Glou-Glou Loup User Manual
User Guide
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Loupé
V1.0 User Guide
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Table of Contents
Overview 9
Connections ...............................................10
Switches ......................................................10
Encoders .....................................................10
Displays .......................................................11
Audio Path ..................................................12
Filters ...........................................................12
Dry/Loop .....................................................13
Decay ..........................................................13
Games 15
Game select ................................................16
Game Edit ...................................................16
Game Exit and Save ...................................17
Params .........................................................17
Functions Basics 19
LED Status ...................................................20
Toggle / Sustain .........................................20
Alternate Endings ......................................21
Bar Clock, Quant Clock, QuantDiv ...........21
Quantized Functions..................................22
First Loop ....................................................23
Record .........................................................23
Reset ............................................................23
Default Mode .............................................24
Sample ........................................................24
Tails ..............................................................24
Overdub ......................................................24
Replace .......................................................25
Substitute ....................................................25
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Cycling Functions 27
Time Limit ...................................................28
Insert ...........................................................28
Instut............................................................28
Multiply .......................................................29
Stack ............................................................30
Record/BPM ...............................................30
Rounded Functions ....................................32
Unquantized Cycling Functions ................33
Mute and Trig 35
Mute ............................................................36
Pause ...........................................................36
Mutrig ..........................................................36
Trig, Trig/Q ..................................................37
Trig Point, Start, Start/Q .............................37
Undo 39
Undo Display ..............................................40
Alternate Ending ........................................41
Undo and Decay ........................................41
Overdub Trick .............................................41
Scroll 43
Operation ...................................................44
Scroll Exit and Undo ..................................45
Recording Scroll with Multiply ..................45
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ReadFX 47
General Philosophy ...................................48
More in Depth ............................................48
Multiple ReadFX in a Game ......................49
ReadFX Display ..........................................49
Composing your ReadFX, Preview ...........50
Copying ReadFX ........................................50
Recording of ReadFX.................................50
ReadFX Parameters 51
Mix ...............................................................52
Feedback ....................................................52
Pitch .............................................................53
Reverse .......................................................53
Stutter ..........................................................54
Drift ..............................................................56
Auto-Follow ................................................57
Modulation .................................................60
Redux ..........................................................60
Special Modes 61
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ForceDry .....................................................62
Expression Pedal (EXP) ..............................63
Feedback ....................................................63
Swell 1 .........................................................64
Swell 2 .........................................................64
Soft Replace ................................................65
Sync / OS Update 67
Synchronization ..........................................68
Audio Bootloader ......................................69
Endnotes 71
Factory Games 79
Acknowledgements 83
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Overview
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Connections
To power Loupé, use a center-negative 9V DC 400mA power supply (not
included) and plug it in the DC jack input (DC).
Loupé is a stereo device, with two mono inputs (JK1, JK2) and two mono
outputs (JK3, JK4).
If one input is connected (For example, the Left Audio In) then sound will
only come out of one output (the Left Audio Out, in this case).
Input can be either:
• Line: Suited for instrument level (guitar, bass) and line level (synth,
mixer aux) signals. This is the factory default. (To avoid distortion, adjust
the output volume of external equipment to match line level)
• Mic: Suited for a dynamic microphone. (With use of a XLR to TRS cable
or adapter) Line/Mic input selector is on the left side of Loupé. (1)
Exp In (JK5) is for connecting an expression pedal. (see Special Modes)
Sync Out (JK6) sends a pulse clock to synchronize external equipment. (see
Master Synchronization)
Switches
Loupé features 5 footswitches (FSW1-5) and 4 tactswitches (TSW1-4) that
you can assign Functions or ReadFX to.
Tactswitches 5 and 6 (TSW5-6) are for navigating Play mode and Game Edit
mode.
Encoders
ECD1 and ECD2 are digital encoders that serve different roles.
In Play mode, they change Game (ECD1) and activate Scroll (ECD2).
In Game Edit mode, they are used to navigate drop-down menus.
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FSW5
FSW4
FSW3
FSW2
FSW1
TSW1
TSW2
TSW3
TSW4
ECD1 ECD2
POT1 POT2
TSW5 TSW6
7seg1 7seg2
LED5LED4LED3LED2LED1
LED6 LED7
JK1 JK2 JK3 JK4 JK5 JK6DC
LCD
Displays
Loupé has a variety of flashing lights that display information about playing
and programming.
