where the base frequencies, the low frequencies are at the bottom of the display, and the treble, the high frequencies are at the top, and the color indicates the intensity of the frequency. Blue, there's nothing there, light blue, a little bit there, green, sort of moderate, yellow, getting louder, and red, getting more and more intense. So what we can do by looking at this spectrum is we can see where our frequencies are located and whether they are hovering at the low, the middle, or the high end of the frequency bend.
We'll be talking how we can edit these frequencies inside Soundtrack a little later in this training. I don't want to spend a lot of time with terminology, but if we don't understand some basic terms, then we all sort of feel lost as we go through the learning process of this software. This is sort of a way of setting a foundation to make sure we all have an understanding of these core terms, but next, let's talk about something more interesting, the new features inside Soundtrack Pro.
- Learning the Soundtrack Pro 2 interface
- Setting up General, Project, Recording, and Sync preferences
- Recording audio
- Using the Multitake Editor
- Creating and using markers
- Improving and repairing audio files
- Applying multitrack editing options
- Using envelopes and keyframes
- Exploring soundtrack scripts
- Adding music loops and sound effects
- Editing waveforms and frequencies
- Mixing audio tracks
- Applying filters
- Creating surround sound
- Exporting finished files
Skill Level Beginner
Q: When sending a clip from Final Cut Pro to Soundtrack Pro, despite having the In and Out in the timeline, the whole clip gets sent to the browser. Is there a way to work only with the portions done with the razors and send only these portions to Soundtrack Pro?
A: In Sountrack Pro, this is not an option.
Soundtrack Pro 3 makes it a bit easier by marking the In and the Out, but the entire clip will always be duplicated and loaded.
The workaround is to export just the audio you need as a self-contained QuickTime file.