An AKAI MPC2000 sampler

Akai MPCs (originally MIDI Production Center, now Music Production Center) are a popular and well respected series of electronic musical instruments originally designed by Roger Linn and produced by the Japanese company Akai from 1988 onwards. Intended to function as a powerful kind of drum machine, the MPCs drew on design ideas from machines such as the Sequential Circuits Inc. Studio 440 and the Linn's own Linn 9000, combining a powerful MIDI sequencer with the ability to sample one's own sounds. Later models feature increasingly powerful sampling, storage, interfacing and sound manipulation facilities, which broaden the use of instrument beyond just drum and rhythm tracks. Download high resolution version (1280x960, 212 KB)Photo of an AKAI MPC2000 for the Sampler (musical instrument) article. ... Download high resolution version (1280x960, 212 KB)Photo of an AKAI MPC2000 for the Sampler (musical instrument) article. ... Telharmonium, created by Thaddeus Cahill 1897 Luigi Russolo and his assistant Ugo Piatti with their Intonarumori, 1913 Léon Theremin and his Theremin, 1919 Trautonium, 1928 An electronic musical instrument is a musical instrument that produces its sounds using electronics. ... Roger Linn is a musical instrument designer, mainly of electronic drum machines, and has recently branched out into guitar effects pedals. ... Akai () was a Japanese consumer electronics producer founded in 1929. ... A Boss DR-202 Drum Machine A drum machine is an electronic musical instrument designed to imitate the sound of drums and/or other percussion instruments. ... Sequential Circuits Inc. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... The word sequencer can mean: a microsequencer in a computer CPU a music sequencer in the field of electronic music a DNA sequencer or a protein sequencer in the field of biology Sequencer (album) This is a disambiguation page — a navigational aid which lists other pages that might otherwise share... An AKAI MPC2000 sampler Playing a Yamaha SU10 Sampler A sampler is an electronic music instrument closely related to a synthesizer. ...

History

The original MPC60 was designed by Roger Linn, then a lead designer at Akai. He conceived the entire function design, including the panel layout and software/hardware specifications. He then created the software with a team of engineers. The hardware electronics was designed by English engineer David Cockerell and his team.^[1] Cockerell was a founder member of the synthesizer firm EMS (co-creater of their famous VCS3 along with Peter Zinovieff,^[2]), and had then worked for effects manufacturers Electro-Harmonix. The Akai MPC60 (MIDI Production Center 60) was an electronic musical instrument produced in 1988, by the Japanese company Akai in collaboration with celebrated designer Roger Linn. ... Roger Linn is a musical instrument designer, mainly of electronic drum machines, and has recently branched out into guitar effects pedals. ... Electronic Music Studios (London) Ltd. ... The VCS 3 (from Voltage Control for Studio with 3 components) is an oscillation effects musical analog synthesiser, initially made in 1969 by EMS. The VCS 3 was smaller and less cumbersome than the Moog Taurus and similar early synthesizers. ... Peter Zinovieff is a British inventor, most notable for his EMS company, which made the famous VCS3 synthesiser in the late 60s. ... The Electro-Harmonix logo Electro-Harmonix is a company that makes electronic sound processors based in New York. ...

Shortly after the MPC60's release, the MPC60-II was designed. Released in 1991, the MPC60-II offered most of the same features as the MPC60, with an added headphone output and a plastic case to replace the original's metal one.^[3] In 1994, Akai released the MPC3000, which boasted 16 bit 44 kHz sampling, 32 voice polyphony, and SCSI data transfer.^[4] The MPC3000 was the last MPC designed by Roger Linn, due to the fact that Akai no longer wanted to pay his royalty fees.^[1] Akai fired Roger Linn and released the MPC2000 in 1997. It came with 2 MB of RAM, on board effects, and a 100,000 note 64-track sequencer.^[5] The MPC2000 was replaced by the MPC2000XL in 2000. The MPC2000XL added an improved 300,000 64-track mixer and time-stretch and resample features. Four limited edition models of the MPC2000XL were released.^[5] Akai () was a Japanese consumer electronics producer founded in 1929. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ...

In 2002 Akai unveiled the MPC4000, the most powerful MPC to date. The MPC4000 features 8 assignable outputs, a hard drive and CD-ROM drive. The MPC4000's memory can be expanded to up to 512 MB of RAM, the largest amount on an MPC to date.^[6] Only two years after the release of the MPC4000, Akai released the MPC1000, which was the smallest in the MPC product line at the time of its release. It is also the first MPC to utilize CompactFlash memory.^[7]. Both the MPC2500 and the MPC500 were added to the Akai MPC series in 2006. The MPC2500 is a mid-range MPC with 8 assignable outputs and CompactFlash storage.^[8] Designed for portability, the MPC500 features 1 MIDI In/Out and CompactFlash storage, and can be powered by 6 AA batteries.^[9] A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ...

