OPERATOR'S MANUAL
Table of contents

Glossary

DAW
Multipass is not a standalone program, it needs to be used in conjunction with a host application where it is loaded as a plugin. These programs are usually called "DAWs" (Digital Audio Workstations) or simply "hosts". There are many different DAWs available on the market, and Multipass works with those that support either the VST or the Audio Unit plugin architecture.
Patch
A patch is a configuration of Multipass that gives it a certain sound. Whenever you pull a slider or turn a knob you modify the current patch.
Preset
Presets are ready-made patches which ship with Multipass. In Multipass you will find hundreds of different presets ready to be used in any song. Presets also make good starting points for your own patches. Presets are grouped into banks. More preset banks may be available to download using the Kilohearts installer.
Snapin
Similarly to how a DAW will load Multipass as a plugin, Multipass itself can also load small audio effect modules called snapins. Snapins can be used either directly in your DAW as a VST or Audio Unit, or used as building blocks in a Multipass patch.

System requirements

These are the minimum recommended system requirements for running Multipass.

CPU
2 GHz or faster
Memory
1 GB or more
Operating System
Windows (7 or newer) or Mac OS X (10.7 or newer)
Software
A VST or Audio Unit compatible DAW

If you have many instances of Multipass running, or use a lot of snapins at the same time in your patch the CPU usage will increase accordingly. Thus, we cannot guarantee that Multipass will work flawlessly in all use cases even if your system does meet the minimum recommended system requirements.

Overview

Multipass is a multiband effect plugin with many uses. At the heart of the plugin is a band splitter which splits the audio into several different frequency bands which can be processed independently. Multipass delegates the actual processing of the bands to other single-purpose effect plugins known as snapins. Snapins come in many different flavors, and implements many classic effects like distortion or chorus as well as more unusual ones like formant filtering and frequency shifting.

In addition to being loaded into Multipass, snapins can also be loaded as plugins directly in your DAW. Multipass is bundled with a few different snapins, and more can be bought from the Kilohearts website.

User interface

Overview

This is an overview of the plugin UI. It may look a bit overwhelming at first, but let's try to break it down a bit.

  1. In the top bar the name of the current patch is shown. By clicking the patch name you will open up the preset browser from where you can save and load presets.
  2. The eight large knobs under the patch name are known as the macro knobs. These knobs can be routed by the sound designer to any other parameters in the patch in order to provide a few easy-to-reach knobs for tuning the sound of the patch. A single macro knob can even be routed to several parameters.
  3. To the right of the macro knobs sits the modulation area. From here you can modulate parameters of your patch using LFOs (low frequency oscillators), Envelopes or MIDI input. The different modulation options are described in detail below.
  4. The large spectrum displayed in the middle of the plugin is the band splitter. It splits the audio signal into up to five different frequency bands which can be processed independently.
  5. The big space below the band splitter holds the snapin lanes. Each lane can hold several snapins. Adding new snapins is as easy as clicking the empty space at the bottom of a lane.
  6. Under each lane, at the very bottom of the window, sits the lane mixing controls. Here you can adjust the gain and pan of each lane independently, among other things.

Signal path

Now that we have some intuition on what parts make up Multipass and where to find them on the screen, let's take a peek under the hood to see how Multipass processes the audio you send into it.

Signal path

The figure above is a schematic of the signal path through Multipass. The audio signal enters the plugin in the top left corner, and passes through a few stages of processing before leaving at the bottom right. Let's take a look at each of the stages in turn.

Pre FX Lane
Before reaching the band splitter the signal will pass through the pre FX lane where snapins can be added which will affect the signal as a whole before band splitting.
Band splitter
Next up is the band splitter, which splits the signal into up to five bands and sends each band into its own band lane. The band splitter uses Linkwitz–Riley crossover filters, which ensure that a flat frequency response is achieved when the bands are mixed back together.
Band lanes
Each audio band is processed separately by the snapins in its band lane.
Band mixer
After the audio bands have been processed by the snapins in the band lanes they are mixed back together. The band mixed also allows blending between the dry unprocessed signal coming out of the band splitter, and the wet signal which has been processed by the snapins in the band lane.
Post FX Lane
Before the audio signal leaves Multipass the post FX lane provides one last chance to process the audio signal as a whole, after the bands have been mixed down. This can, for example, be a good place to place a compressor or limiter snapin to keep the signal level in check. The band mixer also controls how much of each band is sent to the post FX lane, and how much is passed straight to the output without post FX processing.

