Tascam have updated their ubiquitous DTRS format with an affordable and compatible 24‑bit modular digital multitrack. Hugh Robjohns tries out the DA78HR.
Since its introduction almost a decade ago, Tascam's DTRS format has become the de facto standard interchange format for multi‑channel film soundtrack material worldwide, as well as being a very cost‑effective and hugely popular medium for professional multitrack music sessions, particularly in location recording applications. By contrast, the Alesis ADAT format, although conceptually similar and launched around the same time, has found its main market in semi‑professional applications and has failed to break into the audio post‑production or broadcasting markets.
Both the DTRS and ADAT formats were devised at a time when 16‑bit resolution was impressive. However, technology has moved on since then, with 20‑ and now 24‑bit resolution being de rigeur. Alesis launched their 20‑bit ADAT format in the shape of the XT series a few years ago, and consequently Tascam's family of 16‑bit DTRS machines has started to look a little long in the tooth by comparison.
Range Finding
The DA78HR features comprehensive timecode and sync facilities, making it suitable for a range of post‑production and soundtrack applications.
Tascam's counter strike is their first 24‑bit DTRS machine, the DA78HR — the HR suffix standing for High Resolution. This new recorder is similar in appearance to the current DA38 16‑bit machine, but introduces a number of new features alongside the ability to record eight tracks of 24‑bit audio with exactly the same tape running times as a 16‑bit DTRS machine. Not only is this new machine compatible in every way with Tascam's existing family of 16‑bit recorders but, amazingly, it costs exactly the same as the old DA38, at a pound under the magic two‑grand mark. This represents excellent value for money, and is also exactly the same list price as the Alesis ADAT XT20 and the Yamaha D24 eight‑track MO recorder (reviewed in last month's Sound On Sound), putting it plumb in the middle of some strong competition.
The new DA78HR is also soon to be joined by a big brother, the DA98HR — a 24‑bit version of the current DA98 flagship machine. This revised model was shown at the NAMM show in America a few months ago and is scheduled for launch in August this year at a VAT‑inclusive price of around £3599. The current trio of 16‑bit DTRS machines — the 88, 38 and 98 — will be phased out with the introduction of these two new HR recorders.
In terms of features, the usual tape/source monitoring, auto punch‑in/out, rehearse/record modes and autolocate functions are all provided, along with varispeed record and playback (up to ±6 percent) and 'rock and roll' audible shuttle cueing. Like the other DA‑series machines, the 78HR can be linked with up to 16 other recorders using the rear‑panel Sync‑In/Out sockets, to provide up to 128 sample‑accurate synchronised tracks. An internal patchbay facility allows comprehensive input‑to‑track assignment, permitting any analogue or digital input, or track output, to be allocated to any other track. There is also a built‑in 8:2 digital monitoring mixer with adjustable level and pan for each track (all controllable via MIDI), the output of which is available via an S/PDIF socket as well as via tracks 7&8 of the TDIF and analogue outputs, if required. These facilities allow internal bounce‑downs as well as flexible interfacing and monitoring.
An internal calibration oscillator is included and both SMPTE/EBU and MIDI timecode are fully supported, complete with a range of chase synchronisation modes. The machine can be controlled remotely via MIDI Machine Control (MMC) but the industry standard RS232/422 'Sony 9‑pin' remote control protocol is absent — one of only a very few economies apparent on the machine.
Connectivity
The rear panel follows much the same arrangement as seen on the earlier DA‑series recorders. Balanced +4dB analogue I/O is provided using a pair of 25‑way D‑Sub connectors, while unbalanced analogue I/O is provided through 16 phono connectors operating at ‑10dBV. All analogue conversion is to 24‑bit resolution courtesy of 128x oversampled delta‑sigma A‑D and D‑A circuitry; the A‑D section has switchable dithering to 16 bits with either triangular or rectangular distribution. The rectangular dither option is claimed to be around 3dB quieter than triangular, but suffers subtle noise modulation artefacts which may be audible with some programme material.
Digital I/O takes the form of an S/PDIF input and output along with the familiar TDIF‑1 eight‑channel interface using a 25‑way D‑Sub socket. The S/PDIF output normally carries tracks 7 and 8, but can be assigned to the output of the internal 8:2 submixer. The S/PDIF input can be routed to any pair of tracks via the input patchbay facility. Also contained in this row of connectors are a pair of 15‑way D‑Sub ports providing the Sync In and Out interfaces used to link multiple DA‑series machines, as well as for connecting with one of Tascam's remote control panels (the RC828 or RC898).
