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Aligning Kick & Bass Parts

Steinberg Cubase Tips & Techniques
By Simon Millward

Kick drums and bass instruments underpin most contemporary popular music, and it sometimes pays to tweak performances so they work better together.

Most of us are familiar with the idea of quantising MIDI parts such as drums in order to create a specific feel or groove, but sometimes you want to take quantising a bit further, both with audio and MIDI, so this month I'll explain how you can align one part to another, using the kick drum and bass instruments as an example — after all, these parts form the backbone of most modern popular music, and changes here can have a profound effect.

Your arrangement doesn't have to have your kick and bass sound at the same time, but when you do want them to double up, you want them to be really tight because if they're not, all the compressing and EQing in the world isn't going to help.

The Task & The Tools

Although aligning kick and bass parts may sound simple, this kind of processing does't lend itself kindly to automation — and it can prove complicated and time-consuming to set up — but a combination of tools and techniques can make the process easier, while avoiding the painstaking editing of events one at a time.Aligning Kick & Bass Parts

Screen 1: The first tool to create is this Project Logical editor preset. This is a filter which selects only those audio events whose start positions are inside the range of the left and right locators and whose name contains the word 'bass'.Aligning Kick & Bass PartsScreen 2: This Logical editor preset is supplied with Cubase and is found in the 'Added for version 3' sub-menu. This is going to help us split MIDI parts at each MIDI note position.

The first thing to decide is which instrument provides the rhythmic hooks on which you wish to hang the other. It's often easier to move the bass notes to the positions of the kicks, partly because this avoids phase-cancellation problems when working with multitrack-audio drum recordings (for example if you move the kick part but leave the corresponding overhead signals where they are). Of course, this approach requires that the timing of your drum part is already as you want it, and an alternative would be to lock both bass and kick to the metric time of Cubase. It doesn't really matter which you opt to do, because the steps described here can be applied to either approach.

There are a number of techniques you can use, including splitting events at hitpoints, quantising, using macros and lining up events manually. Which are appropriate depends on whether you're using MIDI tracks, audio or a mix of both. Some rely on the use of specialised tools, including a Project Logical editor preset, a standard Logical editor preset and two macros.

The Project Logical editor (PLE) is useful for all kinds of project-window tasks such as naming, selecting and deleting, but I'm using it here to make selections when an event conforms to certain conditions. Copy the settings shown in Screen 1 to create your own version of this PLE preset and name it 'Select if inside cycle'. The standard Logical editor is designed for processing MIDI data only, so I'm using it here to select all MIDI events beyond the project cursor position using the supplied preset named 'Select all events beyond cursor' (see Screen 2). The intention is to use these two presets in two macros called 'Align bass to kick' and 'Split MIDI Part at next note' (see the boxes on this page for the commands you need to create your own versions of these macros). Macros are created in the lower section of the Key Commands window, and you can read more about creating them in Mark Wherry's article in SOS July 2003 (www.soundonsound.com/sos/jul03/articles/cubasenotes0703.asp). You need only create these tools the first time you use them, so processing subsequent projects will be less time-consuming.

Macro 1: Align Bass To Kick

This macro moves the project cursor to the start of the next marker on the Marker track, sets a cycle range around this position, selects audio events that fall within this cycle range and have the word 'bass' in their name and, finally, moves any selected event to the current cursor position. The name used in the associated PLE preset must match a generic word found in all the events on the bass track.

1.      Transport / Locate Next Event

2.      Transport / Nudge Frame Up

3.      Transport / Nudge Frame Up

4.      Transport / Set Right Locator

5.      Transport / Nudge Frame Down

6.      Transport / Nudge Frame Down

7.      Transport / Nudge Frame Down

8.      Transport / Nudge Frame Down

9.      Transport / Set Left Locator

10.      Transport / Locate Next Event

11.      Process Project Logical Editor / Select if inside cycle

12.      Edit / Move to Cursor

When you've created this macro assign a key command to it so you're able to run it easily.

