The Zaxcom Deva II Recorder

Location sound recordists are bound to fall into one of three categories:
(1) Hanging on to their love affair with their Nagra.
(2) Using a DAT until something really better comes along.
(3) Like me, both.
Guess what? The wait may be over. Those that have recently invested in a DAT recorder need not anguish; there are far to many DATs in the field to become obsolete overnight. But for those who have been waiting for a new generation of dream machine, that time is now. When asked by Audio Media magazine to review the new Deva-II recorder, reluctance set in because I feared the truth I would have to tell. But the guarded bias I started out with now only adds credibility to my final impression of the Deva-II. Here is a reprint of the Deva-II article:

The Zaxcom DEVA II by Glen Trew (For Audio Media magazine, USA & UK September editions)

Film production in general, and film production sound in particular, has always been slow to change standards, and only then with the reluctance of retiring a cherished old leather jacket. While portable DAT recorders have had a short life in film production, for most of the last thirty years the undisputed standard, "The One", has been the Nagra. For me, operating a Nagra is still like putting on my old leather jacket.

The possibilities that the current state of digital technology finally offer us mandate that we do, indeed, need a standard other than open reel analog recorders. Only in the last few years have production mixers reluctantly allowed Nagra’s spot to be shared by portable DAT recorders, and while DATs have not been all bad, they do suffer from quality limitations and reliability concerns that will always keep them from becoming a long lived standard.
To those that use them, it’s no surprise. In fact, it’s fair to say that production sound mixers have always assumed that the DAT was a short-term answer to the need of new technology. So for now, there has yet to be a new standard embraced. Deva hopes to change that.

While the DAT manufacturers were happy to profit from supplying their short term answer, Zaxcom designer, Glen Sanders, was building his long term answer, the Deva recorder, which is now enjoying an increasing acceptance of it’s second version, the Deva II. From the drawing board, Sander’s intent was to produce a portable recorder specifically for synchronous film and television production; not a device that would be stocked by music super stores or a machine that could be priced for the home studio. To eliminate
the masses right from the start not only took courage, but also an understanding of the special requirements of production sound mixers, not to mention an understanding of the rewards that would surely come if his recorder is accepted as "The One".

The recorder that wins this spot in film production must meet certain unique criteria. It must be small and portable, rugged, simple, internally and externally battery powerable, four recording channels, a built in mixer, selectable mic or line level, high gain mic pre’s, 48V phantom, selective headphone monitoring, removable recording media, complete time code versatility, and reliable, reliable, RELIABLE! Notice that price was not mentioned in this list. While cost is admittedly a fact of life to be dealt with, it’s usually the last question successful professional sound mixers ask.

While the Deva is to be commended on a layout that makes the transition from analog tape recorder as painless as possible, it’s still a computer and while many of us grumble when making this transition we might as well grin and bare it as another fact of life. Yes, the earth is round, and yes, reels of tape will eventually be looked at like the Gramophone and the rotary dial telephone. That being said, the only option is to make the best of what the new technology has to offer, which is considerable. So, let’s take a look at the Deva II.

Using The Deva II

In a word, it’s a breeze. Let’s assume for a moment that all of the user options have been selected, levels have been set, and it’s all ready to go. Press REC, STOP, or PLAY to, well, record, stop, and play. It’s actually possible to go through the entire day doing nothing else. Its complexity only comes into play when considering the possible options, which are available from selections in eleven different menus. With a little familiarization, even these become simple. I was able to become familiar with and understand every option on the Deva in about three hours. After a few days of occasional use, I was an expert.

Probably the single most useful and unique feature on the Deva is its ability to maintain a pre-record buffer of up to 10 seconds. If this option is chosen, the Deva automatically starts the recording 10 seconds before the record button is pressed. Nice trick. Not only does this give a preroll for postproduction use, but also it makes clipping the beginning of a take nearly impossible. In documentary production, where sometimes you don’t know that there’s something worth recording until after it’s already happened, this feature would be indispensable.

Resolution

The Deva II uses high quality 24 bit, 48K AD/DA converters and records uncompressed, putting it well above any of the DAT recorders and up there with the Nagra analog recorders (finally), and arguably, equal to the Nagra D. The next step up would be to 96K sampling, but no doubt being limited to 2 channels.

The Media

The largest obstacle that Deva has to overcome is in the minds of those leery of recording to hard drive. Today, with recording to hard drive being commonplace in studios, this would seem like an archaic phobia. Maybe it is, but when considering the process that film sound goes through, it is at least understandable. For one thing, the day’s work is sent to a transfer facility at the end of every day. Originally with the Deva, the only option as to hand over the $500+ hard drives to a 2nd AD or production assistant at the end of each day to be shipped to the transfer facility as casually as we had with a $10 DAT cassette. After a couple of days, the drives are returned and recycled back into service for more recording. This presented two problems, again, mostly in the mind: (1) Shipping the original recording with no back up on expensive drives back and forth, sometimes internationally, every day for months, and (2) even more unsettling, erasing the original recording when putting the drives back into service. In our little world as mixers, it’s got to be the equivalent of the big red button on the President’s desk. There is a loud voice in the back of our mind that says, "Don’t do it!".