• LED1-5 show the activity status of main functions
• LED7 flashes at the start of every bar
• LED6 flashes on subdivisions of that bar
• 7seg1 indicates the current Game
• 7seg2 counts cycle multiples or subdivisions
• LCD is the most flexible. In Play mode, it displays the current function or
ReadFX. In Game Edit mode, it displays drop-down menus.
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Loupé’s core audio processor is an STM32 ARM CPU clocked at 180MHz,
paired with 32MB of SDRAM.
The analog input signal is converted to digital information by a 24-bit Cirrus
Logic stereo codec running at 48kHz. In the digital domain, all of the signal
processing operations are performed with 32-bit floating point resolution,
and loops are stored as such in the SDRAM before being sent back to the
24-bit D/A converter.
The internal audio buffer size is 32 samples, which corresponds to an
imperceptible 1.33ms of latency between input and output.
While there is no bypass switch for the internal circuitry, the input and
output impedance were selected to guarantee a high impedance bridging
connection to/from any typical low-power load/source.
Audio Path
The diagram opposite shows us the audio path including live input,
pre-memory filtering, memory, feedback path (Decay pot), ReadFX mixing,
Dry/Loop mixing and output.
Expert users: The four green circles [delin] for delay in, [feed] for feedback,
[dry] and [loop] are virtual switches that can be open (1) or closed (0) resulting
in a certain behaviour. The main Functions of Loupé correspond to different
configurations.
Filters
Before being written to memory, the mix of the live input and the feedback
loop goes through two filters and a limiter.
These filters are a high-pass with cutoff frequency ranging in steps from
20Hz to 500Hz and a low-pass with cutoff frequency ranging in steps from
24KHz to 0.5KHz. Filter settings are specific to each Game (see Game
Edit/Params). Filters have -12dB/octave slopes which gives a soft filtering,
however many rounds of a loop (e.g. long Overdub) will progressively
intensify filtering.
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Live
input
Output
Dry
Decay
high-pass
filter
low-pass
filter
limiter
Loop
memory
write
Dry
Head
FX
Head
memory
read
ReadFX
Mix
ReadFX
Fbk
Dry/Loop
The Dry/Loop knob (POT1) controls the mix between the dry input and the
playing loop. At 12 o’clock, dry and loop are at the same level; fully counter
clockwise you will hear only the dry signal, and fully clockwise only the loop.
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Decay
The Decay knob (POT2) controls how long the loop plays, from continuous
playback to a single repeat.
When using Loupé as a looper, keep the Decay pot fully clockwise for
infinite repeats. When the Decay pot is less than fully clockwise, it will
function like a highly interactive and customizable delay pedal.
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Games
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On the enclosure of Loupé, the printed labels associated with footswitches
(Record, Overdub, Replace, Insert, Multiply) and tactswitches (ReadFX,
Undo, Reset, Mutrig) are there to help new users find their way. In practice,
any function or ReadFX can be assigned to any footswitch or tactswitch.
A collection of these assignments can be saved in what we have decided to
call a Game.
There are 99 Games: 50 factory slots (1-50) that cannot be overwritten, and
49 user slots (51-99) to store your very own custom Games.
In addition to these switch assignments, each Game also saves a set of
parameters contained in the Params menu.
Game select
The current Game number is displayed by 7seg1.
To select a different Game, turn ECD1, 7seg1 will start flashing and you can
scroll through the saved Games.
Once you have chosen a Game, press ECD1, 7seg1 will stop flashing and
the new Game is active.
You can change Game on the fly without affecting audio, sync, or any
function that might be running. Only the current ReadFx will be ended.
Game Edit
When you enter the Game Edit menu, Loupé’s sound will still be running,
but FSW1-5 and TSW1-4 are no longer operational.
To enter Game Edit, press TSW5. The LCD will display [Press to Assign] and
[Exit / Params]. Here we can either press any switch and assign a function to
it, enter the Params menu, or Exit.
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Let’s first look at how to assign functions to switches.
If we press FSW1, the LCD will display its current assignment and its
parameters in a list. The Switch’s name will be displayed as the first item in
the list and the second item is the function currently assigned to said switch.