Finally, the top row of rear‑panel connectors provides digital word clock in, out and through (all on BNCs), and SMPTE/EBU timecode in and out. The latter are, unfortunately, unbalanced on phono connectors, which is a minor frustration (the DA98 provides these facilities via proper balanced XLR ports), but the timecode output is at a healthy level and the input seems respectably sensitive. This row also contains a quarter‑inch socket to accept a punch‑in/out foot switch, a multi‑pin DIN socket for the RC808 transport control panel, and the usual trio of MIDI In/Out/Thru sockets.
Overall, the connectivity is straightforward but flexible and remains wholly compatible with other DA‑series machines, not to mention all those modular digital multitrackers from other manufacturers who have adopted identical interfacing arrangements.
Eyes Front
The front panel controls follow the well‑established DA‑series house style, with metering to the right and transport controls to the left. In fact, the arrangement employed in the DA78HR is extremely similar to that of the DA38, with the same central array of utility buttons and the economic 3U case (the DA88 and DA98, by contrast, occupy 4U of rack space). The metering uses the same 15‑segment bar‑graph displays as the DA38, with a 40dB range, adjustable ballistics (fast, slow or medium release) and peak hold times (0‑9 seconds or continuous). The track‑arming buttons below each meter double up as channel selectors for the input patching, track delay and submixer functions. These meters are also used to provide a wealth of other information after entering the appropriate menu modes, where the bar‑graphs can represent relative track delay times, tape playback error rates (edge and centre), mixer levels, pans and mutes, and input and output patchbay routings.
The five large transport buttons follow the common arrangement where Record is adjacent to Play, with Stop, FFWD and Rewind arranged to their left. Above the transport keys a large display panel contains an eight‑digit display along with a small array of eight square LEDs. These indicate the machine's status, displaying such features as HR mode, sample rate (44.1 or 48kHz), ABS or TC time display reference, active Timecode Offset, and digital Clock source (Internal, Digital In, Word Clock In, or clocked via the Sync In connector). To the right of the counter display is a final LED labelled PB Condition which is supposed to illuminate when the off‑tape error rate exceeds some nominal amount. The only time I observed this to light was when running off the end of a formatted section of tape — well‑used five‑year‑old DA88 archive tapes gave no hint of problems at all!
Completing the transport control section is a column of three small push buttons; these cycle through word clock sources, and toggle the HR mode and sampling rates. The sample rate switch also initiates tape formatting with a rapid double‑press action. Above the transport section two square buttons, one either side of the tape mechanism slot, provide mains power switching and tape ejection.
All the clever aspects of the machine are controlled from an array of 13 small buttons (10 of which illuminate) plus the shuttle wheel mounted in the centre section of the panel. All of these buttons have dual functions, the primary mode being labelled in white with secondary operation indicated by a blue legend. Secondary functions are accessed by first pressing the Shift button, which resides in the bottom right‑hand corner of the array. Most of the functions controlled by these buttons will be familiar to users of any MDM machine and are virtually identical to the equivalent buttons on the Tascam DA38. The majority are reasonably self‑explanatory, such as Auto‑In/Out to enable the auto‑punch mode, and RHSL to start a rehearse pass of an automated drop‑in. The Clear button cancels the Auto and RHSL modes, while Varispeed does just what you'd expect, and the All Input and Auto Mon buttons probably need no further explanation either! The DA78HR's comprehensive timecode facilities includes a chase synchroniser which is activated, logically enough, with the Chase button. There are two chase options: Rechase and Free Run. The former continuously aligns the off‑tape timecode to the incoming timecode, with a selectable 10‑ or 30‑frame error window to accommodate minor code dropouts. The Free Run mode establishes initial timecode synchronisation and then ignores the external timecode completely, running at a speed determined by the internal or external word clock, as appropriate. This mode has the added versatility of a selectable 'error window' which forces a resync if the difference between tape and external timecodes exceeds either 1 or 2 seconds. This can be useful when working with discontinuous timecodes.
One nice feature of the DA78HR is the ability to measure and set automatically the optimum pre‑roll time when working as a slave to an external timecode source, thereby ensuring the fastest possible synchronisation. There is an internal timecode generator to stripe tapes (locked to internal or external word clocks) and ABS tape time can be converted to both SMPTE/EBU and MTC timecodes for synchronising non‑timecoded tapes.
One welcome new function is the Mixdown 8:2 sub‑mixer, accessed through a dedicated button. As I have already mentioned, this can be used to provide a monitoring mix as well as to facilitate internal bounce‑downs, and although setting it up is somewhat tedious and clumsy, it can be operated via MIDI. Since the DTRS format employs a four‑head arrangement configured to replay each audio track before overwriting, the system allows mixdown of all eight recorded tracks to a stereo submix, replacing any of the original tracks, either singly (for a mono mix) or as a stereo pair.
