Pro Tools
Pro Tools is a digital audio workstation developed and released by Avid Technology for Microsoft Windows and macOS used for music creation and production, sound for picture and, more generally, sound recording, editing and mastering processes.
Pro Tools can run as standalone software or operate using a range of external analog-to-digital converters and internal PCIe cards with on-board digital signal processors, used to provide additional processing power to the host computer to process real-time effects—such as reverb, equalization and compression— and to obtain lower latency audio performance. Like all digital audio workstation software, Pro Tools can perform the functions of a multitrack tape recorder and a mixing console along with additional features that can only be performed in the digital domain, such as non-linear and non-destructive editing—most of audio handling is done without overwriting the source files—, track compositing with multiple playlists, and faster-than-realtime mixdown.
Audio, MIDI and video tracks are graphically represented in a timeline. Audio effects, virtual instruments and hardware emulators—such as microphone preamps or guitar amplifiers—can be added, adjusted and processed in real-time in a virtual mixer. 16-bit, 24-bit, and 32-bit float audio bit depths at sample rates up to 192 kHz are supported. Pro Tools supports mixed bit depths and audio formats in a session: BWF, AIFF and MXF. It also imports and exports in the lossy formats mp3, aac, m4a and imports audio from video files. It has also incorporated video editing capabilities, so users can import and manipulate high definition video file formats such as XDCAM, MJPG-A, PhotoJPG, DV25, QuickTime, and more. It features time code, tempo maps, elastic audio and automation; supports mixing in surround sound, Dolby Atmos and VR sound using Ambisonics.
The Pro Tools TDM mix engine, supported until 2011 with version 10, employed 24-bit fixed-point arithmetic for plug-in processing and 48-bit for mixing. Current HDX hardware systems, HD Native and native systems use 32-bit floating point resolution for plug-ins and 64-bit floating point summing; the software and the audio engine were adapted to 64-bit architecture from version 11.
History
The beginnings: Digidrums (1983–1985)
Pro Tools was developed by UC Berkeley graduates Evan Brooks, who majored in electrical engineering and computer science, and Peter Gotcher.In 1983, the two friends, sharing an interest in music and electronic and software engineering, decided to study the memory mapping of the newly released E-mu Drumulator drum machine to create EPROM sound replacement chips. The Drumulator was quite popular at that time, although it was limited to its built-in samples.
They started selling the upgrade chips one year later under their new Digidrums label. Five different upgrade chips were available, offering different alternate drum styles. The chips, easily switchable with the original ones, enjoyed great success between the Drumulator users, selling 60,000 units overall.
Digidesign Sound Designer (1985–1989)
When Apple released its first Macintosh computer in 1984, the pair thought to develop a more functional and flexible solution which could take advantage of a graphical interface. In collaboration with E-Mu, they developed a Mac-based visual sample editing system for the Emulator II keyboard, called Sound Designer, released under the Digidesign brand and inspired to the interface of the Fairlight CMI. This system, the first ancestor of Pro Tools, was released in 1985 at the price of US$995.Brooks and Gotcher rapidly ported Sound Designer to many other sampling keyboards, such as E-mu Emax, Akai S900, Sequential Prophet 2000, Korg DSS-1 and Ensoniq Mirage. Thanks to the universal file specification subsequently developed by Brooks with version 1.5, Sound Designer files could be transferred via MIDI between sampling keyboards of different manufacturers. This universal file specification, along with the printed source code to a 68000 assembly language interrupt driven MIDI driver, were distributed through Macintosh MIDI interface manufacturer Assimilation, which manufactured the first MIDI interface for the Mac in 1985.
Starting from the same year, a dial-up service provided by Beaverton Digital Systems, called MacMusic, allowed Sound Designer users to download and install the entire Emulator II sound library to other less expensive samplers: sample libraries could be shared across different manufacturers platforms without copyright infringement. MacMusic contributed to Sound Designer success by leveraging both the universal file format and by developing the first online sample file download site in the world, many years before the World Wide Web use soared. The service used 2400-baud modems and 100 MB of disk with Red Ryder host on a 1 MB Macintosh Plus.
