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Tapeless 24-track Digital Recording System By Hugh Robjohns
Published January 1999

Otari RADAR II 24-bit digital recording system.

Designed as a replacement for high-end tape-based multitracks, Otari's original RADAR 24-track random access recorder/editor captured a sizeable chunk of the pro market. We take a look at its successor, RADAR II, which offers a host of enhancements including 24-bit audio.

Tapeless multitracks seem an obvious development for the recording industry, offering instant access to any part of the recording, absence of degradation through wear, and non-destructive editing. This concept has been realised in a variety of ways by different manufacturers, from full-blown recording/editing packages like Pro Tools and Sonic Solutions, to modular stand-alone recorders from companies like Akai, amongst others. Until recently, however, only Otari had made the commitment to a 24-track machine designed as a direct drop-in replacement for an analogue multitrack. The first RADAR (Random Access Digital Audio Recorder) appeared in 1994 and has built a keen following, becoming the recorder of choice for many studios, artists, composers, engineers and producers.

Having dominated the market for many years, Otari now have direct competition from Euphonix with their soon-to-be-released R1. However, Otari have moved the goal posts by introducing the new RADAR II, taking advantage of the latest technology combined with a wealth of experience gained from the original model. RADAR II now provides 24 tracks of 24-bit digital audio on a single hard drive, with simple editing facilities, the ability to be linked with other machines providing up to 192 sample-synchronised tracks, and remains capable of replaying original RADAR recordings.

Out With The Old

Whilst instantly recognisable, the new RADAR II is radically different from its older sibling, both in appearance and internal technology. The original machine featured track meters, transport controls, an LCD screen and a floppy disk drive on the front of the main rackmounting unit itself, while the large ergonomic remote control panel — one of the major strengths of the machine — provided a host of dedicated transport and editing buttons plus a repeat of the LCD information screen. The machine's three hard disks (at the time, a drive could barely accommodate simultaneous record and replay of up to eight tracks), were fixed internal devices, although external drives could be appended to the SCSI buss.

That design has now evolved somewhat. The front of the main rack unit (which remains the same size as the earlier model) is rather plain in comparison. Otari found that no-one used the controls on the machine itself, as they all preferred to use the remote control, and by removing the meters, transport and track-arming buttons, sufficient space was gained to incorporate a single removable hard drive bay and an Exabyte tape drive for backing up and archiving recorded material (the floppy disk drive has been retained for software updates). Integrating the backup medium into the machine is a very positive step and helps to mitigate this time-consuming drawback of all hard disk recorders.

The remote controller looks much like the original, with the vast majority of buttons being in the same place and performing the same function. Indeed, the new panel can be used with original RADAR units if required, and RADAR power-users whose fingers fly around the controller in a blur will still be able to hit the right buttons in the right order! In fact the only obvious difference, to the casual observer, is that the track-arming buttons have been moved from an 8x3 group on the left hand side to a 2x24 group along the top edge (enabling direct 48-track working with a pair of linked machines).

The space vacated by the track-arming buttons has been used for a new 4x8 group of function buttons (of which 17 are currently unallocated) which provide direct access to various housekeeping functions including project and media management — facilities which were previously only available through the screen menus.

Aside from this subtle but effective makeover to the remote, the other important change is the ability to attach a meterbridge to its rear edge. Currently, only a 24-track meter display is available, but since there are now 48 arming buttons on the controller I would not be surprised if Otari produced a 48-track version in the future.


The most important technical improvement over the original machine is the ability to record 24-bit samples instead of 16-bit, although it can be configured for 16-bit working for compatibility with older RADAR files. RADAR has always received acclaim for the sound quality of its converters, often being described as sounding 'very analogue', and so the new machine also employs Crystal Semiconductor's converter chips.

These are the latest generation of 24-bit, 128-times oversampling types, and it is interesting to note that around 50 percent of the cost of the machine is attributed to these converters, which are the same as those used in many high-end hi-fi products. Certainly, the feedback received from users (including classical music engineers) suggests that the new machine has retained all the desirable analogue-like characteristics of its forebear, including tolerance to minor overloads, whilst extending the dynamic range to over 100dB (A-weighted). One area of technology which has advanced enormously in recent years is hard disk design. Current drives are significantly faster than models of only a few years ago, and storage capacities have increased dramatically. Whereas the original RADAR required three separate drives, each handling just eight tracks, the current machine achieves 24-track, 24-bit recording on a single drive. Furthermore, like most early hard disk recorders, the RADAR often suffered a gap in the monitoring when dropping out of record — a common problem caused by the hard drive and its buffers being incapable of simultaneously recording and replaying sufficient data. Data transfer rates are now so much faster, and buffer memory cheaper, that providing gap-less dropouts across all 24 tracks is no longer a problem for RADAR II.

