Editing Pro Tools (section)

==History==
{{Timeline of release years
| title = Pro Tools milestones
| range1 = 1985-2099
| range1_color = #6E2A8D #421A54
| 1985  = '''Sound Designer'''
| 1987  = ''Sound Designer Universal (1.5)''
| 1989a  = '''Sound Tools'''
| 1989b  = ''Sound Designer II''
| 1991  = '''Pro Tools'''
| 1992  = '''Sound Tools II'''
| 1993  = '''Pro Tools II'''
| 1994a = '''Pro Tools TDM'''
| 1994b = '''Pro Tools III'''
| 1996  = '''Pro Tools PCI'''
| 1997a = ''Pro Tools 4''
| 1997b = '''<nowiki>Pro Tools | 24</nowiki>'''
| 1998  = '''<nowiki>Pro Tools | 24 MIX</nowiki>'''
| 1999a = ''Pro Tools 5''
| 1999b = Pro Tools LE
| 2001  = Pro Tools Free
| 2002  = '''<nowiki>Pro Tools | HD</nowiki>'''
| 2003  = ''Pro Tools 6''
| 2005  = ''Pro Tools 7''
| 2008  = ''Pro Tools 8''
| 2010  = ''Pro Tools 9''
| 2011a = '''<nowiki>Pro Tools | HDX</nowiki>'''
| 2011b = ''Pro Tools 10''
| 2013  = ''Pro Tools 11''
| 2015a = ''Pro Tools 12''
| 2015b = <nowiki>Pro Tools | First</nowiki>
| 2018  = ''Pro Tools 2018+''
}}

=== The beginnings: Digidrums (1983–1985) ===
Pro Tools was developed by [[University of California, Berkeley|UC Berkeley]] graduates Evan Brooks, who majored in [[electrical engineering]] and [[computer science]], and Peter Gotcher.<ref>{{Cite web|url=http://www.eqmag.com/article/the-software-chronicles/Mar-06/19100|title=The Software Chronicles|last=Payne|first=John|date=2008-10-04|website=EQ Mag|url-status=dead|archive-url=https://web.archive.org/web/20081004165207/http://www.eqmag.com/article/the-software-chronicles/Mar-06/19100|archive-date=2008-10-04|access-date=2019-12-13}}</ref>

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.<ref name=":6">{{Cite web|url=https://www.musicradar.com/tuition/tech/a-brief-history-of-pro-tools-452963|title=A brief history of Pro Tools|date=2011-05-30|website=[[MusicRadar]]|language=en-gb|access-date=2019-12-13}}</ref>

They started selling the upgrade chips one year later under their new Digidrums label.{{sfn|Battino|Richards|p=38–39|2005}} Five different upgrade chips were available, offering different alternate drum styles. The chips, easily switchable with the original ones, enjoyed remarkable success between the Drumulator users, selling 60,000 units overall.<ref name=":28">{{Cite web|url=http://www.soundonsound.com/sos/1995_articles/mar95/digidesign.html|title=Digidesign Past & Present|date=March 1995|website=[[Sound on Sound]]|url-status=dead|archive-url=https://web.archive.org/web/20150606114258/http://www.soundonsound.com/sos/1995_articles/mar95/digidesign.html|archive-date=2015-06-06|access-date=2020-01-13}}</ref>

=== Digidesign Sound Designer (1985–1989) ===
When Apple released its first [[Macintosh 128K|Macintosh]] computer in 1984, the pair thought to design a more functional and flexible solution which could take advantage of a graphical interface.{{snf|Milner|2009|p=245}} In collaboration with [[E-mu Systems|E-Mu]], they developed a Mac-based visual sample editing system for the [[Emulator II]] keyboard, called Sound Designer, released under the [[Digidesign]] brand<ref>{{Cite journal |last=Devereux |first=Brian |date=May 1986 |title=Sound Designer 2000 Software |url=http://www.muzines.co.uk/articles/sound-designer-2000-software/1682 |journal=Electronic & Music Maker |issue=May 1986 |pages=24 |via=Muzines}}</ref> and inspired by the interface of the [[Fairlight CMI]].<ref name=":7">{{Cite web|url=http://www.emulatorarchive.com/SampleDesign/SDSoundDesigner/sdsounddesigner.html|title=Sample Editors: Sound Designer|date=2009-02-25|website=Emulator Archive|url-status=dead|archive-url=https://web.archive.org/web/20090225214242/http://www.emulatorarchive.com/SampleDesign/SDSoundDesigner/sdsounddesigner.html|archive-date=2009-02-25|access-date=2019-12-13}}</ref> This system, the first ancestor of Pro Tools, was released in 1985 at the price of US$995.<ref name=":6" />