With the release of Apple Macintosh II in 1987, which provided card slots, a hard disk and more capable memory, Brooks and Gotcher saw the possibility to evolve Sound Designer into a featured digital audio workstation. They discussed with E-mu the possibility of using the Emulator III as a platform for their updated software, but E-mu rejected this offer. Therefore, they decided to design both the software and the hardware autonomously. Motorola, which was working on their 56K series of digital signal processors, invited the two to participate to its development. Brooks designed a circuit board for the processor, then developed the software to make it work with Sound Designer. A beta version of the DSP was ready by December 1988.
Digidesign Sound Tools and Sound Designer II software (1989–1990)
The combination of the hardware and the software was called Sound Tools. Advertised as the "first tapeless studio", it was presented on January 20, 1989 at the NAMM annual convention. The system relied on a NuBus card called Sound Accelerator, equipped with one Motorola 56001 processor. The card provided 16-bit playback and recording at 44.1/48 kHz sample rates through a two-channel A/D converter, while the DSP handled signal processing, which included a ten-band graphic equalizer, a parametric equalizer, time stretching with pitch preservation, fade-in/fade-out envelopes and crossfades between two sound files.Sound Tools was bundled with Sound Designer II software, which was, at this time, a simple mono or stereo audio editor running on Mac SE or Mac II; digital audio acquisition from DAT was also possible. A two-channel digital interface with AES/EBU and S/PDIF connections was made available later in 1989, while the Pro I/O interface came out in 1990 with 18-bit converters.
The file format used by Sound Designer II became eventually a standard for digital audio file exchange until the WAV file format took over a decade later. Hard drives were used to stream audio and non-destructive editing and the software was still limited by their performance, so densely edited tracks could cause glitches. However, the rapidly-evolving computer technology allowed developments towards a multi-track sequencer.
Deck, Pro Tools, Sound Tools II and Pro Tools II (1990–1994)
The core engine and much of the user interface of the first iteration of Pro Tools was based on Deck. The software, published in 1990, was the first multi-track digital recorder based on a personal computer. It was developed by OSC, a small San Francisco company founded the same year, in conjunction with Digidesign and ran on Digidesign's hardware. Deck could run four audio tracks with automation; MIDI sequencing was possible during playback and record, and one effect combination could be assigned to each audio track.The first Pro Tools system launched on June 5, 1991. It was based on an adapted version of Deck along with Digidesign's new editing software, "ProEdit"; Sound Designer II was still supplied for two-channel editing. Pro Tools relied on Digidesign's Audiomedia card, mounting one Motorola 56001 processor with a clock rate of 22.58 MHz and offering two analog and two digital channels of I/O, and on the Sound Accelerator card. External synchronisation with audio and video tape machines was possible with SMPTE timecode and the Video Slave drivers. The complete system was selling for US$6,000.
Sound Tools II was launched in 1992 with a new DSP card, along with the Pro Master 20 interface, providing 20-bit A/D conversion, and the Audiomedia II card, with one Motorola 56001 processor running at 33.86 MHz and improved digital converters.
In 1993, Josh Rosen, Mats Myrberg and John Dalton, the OSC's engineers who developed Deck, split from Digidesign to focus on releasing lower-cost multi-track software that would run on computers with no additional hardware. This software was known as Session and Session 8 and was selling for US$399.
Peter Gotcher felt that the software needed a major rewrite. Pro Tools II, the first software release fully developed by Digidesign, followed in the same year and addressed the weaknesses of its predecessor. The editor and the mixer were merged into a single application, while a specific software, the Digidesign Audio Engine, was provided as a separate application to favor hardware support from third-party developers, enabling the use of Pro Tools hardware and plugins on other DAWs. Selling more than 8,000 systems worldwide, Pro Tools II became the best selling digital audio workstation.
Pro Tools II TDM: 16 tracks and real-time plug-ins (1994)
In 1994, Pro Tools 2.5 implemented Digidesign's newly developed time-division multiplexing technology, which allowed routing of multiple digital audio streams between DSP cards. With TDM, up to four NuBus cards could be linked obtaining a 16-track system, while multiple DSP-based plug-ins could be run simultaneously and in real-time. The wider bandwidth required to run the larger number of tracks was achieved with a SCSI expansion card developed by Grey Matter Response, called System Accelerator.In the same year, it was announced that Digidesign would have merged into the American multimedia company Avid, developer of the digital video editing platform Media Composer and one of Digidesign's major customers. The operation was finalized in 1995.
