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Logic: Working To Picture

Logic Notes
By Ingo Vauk

The Create Tempo Curve option in the Tempo Operations window can be used to create gradual progressions between hit points.The Create Tempo Curve option in the Tempo Operations window can be used to create gradual progressions between hit points.

This month we continue our advice on working to picture in Logic with tips on how to work around your visual hit points.

Last month we arrived at a point in the proceedings where Logic was ready for the composer to bite the bullet and start making some important choices about the tempo and time signature of the cue that needs to be written. Everyone has their own method of making these decisions, but I find playing along to the picture a good way of getting the right idea. Once you have decided on tempo and signature you can put them into the appropriate windows in the transport. The tempo is only a rough guide, which will be edited to fit the picture precisely in the next few steps. Since the intro to this example piece is going to be 'ambient', in the sense that it will not contain any rhythmical information, the tempo of it is less relevant. What is important is the tempo between your second flag and the last downbeat of the cue.

Have Your Say!

If you want to suggest changes or improvements to Logic, then here's your chance! The Emagic development team are inviting SOS readers to send in their suggestions of what they'd most like added or changed in Logic. Email your top five suggestions (in order of preference) to logicnotes@soundonsound.com, and we'll forward your lists on to the Logic team. We'll be asking them for feedback on which changes users deem most important and how these might be addressed.

Positioning The Downbeats

So lets say you have played along to the film and decided on a rough tempo of 110bpm, which results in approximately 15 bars of rhythm between xx:xx:xx:xx and zz:zz:zz:zz. The first thing to do is to make sure that xx:xx:xx:xx lands on a downbeat, so click on the flag object locked to that position, toggle the Event Float window to display bars and beats, and make a note of the closest downbeat. Move the Song Position Line to that downbeat and then toggle the Event Float window back to its timecode display. Double-click the timecode value and copy it into clipboard, and then open the Tempo Graphic Editor window from the Tempo submenu of the main Options menu. Alternatively, it can be opened by clicking and holding on the Transport window's clock symbol and then selecting Open Graphic Tempo from the menu.

Once you're in the Tempo List Editor, click on the Create button to insert a tempo change at the Song Position Line. Double-click the timecode display for this Tempo event (the At SMPTE Position field) and paste the timecode reference from the clipboard. By pasting the timecode reference into the position box, Logic alters the previous tempo to make the musical downbeat match the desired timecode position. Rolling the video now should give you a downbeat at ww:ww:ww:ww with a new tempo, another downbeat at xx:xx:xx:xx with a new tempo that will run roughly to position zz:zz:zz:zz in 15 bars, depending on how well you estimated the tempo.

The next step is to make sure that there is also a downbeat precisely on zz:zz:zz:zz. For this we repeat the previous procedure, copying the timecode reference from the Event Float using the flag object, inserting a new Tempo event 15 bars after the last one in the Tempo List Editor window, and pasting the timecode reference into the position box.

Hitting Mid-cue Events

Now all that remains to do is to take care of the event in the middle of the cue. There are several options here, depending on the music. Although it is amazing how much more of a tempo variation you can get away with when working with visuals, because the listener is being distracted (by being a viewer), it is always best to keep tempo variations to a minimum when they are not there for a musical purpose — in other words, if they are being used purely to lock the music to picture. So it is worth investigating if that event could naturally fall where it happens to be, or whether the nearest quantisation value (say, the nearest 16th note) would do. This means that you should write into your cue a musical accent that is as close to the 'natural' location as possible, as long as it makes musical sense. So if it isn't the nearest 16th note, then try the nearest eighth or quarter note before going for the downbeat. It also makes for more interesting music if not every cut is predictably going to land on a downbeat. Once you have made this musical decision you then adjust the Tempo List Editor again to place this event on the exact timecode location.

You can create a Fader object in the environment to adjust the tempo in real time while the visuals play back.You can create a Fader object in the environment to adjust the tempo in real time while the visuals play back.If it was within a couple of frames of where it should have been, you'll probably get away with repeating the above process for position yy:yy:yy:yy and zz:zz:zz:zz once more. However, you might end up with too much of a tempo jump, in which case another technique will yield a better result. Using the Tempo Graphic Editor window, it is possible to draw tempo variations in the same way that you can draw MIDI controller curves in the Hyper Edit window, and therefore make more seamless changes. If, for example, it is necessary to run the second part (between yy:yy:yy:yy and zz:zz:zz:zz) of your material quite a bit faster than the first, it might be an idea to gradually step up to that speed. By doing so you will inevitably reach the point in the music that should land on yy:yy:yy:yy too early. Therefore it will be necessary to compensate for this by using a tempo slower than the original one you calculated between xx:xx:xx:xx and yy:yy:yy:yy and then increasing it gradually in order to get to your second tempo setting right on time. This requires a certain amount of experimentation, but will, when used appropriately, give you the best result.