To change the function, turn ECD1 one step clockwise to move the cursor
down to the line [Func] then turn ECD2 to scroll through the different
functions. Now choose the Switch Mode (Toggle/Sustain) by moving the
cursor down to the line [SwMode]. This changes whether the selected
switch will operate in a momentary or latching fashion.
Game Exit and Save
Press TSW5 to exit the Game Edit menu, the message [Overwrite ? Y/N] is
displayed and the Game number flashes.
There are 3 possible cases:
• You do not want to save any modifications, select [N] by pressing TSW6.
• You do want to save modifications made to the selected Game, select
[Y] by pressing TSW5.
• You do want to save your modifications, but in a different Game slot,
turn ECD1 to select another Game (7seg1 will start flashing), then select
[Y] by pressing TSW5.
Params
The Params menu contains parameters specific to each saved Game.
Once in the Game Edit menu, press TSW6 to enter the Params page.
You can navigate up and down the menu with ECD1 and change values
with ECD2.
These parameters relate to:
• Clocks: QuantDiv (see Clocks), SyncDiv (see Sync), ScrollDiv. (see Scroll)
• Filters Cutoff frequencies. (see Filters)
• Activation of Special Modes: ForceDry, EXP. (see Special Modes)
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Functions Basics
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There are two types of functions: One-Shot and Two-Step.
These names are self explanatory, as One-Shots require you to hit the switch
once, and Two-Step require you to hit the switch twice.
• One-Shot functions are: Undo, Trig, Start, Reset.
• Two-Step functions are: Record, Overdub, Replace, Substitute, Insert,
Instut, Multiply, Stack, Mute, Pause, Mutrig.
Two-Step functions can only be used one-at-a-time. In other words, starting
a new function will automatically end any current function you have not
stopped. (see Alternate Endings)
LED Status
Two-Step functions are associated with LED1-5:
• LED5: Record, Record/BPM
• LED4: Overdub
• LED3: Replace, Substitute
• LED2: Insert, Instut
• LED1: Multiply, Stack
• LED1-5: Mute, Pause, Mutrig
When a function is activated, the associated LED turns from green to red.
When a function is deactivated, the associated LED turns back from red to
green.
Toggle / Sustain
For all Two-Step functions, two switch behaviours are available and can be
set when assigning the function to a switch in Game Edit.
• Toggle: one short press to start a function, another short press to end.
This is often referred to as latching
• Sustain: press and hold to start a function, release to end. This is often
referred to as momentary.
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Alternate Endings
There is an alternate way to end a Two-Step function. Instead of pressing the
same switch to end, you can start another function and this will automati
cally end the previous one.
This is convenient when using Toggle Switch behavior as you will save many
switch presses.
For example, let’s say you want to use Multiply just after Recording a loop,
and then begin to Overdub. With standard endings your presses would be:
Rec / Rec / Mult / Mult / Dub
With Alternate Endings your presses are:
Rec / Mult / Dub
By using Alternate Endings you save switch presses and keep the music
flowing.
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Bar Clock, Quant Clock, QuantDiv
Before going further, we need to understand how the different Clocks work.
We have seen that LED7 flashes on the start of each bar, whereas LED6
flashes on each subdivision. In other words LED7 shows the Bar Clock and
LED6 the Quant Clock.
Besides giving us visual timing cues, both Clocks are also used to quantize
functions. (A third Clock with no visual feedback exists, this is the Sync Clock
allowing synchronization of slave machines)
These three Clocks start as soon as you finish your first recording.
Bar Clock (LED7) indicates the first beat of the bar. Quant Clock (LED6) is
derived from Bar Clock and runs 2, 4, 8 or 16 times faster.
QuantDiv (Game Edit/Params) sets the ratio between Bar Clock and
Quant Clock. Subdivisions can be half, quarter, eighth, or sixteenth notes.
(QuantDiv=2, 4, 8, 16)
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Quantized Functions
Most functions are available in several versions.
The basic unquantized function (e.g. Replace), as well as two other
quantized versions. (e.g. Replace/B and Replace/Q)
Instead of being activated immediately, these quantized functions activate
and deactivate exactly at the start of a bar or a musical subdivision, which
has the effect of framing content and maintaining or creating rhythmic
coherence.