Pro Tools III: 48 tracks, DSP Farm cards and switch to PCI cards (1995–1997)
With a redesigned Disk I/O card, Pro Tools III was able to provide 16 tracks with a single NuBus card; the system could be expanded using TDM to up to three Disk I/O cards, achieving 48 tracks. To increase the processing power needed for a more extensive real-time audio processing, DSP Farm cards were introduced, each equipped with three Motorola 56001 chips running at 40 MHz; multiple DSP cards could be added for additional processing power. A dedicated SCSI card was still required to provide the required bandwidth to support multiple-card systems.With the launch of Pro Tools III, Digidesign launched the 888 interface, with eight channels of analog and digital I/O, and the cheaper 882 interface. The Session 8 system included a control surface with eight faders. A series of TDM plug-ins were bundled with the software, including dynamics processing, EQ, delay, modulation and reverb.
In 1996, following Apple's decision to drop NuBus in favor of PCI bus, Digidesign added PCI support with the release of Pro Tools 3.21. The PCI version of the Disk I/O card incorporated a high-speed SCSI interface along with DSP chips, while the upgraded DSP Farm PCI card included four Motorola 56002 chips running at 66 MHz.
This change of architecture allowed convergence of Macintosh computers with Intel-based PCs, for which PCI had become the standard internal communication bus. With the PCI version of Digidesign's Audiomedia card in 1997, Sound Tools and Pro Tools could be run on Windows platforms for the first time.
24-bit audio and surround mixing: Pro Tools | 24 and Pro Tools | 24 MIX (1997–2002)
With the release of Pro Tools | 24 in 1997, a new 24-bit interface and a new PCI card were introduced. The d24 was based on Motorola 56301 processors, offering increased processing power and 24 tracks of 24-bit audio, later increased to 32 tracks with a DAE software update. To keep up with the increased data throughput, a SCSI accelerator was needed. The proprietary Digidesign SCSI controller was dropped in favor of commercially available ones.64 tracks with dual d24 support were introduced with Pro Tools 4.1.1 in 1998, while the updated Pro Tools | 24 MIX system provided three times more DSP power with the MIX Core DSP cards; MIXplus systems combined a MIX Core with a MIX Farm, obtaining a performance increase of 700% compared to a Pro Tools | 24 system.
Pro Tools 5 saw two important software developments: extended MIDI functionality and integration in 1999 and the introduction of surround sound mixing and multichannel plug-ins—up to the 7.1 format—with Pro Tools TDM 5.1 in 2001.
It was at this point that the migration from traditional, tape-based analog studio technology to the Pro Tools platform took place within the industry. Ricky Martin's "Livin' la Vida Loca" was the first Billboard Hot 100 number-one single to be recorded, edited, and mixed fully within the Pro Tools environment, allowing a simpler and meticulous editing workflow.
While consolidating its presence in professional studios, Digidesign began to target the mid-range consumer market in 1999 with the introduction of the Digi001 bundle, consisting in a rack-mount audio interface with eight inputs and outputs with 24-bit, 44.1/48 kHz capability and MIDI connections. The package was distributed with Pro Tools LE, a specific version of the software without DSP support, limited to 24 mixing tracks.
High-resolution audio and consolidation of digital recording and mixing: Pro Tools | HD (2002–2011)
Following the launch of Mac OS X operating system in 2001, Digidesign made a substantial redesign of Pro Tools hardware and software. Pro Tools | HD was launched in 2002, replacing the Pro Tools | 24 system and relying on a new range of DSP cards, new interfaces running at up to 192 kHz or 96 kHz sample rates, along with a new version of the software with new features and a redesigned GUI, developed for OS X and Windows XP. Two HD interfaces could be linked together for increased I/O through a proprietary connection. The base system was selling for US$12.000, while the full system was selling for US$20.000.Both HD Core and Process cards mounted nine Motorola 56361 chips running at 100 MHz, each providing 25% more processing power than the Motorola 56301 chips mounted on MIX cards; this translated in about twice the power for a single card. A system could combine one HD Core card with up to two HD Process cards, supporting playback for 96/48/12 tracks at 48/96/192 kHz sample rates and 128/64/24 tracks at 48/96/192 kHz sample rates.
