Steinberg WaveLab 3 Operation Manual

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Using samplers and creating loops 28 – 671
Using the Crossfade Looper
What is the Crossfade Looper?
The Crossfade Looper is a special tool for creating “seamless” loops. It 
allows you to “nudge” the loop points while at the same time providing vi-
sual feedback of the “join” between the start and end point.
The Crossfade Looper can also automatically find loop points for you, by 
scanning the area of the waveform that is in the current loop points’ vicin-
ity. You can specify parameters for how “finicky” the program should be 
when suggesting loop points.
Finally, if you can’t find a good enough loop point using the methods de-
scribed above, the Crossfade Looper allows you to process the waveform 
to allow for smoother loops. It does this by crossfading areas of the wave-
form close to the loop start and end points.
Opening the Crossfade Looper
Before you open the Crossfade Looper we suggest you set up a basic 
loop as described on the previous pages. Then proceed as follows:
1.If you have several loops, place the wave cursor somewhere inside the 
one you want to work on.
This can be done by clicking somewhere between the loop markers.
2.Select Crossfade Looper… from the Sampling menu.
3.Click on the “Loop points” tab.
This tab should be your starting point, since this is where you adjust the loop points.
• The following sections describe the common procedures for using the 
Crossfade Looper – for details about the dialog itself, click the question 
mark icon in the dialog.
About the Crossfade Looper dialogs
The Crossfade Looper dialogs are non-modal. While they are open, you 
can still access other windows (e.g. the Transport bar). However, all edit-
ing of the Wave window on which you are working is blocked out (except 
moving the current pair of loop markers, of course).
Furthermore, each time you click Apply, the process starts out from the 
wave data as it was when you opened the Crossfade Looper (since you 
want to be able to try out various types of crossfading without re-process-
ing the wave each time). This affects the undo function: there is only one 
step of undo and no redo in the Crossfade Looper. 
						

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28 – 672 Using samplers and creating loops
Moving the loop points “manually”
Let’s assume you have set up a basic loop that you are happy with, except 
for glitches or “bumps” at the turning point. You can then use the Cross-
fade Looper to move the points manually, in small steps, to eliminate the 
glitch.
This is actually technically no different from moving the loop points in the 
wave display, but the features of this dialog makes it much easier to find 
good loop points, since the display gives you visual feedback as you go 
along. We also recommend that you have playback going on in “Loop as 
marked” mode since you will then also hear what you are doing!
The two ways of moving loop points
There are two ways of moving the loop points: dragging in the actual 
waveform (position the mouse pointer in the display and drag sideways) 
and using the “nudge” buttons.
• Dragging in the waveform allows you to perform larger moves more quickly.
• The nudge buttons are more useful for fine-tuning since they move the points by 
one screen pixel. This means that in 1:1 zoom mode, each press on a nudge but-
ton moves the loop point a single sample.
The various moving options
• By moving the left part of the display, you are moving the end point to a later (left) 
or earlier (right) position.
• By moving the right part of the display, you are moving the start point to a later 
(left) or earlier (right) position.
• If you activate Linking, both the start and end points will move simultaneously. 
That is, the loop length will be exactly the same, but the entire loop will move.
• You can switch to the Wave window and adjust the markers there, if needed.
You can drag either side of the waveform directly…
…or use the nudge buttons.  
						

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Using the auto-find feature
If desired, you can have the program search for good loop points auto-
matically. This is technically no different from adjusting the loop points 
yourself, only that the program uses pattern matching algorithms to sug-
gest loop points for you.
Let’s say that you want to let the program find a better start point for the 
loop. You first set up a start and end loop marker, to get a basic loop, as 
described above. You then invoke the automatic searching, and the pro-
gram searches the waveform from the current start point, 
trying to find a 
section that is as similar as possible to the area just 
after the current end 
point. When it finds a match it stops.
You decide how similar the section must be to be considered a match.
Setting up the parameters
The auto-find parameters.
There are two parameters for the auto-find feature, desired correspon-
dence and search accuracy.
• Search accuracy is a parameter for determining how many samples should be in-
cluded in the analysis. Higher values result in greater accuracy, but also longer 
processing times.
• Desired correspondence is a value for how well the found section must resemble 
the section to which it is compared, to be considered a match.  WaveLab uses 
two methods for comparison, “phase match” and “join match” (which provide 
much better matching than the simple zero crossing detection used by most other 
programs. Phase matching also ensures that no harmonic cancellation will occur 
when you crossfade, see later in this chapter). First phase matching is performed 
and then, to “fine tune”, a join match is employed. A value of 1000 will most likely 
fail completely, since it requires a 100% perfect match.  
						