Brooks and Gotcher rapidly ported Sound Designer to many other sampling keyboards, such as [[E-mu Emax]], [[Akai S900]], [[Sequential Circuits Prophet 2000|Sequential Prophet 2000]], [[Korg DSS-1]], and [[Ensoniq Mirage]].<ref name=":7" /> Thanks to the universal file specification subsequently developed by Brooks with version 1.5,<ref name=":7" /> Sound Designer files could be transferred via [[MIDI]] between sampling keyboards of different manufacturers.<ref>{{Cite journal |last=Mellor |first=David |date=October 1988 |title=Sound Designer Universal |url=http://www.muzines.co.uk/articles/sound-designer-universal/3988 |journal=[[Sound on Sound]] |volume=36 |pages=24–26 |via=Muzines}}</ref> This universal file specification, along with the printed source code to a 68000 assembly language interrupt-driven MIDI driver, was distributed through [[Mac (computer)|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's success by leveraging both the universal file format and developing the first online sample file download site globally, many years before the [[World Wide Web]] use soared. The service used 2400-[[baud]] modems and 100 MB of disk space with Red Ryder host on a 1 MB [[Macintosh Plus]].<ref name=":7" />

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 opportunity 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 its [[Motorola 56000|56K series]] of [[digital signal processor]]s, invited the two to participate in 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.{{sfn|Milner|2009|p=245}}

=== 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",{{sfn|Milner|2009|p=245}} it was presented on January 20, 1989, at the [[NAMM Show|NAMM International Music & Sound Expo]]. The system relied on a [[NuBus]] card called Sound Accelerator, equipped with one [[Motorola 56000|Motorola 56001]] processor. The card provided 16-bit playback and 44.1/48&nbsp;kHz recording through a two-channel [[Analog-to-digital converter|A/D converter]] (AD In), while the DSP handled signal processing, which included a ten-band [[graphic equalizer]], a [[parametric equalizer]], [[Audio time stretching and pitch scaling|time stretching]] with pitch preservation, fade-in/fade-out envelopes, and crossfades ("merging") between two sound files.{{sfn|Manning|2013|p=387}}<ref>{{Cite journal |last=Lehrman |first=Paul D. |date=August 1989 |title=Digidesign Sound Tools |url=http://www.muzines.co.uk/articles/digidesign-sound-tools/5626 |journal=[[Sound on Sound]] |volume=46 |pages=60–63 |via=Muzines}}</ref>

Sound Tools was bundled with Sound Designer II software, which was, at this time, a simple mono or stereo audio editor running on [[Macintosh SE|Mac SE]] or [[Macintosh II|Mac II]]; digital audio acquisition from [[Digital Audio Tape|DAT]] was also possible.<ref>{{Cite journal |last=Mellor |first=David |date=November 1991 |title=Hands on: Sound Tools |url=http://www.muzines.co.uk/articles/hands-on/7527 |journal=[[Sound on Sound]] |volume=73 |pages=70–74 |via=Muzines}}</ref> 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.{{sfn|Collins|2002|p=9}}

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. Since audio streaming and [[non-destructive editing]] were performed on hard drives, the software was still limited by their performance; densely edited tracks could cause glitches.<ref>{{cite web|url=http://www.namm.org/library/oral-history/evan-brooks|title=NAMM Library: Oral History|last=Brooks|first=Evan|date=2007-01-20|work=NAMM.org|access-date=20 June 2015}}</ref> 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.<ref name="wired212">{{cite magazine|url=https://www.wired.com/1994/12/osc/|title=Consume the Minimum, Produce the Maximum|last=Goldberg|first=Michael|date=December 1994|magazine=[[Wired (magazine)|Wired]]|access-date=2020-01-07}}</ref> 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 equalizer, 1-band EQ with [[Delay (audio effect)|delay]], 1-band EQ with [[Chorus effect#Electronic effect|chorus]], delay with chorus).<ref>{{Cite journal |last=Lehrman |first=Paul D. |date=November 1990 |title=Digidesign Deck |url=http://www.muzines.co.uk/articles/digidesign-deck/7318 |journal=[[Sound on Sound]] |volume=61 |pages=60–64 |via=Muzines}}</ref>