• Functions with /B modifiers are quantized to the Bar. (Mostly used with
Cycling functions). All these functions will start and end at the beginning
of a bar, ensuring tempo and structure are maintained. (Game 03+04)
• Functions with /Q modifiers are quantized to the subdivision, these
functions will start and end at the beginning of a subdivision (e.g.
an eighth note if QuantDiv=8). In practice, use of /Q functions leads
to composition in a sequencer/arpeggiator style with Non-Cycling
functions (Overdub, Replace, Substitute), or to complex odd time
signatures with Cycling functions. (Multiply, Insert) (Game 05+06)
• The /R modifier (Rounded) is a special kind of quantization, only
available for Multiply and Stack. In this case, starting the function is
immediate whereas the ending is quantized.
Concerning the LEDs associated to Functions (LED1-5): as well as inactive
status (green) or active (red), we also have a third status "waiting" (orange),
informing us that the start or end of a quantized function is about to
happen.
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Let’s look at an example of a Replace/Q function using Toggle Switch Mode:
On the first press, LED3 turns from green to orange (function has not yet
started). On the next Quant Clock tick the function effectively starts and the
associated LED turns from orange to red.
Similarly on the second press, the associated LED turns from red to orange
(function still running). On the next Quant Clock tick the function effectively
ends and the associated LED turns from orange to green.
First Loop
When you turn on Loupé, you will be in Reset Mode. All clocks are stopped
and the LCD displays [Ready]. This is your blank canvas.
Your first loop can be recorded with the Record function, or a Cycling
function. (2)
Record
[delin=1] [feed=0] [loop=0]
With Record, create your first loop and abandon it at any time to create a
new one. During Record LED5 turns red, then once Record is ended, it turns
back to green and you will be in the Default Mode.
Successive Records can be undone.
Reset
[delin=0] [feed=0] [loop=0]
This function instantly returns us to Reset Mode regardless of any active
function, be it quantized or unquantized. (3)
The current loop is interrupted and definitively lost.
Undo is reset and Scroll is no longer available.
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Default Mode
A Default Mode is the mode you return to after ending Record or any other
Two-Step function. (4)
The Default Mode can be either Sample, Tails or Overdub.
Sample
[delin=0] [feed=1] [loop=1]
Sample is the Default Mode if Decay is fully clockwise.
In this mode, the loop is read without being rewritten on each pass.
Tails
[delin=0] [feed=1] [loop=1]
Tails is the Default Mode if Decay is not fully clockwise.
In this mode the loop fades away like a delay, each repetition is processed
through the filters, and written to memory.
Overdub
[delin=1] [feed=1] [loop=1]
This is any looper’s basic function, allowing you to record layers and layers
of sound.
You can record an infinite number of layers, but if an overdub lasts over
43 seconds undo will not be possible anymore. (Scroll however remains
available)
If Overdub is activated, it becomes the Default Mode until it is deactivated
and ending any other Two-Step function will put you back in Overdub. (5)
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In this case, while the other function is active, LED4 turns orange indicating
that Overdub is ready to take over at the end of that function.
Overdub takes into account the Decay pot, and if it is set to less than 100%,
the feedback amount is displayed on the LCD.
Replace
[delin=1] [feed=0] [loop=0]
This lets you replace all or part of an existing loop with completely new
material. While using Replace, loop playback is muted.
Let’s describe two typical uses:
• If the Replace duration is shorter than the loop length, you can replace
the loop bit by bit. This is ideal for click and cut style.
• If the Replace duration is longer than loop length, you are constantly
writing the incoming signal to memory. This is good for rehearsing a
pattern until you are satisfied, and ending Replace will keep your last
take.
Substitute
[delin=1] [feed=0] [loop=1]
This is a Replace variant in which loop playback is not muted.
While you will have the same result using either Replace or Substitute,
Substitute will give you a guide for your playing while you record.
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The following diagrams give us a good visual example of what makes these
Playing Loop
Live Input
Actions
New Loop
Replace/B (3 Cycles)
in out
vv
Playing Loop
Live Input
Actions
New Loop
Substitute/B (3 Cycles)
in out
vv
Playing Loop
Live Input
Actions
New Loop
functions unique. The thing they have in common is that they do not change
the loop length.
Overdub/B (3 Cycles)
in out
vv
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Cycling Functions
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