Technology Institute for music educators ti: me course 2a Advanced Sequencing, Second Edition
Download 3.6 Mb.
|
Appendix H: Musical SequencingObjectives: Discuss techniques for making MIDI sequences more musical MIDI sequences often sound artificial and unmusical. How can a sequencer be used to emulate the idiosyncratic expressive characteristics of human performance and the natural behavior of acoustic instruments? This article will discuss orchestration techniques and tips for using automation and continuous controllers to mimic phrase shaping, dynamics and other aspects of human musical performance. MIDI sequences referred to as “mock-ups” are often a composer’s only method of evaluating a composition’s orchestration, form and balance. Most film producers want to review a MIDI mock-up before granting approval to release funds for a recording project to move forward. Therefore, it is critical that a composer have the tools to musically express their compositions and arrangements in the form of a MIDI sequence. Creating musical and effective MIDI sequences starts with a basic knowledge of music. Many poor MIDI recordings are result of a lack of background or attention to orchestration and musical style. A MIDI sequencing program can’t take into account an instrument’s range or what happens when an instrumentalist plays louder or when they play in the extreme ranges of their instrument. Yes, a trumpet sample is going to sound squeaky, sound wrong when played out of the instrument’s range. So, good sequences start with creating parts that are realistic, that a real musician can actually play. MIDI can be recorded in step-time (non-real time), notes can be added with the “pencil tool” and sequencing software can be set up to snap events to a grid. Sections of a piece that are chordal, or more homophonic in nature, can be recorded pianistically on a single track using a “section” sample. However, all of these techniques (bad habits) lead to mechanical, unmusical sequences and can be avoided by following these guidelines. Record parts in real time. Rerecord a part until you can’t do any better. Record section parts one part a time. If there are five trumpet parts, create and record 5 tracks. This will add subtle differences in articulation, rhythm, note length, etc. to each part. These differences are a natural part of any real ensemble performance. Record unison lines one part at a time and avoid using “section” samples. Where possible, use different samples for the different members of a section. You wouldn’t expect all the members of a section to play an instrument of the same brand and vintage. Using samples from multiple libraries will create a more realistic and more complex timbre. Where possible, replace lead part(s) with a real performance (audio recording) Don’t expect that using a single sound per part will create as complex a timbre as a real instrument. Doubling parts with other sampled or synthesized instruments will create a more complex sound just as if would if you were orchestrating for real, acoustic instruments. Doubling a part at the octave can enhance thin or wimpy sounds. A MIDI part can also be enhanced by simply duplicating the track—two is better than one. Then try delaying or offsetting the duplicated track by a 20-50 milliseconds to create a doubled effect. MIDI Editing: Quantizing Quantization is often the most frequently used (and misused) MIDI editing feature. Quantization allows a user to correct the rhythmic performance in a MIDI sequence using a grid based on the bar, beat structure of a piece and the locations of the recorded MIDI events in the sequence. Any competitive, modern MIDI sequencing program gives the user control over the resolution of the grid, what parameter(s) will be quantized (note start, note duration, note release, etc.), and how strictly the chosen material will be quantized. In addition, special accommodations are made for quantizing music with a swing feel. For example, Pro Tools allows a user to switch on or off the swing characteristic. When enabled, a swing percentage of 100% will yield a triplet feel—in an 8th note passage, notes not on the beat will move to the third 8th note of an 8th note triplet. Settings of less than 100% will result in a less dramatic swing feel while settings of more than 100% will gradually make the feel closer to a dotted 8th and 16th feel. Example: Unquantized MIDI Notes Against a Triplet Grid 
Example: Quantized MIDI Notes Against a Triplet Grid 8th notes quantized with a swing feel at 100% 
So, again it is important to listen to and analyze real performances and recordings and put that knowledge to use in your MIDI sequences. The rhythmic resolution of MIDI is measured in ticks. The actual resolution varies from program to program, but a higher number of ticks per quarter note results in a more accurate rendering of a performance. It is very important to know what a note’s rhythmic value equals in ticks so that you can understand how much a note is early or late in respect to the rhythmic grid. For example, in Pro Tools the resolution is 960 ticks per quarter note. Consequently an 8th note is equal to 480 ticks, and 8th note triplet is 320 ticks and a 16th note is worth 240 ticks. Therefore, a quarter note quantized exactly to the grid starts at 0 ticks, 8th notes start at 0 or 480 ticks, or an 8th note triplet notes start at 0, 320 or 640 ticks. Moving a note 5 – 20 ticks before or after the related grid point – though inaccurate in an absolute, mathematical sense – won’t harm the perceived rhythmic accuracy of a musical passage but, it will allow you to subtly alter the feel or add life-like nuance to the rhythmic performance. As suggested earlier, misuse of quantizing can yield very bland results. Some suggestions to avoid this quandary are provided below … Avoid the wholesale snapping to grid of any notes that don’t “visually” look right! Always set the quantize value to the smallest rhythmic value in the selection to be quantized. Use the strength parameter when quantizing. Passages that are 85 to 90% quantized still retain some of the original performance and will not sound as “mechanical.” Quantize small sections at a time Instead of quantizing everything, select a note and use the Nudge feature to move it 5-10 ticks. This improves the rhythmic accuracy but, at the same time, retains some of the human element. Velocity or MIDI Volume The MIDI protocol allows for a resolution of 128 (0 – 127) steps or degrees for volume. While this resolution is small when compared to our ability to hear changes in volume, it has served well since the inception of MIDI. Many times, the problems in a poor sequence relate to uneven or unmusical note velocities. This issue is often related to a person’s piano skills or to recording a sequence using a non-weighted controller. But, velocity problems can easily be edited using the event list editor or velocity editor in a DAW. After viewing the velocity information on a track, common sense can direct decisions about where and how to edit MIDI velocity. Many sample libraries and virtual instruments are made more realistic by using velocity information to trigger different samples. This makes a MIDI performance more realistic because, as instruments get louder, their timbre usually gets brighter (and the opposite when they get softer). Also, in addition to this timbral variation, as wind or brass instrumentalists play louder, they tongue harder which results in a more aggressive articulation. Modern sample library manufacturers often sample each note of an instrument 10 – 15 times to capture these subtle differences. The resulting samples are mapped to velocity ranges or “layers.” For example, the softest sample is mapped to the velocity range 0 – 10. At the juncture of the ranges, crossfades are added between samples so that it is very difficult to tell when you move from one velocity layer to the next. MIDI sequences can be improved substantially with this knowledge of MIDI velocity and the specific setup of a sample library. Musical accents can be highlighted or the desired timbre can be triggered by increasing the velocity of a note and, as a result, switching to a more appropriate sample in a different velocity range or layer. Also, a legato passage can be made more effective by slightly reducing the velocity for any notes that are slurred and not individually articulated. In the example below, the velocity of each note is represented by the vertical “stalk” at the beginning of the note. Example: Unedited Velocity “Stalks” 
Download 3.6 Mb. Share with your friends:
|