The first Pro Tools system was launched on June 5, 1991. It was based on an adapted version of Deck (ProDeck) along with Digidesign's new editing software, ProEdit, created by Mark Jeffery;<ref>{{cite web |last=Gotcher |first=Peter |date=2004-02-01 |title=Pro Tools user since the beginning |url=http://duc.avid.com/showpost.php?p=554780&postcount=29 |access-date=2022-08-03 |website=Avid Pro Audio Community}}</ref> Sound Designer II was still supplied for two-channel editing.{{sfn|Collins|2002|p=10}} Pro Tools relied on Digidesign's Audiomedia card, mounting one Motorola 56001 processor{{sfn|Manning|2013|p=389}} with a [[clock rate]] of 22.58&nbsp;MHz<ref>{{Cite web|url=http://duc.avid.com/showthread.php?t=102247|title=Audiomedia I in/out specification - Avid Pro Audio Community|website=duc.avid.com|access-date=2020-01-12}}</ref> and offering two analog and two digital channels of [[Input/output|I/O]], and on the Sound Accelerator card. External synchronization with audio and video tape machines was possible with [[SMPTE timecode]] and the Video Slave drivers.{{sfn|Collins|2002|p=10}} The complete system was selling for US$6,000.{{sfn|Millner|2009|p=216}}

Sound Tools II was launched in 1992 with a new DSP card. Two interfaces were also released: Pro Master 20, providing 20-bit A/D conversion,{{sfn|Collins|2002|p=10}} and Audiomedia II, with improved digital converters and one Motorola 56001 processor running at 33.86&nbsp;MHz.<ref>{{Cite web|url=http://archive.digidesign.com/support/propix/AM2.html|title=Audiomedia II|website=archive.digidesign.com|access-date=2019-12-13}}</ref>

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 multichannel audio interfaces) and was selling for US$399.<ref>{{Cite journal|last=Waugh|first=Ian|date=November 1993|title=Digidesign Session 8|url=http://www.muzines.co.uk/articles/digidesign-session-8/7647|journal=Music Technology|volume=85|pages=56–58|via=www.muzines.co.uk}}</ref><ref name="wired212" />

Peter Gotcher felt that the software needed a significant rewrite. Pro Tools II, the first software release fully developed by Digidesign, followed in the same year and addressed its predecessor's weaknesses.<ref name=":28" /> The editor and the mixer were merged into a single Pro Tools application that utilized the Digidesign Audio Engine (DAE) created by Peter Richert.  DAE was also provided as a separate application to favor hardware support from third-party developers, enabling the use of Pro Tools hardware and plug-ins on other DAWs.
<ref name=":6" /><ref>{{cite web |last1=Curigliano |first1=Vin |title=Episode 19 : DAW Evolution III : Pro Tools – Past, Present, Future ! |url=https://dawbench.libsyn.com/episode-19-daw-evolution-vi-pro-tools-past-present-future |website=DAW Bench Radio Show |access-date=18 August 2022 |at=1:13:05}}</ref> Selling more than 8,000 systems worldwide, Pro Tools II became the best-selling digital audio workstation.<ref name=":28" />

=== 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.<ref name=":25" /> 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.{{sfn|Collins|2002|p=10}}

In the same year, Digidesign announced that it merged into the American multimedia company [[Avid Technology|Avid]],<ref>{{Cite news|url=https://www.nytimes.com/1994/10/26/business/company-news-avid-technology-plans-to-acquire-digidesign.html|title=Company News; Avid Technology Plans to Acquire Digidesign|last=The Associated Press|date=1994-10-26|work=[[The New York Times]]|access-date=2019-12-18|language=en-US|issn=0362-4331}}</ref> 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.<ref name=":25" />