The machine is currently being supplied with a single 9Gb hard drive capable of storing 40 minutes of continuous 24-bit audio on all 24 tracks. In practice, with some tracks carrying only sporadic recordings, the running time is likely to be well in excess of 40 minutes. If more time is required, additional hard disks can be connected to the SCSI2 port on the rear panel of the machine, and a compatible 18Gb removable drive will also shortly become available, offering roughly double the recording time.


The rear of the main rack unit has been extensively redesigned. One of the most obvious differences is the absence of individual analogue inputs and outputs. The 48 quarter-inch jack sockets of the first RADAR have been replaced by six 25-way D-Sub connectors on the right hand side of the rear panel. These conform to the Tascam (DA88) wiring convention (which has virtually become an industry standard) and each connector provides eight channels of balanced audio with inputs and outputs on separate sockets. The system can be configured for one of four different peak operating levels in 2dB steps between +18 and +24dBu.

To the left of this analogue I/O is a familiar PC interface panel. A collection of more D-Sub connectors provides facilities for linking multiple RADAR machines, an RS422 machine control port, the remote control panel connector, the external VGA display screen port, and the SCSI2 buss.

The remaining rear panel space is taken up with an assorted collection of connectors, starting with four BNCs to provide video and wordclock syncs in and out (the former with a 75(omega) termination switch). Stereo AES-EBU and S/PDIF interfaces are provided on XLRs and phono connectors respectively, and the usual trio of MIDI sockets is also present. Linear timecode in and out is available on another pair of XLRs.

Standard on the RADAR II (optional on the earlier machine) are three 25-way D-Sub connectors providing 24 channels of digital I/O. On the original RADAR, digital I/O was available only in Tascam TDIF standard; this standard is also RADAR II's default digital I/O format, although an AES-EBU format will also be available shortly. A further D-Sub allows access to the PC's parallel port, and towards the bottom of the panel is an IEC mains socket with voltage selector, chassis and analogue ground terminal posts, and the cooling fan vent.

Remote Control

The heart of the system as far as the user is concerned has to be the remote control panel, which can be located up to 15 metres away from the main RADAR frame, powered directly through its connecting cable.

RADAR II remote controller plus meter bridge.RADAR II remote controller plus meter bridge.

Clearly designed with right-handed operators in mind, the vast majority of routine commands are catered for by buttons on the right-hand side of the panel, the left side being occupied by the QWERTY keyboard (used for naming projects and cue points) and the new direct menu and macro keys.

The small illuminated transport buttons are positioned in the centre of the panel right at the front, where they fall readily to hand. These are customisable to some extent with, for example, the record function being configurable for the usual Record + Play operation, or the Record button only. The Wind keys offer varying 'spool' speeds depending on how many times the button is pressed, and a superb reverse play mode is activated by pressing Rewind and Play together. Unfortunately, there is no audible high-speed wind mode — the cue mode found on most analogue recorders — but the user can set up to 99 locate points in any recording to allow rapid navigation.

All the functions which might be expected of a decent multitrack machine can be found on the RADAR, including an AutoPlay mode to enter replay immediately after recueing on a locate for example. There is also a cycle facility with definable pre- and post-rolls for rehearsing, and an AutoPunch mode to drop in and out of record between the defined points.

To the right of the transport buttons is a nicely weighted jog/shuttle wheel with associated illuminated mode button. In shuttle mode it provides smoothly variable speeds from dead slow to real time — but no faster, which seems a shame. Jog mode allows an extremely good reel-rock simulation to locate a precise position for editing or cueing. The DSP card processes the data stream from all 24 tracks in both these modes to maintain a constant digital sample rate at the output — essential when working with a digital console. (Varispeed mode, by contrast, does alter the sample rate.)