Operating the controls

Most parameters of Multipass are controlled by the knobs and the sliders seen in the UI. To move a knob or slider simply click on it, and while holding the mouse button down move the mouse up or down.

Sometimes you might want more precise control when tuning a parameter. Hold the shift key while moving a knob or slider to enter fine tuning mode, where the knob or slider will move more slowly.

You can reset a knob to its default position by double clicking it.

Finally, most controls support entering the value using your keyboard by right-clicking on them.

Working with patches

The first thing you want to do after installing Multipass is probably to try out some of the presets it comes with. To reveal the preset browser, click on the name of the current patch in the top most part of the UI.

Patch selector

Loading a preset in the preset browser is as easy as clicking on it. The preset browser also allows saving presets, and organizing them into folders. Presets are divided into two categories, factory presets and user preset.

Factory presets are included with Multipass or downloaded using the Kilohearts installer. Factory presets are write protected to protect them from accidental corruption.

The user presets folder is where you as the end user should store your own presets. By default this folder is located in your documents folder, but you are free to relocate it elsewhere.

Building your sound

Once you have checked out some of the presets you are probably eager to get your hands dirty and create your own patches. We designed Multipass to be easy and fast to work with, and we hope you will enjoy experimenting and discovering the possibilities. Still, knowledge is power, so in this section we will go through all the features of Multipass in detail.

Band splitter

Band splitter

The band splitter lets you adjust the crossover frequencies for the different bands. The spectrum analyzer in the background is a visual representation of the sound as it is when it enters the band splitter (i.e. right after the pre FX lane).

To change the crossover frequencies, click and drag the vertical bars representing the splits across the spectrum. You will notice that you can't drag splits across each other.

As you enable and disable different lanes, splits will be added and removed automatically as needed.

Lanes

Lane Lanes are divided into three parts. The header, where you will find a few toggle buttons, the main part of the lane, which holds the snapins in the lane, and the footer where you will find some mixing controls.

In the lane header you will find the following controls:

Enable button
This toggle button will turn on or off the whole lane. When the lane is turned off no sound will pass through it at all, and any snapins sitting in it will have no effect. This will also turn off this band completely in the band splitter, sending the audio that would normally pass through this lane into the lanes next to it. It is advisable that you turn off all lanes that you are not using, to spare some CPU cycles, and to avoid unnecessary phase distortion from the filters in the band splitter.
Mute button
A toggle switch for muting a lane. The band splitter will still send audio to the lane, but it will simply be discarded.
Solo button
This toggle button will mute all all other lanes. It is useful during sound design if you temporarily want to listen to the audio that passes through just one lane.

In the lane footer you will find some knobs which impact how the output of the lane is mixed down during lane mixing:

Gain
Changes the volume of the output of the lane.
Pan
Pans the output of the lane left or right.
Mix
Adjust the output mix of the lane between completely unprocessed at 0% to fully processed with snapins at 100%.
Post
Adjusts how much of the output of this lane to send to the Post FX Lane for processing. At 0% the output of this lane skips the Post FX Lane completely, at 100% all of the output is sent through the Post FX Lane.

Snapins

Add snapin icon To add a new snapin to a lane, click the add snapin icon which appears when you hover the empty space in a lane. This will make a dialog appear giving you a selection of all the snapins you have installed. Simply click one to add it to the lane.

Snapins can be reordered or moved between lanes by clicking their title bars and dragging them. If you hold the ctrl key when dropping the snapin you will make a copy of it instead of moving it

To remove a snapin simply click the little X icon in the top right corner of the snapin.

Modulation

Almost all parameters in Multipass and in snapins can be modulated. In Multipass you will find five different modulation sources that can be used for modulation; macro knobs, LFOs, envelopes, pitch tracking and MIDI.

