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Conforming to the Groove
Wrapping up this month's look at all things Beat Detective,
I am going to show you a great little trick for tightening
up one performance to another using a Groove in Pro Tools.
In last week's installment we discussed how to conform
a freely recorded performance to Pro Tools, so that the
performance follows Pro Tools. This essentially enabled
us to quantize audio to the Grid in Pro Tools. Although
this is great for tightening the timing of a performance,
it can make things "too perfect" if not used
judiciously. Rather than aligning the performance to the
Grid, we can actually quantize it to one of Pro Tools Grooves,
or even better, create our own groove from one track and
apply it to another, so they both really come together.
As we wrap up our series on Beat Detective, make you have
read each installment before moving forward:
• May
18th, 2006
• May
11th, 2006
• May
4th, 2006
• December
2nd, 2005
Once again, I have a stereo drum track to a song that has
a tempo of about 134 bpm (beats per minute) and a bass track.
In this case we want to align the performance of the bass
track, which is not exactly spot-on, to a Groove created
from the drums, so that the drum and bass tracks are tightly
integrated and lock in the rhythm.
When we zoom in, you can see that the MIDI performance
is not aligned with the drum track.
Before we can work on the bass track, we need to create
a Groove from the drum track. We will then use this
Groove to quantize the bass track, aligning both of the
performances.
- Ignoring the first eighth note pick up, you can see
the transient of the downbeat for bar 3.
- Start playback in Pro Tools and count off 8 bars of
material, make sure to identify the transient that ends
the fourth bar.
- Make sure that the Tab to Transients button is enabled
in the upper left of the Edit window.
- Tab up to the transient of the down beat, and while
holding down Shift, press the tab key until you tab all
the way through the end of the fourth bar, right up to
the transient for the downbeat of the next bar. This
will make a perfect four bar selection of the performance,
which
you can verify using loop playback. Remember to zoom
in and out as needed, so you can really see what you
are doing
here.
- Choose Event > Beat Detective to open the Beat
Detective window.
- In the Operation section make sure that Audio is selected,
and choose Groove Template Extraction
- The Selection section is where you tell Pro Tools
where this selection should start and end in Pro Tools.
In this
case, this selection should start exactly on bar 3 (3|1|0)
and end at bar 10 (11|1|0).
- Use the pop-up menu in the Selection section to indicate
the smallest note value in the recorded material, so
that Beat Detective can better understand the material
and the
position/value of the transients. In this case the lowest
note value found in the performance is an eighth note.
- In the Detection section make sure that Normal is
selected and choose High Emphasis for material containing
high frequency
content (such as the hi-hat ride in this recording) or
Low Emphasis for lower/middle frequency content (for
example if we were only working with a kick or snare
drum here).
- Click Analyze and slowly drag the Sensitivity Slider
from the lowest setting (0%) to a higher setting, stopping
when each transients has been identified–no more
and no less. It is very important to zoom in and make
sure that Beat Detective is not creating too many or
too few
divisions. In this case, I am able to identify each transient
so each is on its own division.
- Once you have verified that each beat and sub-beat
has been properly identified, click Extract. Beat Detective
will then use the trigger for each transient to create
a Groove Template which contains the timing of each transient,
so it can be used to align other material to. Just to
be clear here, no change has been made to the drum track,
we are simply extracting the rhythmic feel of the performance.
- From the Extract Groove Template dialog, confirm
the length of the selection, enter any comments you wish
to
include, and click Save to Disk.
- You will the be asked to name the file and save it.
You should simply save it to the default location (the
Grooves folder) so it can be easily recalled. At this
point, we simply need to Quantize the MIDI track using
the Groove
Template.
- Close the Beat Detective window and make a selection
of the corresponding 8 bars on the bass track.
- Choose Event > MIDI > Grid/Groove Quantize.
- From the Quantize Grid pop-up menu choose the Groove
Template you created using Beat Detective, in this case
I named it Recorded Drum Groove. Click Apply and close
the MIDI Operations dialog.
That’s all there is to it, we just quantized MIDI
to the timing of recorded audio. When we zoom in, you can
see that the MIDI performance is now aligned with the drum
track. I don’t want you to think that this example
was purely academic, aligning the bass track whether MIDI
or audio to the drum track is a great way to really get
a performance, to well…groove.
Although we quantized MIDI-to-audio, you could also quantize
audio-to-MIDI by using Beat Detective to extract the
Groove of a MIDI performance and then separate and
conform the
regions of an audio performance to that Groove. You
can even quantize audio-to-audio using these techniques.
As you have learned, Beat Detective is a powerful tool
for working with the rhythmic and percussive elements
in your session. Although there are a variety of things
you
can accomplish using Beat Detective, the basic principles
we have discussed this month are the core concepts
to master to become a real Beat Detective Guru!
Pro Tools Tidbits
If you have a Pro Tools related question that you would
like me to take a shot at answering or have any feedback,
please send it to scott@audioMIDI.com. I will do my best
to select the questions that seem to stump the most people.
As always, stay tuned to the audioMIDI.com eNews for the latest reviews and new product info.
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