Aligning MIDI Parts

Let's start with the relatively simple case of matching the feel of a MIDI bass line to that of a MIDI kick drum. Groove quantise works well with MIDI material, so we'll use that here, and since we're using the kick drum for the timing, we need to extract the groove of the kick drum track before applying it to the bass track. Thankfully, Cubase has some ready-made tools for this:Aligning Kick & Bass Parts

Screen 3: Before and after groove quantising the MIDI bass line. Before processing, the timing of the bass line (shown in green) does not match the kick drum (shown in purple). After processing the events match perfectly.

1. Arrange the kick and bass tracks so that they appear one above the other in the track list. If they aren't already the same lengths, edit the first kick drum and bass parts in the arrangement to be the same lengths using the split and/or glue tools. The idea is to finish with simultaneous kick and bass parts of the same duration. The maximum number of bars which can be handled in a groove template is 16, though, so don't select more than that.

2. Now select the first kick drum part and select MIDI/Advanced Quantize/Part to Groove. A new groove template should appear in the Quantize type menu.

3. Select MIDI/Quantize setup and set Max. Move to 32nd. This stops MIDI events being dragged too far when you apply the groove.

4. Now select the corresponding bass part and, with the new groove template still selected, press Q... and watch in wonder as the bass notes get lined up to the nearest kick drums! You can then proceed in a similar manner to process all the kick drum and bass parts.

Macro 2: Split MIDI Part At Next Note

This macro steps through the MIDI notes on the currently selected MIDI track and splits the MIDI part at the position of each note. It comprises the following commands, which should give you an idea how it works:

1.      Edit / Open Key Editor

2.      Navigate / Right

3.      Process Logical Preset / Select all Events beyond cursor

4.      Transport / Locate Selection

5.      Edit / Open/Close Editor

6.      Edit / Select All on Tracks

7.      Edit / Split at Cursor

8.      Transport / Nudge Frame Up

Again, when you have created this macro, assign a key command to it.

Audio Alignment

Aligning MIDI parts in this way is a relatively painless process and results in tightly synchronised kick drum and bass, but it is less immediately obvious how best to line up your kick and bass audio events. One approach is to extract the feel of the kick drum as a groove template, then apply this template to the bass line. Although this sounds easy enough, when you actually try to do this with audio material you'll soon discover serious limitations, and the processing is very time-consuming too.Aligning Kick & Bass Parts

Screen 4: Use the sensitivity slider to calculate hitpoints at each and every kick drum and then select Create Markers.Aligning Kick & Bass PartsScreen 5: Markers at the positions of the kick drums after processing is complete.

My own solution avoids grooves and time-stretching, is relatively quick, and it automates most of the processing with the tools made earlier. We'll start by creating guide kick-drum markers. If it isn't already present, you'll need to add the Marker track to the project. Then select all the audio events on the kick drum track, and press Ctrl+E (or the equivalent Mac command)) to open a sample editor for each audio clip associated with the selected events.

Working on each clip in turn in the Sample Editor's hitpoints section, use the sensitivity slider to calculate hitpoints at every beat of the kick drum and select Create Markers (Screen 4). Close the sample-editor window when processing is complete for each clip. (For more details about hitpoint calculation see my article about audio slicing in SOS May 2008.)

The markers form the guide track to which the bass notes are to be lined up (Screen 5), but first we need to divide the bass track into single-note events, which requires a similar approach:

1. Select all audio events on the bass instrument track.

2. Press Ctrl+E to open multiple sample editors for all audio clips associated with the selected events.

3. Working on each clip in turn in the sample editor's Hitpoints section, use the sensitivity slider to calculate hitpoints at each and every bass note and then select Create Events (Screen 6). The objective is to split events into separate shorter events, each containing a single bass note. Close the sample editor window each time processing is complete for each clip.