Another way of getting to the same result is by using the Create Tempo Curve Operation within the Tempo Operations window, before fine-tuning the result in the Tempo List Editor. As you can see there are a lot of windows involved in these tempo manipulations, and it is a generally a good idea to set up a Screenset for these tasks so that you can toggle between tempo editing and reviewing the result.

Soft Synchronisation Techniques

There are also more aesthetic reasons to vary the tempo with time. Very often music actually works more elegantly when it is written around the concept of 'soft synchronisation' — in other words, when the music follows the flow and pace of the images (and storytelling), but does not land hard on every hit point. In fact, exaggerated synchronisation can be extremely counterproductive, for example when it results in involuntary comical effects that run counter to the story line. Also, certain instrumentations (for example orchestral) sound a lot more real when they are sequenced in a more 'conducted' fashion. There are several ways to skin this particular cat: using the tempo fader, re-clocking the Song, or using the Tempo Interpreter window. For all these methods it is useful to establish a general tempo for the cue and work to that.

Current Versions

Mac OS X: Logic Audio Platinum v6.3.3
Mac OS 9: Logic Audio Platinum v6.3.1
PC: Logic Audio Platinum v5.5.1

With the tempo fader, it's possible to manipulate the tempo in real time. Create a tempo fader from the Environment window's New menu, by following the Fader submenu to the Special submenu, and then selecting Tempo Control. Cable this new Fader object between the physical and sequencer inputs. Open up the Recording Options from the Song Settings submenu of the main Options menu, and make sure that Allow Tempo Change Recording is active. It is now possible to change the tempo by moving this fader and recording the result onto the tempo track (in record mode). This method has a couple of drawbacks, though. Firstly the fader only generates whole-number bpm values, but in practice this is actually enough resolution for most scenarios — keep in mind that you can always edit the result in the Tempo List Editor later. Secondly tempo recording does not work when you're sync'ing to external timecode, so if you want to use it while watching your U-Matic tape, you can't. On the plus side, it is a very quick way of generating tempo variation without headache.

That is something that cannot be said for the second method, re-clocking the Song — accessed through the main Options menu's Tempo submenu. This is where Logic generates a set of tempo changes from MIDI data that has been played in without a tempo reference. The beauty of this method is that you can play to the picture intuitively and worry about the sync later. Logic will (so it says) create tempo changes that correspond to what was played in, as long as you tell it how many bars you played. It has to be said that the success of this operation depends very much on the rhythmic consistency of the material. It also inevitably requires quite a lot of faffing in the tempo editing windows once the re-clocking is done, so it's only worth embarking on when you are dealing with the definitive killer performance that needs major orchestration.

Along similar lines, but a lot less painful, is the use of the Tempo Interpreter window, which can be opened from the same Tempo submenu. It too uses a recorded performance to generate tempo changes, but more in the traditional sense of deriving it from a source (audio or MIDI) that is being played at a roughly pre-determined tempo and within a pre-defined window of deviation. This makes it a relatively robust tool, which handles gaps in the performance quite gracefully by 'flywheeling' past them. I've found that a great way of using this is to work on the arrangement of the cue in a fixed tempo, and then create the tempo by playing a steady trigger (quarter or eighth notes) manually while looking at the picture. With the Smoothing box ticked, this method is also quite a fast and effective way to inject a certain feel into what might otherwise be quite a mechanical piece.

Logic Tips

When you want to unpack only selected items in a Folder, first choose all the items you don't want unpacked and pack them into a new Folder. Unpacking the original Folder will then unpack the desired items to the next level up and leave the rest in a Folder on that same level. Len Sasso

If you set up the Compressor plug-in with the Auto Gain button activated, as is the default, using the Bypass button to evaluate the results can be misleading, because the processed result will sound louder. For a more meaningful comparison of processed and unprocessed signals, switch off Auto Gain and match the loudness as well as you can by ear, using the Gain slider. It then becomes much more apparent whether your processing improves the sound, rather than just making it louder. Mike Senior

Logic 's Bounce operation usually produces a mono or stereo audio file corresponding to the output of a single Audio Output object. If you want to bounce several outputs simultaneously to separate audio files, use the Surround Bounce option. You can Bounce up to eight separate mono channels that way. Use the global Audio menu's Surround option to view and set labelling for the available surround setups. Len Sasso

Team Work

At the end of the day, as with any studio technology, it doesn't matter which method you apply to get to the desired result. It's worth keeping in mind that these techniques are only really useful if they help you to achieve your goal in time, and no-one ever gets enough time to write music for film. So while it is worth spending some of it on the pursuit of perfect synchronisation, don't forget all the other tricks you know. For example think about creating a number of groove templates to quantise to if you are dealing with short pieces of music, especially when re-clocking proves too much of a nightmare, or just trust your eyes and ears and adjust things manually.

Published April 2004