When Apple changed the expansion slot architecture of the Mac G5 to PCI Express, Digidesign launched a line of PCIe DSP cards that both adopted the new card slot format and also slightly changed the combination of chips. HD Process cards were replaced with HD Accel, each mounting nine Motorola 56321 chips running at 200 MHz and each providing twice the power than a HD Process card; track count for systems mounting an HD Accel was extended to 192/96/36 tracks at 48/96/192 kHz sample rates. The use of PCI Express connection reduced round-trip delay time, while DSP audio processing allowed the use of smaller hardware buffer sizes during recording, assuring stable performance with very low latency.
Through the decade, Pro Tools, offering a solid and reliable alternative to analog recording and mixing, eventually became a standard in professional studios, while editing features such as Beat Detective and Elastic Audio redefined the workflow adopted in contemporary music production.
Other software milestones were background tasks processing, real-time insertion of TDM plug-ins during playback, and a browser/database environment introduced with Pro Tools 6 in 2003; Automatic plug-in Delay Compensation, introduced with Pro Tools 6.4 in 2004 and only available with TDM systems with HD Accel; a new implementation of RTAS with multi-threading support and improved performance, Region groups, Instrument tracks and real-time MIDI processing, introduced with Pro Tools 7 in 2006; VCA and volume trim, introduced with Pro Tools 7.2 in 2006; support for 10 track inserts, MIDI Editor and MIDI Score, introduced with Pro Tools 8 in 2009.
Pro Tools | MIX hardware support was dropped with version 6.4.1.
Native systems: Pro Tools LE and Pro Tools
Pro Tools LE, first introduced and distributed in 1999 with the Digi 001 interface, was a specific Pro Tools version in which the signal processing entirely relied on the host CPU. The software required a Digidesign interface to run, which acted as a copy-protection mechanism for the software. Mbox was the entry-level range of the available interface; Digi 001 and Digi 002/003, which also provided a control surface, were the upper range. The Eleven Rack also run on Pro Tools LE, included in-box DSP processing via a FPGA chip, offloading guitar amp/speaker emulation and guitar effects plug-in processing to the interface, allowing them to run without taxing the host system.Pro Tools LE shared the same interface of Pro Tools HD, but had a smaller track count and supported a maximum sample rate of 96 kHz. Some advanced software features, such Automatic Delay Compensation, surround mixing, multi-track Beat Detective, OMF/AAF support and SMPTE Timecode were not included. Some of them, as well as support for 48 tracks/96 voices and additional plug-ins, were made available through an expansion package, called "Music Production Toolkit". The "Complete Production Toolkit", introduced with Pro Tools 8, added support for surround mixing and for 128 tracks.
With the acquisition of M-Audio in 2004–2005, Digidesign released a specific variant of Pro Tools, called, which was equivalent to Pro Tools LE and could be run with M-Audio interfaces.
The Pro Tools LE/ line was discontinued with the release of Pro Tools 9.
Advanced Instrument Research (AIR): built-in virtual instruments and plug-ins
In response to Apple's decision to include Emagic's complete line of virtual instruments in Logic Pro in 2004, and following Avid's acquisition of German virtual instruments developer Wizoo in 2005, Pro Tools 8 was supplied with its first built-in virtual instruments library, the AIR Creative Collection, as well as with some new plug-ins, to make it more appealing for music production. An expansion was also available, called AIR Complete Collection.Pro Tools 9: hardware-independent native systems (2010–present)
Pro Tools 9, released on November 4, 2010, was the first version not requiring proprietary hardware, allowing use of the software with any interface. It could operate using the internal sound card of a PC via the ASIO driver and a Mac using Core Audio. Core Audio also allowed, for the first time, the use of aggregate devices, allowing the use of more than one interface at the same time. This could also be achieved on a PC by using any ASIO free anternatives. Some of the most advanced features of Pro Tools | HD software, such as automatic plug-in delay compensation, OMF/AAF file import, Timecode ruler and multitrack Beat Detective were included into the standard version of Pro Tools 9.When operating on a machine containing one or more HD Core, Accel or Native cards, the software ran as Pro Tools HD, with the complete HD feature set. In all other cases it ran as Pro Tools 9, with a smaller track count and a number of advanced features turned off.