Hooking up a modulation source to a target parameter is done in pretty much the same way for all modulation sources. Look for the little link icon appearing when you are hovering your mouse pointer over a modulation source. Clicking the link icon selects the modulation source and switches the UI over to modulation target selection mode. In this mode a small orange modulation knob will appear next to each possible modulation target. Click and drag on the modulation knob to connect the modulation source to the target parameter and set the modulation level. The modulated control will to turn an orange color to indicate that it is being modulated.

After a modulation source has been connected to a target parameter the modulation knob will be visible next to the modulation source at all times. The modulation knob will also appear next to the modulation target when the target is hovered. The modulation knob can be dragged to adjust the level of modulation. To disconnect the modulation, double click the modulation knob.

Macro knobs

Macro Area

The macro knobs can be routed to any other parameter in Multipass or in Snapins using the modulation system. This lets you control many different aspects of the sound of the patch using a single macro knob. The macro knobs can be renamed by clicking on their label. The new name is stored in the preset.

The macro knobs are probably the first thing you should take a look at when trying out new presets, since the preset maker may have routed them to allow quick adjustment of some key parameters in the preset.

LFOs

LFOs

Multipass is equipped with two low frequency oscillators, or LFOs for short, which are ideal for modulating parameters in an oscillating and rhythmic fashion.

Frequency
Controls the speed of the oscillator, either in Hertz when in free running mode, or as a note length when running in synced mode.
Shape
Oscillator shape can be one of sine, triangle, square, saw tooth, soft noise, hard noise.
Depth
Adjusts the amplitude of the LFO. Can be modulated in order to, for example, make the LFO modulation fade in using an envelope.
Phase
Adjusts the phase of the LFO. Is especially useful when the LFO is in synced mode, or when retriggering is enabled. The phase parameter can also be modulated, for example by the other LFO, for interesting effects.
Retrigger
The LFOs in Multipass offers two different retrigger modes. Setting retrigger to on causes the LFO to restart whenever the trigger condition is met. The sample & hold mode instead cases the value if the oscillator to be sampled whenever the trigger condition is met.
Source
This drop down selects which input signal controls triggering. When this setting is set to note on the LFO will retrigger whenever a MIDI note on event is sent to Multipass (this requires that your DAW sends MIDI events to Multipass in the first place). The other option is to retrigger whenever the audio level goes over a certain threshold. You can select audio signals for retriggering between main (the main input to Multipass), external (secondary / sidechain input to Multipass) or band for input signal to a certain band.
Gate
If the trigger source is set to one of the audio sources the threshold for when triggering should occur can be set using this fader. The current peak level for the selected audio channel is shown on the encoder of the fader.

Envelopes

Envelopes

Multipass is equipped with two envelopes, which can be used to modulate parameters using the audio volume or MIDI note events.

Mode
Three envelope modes are available. In peak and RMS modes the volume of the audio is tracked and used as the modulation value. There is a subtle difference in how peak and RMS tracks the audio volume. Peak mode tracks peaks in the audio volume and is thus very responsive to transients such as drum hits. RMS mode tracks the power of the signal using the root mean square method, which can give more stable results than peak mode, though the tracking may be less responsive. Finally, in ADSR mode the envelope will act like a attack / decay / sustain / release envelope of the kind that can often be found on synthesizers. The ADSR envelope can be triggered either by MIDI input or by audio volume.
Attack
When you trigger a note the envelope will start to climb up from zero to it's maximum level. This is known as the attack phase, the length of which is decided by the attack parameter of the envelope. Keep the attack low for a short snappy sound, or make it high for a slow sound which builds up over time.
Decay
Next follows the decay phase, where the envelopes drops down from its maximum level down to the sustain level. The time this takes depends on the decay parameter. The decay parameter is only available if the envelope is running in ADSR mode.
Sustain
After the envelope has dropped down to the sustain level comes the sustain phase, which lasts until the note has ended. Thus, the sustain parameter does not influence the length of this phase but rather how high the sustain level is. The sustain parameter is only available if the envelope is running in ADSR mode.
Release
When the note is released the envelope moves on to the release phase, where the envelope drops back down to zero. The time this takes is dictated by the release parameter.
Source
This drop down selects which input signal to follow or to use for retriggering. When this setting is set to note on the envelope will retrigger whenever a MIDI note on event is sent to Multipass (this requires that your DAW sends MIDI events to Multipass in the first place). The other option is to follow the volume level of an audio signal. You can select audio signals between main (the main input to Multipass), external (secondary / sidechain input to Multipass) or band for input signal to a certain band.
Gate
If the mode is set to ADSR and the source is set to one of the audio sources the threshold for when the envelope should be triggered can be set using this fader. The current peak level for the selected audio channel is shown on the encoder of the fader.
Curve
Selects between exponential and linear falloff in the decay and release phases when the envelope is in ADSR mode.
Legato
Selects whether the envelope should restart from zero or if it should continue from its current value when it is triggered in ADSR mode.