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28 – 674 Using samplers and creating loops
Searching
1.Set up the search parameters.
2.Click on one of the buttons in between the “nudge” buttons.
Each time you click, the program scans from the current point (forwards or backwards, de-
pending on which button you clicked) until it finds a point that matches. It then stops. If you 
wish you can stop at any time by clicking the right mouse button, by using the Stop button 
on the status bar or by hitting [Esc]. The program will then jump back to the best match 
found so far.
3.Check the loop by playing back.
4.If you think there might be a better point, at some later or earlier position, 
just click the button again, and scanning continues from this point on-
wards.
Remember that you can always go back to the main Wave window and 
adjust the markers manually.
Working with candidates
Often you will want to try various alternatives before committing to a loop. 
To be able to compare several alternatives, WaveLab offers looping can-
didates. These allow you to store sets of loop points in memory locations 
for later recall.
When you have set up the loop points as desired, you store them by se-
lecting “Save candidate” from the options pop-up menu in the dialog, and 
then selecting one of the five memory locations.  
						

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Using samplers and creating loops 28 – 675
To recall a stored candidate, select “Restore candidate” from the pop-up 
menu, and then select the desired memory location from the submenu. 
The points are now recalled and the loop points in the wave are moved to 
the positions stored in the memory location.
• To compare several candidates, you can for example have playback going, 
select them one after the other, and listen to the difference.
Once you have found your candidate, you can select OK to exit this window or proceed to 
crossfading.
Things to note about candidates
• There is only one set of candidates per Wave window, not one per set of loop 
points. This means that if you have several sets of loops in your file, you must be 
careful so that you don’t recall the wrong set.
• Crossfading is not part of the candidate, only loop positions are. You should de-
cide on a candidate to use before you apply crossfading.
Creating a crossfade
What is a crossfade and when do I need it?
Sometimes it is impossible to find a loop that doesn’t cause any glitches. 
This is especially true for stereo material, where you might be able to find 
a perfect candidate for either channel, but not for both at the same time.
One solution to this problem is to use crossfading. This technique 
“smears” the material around the end loop point so that it loops perfectly. 
It does this by mixing material before the loop start with material just be-
fore the loop end.
The only problem with this technique is that it alters the waveform and 
hence changes the sound. However, normally you can find settings that 
minimize this problem. 
						

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Setting up
1.While still at the “Loop points” tab (in the Crossfade Looper dialog), try to 
create as good a loop as you can.
2.Click on the Crossfade tab.
3.Make sure the Crossfade check box is activated.
There is a corresponding check box on the Post-Crossfade tab. This lets you choose if reg-
ular crossfading and/or post-crossfading will be performed when you click Apply later.
The Crossfade tab with crossfading activated.
4.Decide on a length for the crossfade either by dragging the length handle 
or by adjusting the Length value below the graph.
The length is used to adjust the amount of the audio file that will be processed. This area is 
always located just before the end of the loop, but the Length value adjusts how far towards 
the start of the loop it stretches. As you can see, an equally large area before the loop start 
is used as basis for the processing. However, this area is not processed, just analysed.
Generally you will want the crossfade to be as short as it can be, with an 
acceptable result:
• Using a long crossfade will be a better guarantee that the loop will be smooth. How-
ever, more of the waveform will be processed and hence changed in character.
• Using a short crossfade will ensure the sound is affected as little as possible. 
However, the loop might then not be as smooth as otherwise.
5.Decide on a crossfade shape, by dragging the shape handle or by adjust-
ing the shape value.
The considerations for this are the same as when creating other crossfades, see “Cross-
fade” on page 192. 0% means that the sound level will be equal in the middle of the cross-
fade, whereas 100% means that the energy will be equal in the middle of the crossfade. 
Use low values for “simple” sounds and high values for “complex” sounds.  
						

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Applying and checking the crossfade
When you click Apply, the sound is processed. If you have playback go-
ing, repeating the loop you will hear the change take effect after a short 
while.
• You can check the crossfade visually by opening the “Loop points” tab and 
activating “Display processed signal” on the options pop-up menu.
When this is activated, the display will show the waveform as it looks when crossfaded. 
When the option is deactivated, the display will show the waveform as it originally was. 
Switching back and forth allows you to compare the two.
• You can undo the crossfade by selecting Undo from the Edit menu.
• If you click OK, the dialog closes and crossfading is made permanent.
If you click Cancel instead, the dialog closes and the waveform is reverted back to the way 
it was before crossfading.
Do not move the loop points after performing a crossfade! The waveform 
has been processed specifically for the current loop settings!
Creating a post-crossfade
The post-crossfade is accessed from its own tab.
This is identical to the regular crossfade, but it is applied to the area after 
the loop. This means that it is used to fade the material so that there will 
be no glitch when playback continues out of the loop.  
						

