There is a technique many people overlook today that involves chopping up a sample into really small chunks, then looping those chunks in a sampler. This can give phat & nasty results, and is essentially a homemade wavetable oscillator.
The technique is easy: find a sample, chop out a small section, import the small section into your sampler and loop it. While using a single wavecycle is often sufficient, you can also use any length sample so long as it is really really short in length.
By using short clips of other premade bass samples, you can process your sounds into the filthiest sounds that even Noisia or Borgore would be scared of!

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Wavecycles and Wavelength - Important information to know before starting the tutorial
Before we start the tutorial, you need to understand what a wavecycle is.
A simple introduction to wave cycles and wave lengths can be found at http://zonalandeducation.com/mstm/physi ... eParts.htm

Now that you hopefully understand what a wave cycle is, we can start the process of creating our own!

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Step by step tutorial for 'single cycle' resampling
1> Find yourself a sample that you like, or make your own using a synthesiser. (I often create nice sounds using a normal synthesiser, and apply effects to the sound using my sequencer package before bouncing the .wav).
This is the sample I am going to edit.

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2> Import your sample into an audio editor. (If you don't have an audio editor, download Audacity which one of the best free ones available).
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3> Zoom in on the waveform and find a section that looks interesting.
Here I am selecting a portion of the waveform to use.

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4> Select the area you like and trim the sides off. (Most audio editors have an edit command which allows you to delete outside the selection only, if not delete each end one at a time).
Here is the waveform I have saved and will import into my sampler. [NOTE: The start of the slice has not been cut at a zero-crossing. This will cause distortion once looped in a sampler due to the mismatched zero crossings (see below)].

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5> In order to avoid adding distortion as the waveform loops, it is wise to make the cuts at zero crossing points. (The 'zero-crossing' is the point where the coloured waveform lines cross over the vertical white lines in the top-most picture of this tutorial). So by ensuring that the volume is matched at both ends of the audio segment, you can avoid introducing distortion.
You can fix this by applying a very short fade in and fade out at the start and end of your selected audio. This should match the start and end points of the loop at the zero-crossing automatically.

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6> Save the new waveform as a .wav.
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7> Reimport the new short waveform into your sampler and switch on playback looping (for the sample). (You may also need to map the sample across the keyboard depending on your sampler).
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8> Play a few notes... You now have created your own homemade wavetable synthesiser!

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9> Apply effects as you would normally.
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10> Repeat the process with a new section of a waveform, and build up a library of wavecycles!

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Step by step tutorial for 'single cycle' resampling
TIP 1: If your sample sounds 'buzzy' in your sampler, cut a longer section of your source sample. You can also try playing lower notes on the keyboard.
TIP 2: Experiment with the length of the samples you cut for interesting results.
TIP 3: Try slicing samples you wouldn't normally make basslines with. You'll be surprised at the basslines you can make using these types of samples as your source material for the slicing!

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Extra Info
The quote below may help shed more light on the technique.
As you can see, there are lots of points that could be sampled in that waveform, the most obvious one being the sustain section (described in more detail below).
--------------------------------------------------------------------------lilt wrote:
In the picture above you can see how there are some very large peaks at the start of the waveform (on the left).
This is called the 'transient' and is defined by the Attack and the Decay stages on an ADSR envelope.
Can you see how there is one particular section of the wave that has been repeated over and over again (looped)? This is the Sustain portion of the waveform.
What is missing from the waveform in the picture is the end section (the Release portion of an ADSR) which is where the sound trails off into silence.
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A sampler that has the ability to set loop points can be used to sustain a really short section of a sample, thus creating a wavetable oscillator.
You will find most samplers have the ability to loop until 'note off', which means that once a note is played, the sound will loop until the note is released and fades away to silence.
Loading wavecycles into synthesisers
Some synthesisers allow users to load their own wavecycles into the oscillators. In some cases this gives the users more options for working with the waveform. For instance, some synths allow phase width modulation of user waveforms, and this is extremely powerful*.
These include:
Jeremy Evers Atlantis* (free)
SKnote Grainz (free)
Vember Audio Surge* (payware)
Camel Audio Alchemy (payware)
FAW Circle (payware)
3xOsc in FL Studio (payware)
Zebra2 (payware)
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Hand drawn wavecycles
There are also synthesisers that allow users to draw custom waveforms directly into the synthesiser. This is great for those of us who wish to define their own waveforms without having to slice them.
My personal favourite is the freeware synth called Fuzzpilz Oatmeal. It allows for phase modulation on the user drawn waveforms, which is very powerful. It can also be reskinned if you don't like the default graphics, my favourite theme being 'lf_lumina'.
Another synth that allows users to hand draw waveforms is 'Freehand' by Angular Momentum.
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Summary
If you find this tutorial helpful, vote yes in the poll at the top of the thread.
Also share your own tips, methods and experiences of this technique below!
If any of you have experience of this technique using specific programs, if you have the time, it would be great if you could post step-by-step methodologies for your selected program. Remember to include screenshots too!
Many thanks and have fun making basslines!

Patrick