=== 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;{{sfn|Collins|2002|p=11}} the system could be expanded using TDM to up to three Disk I/O cards, achieving 48 tracks.<ref name=":25" /> DSP Farm cards were introduced to increase the processing power needed for a more extensive real-time audio processing; each card was equipped with three [[Motorola 56000|Motorola 56001]] chips running at 40&nbsp;MHz.<ref name="dspfarmnubus" /> Multiple DSP cards could be added for additional processing power; each card could handle the playback of 16 tracks.{{sfn|Manning|2013|p=389}} A dedicated SCSI card was still required to provide the required bandwidth to support multiple-card systems.{{sfn|Collins|2002|p=11}}

Along with Pro Tools III, Digidesign launched the 888 interface, with eight channels of analog and digital I/O, and the cheaper 882 interface.{{sfn|Collins|2002|p=11}} The Session 8 system included a control surface with eight faders.<ref>{{Cite web|url=https://rapmag.com/a/281-94/mar94/1115-test-drive-the-digidesign-session-8|title=Test Drive: The Digidesign Session 8 – Radio and Production|last=Boss|first=Todd D.|date=March 1994|website=rapmag.com|access-date=2019-12-13}}</ref> A series of TDM plug-ins were bundled with the software, including [[Dynamic range compression|dynamics processing]], EQ, delay, modulation, and [[Reverberation|reverb]].<ref name=":25" />

In 1996, following Apple's decision to drop NuBus in favor of [[Conventional PCI|PCI bus]], Digidesign added PCI support with Pro Tools 3.21. The PCI version of the Disk I/O card incorporated a high-speed SCSI along with DSP chips,{{sfn|Collins|2002|p=11}} while the upgraded DSP Farm PCI card included four Motorola 56002 chips running at 66&nbsp;MHz.<ref name=":26" />

This change of architecture allowed the convergence of Macintosh computers with [[Intel]]-based PCs, for which PCI had become the standard internal communication bus.{{sfn|Manning|2013|p=389}} With the PCI version of Digidesign's Audiomedia card in 1997 (Audiomedia III),<ref>{{Cite web|url=http://archive.digidesign.com/support/propix/AM3.html|title=Audiomedia III|website=archive.digidesign.com|access-date=2019-12-13}}</ref> Sound Tools and Pro Tools could be run on Windows platforms for the first time.{{sfn|Manning|2013|p=389}}

=== 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, Digidesign introduced a new [[24-bit audio|24-bit]] interface (the 888|24) and a new PCI card (the d24). The d24 relied on [[Motorola 56000|Motorola 56301]] processors, offering increased processing power and 24 tracks of 24-bit audio<ref name=":21" /> (later increased to 32 tracks with a DAE software update). A SCSI accelerator was required to keep up with the increased data [[Throughput (disk drive)|throughput]]. Digidesign dropped its proprietary SCSI controller in favor of commercially available ones.<ref name=":25">{{Cite web|url=https://www.pro-tools-expert.com/home-page/2018/2/22/the-history-of-pro-tools-1994-to-2000|title=The History of Pro Tools - 1994 to 2000|last=Thornton|first=Mike|date=2018-11-03|website=Production Expert|language=en-GB|access-date=2019-12-18}}</ref>

64 tracks with dual d24 support were introduced with Pro Tools 4.1.1 in 1998,<ref name=":2" /> 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.<ref name=":25" />

Pro Tools 5 saw two substantial software developments: extended MIDI functionality and integration in 1999 (an editable piano-roll view in the editor; MIDI automation, quantize and transpose)<ref name=":25" /> and the introduction of surround sound mixing and multichannel plug-ins—up to the [[7.1 surround sound|7.1 format]]—with Pro Tools TDM 5.1<ref name=":29">{{Cite web|url=https://www.pro-tools-expert.com/home-page/2018/2/26/the-history-of-pro-tools-2000-to-2007|title=The History of Pro Tools - 2000 to 2007 {{!}} Pro Tools|last=Thornton|first=Mike|date=2018-11-03|website=Production Expert|language=en-GB|access-date=2019-12-18}}</ref> in 2001.<ref name=":2" />

