Kilohearts Multipass User guide

OPERATOR'S MANUAL

1

Table of contents

Glossary ...................................................................................................................... 3

System requirements .................................................................................................. 4

Overview ..................................................................................................................... 5

User interface ........................................................................................................ 5

Signal path.............................................................................................................6

Operating the controls ........................................................................................... 7

Working with patches .................................................................................................. 8

Building your sound................................................................................................... 10

Band splitter.........................................................................................................10

Lanes ................................................................................................................... 10

Snapins................................................................................................................ 11

Modulation ........................................................................................................... 11

Macro knobs ........................................................................................................ 12

LFOs .................................................................................................................... 13

Envelopes ............................................................................................................ 14

Pitch tracking ....................................................................................................... 15

MIDI ..................................................................................................................... 16

Snake................................................................................................................... 17

Multiple outputs ......................................................................................................... 18

Snapin mode ............................................................................................................. 19

Acknowledgements ................................................................................................... 20

2

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 2, AAX 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.

3

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 DAW supporting VST 2, AAX, or Audio Unit plugin standards.

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.

The versions of the plugins installed via the Slate Digital installers, like other Slate
Digital products, uses the iLok licensing scheme. If you are using these versions, an
iLok (USB dongle or iLok cloud) with a valid license from Slate Digital is required to
use the plugins.

4

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

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, author and description of the current patch is shown.
By clicking the 'Browse' button you toggle the preset browser. To the right
you will find 'Undo' and 'Redo' buttons, allowing you to undo or redo all actions
in Multipass.

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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.

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.

6

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.

7

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 'Browse' button
next to the Multipass logo.

Loading a preset in the preset browser is as easy as clicking on it. Double clicking will
load the preset and also close the browser. You can also step through all the presets
in the current folder by using the arrow keys, or the arrow buttons in the top bar.

Presets are divided into a number of folders, visible on the left hand side. 'Favorites'
starts out empty but will be filled with any presets you favorite by clicking their heart
icon. 'Factory' contains the presets shipped with Multipass, categorized in subfolders.
The 'User' folder is the default location for saving your own presets, but you are free
to add any number of additional folders by clicking the 'Add Location' button at the
bottom of the list. Hovering a location you've previously added will show an 'x' button,
which allows you to remove it from the list again.

The search field has free text search of all preset information: name, description and
author. All words in your search will be matched in any order. To do exact matches of
multiple words, put your search terms in quotes. You can also quickly search for all
presets by a certain author by clicking the author name in the rightmost column, or
searching for "by:Author Name"

Left of the search field you will find back and forward arrows, which work much like in
a web browser by taking to to the previous folder or search results.

Right-clicking a preset in the browser list shows a small
context menu with controls for setting the default preset
for Multipass. This will make all new instances start with
the specified preset opened automatically.

You can close the preset browser by clicking the 'Browse' button again, clicking the
'X' button on the top right, pressing the escape key, or double clicking a preset

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Your currently selected preset is also shown in the top bar, where you can edit the
name, author and description by clicking them. Saving your changes is done with the
'Save' button, and the 'New' button clears the current patch.

The save dialog lets you choose where to save your preset. Note that write protected
folders like 'Factory' and 'Favorites' are not included. The 'Name' and 'Author' fields
reflect the preset info fields in the top bar, but gives you an opportunity to edit it again
before saving.

At the top of the dialog, the 'Create Subfolder' button lets you create subfolders to
categorize presets in any way you like.

9

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

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

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.

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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

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. To insert a snapin between existing snapins, hold
down alt/cmd (Win/Mac).

Snapins can be reordered or moved between lanes by clicking their title bars and
dragging them. If you hold the ctrl/alt (Win/Mac) 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.

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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.

In addition to just modulating knobs and parameters
directly, you can also use the modulation system to
modulate the depth of other modulations. To set up this
kind of modulation, enter modulation mode and then
click on the yellow star icon under a parameter with an
existing modulation. This will bring up a popup where
you can see all the modulations for the parameter. Click
on the dashed yellow rectangle under the modulation to
scale that modulation.

Modulations that target other modulations will be shown as yellow in the UI.

Macro knobs

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.

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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.

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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.

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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

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.

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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

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.

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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

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.

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Multiple outputs

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.

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Snapin mode

Multipass can also be loaded as a snapin in snapin hosts like
Snap Heap, Phase Plant or itself. In this mode, the Snapin
interface shows all named macros that have any modulation
bindings. At the top, up/down arrows can be used to scan
through presets and a full browser can be opened by clicking
the preset name. To edit the current patch, press the pen icon.
This will open the full Multipass interface in a separate
window.

The External Input selector allows you to choose which
sidechain channel in the snapin host should be mapped to the
external sidechain channel in the contained Multipass
instance.

19

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

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