The secondary functions of the buttons mainly provide lesser‑used operations such as independent slipping of tracks relative to one another (from a 4mS advance to a +150mS delay). A timecode chase offset can also be introduced via a secondary button, and the the pre and post‑roll times for the auto‑punch modes can be set in a similar fashion. Logically, the shifted secondary functions associated with the Loc 1 and 2 buttons store time values in their respective locator memories. The All Input and Auto Mon buttons double up as cursors to increment or decrement data values selected through the various menu pages. The shuttle wheel also has a secondary function allowing it to be used to enter or change data values in the menus as an alternative to the cursors. The menu structure is accessed through the shifted Repeat (Menu) and Chase (Sub Menu) buttons.
In Use
The DA78HR is an excellent machine which will extend the life of the DTRS format considerably. That it provides 24‑bit recording for the same cost as the old DA38 is impressive, but when you also take account of the timecode and inbuilt chase synchroniser facilities, as well as the internal track‑bouncing, I/O matrix and monitor mixer, this machine represents superb value for money.
Everything works just as you would expect: the DA78HR is fast, efficient, reliable, quiet, and sounds phenomenal in the 24‑bit mode. The internal converters are good, and using the machine with a high‑end external converter proved its high‑resolution abilities beyond all doubt. A few operational aspects are less than elegant, but it would be daft to complain given the price point and exhaustive features list. You don't get instant access and non‑destructive editing with a tape‑based MDM system, but you do get very low media costs and long recording times. If this appeals to you, the DA78HR is going to be a hard machine to beat. Thoroughly recommended.
A LA Carte Menu
A machine designed for a very wide range of applications has to offer a considerable degree of flexibility in its configuration, and it has become accepted industry practice to provide this customisation through a system of menus. The DA78HR is no exception and contains eight separate menu pages, each with an average of five or six sub‑pages. The main menus are System, Audio 1, Audio 2, Timecode, TC Chase, TC Generator, MIDI, and Maintenance. While the grouping of functions within these menus is reasonably logical, recognising these pages and understanding what they are trying to display is, frankly, rather difficult. The problem is an inevitable consequence of using the eight‑digit, seven‑segment timer readout. The text characters which can be produced on this kind of display are a strange mishmash of upper and lower case with a few weird hieroglyphs thrown in for extra confusion! For example, bars over the 'n' and 'u' represent M and V, respectively; an upside‑down 'A' is used to mean W, while a mirrored 'y' acts for K and a horizontal 's' replaces the X. The end result is a collection of 'words' which are largely meaningless without the manual to aid in their recognition!
Although this could be described as a weakness, it is hard to see how Tascam could have come up with a better alternative without going to a much more expensive alphanumeric display element — a fluorescent display or LCD panel, for example. Personally, I would rather reach for the manual occasionally when the need arises to access the more obscure menu functions (very few would ever need to be adjusted anyway) than shell out another 500 quid just to get a better display. Indeed, the DA98HR, which incorporates an LCD panel, costs 80 percent more — although it does provide some extra functionality too!
Video Made The Radio Star
Like all previous DTRS recorders, the DA78HR employs standard Hi‑8 video cassettes as its recording medium, allowing up to 108 minutes of continuous eight‑track recording on an NTSC 120 tape. It can record and replay at either 16 or 24‑bit resolution, and the 16‑bit mode is fully compatible with standard DTRS machines. However, tapes recorded to the 24‑bit HR format cannot be replayed at all on 16‑bit machines as the data format on the tape is incompatible.
The tape transport is, essentially, the same rotary magneto‑resistive four‑head mechanism found in all the later DA‑series machines, which has a proven track record of reliability, stability and long life. The new, proprietary 24‑bit tape format follows the same fundamental track pattern as the original 16‑bit DTRS system — which is why tape running times are unchanged in HR mode — and the same read‑before‑write head arrangement with a built‑in head and tape cleaning system. However, the extra 64 bits (eight additional bits on each of the eight tracks) of audio information are accommodated through a greater packing density on the tape. The upside of this re‑engineering is the retained compatibility between HR and standard formats, but the downside is a slightly increased risk of data corruption through tape dropouts or head clogs. For this reason, Tascam recommend using only new tapes for recording and, I suspect, routine maintenance may become more important than was the case with the original format. The handbook recommends a service check and clean every 500 head‑hours, with a routine alignment suggested every 1000 head‑hours.
Pros
- Very attractive price.
- 24‑bit resolution with full 16‑bit backwards compatibility.
- Comprehensive timecode facilities.
- Excellent converters.
- Fast and quiet transport.
- Robust and cheap media.
Cons
- Confusing menu text displays.
- Cumbersome bounce‑down mixer adjustments.
- No RS232 9‑pin remote facility.
Summary
Extending Tascam's DTRS format to include 24‑bit resolution, their new DA78HR eight‑track recorder offers a wealth of professional features — including timecode chase synchronisation — at an extremely attractive price point.