The next step is very important! You need to make sure that the names of all events on the bass track contain the generic word chosen in the 'Select if inside cycle' PLE preset (see Screen 1, above). If this is not the case, rename the bass events accordingly (or change the name in the PLE preset). Try holding down any modifier key when renaming the track to rename all events simultaneously. Also make sure that none of the names of events on other audio tracks contains the chosen generic word, or these too will be subject to the processing.Aligning Kick & Bass Parts

Screen 6: Use the sensitivity slider to calculate hitpoints at each and every bass note and then select Create Events.Aligning Kick & Bass PartsScreen 7: The bass track after being split at each note, shown below the Marker and kick drum tracks. Notice how some of the bass events do not line up precisely with the kick drum hits.

Now that we have our markers and separate bass notes, we can automatically align the bass and the kick drum:

1. Place the project cursor just before the start of the music and make sure the Marker track is selected in the track list.

2. Activate the special 'Align bass to kick' macro by holding down the shortcut key you assigned. The macro automatically repeats itself and steps through all the events in the arrangement.

3. Each bass event should be lined up to the nearest kick drum (Screen 8), but it's also worth auditioning the results and correcting manually where necessary.

4. If the bass track is suffering from clicks on overlapping events, try setting up auto fades on the track using the auto-fades button in the Inspector. De-activate 'use project settings' and try 4ms fade outs.

This process relies heavily upon the 'Align bass to kick' macro and the 'Select if inside cycle' PLE preset, both of which deserve a more detailed explanation. The 'Align bass to kick' macro first defines a capture zone of a couple of frames around each kick-drum marker, which is highlighted by the left/right locator range. The 'Select if inside cycle' PLE preset searches the project for events containing the word 'bass' where the start points are located inside the current locator range (inside the cycle). If the event matches the condition, it's selected. If selected, the final 'Move to Cursor' command in the macro moves the selected event to the current position of the cursor, which is placed at the relevant kick-drum marker. If no event is found within the cycle range then no selection is made, and the 'Move to Cursor' command has no effect, so only those bass events which are near to a kick-drum marker are actually moved. Advanced users may wish to change the capture range, and this is achieved by modifying the number of 'Nudge Frame Up' and 'Nudge Frame Down' commands in the 'Align bass to kick' macro (you'd normally maintain twice as many Nudge Frame Down commands as Nudge Frame Up commands). Note that the 'Align bass to kick' macro has a finite resolution and does not function correctly with closely coincident markers.

Audio Bass & MIDI Kick

The approach is similar when aligning audio bass parts to MIDI drums: the only difference being that we need to divide the MIDI kick drum into separate MIDI parts containing only a single note per part — because this is used instead of the Marker track as the guide. Proceed as follows:Aligning Kick & Bass Parts

Screen 8: Activating the 'Align bass to kick' macro lines up each bass event to the nearest kick-drum marker. In this screenshot the current capture range is located just before the third beat of bar 12, as defined by the left and right locator cycle range. Those bass events which fall outside the capture range are ignored, and only the selected event is moved.

1. Create a guide MIDI kick drum track, duplicate it, and join all MIDI parts on the duplicate into one MIDI part by Alt-clicking on the first MIDI part, using the glue tool.

2. Select the duplicate MIDI kick drum track, and place the project cursor just before the beginning of this track, then hold down the assigned key for the 'Split MIDI part at next note' macro. This macro steps through the MIDI notes and splits the parts at each note.

3. Carefully split the whole track into parts until you get to the end. Be careful to stop at the end of the arrangement (the macro will jump back to the start of the project and attempt to split the parts a second time, which isn't what you need!). When splitting is complete, this track rather than the Marker track forms your guide kick drum track.

Now follow exactly the same procedure as when dividing the bass track into single-note events and lining up the bass events to the kick drum markers, but this time, select the guide MIDI kick drum track (instead of the Marker track) before you activate the 'Align bass to kick' macro. (The 'Align bass to kick macro' works equally well with both the Marker track and audio or MIDI tracks). All bass audio events should now be lined up to the guide kick drum MIDI parts.

Locking Audio To Metric Time

You may prefer to lock both the kick and bass tracks to metric time in your Cubase project, and it is possible to achieve this in two different ways. The first is to split the audio into shorter events, with one kick drum or bass note per event, using the technique for aligning kick and bass audio events, described earlier. Once split, you select all the events on the kick and bass tracks, select a quantize value in the quantize type menu (try 16 for example) and select Over quantize. All events are moved to the nearest grid line. Although this works reasonably well for simple arrangements, it may not be accurate enough for those with complex timing.