Positioned close to this jog/shuttle wheel are three buttons used for marking in, out and sync points for the editing functions. Probably of more use in post-production than music applications, the sync mark identifies a point between the in and out marks which can be used as the timing reference when the audio segment is repositioned — for example a horn blast in the sound effect of a passing car.

Above the transport keys, a numeric keypad is used for entering time values in editing and locating functions, and to the right a set of four cursor keys allow navigation of the LCD menus. A section of 12 buttons to the right again provide the editing facilities, which I will return to later.

The two-line backlit LCD screen directly above the number keypad normally shows the current time position, either in SMPTE hours/minutes/seconds/frames, frames and feet (for use in film dubbing), or bars and beats (if a MIDI tempo map is used). It can also show a recalled locate point time and name, or the time values of in/out points during editing operations. A pair of red seven-segment LEDs show the current project number.

Moving to the right of the display, 10 buttons provide direct access to some of the less frequently used operational facilities such as varispeed, digital input selection and routing, synchronisation and chase modes, edit undo/redo, and locate point marking and editing. The Shift key is also in this group to access alternative functions marked in blue on some of the key caps, for example 'jog' or 'shuttle' and 'paste' or 'listen' (to the audio clipboard — more on this later). The buttons controlling critical functions such as Chase, Sync, Varispeed and so on all have built-in status LEDs.

As mentioned earlier, the track-arm buttons have been moved to the top of the panel, with two rows of 24 catering for full 48-track operation when a second RADAR is linked. These buttons all contain LEDs to indicate their status, and are used not only to arm tracks for record, but also to audition them in the solo monitoring modes (see below). Talking of linking, up to eight machines can be linked together to provide 192 tracks synchronised to sample accuracy!

To the left of the LCD screen, three buttons select Auto-Input monitoring, the Track Solo mode, and track-arm Safe mode (which also clears any soloed tracks when pressed with the Shift key). Further to the left is the new collection of direct access keys and the unassigned macro buttons. These function keys area used to set up, name, and manage projects, control the linking of multiple RADARs, determine the track zoom range on the VGA display, and manage the SCSI peripherals (mount, unmount, backup and so forth).

Anyone with a basic understanding of DAWs and multitrack remotes could master the RADAR controller in a few minutes without any trouble at all. The menu system is so compact and logical that even the advanced functions can be picked up just as intuitively, and the software is written in such a way that 'dangerous' actions are accompanied with warnings and confirmations so it would be hard to wreck a recording accidentally.

The meterbridge attached to the remote controller — which is removable, though I imagine most users will find the controller the best place for it — provides a clear indication of signal levels on all 24 tracks, with LED bargraph meters covering a 60dB range, complete with a peak hold facility. Indicators at the base of each meter also show when tracks are armed for record, soloed or muted.


RADAR II operates in exactly the same manner as its predecessor, with only minor tweaks in the operating software to improve speed and flexibility here and there. Recordings are based around 'Projects' — up to 99 per disk — where a project could be a song, part of a song, an alternative edited version, individual reels or episodes in dubbing applications, or any other subset of 'work in progress'. When a new project is created and named all current system settings are stored with it, such as sample rates, synchronisation options and so on.

If a new project is an alternative version of existing material, the Copy Project button makes a duplicate record of the material, including all of the locate points, although the audio itself is not replicated, to avoid filling the hard disk unnecessarily. If the original project is subsequently deleted, any audio material relating to the later project is automatically safeguarded.

Once the project has been defined, laying tracks and overdubbing works in exactly the same way as you would expect of an analogue multitrack, across all 24 tracks if desired, but without waiting for the tape to spool back! Thanks to the fast data transfer rates of the hard drive, there is no gap in the monitoring following a drop out — an important improvement over the original machine and something which some hard disk recorders still struggle to achieve.

One of the advantages of hard disk recording is that it can be made non-destructive: an overdub that doesn't work can be thrown away and the original restored. However, RADAR II offers only a single level of Undo/Redo, so some care must be exercised in deciding whether to keep or discard a recording or edit. Whilst this might be seen as a good discipline, and is obviously more flexible than an analogue multitrack, it does seem to be an unnecessary limitation given that most DAWs and hard disk recorders routinely offer 10 levels of Undo, if not more. Apparently Otari are looking at possible ways to implement multi-level undo and redo in a future software update.

