Mobius and the Echoplex Digital Pro

January 2011


2.1    8ths/Cycle
2.2    AutoRecord
2.3    Channel
2.4    ControlSource
2.5    FeedBkCont
2.6    Insert Mode
2.7    Loop/Delay (InterfaceMode)
2.8    Loop Copy
2.9    LoopTrig
2.10    MoreLoops
2.11    MuteMode
2.12    OverdubMode
2.13    Overflow
2.14    Quantize
2.15    Presets
2.16    RecordMode
2.17    RoundMode
2.18    SamplerStyle
2.19    Source#
2.20    Switch Quant
2.21    Sync#
2.22    Threshold
2.23    Velocity
3.1    Dump
3.2    Feedback
3.3    GeneralReset
3.4    HalfSpeed
3.5    Insert
3.6    Load
3.7    LoopDivide
3.8    LoopTriggering
3.9    LoopWindowing
3.10    MultiIncrease
3.11    Multiply
3.12    Mute
3.13    NextLoop
3.14    Overdub
3.15    PreviousLoop
3.16    Record
3.17    Rehearse
3.18    Replace
3.19    Reset
3.20    Retrigger
3.21    Reverse
3.22    SamplePlay
3.23    StartPoint
3.24    Stutter
3.25    Substitute
3.26    SUS Commands
3.27    SUSNextLoop
3.28    Undo
4.1    Auto Start Point
4.2    Beat Sync
4.3    Brother Sync
4.4    Global/Local MIDI Clock
4.5    MIDI Sync Indicators
4.6    MuteQuantMIDIStatSong
4.7    QuantMIDIStatSong
4.8    QuantStartPoint
4.9    ReAlign
4.10    SongPositionPointer and Continue
4.11    StartSong, StopSong, Continue
4.12    Stop Sync
4.13    SyncStartPoint
4.14    SyncRecord
4.15    Tempo Select
5MIDI Control
5.1    MIDI Data Wheel
5.2    MIDI Pipe
5.3    MIDI Virtual Buttons
5.4    SysEx
5.5    Transmitting MIDI Commands
6Parameter Presets
7User Interface
7.1    Smart Buttons aka Double Clicks
7.2    Visual Tempo Guide
8General Concepts
8.1    Event Gravity

1 Introduction

Mobius obviously derived much of its design inspiration from the Gibson Echoplex Digital Pro with Loop IV software, commonly known as the "EDP". If you are familiar with the EDP, this document will describe the EDP features that Mobius does and does not implement. The sections are arranged in the same order they appear in the EDP manual, so if you are reading something in the EDP manual you should be able to easily find the corresponding section here.

Note that we will not cover new features in Mobius that are not in the EDP, nor is this an exhaustive reference manual. It is intended only to help people already familiar with the EDP transition to Mobius.

In many cases a parameter will be described as "Not applicable". Typically these are related to the constraints of the EDP as a hardware device that are not relevant to a software application.

2 Parameters

2.1 8ths/Cycle

Mobius calls this Subcycles.

The algorithm for using the subcycle count to determine the MIDI output tempo is similar, but Mobius also uses the Maximum Tempo and Minimum Tempo parameters to constrain the tempo range.

2.2 AutoRecord

This parameter is not implemented but you can achieve the same result by setting the Empty Loop Action parameter to Record.

2.3 Channel

Not applicable.

2.4 ControlSource

Not applicable.

2.5 FeedBkCont

Not applicable.

2.6 Insert Mode

On the EDP, this parameter lets you redefine what the Insert button does on the EDP footswitch. It is not implemented in Mobius because most people use MIDI footswitches with many buttons and you can bind any MIDI message to any function.

2.7 Loop/Delay (InterfaceMode)

This parameter is not implemented, but you can get similar behavior with scripts and bindings. The most important thing that InterfaceMode provides is a second feedback control that is used during Overdub, Multiply, and Substitute. This second feedback control is enabled in the EDP by setting Loop/Delay to EXP, also known as ExpertMode.

Mobius has two feedback controls, one named Feedback and the other named Secondary Feedback. You can enable secondary feedback for all modal editing functions with the Enable Secondary Feedback preset parameter.

Instead of setting Loop/Delay to Stu for StutterMode, Mobius has the Stutter function.

2.8 Loop Copy

Mobius has a similar parameter named Empty Loop Action which may have these values:

2.9 LoopTrig

Not applicable.

2.10 MoreLoops

Mobius calls this Loop Count.

