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Pitch changing, or pitch shifting, is closely
Digidesign's Pitch Shift plug-in allows you to change the pitch of an audio region up or down by as much as two octaves (plus or minus 24 semi-tones) with or without altering its length. As you can see in Figure 7.16, there is a checkbox for time correction in the Pitch Shift plug-in window that also enables the quality parameters at the bottom of the plug-in window, just like the Time Compression Expansion plug-in.
Pitch shifting is very useful as a sound design tool. All sorts of weird sounds can be made by shifting ordinary sounds outside their normal range. You can pitch change dialog to deepen someone's voice or create imaginary voices for animated
There is a very famous use of pitch shifting in the original
movie. The Ti Fighter sound was created by
If you happen to own Pro Tools HD, you can take advantage of higher sample rates. When pitching down sounds recorded at higher sample rates, ultrasonic harmonics that were inaudible in the original recording will come down into the audible spectrum, creating some very interesting effects. This process was used extensively by sound designer Dane Davis on The Matrix Reloaded . Strange mechanical sounds were created by pitch shifting high-resolution recordings of loud metal clangs to reveal their ultrasonic spectrum.
Try experimenting with any sound you can think of, shifting it up or down. Even subtle pitch changes can help sounds fit into the overall mix of elements in ways that EQ or other processing cannot.
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When working with dialog, it might be necessary to adjust the timing of certain lines to compensate for camera moves, tricky edits, or even ADR recording.
When camera angles change in a scene, sometimes directors will use a person's line from another camera angle, and therefore a line from another take. This alternate take might overlap images of the character performing the same lines from the original take. When this happens, editing between the two takes right when the angle changes might work, but often the continuity is lost and the first take must overlap the image of the second take. If luck is with you, the lip-sync will match. If not, you might have to alter the take to match the image. Likewise, sometimes an actor is not able to recreate a performance in the ADR studio that matches well to the picture. In a case like this, you might need to alter the dialog audio to match the original.
Plug-in tools such as Synchro Art's VocALign plug-in are created for matching the timing of one recording to another. This plug-in can analyze an existing vocal take and conform a similar one to match the timing of the original. This can help a
As you can see in Figure 7.17, the VocALign plug-in has two
Choose Audiosuite > VocALign to
Select a region that contains the dialog take you want to reference. This region will be used as a guide to which the new take will be aligned.
Press the top guide button, indicating that the file to be analyzed is a guide track.
Press the Guide button. A waveform display of the selected region should appear in the Guide window, as seen in Figure 7.17.
Select the region that contains the new dialog that you wish to align.
Click the Dub button to
Click the Align button. An outline of the processed file will appear above the guide track indicating where each peak and valley will line up in the new file, as seen in Figure 7.18.
In order to hear the result, press the Preview button.
Click on the
Decide whether or not you want the new file to replace the unprocessed file. There are several choices. You can leave the processed file in the Audio Regions list without placing it in a track, you can place the new file on another track specified in the Destination pull-down menu, or you can replace the file on the same track. Create a duplicate playlist and append the
Click the process button. Done.
As with any plug-in, overuse is not a good idea. It is always best to get a better performance than to "fix it in the mix." VocALign is a tool, not a crutch.
While editing dialog, you might find that the recordings have unwanted noise on them. In lieu of re-recording them in an ADR session, it might be possible to clean up the tracks using plug-ins that analyze noise content and filter it out, leaving the dialog relatively untouched. Digidesign's DINR and the Waves Restoration Bundle are two popular systems for removing noise. Sonic Solutions NoNoise is one of the oldest developers of this type of technology, and it, too, is now becoming available to TDM systems. Sonic Solutions and Waves plug-ins have more sophisticated tools for removing hum and clicks, but all three have a similar broadband noise reduction plug-in that will analyze the noise content of a signal and create an inverse noise-canceling algorithm to remove the noise while leaving useful program material intact.
You must have a section of audio without any dialog that contains the same type and level of noise as the areas you wish to clean up. A second or so of background noise will usually do
In this example, you have some production dialog audio that was recorded on a set using several fans to create wind for the scene. These fans made a decent amount of noise, which was recorded through the boom mic. The director would like to keep the original dialog recording for this scene because the performance was very special. You must remove as much of the fan noise as possible in order to make this recording usable. Here's how:
Instantiate the Waves X-Noise plug-in on the dialog track in question.
Find and select a section of audio that is just the background noise without any dialog. A second or two will do.
The noise you select is critical. Analysis of the noise sample will be used to cancel noise in audio that has dialog in it. If the noise floor changes between shots in a scene or even between different takes in one shot, reanalysis will be needed in order to accurately remove the noise. Changes in the noise floor could be from movement of the fans, in this example. Air conditioners will often create noise that changes when the unit cycles on and off. Make sure the noise you analyze is the same noise you want to remove.
Open the plug-in window and press the Learn button at the bottom. The button should flash yellow and say Learning, as shown in Figure 7.19. The plug-in needs to analyze this noise sample in order to create a profile that will be used to remove the noise. This is what the Learning mode is for.