The migration from traditional, tape-based analog studio technology to the Pro Tools platform took place within the industry:{{sfn|Milner|2009|p=245}} [[Ricky Martin]]'s "[[Livin' la Vida Loca]]" (1999) was the first [[Billboard Hot 100|''Billboard'' Hot 100]] number-one single to be recorded, edited, and mixed entirely within the Pro Tools environment,<ref>{{cite web|url=http://mixonline.com/mag/audio_recordin_la_vida/|title=Recordin' "La Vida Loca": the making of a hard disk hit|last=Daley|first=Dan|date=November 1999|work=[[Mix (magazine)|Mix Magazine]]|url-status=dead|archive-url=https://web.archive.org/web/20110604161013/http://mixonline.com/mag/audio_recordin_la_vida/|archive-date=2011-06-04}}</ref> allowing a more meticulous and effortless editing workflow (especially on vocals).{{sfn|Milner|2009|p=216}}

While consolidating its presence in professional studios, Digidesign began to target the mid-range consumer market in 1999 by introducing the Digi001 bundle, consisting of a rack-mount audio interface with eight inputs and outputs with 24-bit, 44.1/48&nbsp;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.<ref name=":6" />

=== High-resolution audio and consolidation of digital recording and mixing: Pro Tools | HD (2002–2011) ===
Following the launch of [[MacOS#Launch of Mac OS X|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 [[High-resolution audio|192 kHz]] or 96&nbsp;kHz sample rates (HD 192 and 96, replacing 888 and 882), along with an updated version of the software (Pro Tools 6) with new features and a redesigned GUI, developed for OS X and [[Windows XP]].<ref name=":10" /> 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.{{sfn|Milner|2009|p=245}}

Both HD Core and Process cards mounted nine [[Motorola 56000|Motorola 56361]] chips running at 100&nbsp;MHz, each providing 25% more processing power than the Motorola 56301 chips mounted on MIX cards; this translated to 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&nbsp;kHz sample rates (with a single HD Core card installed) and 128/64/24 tracks at 48/96/192&nbsp;kHz sample rates (with one or two HD Process cards).<ref name=":1" />

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 slightly changed the combination of chips. HD Process cards were replaced with HD Accel, each mounting nine Motorola 56321 chips running at 200&nbsp;MHz and each providing twice the power than an HD Process card; track count for systems mounting an HD Accel was extended to 192/96/36 tracks at 48/96/192&nbsp;kHz sample rates.<ref name=":27">{{Cite web|url=https://www.mixonline.com/recording/digidesign-hd-accel-pci-card-374027|title=Digidesign HD Accel PCI Card|date=2003-09-15|website=[[Mix (magazine)|Mix Magazine]]|language=en-GB|access-date=2020-01-07}}</ref> 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 extremely low latency.<ref name=":16" />

Pro Tools, offering a solid and reliable alternative to analog recording and mixing, eventually became a standard in professional studios throughout the decade, while editing features such as Beat Detective (introduced with Pro Tools 5.1 in 2001)<ref name=":29" /> and Elastic Audio (introduced with Pro Tools 7.4 in 2007)<ref name=":30">{{Cite web|url=https://www.soundonsound.com/reviews/digidesign-pro-tools-74|title=Digidesign Pro Tools 7.4|last=Thornton|first=Mike|date=January 2008|website=[[Sound on Sound]]|language=en-gb|access-date=2018-02-04}}</ref> redefined the workflow adopted in contemporary music production.<ref name=":6" />

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;<ref name=":10" /> Automatic plug-in Delay Compensation (ADC), introduced with Pro Tools 6.4 in 2004 and only available with TDM systems with HD Accel;<ref name=":11" /> a new implementation of RTAS with [[Multithreading (computer architecture)|multi-threading]] support and improved performance, Region groups, Instrument tracks, and real-time MIDI processing, introduced with Pro Tools 7 in 2006;<ref name=":12">{{Cite web|url=https://www.soundonsound.com/reviews/digidesign-pro-tools-v7|title=Digidesign Pro Tools 7|last=Wherry|first=Mark|date=January 2006|website=[[Sound on Sound]]|language=en-gb|access-date=2018-02-04}}</ref> VCA and volume trim, introduced with Pro Tools 7.2 in 2006;<ref name=":13" /> support for ten track inserts, MIDI Editor, and MIDI Score, introduced with Pro Tools 8 in 2009.<ref name=":14" />