2.11 MuteMode

Mobius calls this Mute Mode. It is the same except that Mobius adds the Pause option to make the Mute function behave like the Pause function.

2.12 OverdubMode

This parameter is not implemented. If you want what the EDP calls SUSOverdub you can use the Mobius function Sustain Overdub.

2.13 Overflow

Not applicable.

2.14 Quantize

Mobius calls this Quantize Mode. Escaping quantization by executing a function again after it has been quantized works the same way.

2.15 Presets

Not applicable.

2.16 RecordMode

This parameter is not implemented. If you want what the EDP calls SUSRecord use the Mobius function Sustain Record. The equivalent of RecordMode=Safe in Mobius is setting the Record Resets Feedback parameter to true.

2.17 RoundMode

Mobius calls this Overdub While Rounding.

2.18 SamplerStyle

This parameter is not implemented but you can achieve similar results with the parameters Switch Location, Switch Duration, and Return Location.

2.19 Source#

Not applicable.

2.20 Switch Quant

Mobius calls this Switch Quantize.

On the EDP the Undo function is always a confirmation action for the three Confirm options. In Mobius, you use the Confirm function and Undo behaves normally allowing you to remove functions that have been "stacked". If you want Undo to be a confirmation action add it to the global parameter Switch Confirmation Functions.

During the switch quantization period, Record, Overdub, Multiply, and Insert can be used to rerecord loops or do a sound or time copy. Most other functions can also be stacked, they are simply executed after the switch.

2.21 Sync#

Mobius calls this Sync Mode. What the EDP calls Out User Start Mobius calls Out Manual Start. Mobius does not implement the In sync mode, instead if provides MIDI Beat and MIDI Bar which are similar and don't have to be based on the Subcycles (8ths/Cycle) parameter.

2.22 Threshold

Mobius calls this Record Threshold.

2.23 Velocity

Mobius calls this Switch Velocity Sensitive.

3 Functions

3.1 Dump

Dumping loops over MIDI is not implemented but you can save loops to files using the Save Loop function, or one of several items from the File menu.

3.2 Feedback

Mobius calls Feedback a track control rather than a function but it behaves the same. You can undo loop passes that apply feedback, and you can set the global parameter No Feedback Undo if you would rather not make layers if the only change was applying feedback.

3.3 GeneralReset

Mobius calls this Track Reset. A long press of Multiply will also perform a Track Reset if the current loop is in Reset mode.

3.4 HalfSpeed

In Mobius, the function that toggles half-speed is named Speed. You must bind a trigger directly to this function, you do not use it by setting Insert Mode. Like the EDP you can "arm" half-speed mode while a loop is in Reset mode.

In addition there are two other functions that changes speed without toggling. Halfspeed forces the loop into half-speed if it is not already there. Fullspeed cancels half-speed if it is active.

3.5 Insert

In Mobius, the Insert function always does an insert, it is not redefinable using the Insert Mode parameter. Insertion should behave the same as it does on the EDP. All of the alternate endings work the same including Record to perform an "unrounded insert". In addition most Mobius functions that aren't found on the EDP will end the insert and be executed immediately after the rounding period.

On the EDP, a long-press of Insert will convert the Insert into a Replace. Mobius does not support this.

3.6 Load

Loading loops over MIDI is not implemented, but you can load loops from files using several items in the File menu.

3.7 LoopDivide

What the EDP calls LoopDivide isn't a function, it's really a way of thinking about how the Quantize can be used. Mobius supports quantization of all functions where quantization makes sense.

3.8 LoopTriggering

What the EDP calls LoopTriggering is implemented in Mobius by a set of numbered functions: Loop 1, Loop 2, Loop 3, on up to Loop 8. Mobius does not implement the LoopTrig parameter, you simply bind any MIDI button to any loop.

In the EDP, a long-press of one of the loop trigger functions will reset the loop. Mobius does not support this.

3.9 LoopWindowing

LoopWindowing is not implemented, but we have plans to do something similar in the near future. A consequence of this is that the Undo parameter has no restrictions about what it can undo. For example, with LoopWindowing you cannot undo an Unrounded Multiply, once you do an Unrounded Multiply it sets the loop window size and Undo can only shift backward by the size of the window. In Mobius, you can undo the unrounded multiply and return to the original layer without changing its size.

3.10 MultiIncrease

We don't consider this a function, it is more like an adjustment to the way Multiply mode is ended. Mobius supports this though it isn't called a function and you can't bind a trigger to it. It is simply what happens if you keep executing Multiply during the rounding period.