Pro Tools | HDX (2011–present)
A new series of DSP PCIe cards, named HDX, was introduced in October 2011 along with Pro Tools 10. The new DSP processors, manufactured by Texas Instruments, allowed an increased computational precision, thus improving dynamic range performance. Track playback and signal processing operations were managed independently by the processors; they also provided lower monitoring latency and more computational power.The hardware line included HDX, relying on dedicated DSP and obtaining considerably lower latency for all DSP-reliant operations, and HD Native, relying on the host system's CPU for all audio processing. In order to maintain performance consistency, HDX products were specified with a fixed maximum number of voices. Each HDX card enabled 256 simultaneous voices at 44.1/48 kHz; voice count halved when the sample rate doubled. Up to three HDX cards could be installed on a single system for a maximum of 768/384/192 total voices and for increased processing power. On Native systems, voice count was limited to 96/48/24 voices with the standard version of Pro Tools, and to 256/128/64 voices with Pro Tools HD software.
With Pro Tools 10, a new plug-in format was deployed for both Native and HDX systems, called AAX. AAX Native replaced RTAS plug-ins and AAX DSP, a specific format running on HDX systems, replaced TDM plug-ins. AAX was developed to provide the future implementation of 64-bit plugins, although 32-bit versions of AAX were still used in Pro Tools 10. TDM support was dropped with HDX, while Pro Tools 10 would be the final release for Pro Tools | HD Process and Accel systems.
Notable software features introduced with Pro Tools 10 were editable clip-based gain automation, the ability to load the session's audio data into RAM to improve transport responsiveness, quadrupled Automatic Delay Compensation length, audio fades processed in real-time, timeline length extended to 24 hours, support for 32-bit float audio and mixed audio formats within the session, and the addition of Avid Channel Strip plugin.
Switch to 64-bit architecture: Pro Tools 11 (2013–present)
Features
Workflow in Pro Tools is organized into two main windows: the timeline is shown in the Edit window, while the mixer is shown in the Mix window. MIDI and Score Editor windows provide a dedicated environment to edit MIDI. Different window layouts, along with shown and hidden tracks and their width settings, can be stored and recalled from the Window configuration list.Timeline
The timeline provides a graphical representation of all types of tracks: the audio envelope or waveform for audio tracks, a piano roll showing MIDI notes and controller values for MIDI and Instrument tracks, a sequence of frame thumbnails for video tracks, audio levels for auxiliary, master and VCA master tracks. Alternate audio and MIDI content can be recorded, shown and edited in multiple layers for each track, which can be used for track compositing. All the mixer parameters and plug-in parameters can be changed over time through automation. Any automation type can be shown and edited in multiple lanes for each track. Track-based volume automation can be converted to clip-based automation and vice versa; automation of any type can also be copied and pasted to any other automation type.Tempo and meter changes can be programmed on the timeline; both MIDI and audio clips can move or time-stretch to follow tempo changes or maintain their absolute position. Elastic Audio must be enabled in order to allow time stretching of audio clips.
Editing
Audio and MIDI clips can be moved, cut and duplicated non-destructively on the timeline. Time stretching, pitch shifting, equalization and dynamics processing can be applied to audio clips non-destructively and in real-time with Elastic Audio and Clip Effects; gain can be adjusted statically or dynamically on individual clips with Clip Gain; fade and crossfades can be applied, adjusted and are processed in real time. All other type of audio processing can be rendered on the timeline with the AudioSuite version of AAX plug-ins.MIDI notes, velocities and controllers can be edited directly on the timeline, each MIDI track showing an individual piano roll, or in a specific window, where several MIDI and Instrument tracks can be shown together in a single piano roll with color-coding. Multiple MIDI controllers for each track can be viewed and edited on different lanes. MIDI tracks can also be shown in musical notation within a score editor. MIDI data such as note quantization, duration, transposition, delay and velocity can also be altered non-destructively and in real-time on a track-per-track basis.
Video files can be imported to one or more video tracks and organized in multiple playlists. Multiple video files can be edited together and played back in real-time. Video processing is GPU-accelerated and managed by the Avid Video Engine. Video output from one video track at once is provided in a separate window or can be viewed full-screen.
Mixing
The virtual mixer shows controls and components of all tracks, including inserts, sends, input and output assignments, automation read/write controls, panning, solo/mute buttons, arm record buttons, the volume fader, the level meter and the track name. It also can show additional controls for the inserted virtual instrument, mic preamp gain, HEAT settings, and the EQ curve for each track. Each track inputs and outputs can have different channel depths: mono, stereo, multichannel ; Dolby Atmos and Ambisonics formats are also available for mixing.Audio can be routed to and from different outputs and inputs, both physical and internal. Internal routing is achieved using busses and auxiliary tracks; each track can have multiple output assignments. Virtual instruments are loaded on Instrument tracks—a specific type of track which receives MIDI data in input and returns audio in output.
