Command line options The Main Screen Connecting Presets & banks Preferences Shortcuts
RAKARRACK is a multi-effect processor for guitar players but the signal processing engine allows a full range of parameter adjustment making it suitable for almost any audio processing task. Forty-two effects are included in this version: Lineal EQ, Parametric EQ, Shuffle, Exciter, Compressor,Expander, Distortion, Overdrive, Derelict, DistBand, Echo, MusicalDelay, Arpie, Chorus, Phaser, Analog Phaser, Flanger, Dual Flange, Reverb, WahWah, AlienWah, MuTroMojo, Convolotron, Cabinet, Valve, AutoPan/Extra Stereo, Harmonizer, Noise Gate, Ring, Synthfilter, VaryBand, Looper, MuTroMojo, Echoverse, CoilCrafter, ShelfBoost, Vocoder, Sustainer, Sequence, Shifter, StompBox, Reverbtron and Echotron.
Ten can be used simultaneously on a chain.
Also Rakarrack has a Tuner and a monophonic MIDI Converter, and other features like resampling or Tap Tempo.
Rakarrack can be managed externally by MIDI, the program receive Program Change and the parameters can be controlled via Control Change MIDI messages.
One of the most important things of RAKARRACK is that everything is on a single mouse click. All the effect parameters are on the screen.
The effects are processed on a chain, the chain order processing is fully configurable by the user for each preset. The preset saves all the effects parameters. These presets can be grouped into banks to manage more efficiently. Saving a preset is as easy as typing a name.
Rakarrack is capable of generating high volume output. It has Gain controls in general and some of the effects allow high gain adjustments. Use these gains with caution because they can produce unwanted effects. However, a limiter is applied to the final output which prevents signal level from increasing beyond 0dB. Bear this in mind, for high gains triggering limiting in the output will initiate high-ratio hard-knee compression. This is better than hard clipping distortion, but the audio effect can be undesirable.
Rakarrack is a JACK application, Dave Phillips wrote some good articles in their blog of how to use Linux audio with jack, if you don't know about jack, or you have problems running rakarrack, please read this series of articles:
Troubleshooting Linux Audio, Part 1
Troubleshooting Linux Audio, Part 2
Troubleshooting Linux Audio, Part 3a
Troubleshooting Linux Audio, Part 3b
Please read the INSTALL, README and PACKAGERS.README files provided with rakarrack. You will find there a list of required dependency packages and detailed configuration options.
From 0.5.0 version we have included resampling and convolotron effect, the quality and amount settings of resampling must be set with extremely care, because they use a lot of CPUresources, in fact most computers can't afford the "Best" resampling quality if the amount of resampling is "x4" or greater. The resampling process makes each effect use more CPU resources because need to process more samples, if you combine wrong settings with convolotron or harmonizer effects that use also a lot CPU resources the results can be unpredictable. Wrong settings can hang up you computer. You have been warned.
Of course resampling increase the sound quality, the way to set up is start with the worst resampling settings, amount = "x2" and Quality "Linear", the the jack load CPU value is displayed in the status bar in the preset block, if you want more accurate CPU usage values use top, htop or other CPU monitors, then increase the values thinking that then next step of quality could use double CPU than the actual set, that's not exactly in the lower resampling quality levels, but is more or less accurate in the high levels. You need to find a good balance between amount and quality settings to obtain the better sound that your computer can afford. Don't forget that each effect use also more CPU with resampling, then the best to set the resampling settings is using a preset that has five or six effects.
Convolotron has a "Safe Mode" parameter, that "magically" limits the length of the Impulse Response file read, this is safe because limit the CPU usage, this maximum length is calculated reading the bogomips, is not dynamic and don't measure other tasks that your computer may be performing. We have been careful to calculate this maximum value, but if you use resampling this "safe" value can be ridiculous and may cause depending of the Impulse Response file read that the convolotron effect don't has sound, that can happens if the value is less than 5 ms.