3.11 Multiply

Mobius implements Multiply but in a slightly different way. There are two implementations of multiply selected with the Multiply Mode parameter. For the behavior closest to the EDP select Normal. Mobius supports all of the alternate endings including Record for an "unrounded multiply".

Long-pressing Multiply to convert it to a SUSMultiply is not implemented.

We have not attempted to exactly duplicate the EDP's Multiply, and instead implemented what made the most sense to us. The main difference between the EDP and Mobius appears to be where the start point of the loop is left after the Multiply. The EDP leaves it where the Multiply began, while Mobius "rounds backward" so that the start point is the beginning of the cycle in which the Multiply began. We prefer our implementation.

The distinction is subtle and most people won't notice, especially if you are quantizing. This has been a source of frustration for a few users over the years, who believe that the differences are more important than this but we have not been able to precisely define what the differences are. If you can describe exactly what you think the differences are, please contact us.

3.12 Mute

Mute in Mobius works mostly the same as the EDP. Mobius has an extra Mute Mode parameter value named Pause that makes the Mute function behave the same as the Pause function.

The Insert (SamplePlay) and Multiply (Realign) alternate endings for Mute mode are supported.

In the EDP, the Undo alternate ending to Mute will unmute and use the opposite value of the Mute Mode parameter when determining where the unmuted loop should begin playing. Mobius does not implement this.

In the EDP, a long-press of Mute converts it to a SUSMute. Mobius does not implement this.

3.13 NextLoop

Mobius calls this Next Loop. It works mostly the same. Switch Quantize can be used to quantize the ending or enter a "confirm" mode. The EDP AutoRecord, LoopCopy parameters are implemented in Mobius as the Empty Loop Action parameter.

3.14 Overdub

Overdub in Mobius is the mostly same as the EDP except that Mobius does not support the OverdubMode parameter. Overdub and Sustain Overdub are both functions but they must be bound to different triggers. In Mobius, Overdub may be quantized by setting the Overdub Quantized preset parameter.

In the EDP, a long-press of Overdub converts it to a SUSOverdub. Mobius does not support this.

3.15 PreviousLoop

Mobius calls this Previous Loop. It works mostly the same, see NextLoop for a discussion of the differences.

3.16 Record

The Record function in Mobius is mostly the same as the EDP. Mobius does not implement the Record Mode parameter. Record and Sustain Record are available functions but they must be bound to different triggers. A long-press of Record will do a Reset and the Record Threshold parameter can be used to wait for an appropriate signal level. All of the alternate endings are implemented.

There are some differences in the way synchronized recordings work. See Synchronization for more information.

3.17 Rehearse

This function is partially implemented, but there are a few differences. We are considering removing support for this function.

3.18 Replace

Mobius implements this function.

3.19 Reset

Mobius implements this function.

3.20 Retrigger

Mobius implements this function.

3.21 Reverse

Mobius implements this function. In the EDP, you can only use Undo back to the point where the Reverse happened. Mobius does not have this restriction, you can undo all the way back to the first layer while remaining in Reverse mode.

On the EDP, a long-press of Reverse will convert it to a SUSReverse, Mobius does not implement this.

3.22 SamplePlay

Mobius does not implement this function but you can achieve similar behavior with the numbered loop trigger functions (Loop 1, Loop 2, etc.) combined with the Switch Location and Switch Duration parameters. When Switch Duration is set to Once the loop plays to the end then goes into Mute mode. If you set Switch Location to Start the behavior is the same as the EDP's SamplePlay. If you want this behavior without permanently setting Switch Location and Switch Duration in the preset, you can use scripts to set them temporarily.

3.23 StartPoint

Mobius implements this function. A long-press of the Start Point function will do what Mobius calls Sync Start Point which is the same as what the EDP calls QuantMIDIStartPoint.

3.24 Stutter

In the EDP this is accessible from the Insert button when Interface Mode is set to Stu. In Mobius this is a normal bindable function.

During stutter mode, repetitions of the current cycle will be inserted whenever the end of the cycle is reached. Mobius stutters the cycle you were in when the function was performed. The EDP manual suggests that the stuttered cycle should be the one AFTER the current cycle. We prefer stuttering the current cycle because you can get to the next one just by quantizing.

3.25 Substitute

Mobius implements this function. To use the Secondary Feedback control, set the Enable Secondary Feedback preset parameter to true.

3.26 SUS Commands

Mobius does not have InsertMode=Sustain but the functions Sustain Multiply and Sustain Insert are bindable functions as are most other "modal" editing functions.