Plug-ins are processed in real-time with dedicated DSP chips or using the host computer's CPU.
Track rendering
Audio, auxiliary and Instrument tracks can be committed to new tracks containing their rendered output. Virtual instruments can be committed to audio to prepare an arrangement project for mixing; track commit is also used to free up system resources during mixing, or when the session is shared with systems not having some plug-ins installed. Multiple tracks can be rendered at a time; it is also possible to render a specific timeline selection and define which range of inserts to render.Similarly, tracks can be frozen with their output rendered at the end of the plug-in chain or at a specific insert of their chain. Editing is suspended on frozen tracks, but they can be subsequently unfrozen if further adjustments are needed. For example, virtual instruments can be frozen to free up system memory and improve performance, while keeping the possibility to unfreeze them to make changes to the arrangement.
Mixdown
The main mix of the session—or any internal mix bus or output path—can be bounced to disk in real-time or offline. The selected source can be mixed to mono, stereo or any other multichannel format. Multichannel mixdowns can be written as an interleaved audio file or in multiple mono files. Multiple sources can also mixed down simultaneously—for example, to deliver audio stems.Audio and video can be bounced together to a QuickTime movie file.
Session data exchange
Session data can be partially or entirely exchanged with other DAWs or video editing software that support AAF, OMF, or MXF. AAF and OMF sequences embed audio and video files with their metadata; when opened by the destination application, session structure is rebuilt with the original clip placement, edits and basic track and clip automation.Track contents and any of its properties can be selectively exchanged between Pro Tools sessions with Import Session Data. Similarly, the same track data for any track set—a given processing chain, a collection of clips or a group of tracks with their assignments—can be stored and recalled as Track Presets.
Cloud collaboration
Pro Tools projects can be synchronized to the Avid Cloud and shared with other users on a track-by-track basis. Different users can work on the project simultaneously and upload new tracks or any changes to existing tracks or changes to the project structure.Field recorder workflows
Pro Tools reads embedded metadata in media files to manage multichannel recordings made by field recorders in production sound. All stored metadata can be accessed in the Workspace browser.Analogous audio clips are identified by overlapping longitudinal timecode and by one or more user-defined criteria. An audio segment can be replaced from matching channels while maintaining edits and fades in the timeline, or any matching channels can be added to new tracks.
Multi-system linking and device synchronization
Up to twelve Pro Tools Ultimate systems with dedicated hardware can be linked together over an Ethernet network—for example, in multi-user mixing environments where different mix components reside on different systems, or if a larger track count or processing power is needed. Transport, solo and mute are controlled by a single system and with a single control surface. One system can also be designated for video playback to optimize performance. Pro Tools can synchronized to external devices using SMPTE/EBU timecode or MIDI timecode.Editions
Pro Tools software is available in a standard edition providing all the key features for audio mixing and post-production, a complete edition, which unlocks functionality for advanced workflows and a higher track count, and a starter edition, called "First", providing the essential features.Control surfaces
In mid 1990s, Digidesign started working on a studio device which could replace classic analog consoles and provide integration with Pro Tools. ProControl was the first Digidesign control surface, providing motorised, touch-sensitive faders, an analog control room communication section and connecting to the host computer via Ethernet. ProControl could be later expanded by adding up to five fader packs, each providing eight additional fader strips and controls.Control 24 added 5.1 monitoring support and included 16 class A preamps designed by Focusrite. Icon D-Control incorporated an HD Accel system and was developed for larger TV and film productions in mind. Command|8 and D-Command were the smaller counterparts of Control 24 and D-Control, connected with the host computer via USB; Venue was a similar system specifically designed for live sound applications.
C|24 was a revision of Control 24 with improved preamps, while Icon D-Control ES and Icon D-Command ES were redesigns of Icon D-Control and D-Command.
In 2010 Avid acquired Euphonix, manufacturer of the Artist Series and System 5 control surfaces. They were integrated with Pro Tools along with the EuCon protocols. The Avid S6 and Avid S3 control surfaces followed merging the Icon and System 5 series. Pro Tools Dock was a iPad-based control surface running Pro Tools Control software.