Pitch tracking

MIDI

The pitch tracker allows modulation using the pitch of the input signal. The modulation output of the pitch tracker is set to match any frequency based parameters at 100%. For example, this means modulating the cutoff of the Filter snapin with 100% pitch, the cutoff frequency will follow the tracked frequency of the input similarily to how 100% keytracking in a synth behaves.

Lower and upper note limit
Two vertical handles can be used to select the expected pitch range of the input. This hint helps the algorithm perform better and reduces the risk of glitches in the pitch tracking.
Root
The root parameter acts as an offset in the modulation output. If the input signal has the same note as root, the modulation output will be zero. Lower notes will yield negative modulation values and higher notes will yield positive modulation values.
Sensitivity
This parameter adjusts the sensitivity of the algorithm, and higher values result in faster tracking but is more prone to glitches. The default value of 50% is usually a good compromise of speed versus stability, but this can be tweaked to improve the tracking depending on the input.
Source
This drop down selects which input signal to track the pitch of.
Gate
The gate parameter sets a lower limit of when to run the tracking, to help avoid trying to tracking quiet unpitched sounds like noise.

MIDI

MIDI

The MIDI tab allows modulation using MIDI input. Since Multipass is an effect rather than an instrument, many DAWs will not route MIDI events to it by default. Check the documentation for your DAW for details on how to set up MIDI routing.

Pitch
This wheel is connected to the pitch wheel commonly found on MIDI keyboards. The pitch wheel has its zero position in the middle of the wheel, and spans in range from -1 to +1. Whenever the wheel is released it snaps back to the zero position.
Mod
This wheel is connected to the modulation wheel commonly found on MIDI keyboards. In contrast to the pitch wheel, this wheel ranges from 0 to +1 and does not snap back when released.
Note
This modulation source is based on the last played note on the keyboard. Higher notes give higher modulation values.
Velocity
This modulation source is based on the velocity of the last played note, i.e. the force with which you hit the key on the MIDI keyboard when playing a note.
Pressure
This modulation source is based on the channel pressure, i.e. the force with which you hold down the keys on the MIDI keyboard.
MIDI CC slots
To the right of the slots for note, velocity and pressure are three general purpose MIDI CC slots which can be bound to any MIDI controller. To bind a slot to a controller, simply click on it and then move the controller on your MIDI keyboard.

Snake

Snake

Last but not least, let's not forget that Multipass includes the revolutionary productivity tool snake. Move the snake around the playing field with the arrow keys and consume the fruit as fast as possible to acquire points.

If you want more of a challenge, crank up the speed knob to make the snake move faster.

Multiple outputs

Snake

While Multipass is a regular effect, it does in fact have 5 additional stereo outputs. Usually these are left silent, but in DAWs that support it Multipass can route the separate frequency bands to these additional AUX outputs. At the bottom of Multipass there is a button which can be toggled between three states: MAIN, MAIN + AUX and AUX ONLY. These three modes determine where to send the output of Multipass: To only the main output, to both main and AUX, or to AUX only respectively. Refer to the manual of your DAW to see how to set up multiple output routing, if possible.

Acknowledgements

This development of this product was helped by the following pieces of excellent open source software:

Boost C++ Libraries

Skia Graphics Library
Copyright © 2011, Google Inc.

Symbiosis AU/VST
Copyright © 2010-2013, NuEdge Development / Magnus Lidström

LodePNG
Copyright © 2005-2015, Lode Vandevenne

C++ optimized SHA1 algorithm
Copyright © 2011, Micael Hildenborg

miniz
By Rich Geldreich

FastDelegate
By Don Clugston

FFTReal
By Laurent de Soras