MPC Models

The following MPC models are arranged in the order of their release date:

MPC60

The MPC60 was a 16 voice polyphonic 12-bit 40 kHz sampler / 99 track sequencer designed in large part by Roger Linn after Linn Electronics closed. It was similar to the Linn 9000. Akai released it in 1988. It had 750 kB memory standard, expandable to 1.5 MB. The sequencer is very flexible and powerful, famous both for its "swing" setting, and its easy to use step programming. It had 2 MIDI inputs / 4 MIDI outputs, allowing it to control up to 64 devices. The sequencer itself was offered as a separate product, known as the ASQ10, also released in 1988. The MPC60-II was nearly identical to the MPC60, but it featured a headphone output, and a plastic case, instead of the metal case of the original. It was released in 1991. The Akai MPC60 (MIDI Production Center 60) was an electronic musical instrument produced in 1988, by the Japanese company Akai in collaboration with celebrated designer Roger Linn. ... Roger Linn is a musical instrument designer, mainly of electronic drum machines, and has recently branched out into guitar effects pedals. ...

Features

• 16 velocity sensitive pads
• 4 pad banks (64 voices per program)
• sampling rate of 40 kHz (freq response 20 Hz - 18 kHz)
• 16-bit ADC and DAC, with data stored in special non-linear 12bit format (for lower noise)
• 750 kB sampling memory (13.1 seconds), upgradable to 1.5 MB (26.2 seconds) (expansion card: EXM003)
• 128 sounds in memory, 64 sounds per program, 16 voice polyphony.
• 2 MIDI inputs, 4 MIDI outputs
• 20 songs, 99 sequences, 99 tracks, 60,000 note capacity
• timing resolution of 96ppq (parts per quarter note)
• syncable via MIDI Time Code (MTC), MIDI Clock, FSK24, SMPTE, 1/4 note click.
• SMPTE supported frame rates: 24, 25, 29.97 drop, and 30.
• 8 assignable outputs + 1 stereo + 1 effects send/return
• Internal 3½" floppy drive (Double Density 720 kB)
• optional 3rd=party SCSI interface (by Marion Systems)^[3]

Keyboard expression often shortened to expression is the ability of the keyboard of a keyboard instrument to respond to the dynamics of the music. ... MIDI time code embeds the same timing information as standard SMPTE time code as a series of small quarter-frame MIDI messages. ... A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...

MPC3000

The MPC3000 improved upon the MPC60 by adding 16-bit 44.1 kHz stereo sampling, increased memory, 32 voice polyphony, effects, filters, and SCSI. It was released by Akai in 1994. The MPC3000LE (Limited Edition) is identical to the MPC3000, except for its black custom design. It was released by Akai in 2000 and limited to 2000 units.^[4]

Features

• 16 velocity sensitive pads
• 4 pad banks (64 voices per program)
• sampling rate of 16-bit 44.1 kHz stereo (freq response 20 Hz - 22.1 kHz)
• 2 MB sampling memory (22 seconds), upgradable to 32 MB (officially stated as 16 MB) (6 minutes)
• 32 voice polyphony.
• 2 MIDI inputs, 4 MIDI outputs
• 20 songs, 99 sequences, 99 tracks, 75,000 note capacity
• timing resolution of 96ppq (parts per quarter note)
• syncable via MIDI Time Code, MIDI Clock, FSK24, SMPTE, 1/4 note click.
• SMPTE supported frame rates: 24, 25, 29.97 drop, and 30.
• 8 assignable outputs + 1 stereo + 1 effects send/return
• Internal 3½" floppy drive
• SCSI^[4]

MPC2000

The MPC2000 is a 64-track sampler/sequencer introduced in 1997 and discontinued in 2000. It comes with 2 MB sample memory as standard, and can be expanded to 32 MB. It supports a sampling rate of 44.1 kHz, in 16 bit stereo or mono. In the field of electronic music, a sequencer was traditionally a device or piece of software that allows the user to record, play back and edit musical patterns. ...