All of the following EDP functions that are accessible with MIDI have normal Mobius functions. The first bold name is the EDP name, the second name is the Mobius name.

Mobius also supports sustain variants for these functions.

3.27 SUSNextLoop

Mobius implements this function, see NextLoop for a discussion of the differences in the loop switching functions.

3.28 Undo

Mobius Undo is similar to Undo on the EDP. Mobius does not have the distinction between "Long Undo" and "Short Undo". In Mobius, Undo behaves the most like EDP's "Long Undo".

Mobius Undo will first remove any scheduled events (quantized functions), then it will cancel any modal functions (Multiply, Insert, etc.), then it will roll back to the previous layer.

Undo can be used to escape what the EDP calls "SamplePlay" and what Mobius calls "SwitchDuration=Once" because it removes the Return event scheduled at the end of the loop.

Undo is not by default a switch confirmation action for the various Confirm values for the Switch Quantize parameter. If you want to use Undo for this you must add it to the Switch Confirmation Actions global parameter.

The long discussion of Undo memory management in the EDP manual does not apply to Mobius.

On the EDP, Undo will move the Loop Window backward. Mobius does not implement loop windowing so Undo simply returns to the previous layer.

4 Synchronization

4.1 Auto Start Point

Mobius does not currently support what the EDP calls Auto Start Point. When any form of synchronization is on, Mobius will periodically retrigger the loop so that it stays in sync with the MIDI clock. This "drift retriggering" is disabled when Overdub or another recording mode is active. If retriggering were allowed during recording, it could cause gaps in the recording which you would hear as clicks.

If drift retrigger is disabled and an overdub is left on for several iterations of the loop, the loop can go out of alignment with the MIDI clocks. What Auto Start Point does is automatically set the start point of the loop rather than retriggering it, but only if the feedback level is low enough that the old content of the loop will be inaudible.

Currently in Mobius, if you leave overdub on, the loop will gradually go out of sync with the external device. This may be corrected by leaving overdub and performing a Realign.

4.2 Beat Sync

What the EDP refers to as "beat sync" is not implemented since it relies on hardware specific to the EDP. Mobius can synchronize with other devices using MIDI.

4.3 Brother Sync

What the EDP refers to as "brother sync" is not implemented since it relies on hardware specific to the EDP. Mobius has a similar concept called Track Sync that can be used to synchronize loops in multiple tracks.

4.4 Global/Local MIDI Clock

Mobius implements a similar system called the External Loop that works not only with MIDI but with sync pulses from the plugin host and other sources of sync pulses.

4.5 MIDI Sync Indicators

The EDP will send MIDI note messages at various synchronization points such as the loop start point, global MIDI start point, cycle start point, and sub-cycle start point. Mobius does not.

4.6 MuteQuantMIDIStatSong

Mobius calls this Mute MIDI Start.

4.7 QuantMIDIStatSong

Mobius calls this Sync Start Point.

4.8 QuantStartPoint

Mobius calls this MIDI Start. It applies to both MIDI slave sync and plugin host sync.

4.9 ReAlign

Mobius calls this Realign. When Mobius does the realign is controlled by the Realign Time parameter. Setting this to External is closest to the EDP, the realign will happen when the "external loop" reaches its start point, a concept the EDP calls the "global MIDI start point".

When the Sync Mode parameter is Out or Out Manual Start what Realign does is controlled by the Realign Mode parameter. Setting this to MIDI Start will cause Mobius to send a MIDI Start message at the Mobius loop start point. Setting this to Retrigger will cause Mobius to retrigger its loop when the external loop reaches its start point.

The EDP also has the MIDIMuteReAlign function which Mobius calls Mute Realign.

4.10 SongPositionPointer and Continue

Mobius does not respond to MIDI Song Position and Continue messages. If you are synchronizing with a hardware sequencer or drum machine you need to restart the pattern from the beginning for Mobius to properly track where the "global start point" is.

4.11 StartSong, StopSong, Continue

Mobius should send MIDI Clock, Start and Stop messages in mostly the same way as the EDP. We haven't done an exhaustive analysis of the differences, but a few are obvious.

Mobius does not send MIDI Start when the Undo function is executed when the loop is in Reset mode. You can however execute the MIDI Start function.

4.12 Stop Sync

On the EDP, pressing overdub when the track is reset and Sync=In toggles reception of incoming sync. It also toggles adherence to the tempo specified by TempoSelect. We assume a side effect of this is that you lose the ability to "arm" overdub mode during reset.

Mobius does not support this feature.