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

==== Native systems: Pro Tools LE and Pro Tools {{Nowrap|M-Powered}} ====
Pro Tools LE, first introduced and distributed in 1999 with the Digi 001 interface,<ref name=":4">{{Cite web|url=http://www.soundonsound.com/sos/dec99/articles/digi001.htm|title=Digidesign Digi 001|date=December 1999|website=[[Sound on Sound]]|url-status=dead|archive-url=https://web.archive.org/web/20150609073618/http://www.soundonsound.com/sos/dec99/articles/digi001.htm|archive-date=2015-06-09|access-date=2018-02-06}}</ref> 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 ran on Pro Tools LE, included in-box DSP processing via an 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<ref name=":10" /> and 48 tracks with Pro Tools 8)<ref name=":17">{{Cite web|url=https://www.soundonsound.com/reviews/digidesign-pro-tools-8-part-2|title=Digidesign Pro Tools 8: Part 2|last=Mark|first=Wherry|date=February 2009|website=[[Sound on Sound]]|access-date=2019-12-18}}</ref> and supported a maximum sample rate of 96&nbsp;kHz<ref name=":22" /> (depending on the interface used). Some advanced software features, such as Automatic Delay Compensation, surround mixing, multi-track Beat Detective, OMF/AAF support, and [[Timecode|SMPTE Timecode]], were omitted. 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".<ref>{{Cite web|url=https://www.soundonsound.com/reviews/digidesign-hybrid-music-production-toolkit|title=Digidesign Hybrid & Music Production Toolkit|last=Inglis|first=Sam|date=June 2006|website=[[Sound on Sound]]|access-date=2019-12-18}}</ref> The "Complete Production Toolkit", introduced with Pro Tools 8, added support for surround mixing and 128 tracks (while the system was still limited to 128 voices).<ref name=":17" />

With the acquisition of [[M-Audio]] in 2004–2005, Digidesign released a specific variant of Pro Tools, called {{Nowrap|M-Powered}}, which was equivalent to Pro Tools LE and could be run with M-Audio interfaces.<ref name=":18">{{Cite web|url=https://www.soundonsound.com/reviews/pro-tools-m-powered|title=Pro Tools M-Powered|last=Inglis|first=Sam|date=June 2005|website=[[Sound on Sound]]|language=en-gb|access-date=2018-02-05}}</ref>

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

==== Hardware-independent native systems: Pro Tools 9 ====
Pro Tools 9, released in November 2010, dropped the requirement of proprietary hardware to run the software. Any audio device could be used through [[Core Audio]] on macOS or the [[Audio Stream Input/Output|ASIO]] driver on a Windows. Core Audio allowed device aggregation, enabling using of more than one interface simultaneously. Some Pro Tools HD software features, such as automatic plug-in delay compensation, OMF/AAF file import, Timecode ruler, and multi-track Beat Detective, were included in the standard version of Pro Tools 9.<ref name=":23">{{Cite web|last=Inglis|first=Sam|date=January 2011|title=Avid Pro Tools 9|url=https://www.soundonsound.com/reviews/avid-pro-tools-9|access-date=2018-02-04|website=[[Sound on Sound]]|language=en-gb}}</ref>

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 standard, with a smaller track count and some advanced features turned off.

====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 Technology|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.<ref name=":17" /> An expansion was also available, called AIR Complete Collection.
{| class="mw-collapsible mw-collapsed" style="vertical-align: top;"
|+ style="width: 270px; text-align: left;" | '''List of AIR Virtual Instruments'''
|
{| class="wikitable"
! colspan="2" |AIR Creative Collection
|-
|Structure Free
|[[Sampler (musical instrument)|sampler]] with basic library
|-
|Boom
|electronic drum machine
|-
|Vacuum
|virtual [[Subtractive synthesis|subtractive]]-style synthesizer
|-
|Mini Grand
|sampled acoustic piano
|-
|DB33
|sampled [[Hammond organ|Hammond B3 organ]]
|-
|Xpand!2
|synthesis and sample-based library
|}
| style="vertical-align: top;" |
{| class="wikitable"
! colspan="2" |AIR Complete Collection
|-
|Structure
|sampler with full library
|-
|Strike
|virtual drummer
|-
|Hybrid
|virtual [[Subtractive synthesis|subtractive synthesizer]]
|-
|Velvet
|sampled classic electric pianos
|-
|Transfuser
|real-time loop manipulation tool
|}
|}

