KitStarter

kitstarter is a Qt -based program you can use to "sketch in" a drumkit SFZ file.

Its strongest feature is the samples widget, which allows you to use your mouse to adjust what range of velocities each sample plays at, and automatically adjust at what proportion multiple samples play at when their velocity traigger ranges overlap. More on this below.

The user interface

Instrument list

You are presented with a window with a list of dumkkit instruments on the left panel. Once an instrument has been defined, it is indicated on the instrument list with a check mark.

"Instrument" here refers to a single piece of the drumkit being assembled, i.e. "Low-Mid-Tom", or "Crash Cymbal 1".

Selecting an instrument on the instrument list places it in focus. All the samples which are assigned to that instrument list will show up in the samples widget.

Samples widget

The samples widget allows you to adjust the range of velocities which each sample responds to. You may delete a sample, Adjust the relative volume of that sample, adjust it's tuning in semitones and cents, and adjust the pan of the entire group of samples, which comprises an "instrument".

If multiple samples have been assigned to a single instrument, they will be shown stacked one above the other. Clicking on the button labeled "Spread" will adjust the velocity range of each sample, so that the sample at the top of the widget responds to the lowest velocities, the sample at the bottom of the widget responds to the highest velocities, with each sample taking up an equal range of MIDI velocities which to respond.

You can use the up/down arrows at the right side of each sample entry to change the order in which they appear, placing the sample for the quietest parts at the top, and the samples for the loudest parts at the bottom.

Each sample's velocity range is shown with a graph. The blue area represents the range at which the sample responds. Clicking on the left side of the range will set the lowest velocity ("lovel") that the sample is triggered by, and clicking on the right side of the blue area will set the higest velocity ("hivel").

Checking the box labeled "Snap" causes all the samples' velocity ranges to be respond to the mouse. If the mouse position in the X axis is near either bound of any of the sample velocity range graphs, they will be adjusted as the mouse moves.

The "Cross fade" checkbox allows you to automatically create overlapping amplitude velocity envelopes for each sample. What a velocity envelope does is causes the sample to be played at a volume which varies depending on the incoming MIDI velocity.

For instance

Let's say you have three samples of a bass drum. One quiet, one hit with a medium velocity, and one really loud. These samples are named "bass-drum-low.wav", "bass-drum-mid.wav", and "bass-drum-high.wav"

You want them to play a these velocities:

But instead of switching abruptly from one to the other, you want to mix them, so that at velocities near where you transition from one sample to the other, both are played, but at a different ratio.

That's where the "amplitude velocity envelopes" come in. By overlapping the highest velocity of one sample with the lowest velocity of the next louder sample, and introducing an amplitude velocity envelope, you can do just that.

Here's the updated velocity ranges:

You can see, between MIDI velocity 34 - 53, both "bass-drum-low" and "bass-drum-mid" play. But you don't want them to play at full volume all the way through the overlap. At the lowest velocity in the overlap, you want "bass-drum-low" to play at almost its normal volume (just a little less), and you want "bass-drum-mid" to play very quietly. Together, they should combine to produce a volume at almost the same level as if either one was played with no overlap.

As you go up the scale, "bass-drum-mid" should progressively get louder (relative to its normal volume) until it plays at its normal volume for the incoming velocity, while "bass-drum-low" does the opposite.

Note that there's no real-time "cross fade" ocurring. That may be a little misleading. All we're doing is adjusting the effective velocity of the sample when it is triggered, based on where in the overlapping range the incoming MIDI velocity appears.

Files and samples

At the bottom of the window, you have the file explorer and the sample explorer.

The file explorer allows you to select an sfz file. When you have selected a file, its samples appear in the sample explorer. You can filter the samples displayed to only show the samples which are triggered by the currently selected instrument, by checking the "Filter " check box.

The samples explorer shows you the currently selected samples. If the samplerate of the file is the same as the samplerate of the JACK server, it shows as okay. If the samplerate of the sample differs from that of the JACK server, it shows a warning symbol. This is relevant because during playback it's impossible (or at least, very difficult), to change the rate when it gets sent to the JACK server. So what you hear may not be exactly what you get!

Clicking on a sample in the samples explorer plays the sample. Releasing the mouse button stops it from playing. Right clicking on the sample brings up a context menu, with the following commands:

1. Pin
2. Use "" for ""
3. Copy path to clipboard

"Pinning" samples

"Pinning" samples makes them available in the samples explorer, regardless which SFZ or audio file, if any, is selected in the files explorer. You can choose whether or not to display pinned samples using the "Show pinned" checkbox. Deselecting the "Show selected" checkbox causes only pinned samples to be displayed.

Pinned samples persist between uses, so you can use this feature to keep a list of your favorite samples on disk.

Saving files

When you're satisfied with the sound of your kit (or just need to take a break for awhile), clicking on "File" -> "Save as.." in the main menu brings up a file dialog which allows you to choose where to save your newly created SFZ.

The newly saved SFZ points to the original samples that you used to construct it with. If you would like to gather all the samples in a single folder, the best option, at the moment, is to use the "sfz-copy" script which comes as part of the sfzen package.

"sfz-copy" allows you to copy an SFZ to another location along with its samples. The help text for sfz-copy shows which options are available:

--copy, -c      Copy samples to the target samples folder (default).
--symlink, -s   Create symlinks in the target samples folder.
--hardlink, -l  Hardlink samples in the target samples folder.
--abspath, -a   Point to the original samples - absolute path.
--relative, -r  Point to the original samples - relative path.

Obviously, only the first option will truly make a copy of the source samples. All the other options either create links to the originals, or point to the originals using the sample path.

That's a quick rundown. If you have questions or feedback, please use the issue tracker at github.com, where this project is hosted.