Make sure that both pre- and post-roll are disabled. This ensures that when you play the selection, only the selected audio will be analyzed by X-Noise. Any audio outside your selection might contain desired program material and should not be part of the noise profile.
Play the portion of audio. You will notice a spectral display of the audio inside the X-Noise window while playing.
After playing through the whole selection, stop playback and press the flashing Learning button again to end the analysis. In the spectral display you will see a noise profile that represents the noise
Play the section from which you wish to remove noise. Putting it in Loop Playback mode (Command+Shift+L) might help while adjusting the X-Noise parameters. If you have other tracks playing along, you might notice that the one with X-Noise on it is severely out of sync with the rest. This plug-in has a large amount of latency. It takes more time to process the audio, and therefore it is delayed in playback. For now, just solo this track so as not to be distracted by its lack of sync.
Adjust the Threshold (Thresh) slider up. As the threshold increases, more noise will be removed. The function is similar to a noise gate or downward expander. The threshold is the level at which the signal will be allowed to pass through and be
HOW X-NOISE AND OTHER NOISE REMOVERS WORK
X-Noise uses a large number of downward expanders on individual frequency bands to achieve this quality of noise reduction. The noise profile sets relative thresholds for each frequency
The High Shelf frequency and gain parameters allow you to adjust the threshold of higher frequencies in the noise profile. The higher frequencies in dialog can sometimes be close to the same energy level as other noise components in the signal. Reducing the threshold at these frequencies by entering negative values for the gain parameter can help maintain clarity when performing a large amount of noise reduction. Raising the high-frequency threshold can help reduce noise components in the more audible ranges when the program material itself is
The Dynamics section of this plug-in controls the speed at which the noise reduction works. The Attack parameter determines how long in
LISTENING TO THE "DIFFERENCE"
The Audio and Difference buttons located at the bottom right of the plug-in window can be used to hear exactly what noise is being removed. When you click the Difference button, you will hear only the noise components that are being removed. Anything you are hearing will not be in the processed signal. This is a good way to check and see if you are removing useful program material. If you are listening to the difference and hear any clear dialog, your settings are too severe. Try backing off the reduction and lowering the threshold.
Once you have adjusted all the parameters and come up with a setting that achieves the best noise reduction versus sound quality, you must save the setting as a preset. This preset will be used to perform offline processing using the Audiosuite version of X-Noise. This offline process eliminates the latency issues that arise when using X-Noise in real time as a TDM or RTAS plug-in. To save the preset, choose Save To New File from the Save submenu in the upper-right-hand corner of the plug-in window, as shown in Figure 7.22. It is also possible to save settings from the standard preset menu in the upper left of the window, but with Waves X-Noise, the only way to save the parameters and the noise profile is to use this other submenu. Try to use a descriptive name for the preset that you can identify as applying to this particular section of audio. You might be saving many more noise presets before an entire film is completed. Being able to refer back to these settings can be very important if you decide to alter the settings at a later time.
USING X-NOISE IN RTAS OR TDM
If you want to use the RTAS or TDM version of X-Noise, you will have to compensate for the extreme latency that this plug-in will create. Please refer to the plug-in latency compensation section in Chapter 8, "Mixing to Picture in Pro Tools."
With the preset saved, you are now ready to process the files offline. Choose Audiosuite > X-Noise to open the Audiosuite version of X-Noise.
Click the Load button and choose Open Preset File. Locate the preset you saved in Step 11.
Click the Load button again, and you should see the name of your preset file listed in the middle section of the submenu, as shown in Figure 7.23. Select the Both option to load both the noise profile and the parameter settings from the preset file. Your plug-in should look the same as it did in the RTAS or TDM version.
Before you process these files, you should create a duplicate playlist in which the processing will occur. This gives you a quick way to return to the unprocessed files in case you wish to make a change. Understand that once you process the files with any Audiosuite plug-in, only those portions of audio that are visible inside the regions will be processed. The parent files these regions belong to will not be entirely processed. It will not be possible to "open up" the regions with the Trimmer tool once they are processed. Using an alternate playlist allows you to go back to the
There are other plug-ins that help remove different types of noise. The Waves Restoration Bundle has X-Hum, shown in Figure 7.24, which is designed to remove unwanted hum generated by electrical
The X-Click and X-Crackle plug-ins are primarily designed for vinyl record and optical film sound restoration and are of limited use in video post-production.
Noise reduction tools like the ones presented in this chapter are powerful and complex. Experiment with some
Sometimes the dialog tracks will have small anomalies in them, such as mic "thumps," where someone
Using the example of the mic thump, you can select the affected area of the sound file and then open an Audiosuite EQ plug-in that has a high-pass filter in it such as the Waves Q1. Using the preview function, adjust the parameters of the Q1 to filter out the
This same type of process can be achieved through the use of automation. That technique will be explained in Chapter 8, "Mixing to Picture in Pro Tools". While both
Once you've completed any the offline processing and all editing tasks are complete, it is time to start mixing.
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