An alternative is to use the Quantize Audio function on each of the kick and bass events in turn. The basic process for each event is to: open the sample editor; define the tempo or length of the event; calculate hitpoints; create warp tabs from hitpoints; close the sample editor; select the event in the project window; select the quantize resolution in the Quantize type menu; and, finally, select Quantize Audio. This uses time-stretching to align the warp tabs to the chosen grid resolution and while it can be complicated and time-consuming, in some cases it may provide an effective solution. I won't dwell on the Quantize Audio funtion here, since it isn't the best technique for aligning your bass and kick tracks (and it could easily fill a separate article!) but there's plenty of information on this in the 'Quantizing Audio' section of Cubase 4's manual if you're itching to learn more.

Manual Editing

The complexities of some musical material (such as that featuring a quickfire double kick drum, or intricate slap bass) may be beyond any semi-automated process, in which case manual editing would be the only solution. But manual editing is also a good approach for those projects with only occasional problems, as you need only zoom into the problem sections, without going through the whole track. Likewise, the manual approach is useful where one of the semi-automated processes produces the occasional inaccurate result.Aligning Kick & Bass Parts

Screen 9: The guide MIDI kick drum track being split at each MIDI note using the 'Split MIDI part at next note' macro.

Manual editing would normally still require splitting the events around the positions of inaccurate kick drum hits or bass notes. The split event can then be dragged to a new position in the project window. Subtle moves are best achieved with the snap button de-activated, but if you're working to the grid, you'd normally want the snap button activated, and the desired resolution chosen in the Quantize Type menu.

An alternative approach is to move the audio inside an event by holding Ctrl + Alt and dragging it. In this case, you'd split the bass audio event at the precise position of the nearest kick and then slide the audio event so that the corresponding bass note occurs at the start of the event (and is thus lined up with the kick). Yet another option is to create markers at all the kick drum hits, split the bass track into separate events with one note per event (as described above) and, finally, to manually drag the bass-line events to the positions of the corresponding markers, with the snap button active and 'Events' selected in the snap-type menu.

Shaking The Foundations

The simplicity of the idea of lining up bass notes to kick drum events belies the fact that this is not a trivial process. You are, after all, sliding the foundations of your music around. Unlike the foundations of your house (which do not respond very well to being slid around!), you can do this with multitrack music very successfully — but only if you're well prepared and know how to use the tools. The success of the main techniques described above depends on the rigorous preparation of the kick drum and bass tracks and on the accuracy with which you calculate your hitpoints.

Please bear in mind that the processing I've described above, while very powerful, can inadvertently upset the balance and subtleties which made your arrangement musical in the first place. Remember also that not all kick and bass parts are intended to be tightly locked together, and that the rule to remember above all others is to listen very carefully to make sure you've not downgraded, rather than improved, your arrangement before you decide to save the results! If you'd rather practice before you process your own material, you could try the kick and bass tracks on the demos supplied on the Cubase installation DVD. 

News: Cubase 4.5 Released

As we were going to press, Steinberg announced a major update to Cubase 4.

We've not had chance to install and put it through its paces yet, but Steinberg say that Cubase 4.5 — which is free to download for registered owners of Cubase 4 — introduces several new features. This includes support for Steinberg hardware (such as their MR816 CSX and MR816X interfaces and their CC121 controller, as well as Yamaha's MOTIF XS series and the KX USB Music Studio series). There also looks to be considerable new content for virtual instruments such as Halion One, as well as a new loop library, with content from the likes of Big Fish Audio and Sonic Reality. But of greatest interest to most of us will be the bulging list of bug-fixes and resolved 'issues': the list is far too long to go into here, but if you want to find out whether your personal gremlins have been banished, there's a comprehensive (nine-page) PDF available on the Steinberg web site detailing all the changes. For more details, and to download the update, go to www.steinberg.net

Published October 2008