Features

• 16 velocity sensitive pads
• Internal 3½" floppy drive
• 4 pad banks
• 2 MIDI inputs, 2 MIDI outputs
• 100,000 note capacity 64-track sequencer
• 2 MB sampling memory (upgradable to 32 MB)
• Optional effects board (EB16)
• Optional 8 outputs and digital I/O board (IB-M208)
• SCSI interface^[5]

MPC2000XL

MPC2000XL SE 2

The MPC2000XL is similar to the MPC2000 but with added features; including four pad-bank keys, time stretch along with other new features. In 2004 the 2000XL-MCD version was released, which features a CompactFlash card reader as standard in place of the floppy drive or Zip drives used in earlier models.^[10] There were 4 limited edition 2000XL SE MPCs created between 2000 and 2003. There were two versions of the SE 1, one with an improved control surface, compatible with growing number of sound libraries and one with aesthetic changes. The Limited Edition SE 2 and SE 3 also had only aesthetic changes.^[11] The 4 SE models can be seen here: http://www.loopers-delight.com/tools/akai/MPC2000/MPC2000.html. Image File history File linksMetadata Download high-resolution version (1632x1224, 450 KB) Photo of my Akai MPC2000XL SE 2 (Midi Sequencer / Drum Sampler) I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License... Image File history File linksMetadata Download high-resolution version (1632x1224, 450 KB) Photo of my Akai MPC2000XL SE 2 (Midi Sequencer / Drum Sampler) I, the creator of this work, hereby grant the permission to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License... Time stretching is the process of changing the speed or duration of an audio signal without affecting its pitch. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... Iomega ZIP-100 Drive Logo An internal Zip drive. ...

Features

• 16 velocity sensitive pads
• Internal 3½" floppy drive or 100 MB Zip drive (upgradeable to an MCD card reader)
• 4 Pad Bank keys
• Adjustable angle screen
• Time stretch
• 2 MIDI inputs, 2 MIDI outputs
• Note-repeat key
• 300,000 note capacity 64-track sequencer
• 2 MB sampling memory (upgradable to 32 MB)
• Optional effects board (EB16)
• Optional 8 outputs and digital I/O board (IB-M208)
• SCSI interface^[5]

MPC4000

Released in 2002, the MPC4000 was intended by Akai as a "top-of-the-range" flagship product. Not only was it the most fully-featured MPC product yet (building on the MPC60, 3000 and 2000XL), but it also incorporated the sampling engine from the latest model in Akai standalone sampler range (the Z8, building on the legacy of Akai's well-respected S-series samplers). Today the MPC 4000 has disappeared from the AKAI Product pages, supposedly because it was not a great sales success and is therefore replaced by the more market orientated MPC 5000 which is scheduled to be released in late 2008.

The MPC4000 gained some notoriety amongst users for having a bug-ridden OS and poor product support, with some originally advertised product features still not implemented in 2006.

Features

• 16 velocity and pressure sensitive pads
• 2 MIDI inputs, 4 MIDI outputs
• 96 kHz 24bit sampling
• 16 MB sampling memory, upgradeable to 512 MB
• IDE bays for installation of internal hard disk drive and CD-ROM drive.
• Optional plug-in boards: Effects board, ADAT board, S/P-DIF & wordclock board, 8 analogue outputs board
• SCSI interface^[6]

ATA cables: 40 wire ribbon cable top, 80 wire ribbon cable bottom Advanced Technology Attachment (ATA), is a standard interface for connecting storage devices such as hard disks and CD-ROM drives inside personal computers. ...

MPC2500

The MPC2500 is the mid-range of the Akai line of MPCs. It has a 100,000 note, 64 track mixer with 64 assignable MIDI channels. It has 16 MB of RAM standard and can be upgraded up to 128 MB of RAM with the AKAI EXM128 stick of RAM. It contains an USB port for computer connectivity. It contains a CompactFlash slot for storage of samples, and can be upgraded with a variety of hard drives. A separate carriage is necessary for the hard drive to be installed correctly. The MPC2500 contains 2 MIDI inputs and 4 MIDI outputs. The MP2500 also has the exclusive Chop Shop feature, which automatically chops a sample into as many as 64 pieces. A CD drive can added for burning and reading capabilities. Also comes with a 128 mb compact flash card with sound kits. Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... Note: USB may also mean upper sideband in radio. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. ... A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive,[1] is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ...