Of course increasing the length parameter you will obtain a better convolotron sound, if you unset the "Safe Mode" you can set the length to a desired value without the magical limit, but do that with extremely care. Check the jack load CPU in the status bar or use a CPU monitor to see what your computer can afford. Do that with small steps and checking the CPU usage, or you will hang up your computer. You have been warned.
About Clipping and limiting.
Rakarrack includes an output limiter to help you keep the signal at or below maximum recording levels. There are two indicator lights along the top of the display to indicate when limiting and clipping is active.
Lmt Limit. This is the compressor part of the limiting function. This lets you know when Rakarrack output limiter is automatically reducing volume when the signal level is too high.
Clip The output limiter is clipping the peaks of the signal. Usually the attack of dynamics are clipped for short periods of time before the compressor catches up with the high signal level. When the signal level is extremely high, the peaks will always be clipped. This is indicated with a red flashing light.
Both clip and Lmt mean the same thing to you as the user: Turn down the output until the lights don't blink, or if they blink, very very infrequently. Any time the lights blink, there is some distortion on the output, and it is probably unwanted distortion. It will be noticeably audible distortion if the lights blink frequently, or for long periods of time.
This is not an arbitrary limit. This is at the limit where the input to a recording program such as Ardour or Qtractor will be too hot. If it was not clipping in Rakarrack, it would be clipping in Ardour, and would be worse sounding. Most sound cards will physically clip on the hardware output at these levels. The full range in Rakarrack will produce a full range signal swing.
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Short Format |
Long Format |
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|---|---|---|
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-h |
--help |
Shows the command line options and exits. |
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-n |
--no-gui |
Start the application without GUI |
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-l file |
--load=file |
Load file single Preset |
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-p # |
--preset=# |
Set Preset number # |
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-b file |
--bank=file |
Load a file Bank |
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-x |
--dump-preset-names |
Dump Bank preset names |
rakarrack -l mypreset.rkr Starts Rakarrack and load the preset file mypreset.rkr
rakarrack -n -b mybank.rkrb Starts Rakarrack without GUI and load the bank file mybank.rkrb
The connections shown in the screenshot correspond to a motherboard sound card. The guitar is connected to the input line. Obviously this configuration can vary depending of your sound card. RAKARRACK has two inputs to allow use of stereo devices. The screenshot shows the connection of a guitar, usually mono aural.
The state of the rack can be saved to a file at any time, either pressing the "Save" buttons or via the menu File->Save Preset. Rakarrack suggest the preset name for the filename.rkr in the save operation, but you can put what you want. You can assign the preset name here:
If the user modifies any preset bank, The "compare" button allows you to compare the sound of the current state of rakarrack with the original bank preset from which it departed.
You can use banks to store groups of presets. 60 preset can be saved on a bank. To include a preset in a bank must first indicate the name of preset on the main screen, open the bank window and click on a empty slot with the right mouse button. To retrieve a preset stored in a bank must open the window of banks and clicking the left button on the preset desired, also you can use the Preset selector of the main window.
To save a preset in a bank:
Put descriptive name to the preset
Open the bank window (B)
Press the right mouse button in a empty place OR
Press the right mouse button on an existing preset if you wish to overwrite it.
To retrieve a preset from a bank:
Open the bank window (B)
Click the left mouse button on the preset
To swap presets in the window:
Open the bank window (B)
Click the left mouse button on the preset, drag and drop on the preset you want to swap
When rakarrack starts always load the bank selected in preferences unless you specify another bank in the command line. Of course you can load/save any bank via menu File. By default, is allocated in preferences the installation included bank. This bank ("Default.rkrb") is installed with root properties, then you can't overwrite as user. But is easy to save in any place to work with it. The bank contains default presets developed by the development team and some friends who have contributed in this facet.
The "Random" button generate a random preset
Three banks are released with rakarrack, Default.rkrb, Extra.rkrb and Extra1, they are installed in the data directory selected in the configure process normally in "/usr/share/rakarrack" or "/usr/local/share/rakarrack".
The purpose of buttons "1", "2", "3", "U" is fast bank load function, this buttons loads the Default.rkrb, Extra.rkrb, Extra1.rkrb and the user settings defined banks.
