Pro Tools

Pro Tools was developed by UC Berkeley graduates Evan Brooks, who majored in electrical engineering and computer science, and Peter Gotcher.[13]

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.[14]

They started selling the upgrade chips one year later under their new Digidrums label.[15] 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.[16]

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.[17] 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 to Digidesign brand[18] and inspired to the interface of the Fairlight CMI.[19] This system, the first ancestor of Pro Tools, was released in 1985 at the price of US$995.[14]

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.[19] Thanks to the universal file specification subsequently developed by Brooks with version 1.5,[19] Sound Designer files could be transferred via MIDI between sampling keyboards of different manufacturers.[20] 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.[19]

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.[17]

The combination of the hardware and the software was called Sound Tools. Advertised as the "first tapeless studio",[17] 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 (AD In), 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 ("merging") between two sound files.[21][22]

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.[23] A two-channel digital interface (DAT-I/O) 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.[1]

The file format used by Sound Designer II (SDII) 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.[24] However, the rapidly-evolving computer technology allowed developments towards a multi-track sequencer.

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.[25] 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 (2-band parametric EQ, 1-band EQ with delay, 1-band EQ with chorus, delay with chorus).[26]

The first Pro Tools system launched on June 5, 1991. It was based on an adapted version of Deck ("ProDeck") along with Digidesign's new editing software, "ProEdit"; Sound Designer II was still supplied for two-channel editing.[27] Pro Tools relied on Digidesign's Audiomedia card, mounting one Motorola 56001 processor[28] with a clock rate of 22.58 MHz[29] 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.[27] The complete system was selling for US$6,000.[30]

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,[27] and the Audiomedia II card, with one Motorola 56001 processor running at 33.86 MHz and improved digital converters.[31]

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 (for stereo-only audio cards) and Session 8 (for multi-channel audio interfaces) and was selling for US$399.[32][25]

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.[16] The editor and the mixer were merged into a single application, while a specific software, the Digidesign Audio Engine (DAE), 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.[14] Selling more than 8,000 systems worldwide, Pro Tools II became the best selling digital audio workstation.[16]

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.[33] 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.[27]

In the same year, it was announced that Digidesign would have merged into the American multimedia company Avid,[34] developer of the digital video editing platform Media Composer and one of Digidesign's major customers (25% of Sound Accelerator and Audiomedia cards produced was being bought by Avid). The operation was finalized in 1995.[33]

With a redesigned Disk I/O card, Pro Tools III was able to provide 16 tracks with a single NuBus card;[35] the system could be expanded using TDM to up to three Disk I/O cards, achieving 48 tracks.[33] 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;[36] multiple DSP cards could be added for additional processing power (each card could handle the playback of 16 tracks).[28] A dedicated SCSI card was still required to provide the required bandwidth to support multiple-card systems.[35]

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[35]. The Session 8 system included a control surface with eight faders.[37] A series of TDM plug-ins were bundled with the software, including dynamics processing, EQ, delay, modulation and reverb.[33]

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,[35] while the upgraded DSP Farm PCI card included four Motorola 56002 chips running at 66 MHz.[38]

This change of architecture allowed convergence of Macintosh computers with Intel-based PCs, for which PCI had become the standard internal communication bus.[28] With the PCI version of Digidesign's Audiomedia card in 1997 (Audiomedia III),[39] Sound Tools and Pro Tools could be run on Windows platforms for the first time.[28]

With the release of Pro Tools | 24 in 1997, a new 24-bit interface (the 888|24) and a new PCI card (the d24) were introduced. The d24 was based on Motorola 56301 processors, offering increased processing power and 24 tracks of 24-bit audio[40], 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.[33]

64 tracks with dual d24 support were introduced with Pro Tools 4.1.1 in 1998,[41] 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.[33]

Pro Tools 5 saw two important software developments: extended MIDI functionality and integration in 1999 (an editable piano-roll view in the editor; MIDI automation, quantize and transpose)[33] and the introduction of surround sound mixing and multichannel plug-ins—up to the 7.1 format—with Pro Tools TDM 5.1[42] in 2001.[41]

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.[17] Ricky Martin's "Livin' la Vida Loca" (1999) was the first Billboard Hot 100 number-one single to be recorded, edited, and mixed fully within the Pro Tools environment,[43] allowing a simpler and meticulous editing workflow (especially on vocals).[44]

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.[14]

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 (HD Core and HD Process, replacing MIX Core and MIX Farm), new interfaces running at up to 192 kHz or 96 kHz sample rates (HD 192 and 96, replacing 888 and 882), along with a new version of the software (Pro Tools 6) with new features and a redesigned GUI, developed for OS X and Windows XP.[45] 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.[17]

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 (with a single HD Core card installed) and 128/64/24 tracks at 48/96/192 kHz sample rates (with one or two HD Process cards).[46]

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.[47] 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.[5]

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 (introduced with Pro Tools 5.1 in 2001)[42] and Elastic Audio (introduced with Pro Tools 7.4 in 2007)[48] redefined the workflow adopted in contemporary music production.[14]

Other software milestones were background tasks processing (such as fade rendering, file conversion or relinking), real-time insertion of TDM plug-ins during playback, and a browser/database environment introduced with Pro Tools 6 in 2003;[45] Automatic plug-in Delay Compensation (ADC), introduced with Pro Tools 6.4 in 2004 and only available with TDM systems with HD Accel;[49] 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;[50] VCA and volume trim, introduced with Pro Tools 7.2 in 2006;[51] support for 10 track inserts, MIDI Editor and MIDI Score, introduced with Pro Tools 8 in 2009.[52]

Pro Tools | MIX hardware support was dropped with version 6.4.1.