Features

• USB port (Mass Storage Class)
• CompactFlash card reader
• 16 velocity sensitive pads
• 2 MIDI inputs, 4 MIDI outputs
• 100,000 note, 64-track, MIDI sequencer
• 16 MB sampling memory (upgradeable to 128 MB)
• Included standard effects include:Chorus, Flanger, Bit grunger, 4 band EQ, Compressor, Phase shifter, Tremolo, Flying Pan, Reverb, and Delay.
• It contains 8 assignable outputs and 1 stereo output.
• It has two assignable Q-link sliders and knobs.
• 240 x 64 hinged backlit LCD screen.
• The CD-M25 CD Drive can added.
• JJos compatible^[8]

A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ...

MPC1000

The MPC1000 is a 64-track sampler/sequencer. It comes with 16 MB sample memory as standard, and can be expanded to 128 MB. It supports sampling rates of 22 or 44.1 kHz, in stereo or mono. Its features include a USB port, an internal CompactFlash card reader, two MIDI inputs and outputs, and effects and multiple analog outputs as standard. Its sequencer's resolution is 96 ppq. There have been wide spread problems with the pad sensors in the 1000. This problem was remedied by Akai, when in the latest version of the MPC 1000, the pad sensors design returned to the design of the pad sensors in previous models. This fix has been seen to be pre-installed on the MPC1000BK-N, not the MPC1000 (blue outer casing), or the MPC1000BK. Although this pad problem was eventually fixed by Akai, a frustrated MPC 1000 user, who goes by the name of "Nym," designed, built and sold kits of a pad fix. By comparison, the Akai pad fix uses better sensor technology (Sensitronic FSRs).^[12] Note: USB may also mean upper sideband in radio. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ...

Features

• USB port (Mass Storage Class)
• CompactFlash card reader
• 16 velocity sensitive pads
• 4 pad bank keys
• 2 MIDI inputs, 2 MIDI outputs
• 100,000 note capacity 64-track sequencer
• 16 MB sampling memory (upgradeable to 128 MB)
• Effects as standard
• Multiple analog outputs as standard
• Timestretch and pitch shift (added in OS 2.0)
• JJos compatible^[7]

MPC500

The MPC500 is the smallest MPC ever made and is the first truly portable MPC created. It can be run on 6 AA batteries but also can be run on a 12V DC plug. It combines a 48-track MIDI sequencer and a 32-voice stereo digital sampler. The MPC500 is the first MPC that only has 12 velocity sensitive rubber pads. It comes with 16 MB RAM but can be upgraded up to 128 MB of RAM. It has a CompactFlash slot for storage of samples. One major appeal of the MPC500 is the fact that you can take a project created on the MPC500 and transfer it to any current MPC with a CompactFlash reader. The MPC500 has a USB port for computer connectivity. It has one stereo output, making it the only MPC currently in production that does not have assignable outputs. Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... Note: USB may also mean upper sideband in radio. ...

Features

• USB port (Mass Storage Class)
• CompactFlash card reader
• 12 velocity sensitive rubber pads
• Stereo L+R in & out
• 1 MIDI in and 1 MIDI out
• 4 pad banks
• 2 x 16 character LCD screen with back light
• Standard effects include:Chorus, Flanger, Bit grunger, 4 band EQ, Compressor, Phase shifter, Tremolo, Flying pan, Reverb, and Delay.
• Approximately 4.5 hours of continuous use with LCD backlight on.
• 465.5 sq CM footprint.^[9]

A 32 MB High Speed CompactFlash Type I card CompactFlash (CF) was originally developed as a type of data storage device used in portable electronic devices. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... Musical Instrument Digital Interface, or MIDI, is a system designed to transmit information between electronic musical instruments. ... LCD redirects here. ...

MPC5000

The MPC5000 was launched at the 2008 winter NAMM trade show. Its main innovations are an 8-track streaming hard disk recorder, a 20-voice, 3-oscillator analog synthesizer with arpeggiator, a new sequencing engine with 960 ppq resolution, pad and track muting and mixing, 64 continuous sample tracks. It also has a new FX engine with 4 FX buses and 2FX per bus, and is considered by Akai to be its flagship MPC^[13]. The NAMM (National Association of Musical Merchants) Show is the largest musical trade show in the world. ...

In addition, the MPC5000 features a 64-voice drum/phrase sampler with 64MB memory, expandable up to 192MB. The display is 240x128, twice the size of the MPC2500 and MPC1000, but smaller than the one on the MPC 4000 . Integrated Chop Shop 2.0 now supports stereo chops and Patched Phrases. It is also the first MPC to include Random and Cycle sample playback in addition to velocity Zone Play. A turntable preamp is also included, as on the MPC 4000.