This phobia has been nicely addressed by the Deva II with the installation of a SCSI port that allows duplicates to be made to JAZ (2G), MO (5.2G), DVD (4G), or the storage media of your choice, even in the file format of your choice. These duplicates can be made while recording the original or they can be downloaded at 8X real time at the end of the day. The latter would be the preferred choice in the case of shoulder strapping or high-speed car scenes because of the motion sensitivity of the backup drives. So, the Deva system has evolved into what seemed like too much to ask for: Originals and simultaneous backups from a single recorder.

This presents a choice to be made: Which to ship, the original or the duplicate? The less expensive option would be to ship the duplicates for transfer while keeping just two hard drives to rotate on the set, but so far, most mixers prefer shipping the original hard drives and keeping the backups for safety.

For long projects such as features or television film productions, the shipping of hard drives is not nearly as much of an obstacle as it would be with commercials or, especially, with documentary production. With commercials, the transfer and editing process is often slower and I can easily imagine the return of hard drives getting delayed or even lost in the shuffle. Maybe the answer is for the production companies to own their own hard drives and present them to the sound department at the beginning of the shoot (sweet revenge). For documentaries, the preferred choice may be to download to Jaz or MO and ship off the duplicates. Even then, the safety of multiple hard drives would be needed for us media phobics. It’s important to keep in mind that this media phobia has nothing to do with the reliability and ruggedness of the hard drives themselves. They can withstand 125-G’s of shock while operating and the 24-second record buffer should survive more motion that the operator can take. The perceived need for backups was not originated with the Deva: Simultaneous backups have been commonplace since the introduction of the DAT recorder to film production. Now there’s a phobia worth having.

Size Matters

Small is good, and measuring 8" x 3" x 7.25" the Deva is the smallest entry yet; smaller than the Nagra, the Fostex PD-4 and even the HHB PortaDat. In fact, even though it was probably envisioned to live most of its life on a sound cart, its size and weight make it perfect for documentary work as well.

Powering

For internal battery power the Deva uses the now common NP-1 rechargeable battery, an excellent choice. It’s nearly as common on most production sets as bagels and bottled water and the capacity of these batteries continues to increase. The Deva will run a minimum of two hours on a 12 volt, 2.3Ahr (27 Watt hours) NiCad NP-1 style battery, but if the higher capacity Nickel Metal Hydride version (50 Watt hours) is used, the record time would, logically, nearly double. Using the supplied wall-wart charger, an NP-1 can be recharged while remaining inside the recorder, though operating the recorder while
charging is not recommended.

The low battery warning indicator is displayed when the internal battery drops to 10.5 volts which is fine for 12 volt NP-1’s. But, more and more people are using the 13.2V and 14V version of the NP-1 and when these reach 10.5 volts, it’s all over. In this case the warning is followed by shut down in just a few seconds. The remedy would be to have a setup function that allows the user to program the warning for NP-1 batteries of different voltages. Sanders is looking into including this feature in subsequent software.
With a current draw of only 800mA, the Deva can use a 12-14V DC battery or regulated power supply capable of 1A continuous as external power. Some modern switching type power supplies can introduce noise into the Deva, so the old standard linear type is recommended.

The external power and charger input connections are made on a side mounted 4-pin Lemo connector. This connector is a great choice for size and dependability, but if you ever need to buy one to make a cable you’ll find out that Lemos are far from cheap. I hope it was a size consideration that dictated this choice because I would much prefer the industry standard four pin XLR, if it would fit. Most sound mixers already have block batteries and cables wired with the four pin XLR that would otherwise plug directly
into the Deva.

The Mixer Section

Since a recorder of this type will often be used with an external mixer, only basic front panel mixing ability is needed and is even preferred over the optional clutter. So, Deva kept this section simple, but made excellent use of the microprocessor’s power by offering some very useful user programmable options. The four analog inputs can be mic or line level, independently, and are assignable to any or all of the four recording tracks. 48V phantom power can be selected at each input. The microphone preamps have more than enough available gain, even when used with dynamic microphones, and are very quiet. A 12dB per octave low cut filter is adjustable from 30Hz to 220Hz in 10Hz increments and can be assigned to the four input channels independently.

Something I consider very valuable is the Deva’s ability to record the same mix to separate tracks at different preset reduced levels, down to -9dB. This feature, along with the already high headroom of 20dB, makes problems with digital clipping highly unlikely.

The Deva has an interesting option of assigning any combination of the inputs to be control by any of the input knobs, in effect creating a submaster. However, when using this feature the input knobs that are assigned to a submaster have no effect on their individual levels. So, while useful, this feature is probably limited to riding gain on predetermined mixes such as a stereo microphone or two. For example, if a stereo microphone is plugged into inputs #1 and #2, both the left and right outputs of the microphone can be controlled by input knob #2, but when this is done input knob #1 has no effect.

A very nice feature concerning the input knobs is the ability to set and electronically lock them, eliminating the possibility of unintentional
adjustments. This would probably be my normal mode of operation when using an external mixer.