===Pro Tools | HDX (2011–present)===
In October 2011, Avid introduced Pro Tools 10 and a new series of DSP [[PCI Express|PCIe cards]] named HDX. Each card mounted 18 DSP processors, manufactured by Texas Instruments, allowing an increased computational precision ([[Single-precision floating-point format|32-bit]] [[Floating-point arithmetic|floating-point]] resolution for audio processing and [[Double-precision floating-point format|64-bit]] floating-point summing, versus the previous 24-bit and 48-bit [[fixed-point arithmetic|fixed-point]] resolution of the TDM engine),<ref name=":15" /> thus improving dynamic range performance. Signal processing could be run on the embedded DSP, providing additional computational power and enabling near zero-latency for DSP-reliant plug-ins. Two [[Field-programmable gate array|FPGA]] chips handled track playback, monitoring, and internal routing, providing a lower round trip latency.

A second line of PCIe cards, called HD Native, provided low latency with a single FPGA chip but did not mount DSP (audio processing relied on the host system's CPU).<ref name=":0" /> Round trip latency at 96&nbsp;kHz was 0.7 ms for HDX and 1.7 ms for HD Native (with a 64-sample buffer).<ref>{{Cite web|last=|first=|date=|title=Compare Pro Tools HDX vs Pro Tools HD Native|url=https://www.avid.com/products/pro-tools-hd-native/specifications|archive-url=|archive-date=|access-date=2021-01-31|website=www.avid.com}}</ref>

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&nbsp;kHz; voice count halved when the sample rate doubled (128 voices at 88.2/96&nbsp;kHz, 64 voices at 176.4/192&nbsp;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 256/128/64 voices with Pro Tools HD software.<ref name=":15" />

With Pro Tools 10, Avid deployed a new plug-in format for both Native and HDX systems called AAX (an acronym for Avid Audio eXtension).<ref>{{Cite web|url=https://www.pro-tools-expert.com/home-page/2014/9/22/a-z-of-pro-tools-a-is-for-aax.html|title=A-Z of Pro Tools - A is for AAX|last=Hughes|first=Russ|date=2014-09-22|website=Production Expert|language=en-GB|access-date=2019-12-17}}</ref> 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 plug-ins, although 32-bit versions of AAX were still used in Pro Tools 10. TDM support was dropped with HDX,<ref>{{cite web|url=http://akarchive.digidesign.com/support/docs/50/DigiRack_Plug-Ins_Guide501.pdf|title=Pro Tools DigiRack Plug-Ins Guide: Version 5.0.1 for Macintosh and Windows|year=2000|publisher=Digidesign, Inc.|page=18|access-date=2013-10-23}}</ref> 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 plug-in (based on Euphonix System 5 console's channel strip, following Avid's acquisition of Euphonix in 2010).<ref>{{Cite web|url=https://www.soundonsound.com/reviews/avid-pro-tools-10|title=Avid Pro Tools 10|last=Wherry|first=Mark|date=March 2012|website=[[Sound on Sound]]|access-date=2019-12-18}}</ref><ref name=":29" />

=== Switch to 64-bit architecture (2013) ===
Pro Tools 11, released in June 2013, switched from 32-bit to 64-bit software architecture with new audio and video engines, enabling the application and plug-ins to fully take advantage of system memory. The new audio engine (AAE) introduced support of offline bouncing and simultaneous mixdowns multiple sources; dynamic plug-in processing allowed to reduce CPU usage when active native plug-ins do not receive any input. Two separate buffers were used for playback and for monitoring of record-enabled or input-monitored tracks. The new video engine (AVE) improved performance and handling of multiple CPU cores.

Support for HD Accel systems, legacy HD interfaces, TDM and 32-bit AAX plug-ins was dropped due to their incompatibility with 64-bit architecture.<ref name=":19" /> A free starter edition providing the essential features of Pro Tools, called "First", was launched in 2015 and discontinued in December 2021 for being "unviable to continue on a technical level".<ref>{{Cite web|last=|date=2021-12-15|title=Pro Tools {{!}} First: Discontinued - Avid Pro Audio Community|url=https://duc.avid.com/showthread.php?t=418226|access-date=2022-01-04|website=duc.avid.com}}</ref>