4.13 SyncStartPoint

Mobius does not send MIDI Start when the Undo function is executed when the loop is in Reset mode. You can however execute the MIDI Start function.

4.14 SyncRecord

This feature from page 5-52 of the manual is how recording is done when SyncMode=In and Quantize=Off. The recording begins immediately after the button is pressed but it is rounded up at the end so that the loop will be an even multiple of the MIDI beat length. Mobius does not support this.

4.15 Tempo Select

On the EDP, pressing Undo while in reset mode when Sync=Out activates Tempo Select mode. While in Tempo Select mode, the Feedback knob sets the tempo and the Overdub function cancels Tempo Select rather than it's usual behavior of arming Overdub mode.

Mobius does not support this feature.

5 MIDI Control

Most of the things you can do with MIDI in the EDP you can do in Mobius. Since Mobius doesn't have a hardware interface, it is almost always used with a MIDI footswitch or control surface. Every function and almost every parameter can be directly controlled with MIDI. So what the EDP calls "DirectMIDI" is just the normal way of controlling Mobius. We won't draw comparisons with every section in the MIDI Control chapter but a few need to be mentioned.

5.1 MIDI Data Wheel

Mobius does not support a single continuous controller for editing the currently selected preset parameter. Instead you bind different controllers to each parameter.

5.2 MIDI Pipe

Mobius does not implement this, and it is normally not necessary since the computer running Mobius is rarely a "MIDI Thru" device.

5.3 MIDI Virtual Buttons

Since Mobius does not have a hardware front panel most of these are not applicable. You can however bind MIDI messages to a few functions that control the Instant Parameters user interface component. These let you scroll up and down the parameter list to select one of the, then scroll through the list of possible values for the selected parameter.

5.4 SysEx

Mobius does not support SysEx data dumps but most things can be saved to and loaded from files. The Mobius project is the closest thing to a SysEx dump.

5.5 Transmitting MIDI Commands

Mobius does not send out MIDI Note or Controller messages when functions are triggered from the user interface. If this were absolutely necessary you could do something similar with scripts.

6 Parameter Presets

The Mobius concept of a preset is almost the same as the EDP. Mobius has many more parameters than the EDP and doesn't implement some of the parameters the EDP has. Mobius presets have names to make them easier to identify.

You can select presets with menus in the user interface and also with any MIDI message. There are however no functions for editing presets using MIDI. You can only edit presets by interacting with the popup preset editor window.

7 User Interface

Obviously the Mobius user interface is quite different than the EDP user interface. A few of the same visual elements are there such as the Mobius Loop Counter which is similar to what the EDP calls the Loop Display. But we have no desire to make the Mobius user interface resemble the EDP front panel.

All of the EDP documentation regarding "knobs" and "jacks" is of course not applicable. Mobius has controls that correspond to all the EDP knobs and jacks.

Most of the things that are displayed in the EDP front panel using LEDs are displayed in a different way in the Mobius user interface. We won't describe all of those, but a few user interface elements deserve special mention.

7.1 Smart Buttons aka Double Clicks

This is also known as "double clicking" and applies only to the MIDI messages that trigger individual loops. The following EDP features are not supported, but you can get similar behavior from scripts.

Double-click Loop Trigger/Copy. Triggering a loop twice when SwitchQuant is on will do a LoopCopy from the current loop to the triggered loop.

Double-click Loop Trigger/Record. Triggering a loop twice when the loop is in Reset will start the Record function.

Double-click Loop Trigger/Multiply. Triggering the current loop twice while it is playing will start the Multiply function. Presumably Quantize must be on.

Double-Click Loop Trigger/StopRecord. If the loop is in Record or Multiply mode, and you send the MIDI note for the current loop, the record or multiply is ended. Mobius kind of supports this, the loop will be ended and the loop will be retriggered.

Long-press Loop Trigger/Reset. If you long-press the MIDI note that triggers a loop, the Reset function is performed.

7.2 Visual Tempo Guide

Mobius uses the Beaters display component to flash a light on each subcycle, cycle, and loop start point. If you are using MIDI slave sync, the beat and bar counters are displayed above the loop counter.

Mobius does not currently have flashing lights to convey the global MIDI start point, when a sync correction happens, or when an AutoUndo happened.

8 General Concepts

8.1 Event Gravity

Event "gravity" refers to the EDP's behavior of quantizing events back to a previous quantization boundary rather than moving to the next one if you are within a few milliseconds of the last boundary. Mobius does not implement this. When you are quantizing you need to be sure to press the trigger at least a little bit ahead of the quantization point.