Pro Tools LE, first introduced and distributed in 1999 with the Digi 001 interface,[53] 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 (24 tracks with Pro Tools 5, extended to 32 tracks with Pro Tools 6[45] and to 48 tracks with Pro Tools 8)[54] and supported a maximum sample rate of 96 kHz[55] (depending on the interface used). 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 (extended to 64 tracks/128 voices with Pro Tools 8) and additional plug-ins, were made available through an expansion package, called "Music Production Toolkit".[56] The "Complete Production Toolkit", introduced with Pro Tools 8, added support for surround mixing and for 128 tracks (while still being limited to 128 voices).[54]

With the acquisition of M-Audio in 2004–2005, Digidesign released a specific variant of Pro Tools, called M-Powered, which was equivalent to Pro Tools LE and could be run with M-Audio interfaces.[57]

The Pro Tools LE/M-Powered line was discontinued with the release of Pro Tools 9.

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.[54] An expansion was also available, called AIR Complete Collection.

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.[58]

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.

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 (32-bit floating point resolution for plug-ins, instead of 24-bit fixed-point of TDM systems, and 64-bit floating point summing versus the previous 48-bit fixed),[59] 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 voice representing a monophonic channel). Each HDX card enabled 256 simultaneous voices at 44.1/48 kHz; voice count halved when the sample rate doubled (128 voices at 88.2/96 kHz, 64 voices at 176.4/192 kHz). 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.[59]

With Pro Tools 10, a new plug-in format was deployed for both Native and HDX systems, called AAX (acronym for Avid Audio eXtension).[60] 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,[61] 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 (Clip gain), the ability to load the session's audio data into RAM to improve transport responsiveness (Disk caching), 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 (based on Euphonix System 5 console's channel strip, following Avid's acquisition of Euphonix in 2010).[62][42]

The timeline provides a graphical representation of all types of tracks: the audio envelope or waveform (when zoomed in) 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.[66] Alternate audio and MIDI content can be recorded, shown and edited in multiple layers for each track (called playlists), which can be used for track compositing.[67] All the mixer parameters (such as track and sends volume, pan and mute status) and plug-in parameters can be changed over time through automation.[68] Any automation type can be shown and edited in multiple lanes for each track.[69] Track-based volume automation can be converted to clip-based automation and vice versa;[70] automation of any type can also be copied and pasted to any other automation type.[71]

Tempo and meter changes can be programmed on the timeline; both MIDI and audio clips can move or time-stretch to follow tempo changes ("tick-based" tracks) or maintain their absolute position ("sample-based" tracks). Elastic Audio must be enabled in order to allow time stretching of audio clips.[72]

Audio and MIDI clips can be moved, cut and duplicated non-destructively on the timeline (edits change the clip organization on the timeline, but source files are not overwritten).[73] Time stretching (TCE), pitch shifting, equalization and dynamics processing can be applied to audio clips non-destructively and in real-time with Elastic Audio[74] and Clip Effects;[75] gain can be adjusted statically or dynamically on individual clips with Clip Gain;[76] 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 (non-real-time) version of AAX plug-ins.[77]

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.[78] MIDI tracks can also be shown in musical notation within a score editor.[79] 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.[80]

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 (AVE). Video output from one video track at once is provided in a separate window or can be viewed full-screen.[81]

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.[82] Each track inputs and outputs can have different channel depths: mono, stereo, multichannel (LCR, LCRS, Quad, 5.0/5.1, 6.0/6.1, 7.0/7.1); Dolby Atmos and Ambisonics formats are also available for mixing.[83]

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.[84] Virtual instruments are loaded on Instrument tracks—a specific type of track which receives MIDI data in input and returns audio in output.[85]

Plug-ins are processed in real-time with dedicated DSP chips (AAX DSP format) or using the host computer's CPU (AAX Native format).[86]

Audio, auxiliary and Instrument tracks (or MIDI tracks routed to a virtual instrument plug-in) 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.[87]

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.[88]

The main mix of the session—or any internal mix bus or output path—can be bounced to disk in real-time (if hardware inserts from analog hardware are used, or if any audio or MIDI source is monitored live into the session) or offline (faster-than-realtime). 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.[89]

Audio and video can be bounced together to a QuickTime movie file.[90]

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.[91]

Track contents and any of its properties can be selectively exchanged between Pro Tools sessions with Import Session Data (for example, importing audio clips from an external session to a designated track while keeping track settings, or importing track inserts while keeping audio clips).[92] 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.[93]

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 (such as audio and MIDI clips, automation, inserted plug-ins, and mixer status) or changes to the project structure (such as tempo, meter or key).[94]

Pro Tools reads embedded metadata in media files to manage multichannel recordings made by field recorders in production sound. All stored metadata (such as scene and take numbers, tape or sound roll name, or production comments) can be accessed in the Workspace browser.[95]

Analogous audio clips are identified by overlapping longitudinal timecode (LTC) and by one or more user-defined criteria (such as matching file length, file name, or scene and take numbers). An audio segment can be replaced from matching channels (for example, to replace audio from a boom microphone with the audio from a lavalier microphone) while maintaining edits and fades in the timeline, or any matching channels can be added to new tracks.[96]

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 (such as dialog, ADR, effects, and music) 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.[97] One system can also be designated for video playback to optimize performance.[98] Pro Tools can synchronized to external devices using SMPTE/EBU timecode or MIDI timecode.[99]