Sometimes when checking an overdub or edit it is useful to audition just a subset of the recorded tracks — something normally performed on the mixing console. However, the RADAR II provides its own facilities to solo and mute tracks directly from the controller, using the track arm keys. This turns out to be a very useful and intuitive way of working, and three Solo modes are available: momentary (ie. only when the track arm button is depressed), interlock (only one track at a time), and additive (multiple selections).

As a session develops, it is usually necessary to enter locate positions to navigate around the material, and RADAR supports up to 99 locate points within each project. These locate points are numbered sequentially but can be named as desired. Locate points can be entered on the fly (either at normal play speed or by jogging to a precise point), or by entering a time value, which can be particularly useful in conjunction with the MIDI bars and beats display. Locate memories can be edited at any time to change their title, position or number, and can be recalled either by using the cursor keys to scroll through a list, or by using the number pad for direct access.

Otari RADAR II system showing RADARVIEW on the screen.Otari RADAR II system showing RADARVIEW on the screen.

Editing Functions

Editing on the RADAR is basic compared to, say, a Pro Tools system, but provides all the tools required for typical multitrack editing requirements such as copying and repositioning a chorus. Editing is faster than on the original RADAR, thanks to the use of a single drive (obviating the need to copy audio from one drive to another), although when large numbers of tracks are copied and looped or pasted, there can be a short delay while the audio is processed.

Edit in and out points are defined with the Mark In/Out keys, and selected audio (both in terms of time and tracks) can then be cut, copied, erased, or moved. Cut or Copied audio is stored in an 'audio clipboard' which can be auditioned prior to inserting or overwriting the audio back in to the main project session. Cut removes the selected audio to the clipboard and closes the gap on the selected track(s), whereas Erase simply removes the selected audio for the duration of the edit. Copying is self-explanatory, but Moving is a combination of cutting and pasting on a single key press.

The new insert point is defined either as the point where the machine is parked or located using the jog wheel, by entering a time on the keypad, or recalling a specific locate point or the existing in or out points, and the selected audio can be positioned according to its start, end, or internal sync mark as desired. Inserting causes existing audio after the edit point to move backwards in time (in the same way as splicing in a new piece of tape) whereas Overwrite replaces existing audio with that from the clipboard. A very useful facility is the ability to reverse the audio in the clipboard prior to reinserting, for those classic reverse cymbal crashes and other effects. Selected audio can also be looped to create a rhythm track, or slid backwards or forwards by up to 10 seconds, in millisecond steps, to correct timing errors.


The original RADAR has found a dedicated band of advocates in its four years, and the new RADAR II has undoubtedly built upon the success of its forebear, honing it to perfection in terms of its ergonomics and 'fitness for purpose'. At just under £20,000 pounds, RADAR II is not cheap, but you are getting a lot for your money. A fast, purpose-built multitrack recorder; a basic DAW; and state of the art A-D and D-A converters — plus the remote controller, meterbridge, VGA display screen, built-in digital and analogue I/Os, and a high-speed backup tape drive, all included in the price. A price, incidentally which is exactly the same as that of the old RADAR, representing even better value for money.

Out of the 150-odd RADARs currently in use in the UK, 21 are RADAR IIs. These can be found in studios like PWL, Factory Sound and Master Rock, with producers such as Ray Hedges, Nick Patrick and Mike Tildsley, and artists including Everything But The Girl and Mike Rutherford.

My overwhelming impression of RADAR II is that it does exactly what you want it to do! It is highly intuitive to operate, completely predictable and fuss-free, and works quickly, efficiently and reliably. Where many computer-based DAWs seem to actively get in the way of the recording process, the RADAR maintains that ideal low profile, allowing the user to concentrate on the business in hand rather than fighting technology.

It is almost impossible to find fault with this machine, and the few things I have commented on are very trivial. The RADAR II does everything your tired old analogue multitrack does, probably sounds better, is certainly more flexible, and takes up much less space. Furthermore, 8mm archiving costs are negligible compared to reels of 2-inch tape, and the machine can be extended easily to provide more tracks than you would know what to do with! If you hadn't considered this machine before, I would think again...