Up the Bank windows screenshot, the tittle bar show the loaded bank. Click on preset or use preset counter in the Preset section to change the preset.
Presets marked with (*) use the Select mode in the Harmonizer effect, that means you need to play a monophonic melody in the Key/Chord selected. The harmonizer recognizes what note you play and creates a second voice in the Key/Chord selected.
Buttons 1,2,3,U are for fast load banks, the 1,2,3 loads the Default, Extra and Extra1 banks released with rakarrack, the "U" button, that means user, load the Bank filename defined as default to load in settings.
The choice display the available user banks that you have in the directory specified in the User Directory settings, is also a fast way to load "user" banks
Colors
Through the Settings Look tab window you can configure different aspects of the application. The colors of he four elements on the screen, background, buttons, labels and leds.
Scheme
Also you can select the following schemes of widget decoration, X11, fltk, gtk+ y plastic. Some small example of fltk and plastic.
Font
Select the label font for the main window.
Font Size
Increase/Decrease the font size of some windows.The Reset button set the relative value to "0"
Enable Background Image
Enable background image or use background color
Background Image
You can also select a PNG background image clicking on the 'Browse' button and also adjust the font sizes. Some background pictures are distributed in the rakarrack tarball package, they are installed in the data directory selected in the configure process normally in "/usr/share/rakarrack" or "/usr/local/share/rakarrack".
The Skin save/load menu options located in the main menu save or restore the rakarrack look. If you have made a nice look and you want to share please send this file and the background picture to any of the rakarrack team members and will include on the website.
Fx On at start
This option put the FX On at the start, by default is Off.
Filter Input DC Offset
Input DC Removal. Removes constant offset from input signal. If you experience strange behavior with compressor or distortion, or if you see output signal even when no sound is going in, enable it. A "cheapo" soundcard or microphone inputs can be sources of this problem.
Preserve Gain/Master
The Input Gain and Master Volume are stored in the preset and applied with the preset is loaded. If this option is enabled, the Input Level and Master Volume will not be modified when preset changes.
Update Tap Tempo
If enabled each time you change the preset the Tempo parameter on the active will be updated with the Tap Tempo value/settings. By default, the Tempo settings from the preset are used.
Upsampling
Enable upsampling using libsamplerate. With this enabled, Rakarrack will process the effects with higher sample rate than what is coming from the sound card. All the resample parameters will take effect the next time you launch rakarrack. Enabling upsampling in Rakarrack will use a lot more of your computer CPU resources but will result in very professional sounding effects. Take care to adjust all the upsampling settings in small increments because you can hang your computer if your main processor can not handle the resampling parameters. Each level of libsamplerate quality uses more and more resources, and of course each effect uses more CPU resources because it needs to process a higher amount of data in the same amount of time. We highly recommend start with Linear quality and amount "x2" and check your CPU usage with "top", and then increase the amount/quality as desired.
Amount
Amount of resampling (x2, x3, x4, x5, x6). This is a multiple of your Jack samplerate.
About Resampling Quality
Here is the summary:
Best Best sinc interpolation.
Medium Reduced Bandwidth sinc interpolation.
Fastest Fastest sinc interpolation.
Linear Linear interpolation, not band-limited.
Zero Order Blazingly fast, but does not interpolate.
The only difference between Best, Medium, and Fastest is the bandwidth. "Fastest" limits to 80% of the maximum bandwidth, but the interpolation quality is equal to Best sinc interpolation. As a general rule, you can often save some processing requirement by using a lower quality upsampling setting (Linear, or Zero Order), but it is important to use high quality downsampling if any of the effects you use add higher harmonics not present at the input (distortion, Arpie, Harmonizer).
If using Linear or Zero Order resampling it is advisable to use a low-pass filter on the input (like CoilCrafter or MuTroMojo), then again as the last in line. The filter will perform interpolation before the signal is processed.
Resampling has two uses:
1) Improve the "richness" of filters & Equalizers. This will by nature improve the accuracy of the EQ's while making filter effects such as Chorus, Flanger or Phaser sound more natural.
2) Reduce the amount of aliasing effect produced by nonlinear