Although being marketed as "the ultimate MPC", the MPC 5000 lacks some of the advanced sample editing capabilities of the older MPC 4000. Also, some of its hardware specs are lower (max. 192 MB RAM vs. the 4000's 512 MB, smaller screen), despite the falling prices of hardware since the 4000's 2002 launch. However, with the addition of hard disk sample streaming, the need for large amounts of RAM is eliminated, allowing the MPC5000 to playback more and larger sample than any of its predecessors. Despite the reduced dependency on RAM, the numbers-to-numbers comparison of specifications has resulted in some unfavorable comparisons on the MPC community forums. Also see: 2002 (number). ...

Comparison

The following table offer side-by-side comparison of a variety of statistics across the MPC product-line.

JJ Operating System

In the summer of 2006, an anonymous programmer believed to be an ex-Akai employee released a 3rd party OS for the MPC 1000 and later for the MPC 2500. This programmer was nicknamed "JJ" or "Japanese Jenius" by an enthusiastic fan/beta tester. An operating system (OS) is a software that manages computer resources and provides programmers with an interface used to access those resources. ...

This new software boasts superior features to those of the original OS and also fixed a number of bugs in the Akai software.^[21]. Collective additions include "midi grid edit" (piano roll), extensive qlink support, ADSR settings, aftertouch, portamento, sample layer crossfade and innumerable performance and system tweaks. The demo version lacks a save capability , which is unlocked with the purchase of a password for $30.

As a programmer, JJ is characterized by his frequent updates and attentiveness to customer feedback. Despite a significant language barrier (Japanese-English) JJ OS users maintain a steady stream of dialog with the programmer. This steady flow of dialog between the user and the programmer is further maintained through the ability to report a bug in the system directly to JJ through the "Report a Bug" link on the JJ OS website.

In late December, 2007, JJ released a beta version of OS 2, which has since gone gold. This version gives the 1000 and 2500 features^[22] found on the more expensive MPC 4000, such as ADSR for pitch, amp and filter, keymaps etc. On March 11th, 2008, The 1.0 version of OS2 was released, adding more sound editing possibilities, including: fade in and out, and combine of two sounds. It also added audio track improvements, which mainly focused around the ability to apply pads to markers with in an audio track. These are just an example of improvements made in the 1.0 version. ^[23] An ADSR envelope is a parameter used in synthesizers, including those that produce sound by subtractive synthesis, to control the sound produced. ... An AKAI MPC2000 sampler Playing a Yamaha SU10 Sampler A sampler is an electronic music instrument closely related to a synthesizer. ...

There is an extended community of users of all of the versions of the JJ operating system on mpc-forums.com. This can be located at http://mpc-forums.com/viewforum.php?f=25&sid=23211ef993c46b96a7e2f55157e7a206.

There are three different versions of the JJ OS available for download.

JJ OS 3.08 (free)

This version is the most similar to the Akai OS, and does not include many new features, however it has fixed a series of bugs.

JJ OS1

A version of "OS1" which is the most stable version of the all of the JJ OS's. To have the ability to save in OS1, the user must purchase a password for 30 US dollars. OS1 is currently in version 4.99B. There is a version made for the MPC 2500 which is in version 5.51.

Features

• Splash Screen
• Bit Convert
• Ring Modulation
• Insert Silence
• Increased Sound Editing through TRIM mode
• MIDI Time Clock (MTC) and MIDI Machine Control (MMC)
• MIDI, 6 and 16 pad DRAM, Q-Link, and audio Grid Edit
• Simult Sequence
• Recordable Track Mutes ^[24]

JJ OS2

The last version of the JJ OS is OS2, which was released in beta form in late December 2007. Many of these features that have been added by OS2 have been compared to features included in the high-end MPC 4000. Like OS1, it can be downloaded and tried free of charge, but users are unable to save. This can be unlocked by purchasing a password for OS2, however, users are unable to install OS2 unless they already have installed an unlocked version of OS1 first. On March 11th 2008 version 1.0 was released^[23], and as of 04.08.2008, the JJOS2 is available for both the MPC1000(v1.06) and the MPC2500(v1.04), with both costing $49.

Features

• Filter, Amp, and Pitch ADSR envelopes
• Aftertouch
• Multi-sample instrument programs including portamento
• Sample Layer Crossfade
• Non-destructive Chop
• Track Mixer
• Pad Pattern
• Fade in and out
• Grid Edit Loop Edit
• Improved audio tracks including audio markers and start offset ^[24]