The PC Inside

Like the original machine, RADAR II is based around a standard PC platform, but most users would be completely unaware of this fact. The operating system has been developed specifically for the task of managing audio recording to hard disk, and there are no contributions from Mr Gates' empire! The PC's processor is used to handle the user interfaces (the screen and remote control keyboard) as well as managing the audio data transfers to and from the SCSI drives and logging editing decisions. Audio data manipulation, however, is courtesy of Otari's V24 Audio Engine — a bespoke plug-in DSP card controlled from the PC's processor. This interfaces directly with the SCSI drive(s) to provide high-speed data transfers, as well as performing the crossfades at edit points.

Users of the original RADAR have benefited from regular free software updates, gradually improving and extending the capabilities of the machine, and the same is true of RADAR II. New software is supplied on floppy disks, but unlike the first-generation RADAR, which stored the operating system on the first internal audio SCSI drive, the new machine has a dedicated IDE drive on which the operating system resides.


The RADAR II menu system is comprehensive but not overwhelming, and there are only six menu pages. For example, the Synchronisation menu allows the machine to be clocked from video, TDIF, wordclock or even timecode references, and the Digital I/O menu allows allocation of tracks to and from the stereo AES-EBU and S/PDIF interfaces.

All common timecode formats are supported including 24fps (for film) and drop and non-drop frame NTSC codes for American studios. Similarly, sample rates include the usual 32, 44.1 and 48kHz, along with the 'NTSC rates' of 44.056 and 47.952 as well. The machine will slave to timecode, RS422 (Sony 9-pin) control protocols, or sync to MTC with a tempo map.

The Edit menu provides access, amongst other things, to the 'reverse clipboard' function, and allows standard PC-format WAV files to be imported. A Preferences menu sets sample rate, timecode format, the time remaining on the hard disk when a warning message should be given, and the audio reference levels.

The software contains a comprehensive diagnostic system in case things go wrong, but the hard disk is managed very carefully to avoid problems such as fragmentation. There is even an AutoReclaim feature which monitors and retrieves data clusters from the hard drive which are storing unwanted audio data (eg. from deleted tracks). This was a manually activated process in the original RADAR, and the new auto feature is a welcome bonus.

The Backup and Restore facilities employ a high-speed Exabyte Eliant 8mm tape streamer, and the menu system allows the user to select which projects and versions of projects to back up or restore.


Otari RADAR II RADARVIEW software.Whilst all editing functions can be performed easily and effectively from the remote controller, the RADARVIEW display screen makes things even easier. Computer-phobes rest assured that it is very much a 'nice-to-have' rather than an essential part of the system. The flat-panel colour LCD screen is a standard VGA unit, driven from a normal video port on the rear of the main RADAR frame, and provides a set of bargraph meters across the top together with a large tape time display, a 24-track 'tape' display in the centre showing where the tracks have been recorded, and a vast array of system information down the right-hand side. Standard PC monitor extenders can be used if the screen has to be positioned more than a few metres away from the main RADAR frame.

The tape track display provides track names and their record arm/solo/mute status along the left-hand side, with cue points shown as yellow triangles on the time line along the upper edge. The time resolution of the display can be zoomed in or out via dedicated keys on the controller, and at present, the individual track lines are simple coloured blocks such as red in record, green when soloed, blue when playing and a darker blue when selected for editing functions. However, Otari are apparently investigating the possibility of including waveforms to assist in selecting edit points — but then they said that when the first generation of RADAR was launched four years ago too! Although it seems an obvious thing to request, the jog wheel makes such a good job of audio scrubbing that waveforms are really not required — ears work extremely well for identifying edit points!

The right-hand side of the display permanently shows all the current system settings such as sample rate, sync mode and so on, along with a cue/locate list, available recording time, project start/end times, and editing mark in/out points (together with the duration, which is strangely only available on the RADARVIEW display).


  • Sound quality.
  • Speed.
  • Ergonomics.
  • Price (given its target market).


  • Modest fan noise from main rack.
  • Limited cable length for remote and VGA display.
  • Only one level of undo.


Providing over 40 minutes of 24-track recording in 24-bit audio on a single removable 9Gb hard disk, with simple editing facilities and a built-in backup tape streamer, RADAR II includes both analogue and digital interfaces, an extremely ergonomic remote controller, meter bridge and flat panel VGA display, all at a very competitive price.


£19,975 including VAT.