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28 – 678 Using samplers and creating loops
If you intend to use the sound in your sampler in such a way that the area 
after the loop is never played, you don’t need to worry about this feature at 
all! Some samplers don’t even allow you to play the area after the loop. 
However, if you do intend to use the area after the loop it is very important 
to have post-crossfade activated!
The post-crossfade looks at the part of the waveform that occurs just af-
ter the loop start and processes a certain area beginning at the end of the 
loop. The Length parameter adjusts the size of this area.
Everything else is identical to regular crossfading, see above.
Working with presets
As with effect processors, you can create presets for settings in the dia-
log for quick recall. See “Presets” on page 65 for details. This comes in 
extremely handy for example when processing a number of similar files, 
for example for creating a multisample (several instrumental samples 
mapped across the keyboard). 
						

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Using the Loop Tone Equalizer
The Loop Tone Equalizer is a function for looping those un-loopable 
sounds, for example sounds that constantly decay in level or continuously 
change in timbre. The Loop Tone Equalizer applies drastic processing to 
the sound that evens out changes in level and timbral characteristics, be-
fore and during the loop.
It does this by using one of the following two methods:
•Slice mixing
A number of slices is specified for the looped section. If for example you specify eight slices, 
the loop is cut up into eight sections of equal length. These sections are then mixed together 
as one sound which is repeated eight times. This new piece of audio replaces all audio in-
side the loop in a smart way so that no harmonic cancellation (due to phase offsets) occurs.
•Chorus smoothing
This has nothing to do with a conventional chorus effect, but uses a method known as 
“Phase Vocoding” to filter the harmonics. This method is recommended for looping ensem-
ble and choir sounds.
You can use both slice mixing and chorus smoothing in conjunction, but it 
is highly unlikely that you will ever need to. Note also that the original 
length of the loop will not be changed by the processing.
In addition to the above, the Loop Tone Equalizer includes a crossfade fa-
cility so that the original sound fades into the processed sections as play-
back approaches the loop start.  
						

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28 – 680 Using samplers and creating loops
To use the Loop Tone Equalizer, proceed as follows:
1.Set up a basic loop of the length you desire.
This will probably not be a very good loop. If it was you wouldn’t need to use the Loop Tone 
Equalizer.
2.Select Loop Tone Equalizer from the Sampling menu and click on the 
Loop Tone Equalizer tab.
3.Make sure that either slice mixing or chorus smoothing is activated and 
make the desired settings.
For slice mixing, you need to determine the number of slices. Only experimentation can tell 
how many slices are needed, but generally, the more slices, the more natural the sound (to 
a certain extent). However, the program puts a restriction on the number of slices, so that 
each one is never shorter than 20 milliseconds.
For chorus smoothing, you can make the following settings:
4.Switch to the Pre-Crossfade tab and set up a crossfade.
You will need to use this feature since the Loop Tone Equalizer itself changes the timbre in-
side the loop and only there. This will mean that the transition into the loop will not be as 
smooth as expected, unless you apply crossfading. Generally, this is the same as the cross-
fade in the Crossfade Looper window. However, the difference is that this crossfade is 
made before and up to the loop start. The processed material created by the Loop Tone 
Equalizer is added to the original material before the loop.
5.Click Apply, and the sound gets processed.
If you have playback going, repeating the loop, you will hear the change take effect after a 
short while.
• You can undo the crossfade by selecting Undo from the Edit menu.
• If you click OK, the dialog closes and processing is made permanent.
If you click Cancel instead, the dialog closes and the waveform is reverted back to the way 
it was before processing.
Option Description
Timbre This governs the amount by which the timbral characteristics of the sample 
should be evened out. The higher the value, the more pronounced the ef-
fect.
Chorusing The delay time of the chorus effect varies with the modulation, which 
causes a sweeping effect. What this parameter does is determine the 
width and speed of the chorus sweep.
Enhance Warmth Creates a smoother, warmer sounding effect.
Stereo Expansion This increases the width of the sample in the stereo sound image.