Monitoring

Headphone monitoring is selected from fourteen configuration choices (1 & 2 stereo, 3 & 4 stereo, 1,2,3,4 mono…etc.) though not quite as easily as turning a switch like we’ve been accustomed to. Just below the headphone level knob there are two buttons used to scroll up or down through the monitoring options, a process which could take a couple of seconds to check something and go back. To make up for this minor inconvenience the Deva allows any two of these options to be assigned to the F3 and F4 buttons for toggling back and forth between your two most often used choices. I normally use a monitoring switch to go from stereo, to ch1 mono, to ch2 mono, so I would like to have three choices programmable. Since the F2 button has no apparent other use while in the monitoring (HOME) display, maybe it could be used for a third preset (how ’bout it, Glen?).

Every potential owner of a Deva will ask if "confidence monitoring" is available (monitoring playback while recording). The answer is a definite, kinda-sorta. While the operator does not have the analog Nagra equivalent of monitoring off of the playback head, the microprocessor continually verifies that data is written correctly to the disk and gives a visual and audible warning if there is a problem. To my knowledge this has always been confidence enough and no data has been lost unknowingly.

Record Time & Tracks

The record time varies with the size of the hard drive and the number of recording tracks selected. The Deva price sheet includes drives with capacities of 1.3G ($350), 2.2G ($500) and 4G ($550). With the 2.2 Gig hard drive, the Deva has a "track record time" of 4 hours. The number of recording tracks can be selected from 1, 2, or 4 (three track recording is not an option), so the available record time is interpolated logically; 4 hours of mono, 2 hours of stereo, or 1 hour for 4 tracks. These numbers
double when using the 4 Gig drive.

For productions such as feature films and television movies, two hours seems to be an optimum capacity for a storage media because rarely would more than two hours be needed for a day’s work. This keeps it simple: pop in a drive each morning and ship out just one drive at the end of the day. No more waiting to reload the recorder in the middle of a scene and no "roll-outs" during that once in a lifetime a take. However, if four tracks are needed, the 2.2 Gig hard drive only gives one hour of record time. For this reason, I see the $50 decision between the 2.2 Gig and 4 Gig drives a no-brainer.

Track Agility

Deva describes a "segment" as the disk space used for each take, or each record and stop sequence. To further manage the record time capacity of a hard drive, each segment can have a different number of available tracks selected with relative ease. So, in those sound stage scenes where we have the joy of using a singe boom, there is no need to select more than one track. This machine is starting feel as comfortable as my old leather jacket.

A Real World Metering Concept

When we first started selling portable DAT recorders, nearly every other call I took involved where "zero VU reference" should be. Telling engineers that zero reference could really be anywhere they thought it needed to be to avoid digital clipping was very unsettling to most, even though I always recommended -18dB on the standard DAT peak meter for dialog recording. Well, consistent with the courage that gave birth to the Deva in the first place, Sanders took the bull by the horns and put a "0" where he thought it should be. So, "0 VU" equates to the "0" on the Deva. Thank goodness. My phone bill should start going down now.

The Deva standard for zero reference is actually 20dB below digital clipping, or the equivalent of -20 on a DAT meter. While this is 2dB below the now accepted standard for most DAT recordists, the increase in signal-to-noise ratio that comes with the Deva’s 24 bit converters makes a zero reference of -20dB a logical choice. The extra 2dB of headroom will certainly be appreciated from time to time as well. As any sound mixer who’s ever tried to sneak in a call on their cell phone while they were supposed to be watching levels (all of us) can tell you, a zero reference of -18 was still a little risky for dialog peaks anyway. For times when the Deva is used to master pop music or to make copies of music tracks for playback, one should feel free to set zero reference up as high as -12dB if the peaks allow.

Time Code and Sampling Frequency

Time code for film production is a complicated, mandatory tool and should be a full semester class in film school (that would further reduce my phone bill). But briefly, suffice it to say hat in film production there are special considerations and the Deva addresses all of these. The different frame rates are selectable from 24, 25, 29.97DF, 29.97NDF, 30DF, and 30NDF. To accommodate the process of "pulling up" and "pulling down" for post production and sync playback on the set, the sampling frequency can be selected from 48K, 48.048K and 47.952K, adjusting the record or playback speed up or down by .1%. The clock that runs time code generator is powered by an internal lithium button battery so, in the free-run mode, the time code clock continues to run even without external power or NP-1, literally for years. Hallelujah! Requests for this simple feature had been made to the large manufacturers for the last fifteen years and no one listened. For this feature alone the Deva will get a standing ovation from everyone who’s used any other portable time code recorder in the past.

Setting time code on the Deva is a snap. In the Time Code menu, simply select time code or user bits, type in the number you want and press the JAM key. There is no cursor and no flashing digits to scroll through. User bits may be set to "increment", which automatically advances the user bits by 1 each time a recording is begun, in effect putting the segment number on the slate. The standard options for "record-run", "free-run", and "external" are available, and there is a very nice additional option called "CONTINOUS JAM". This feature looks at an external time code reference and re-jams itself every ten seconds. This option allows external time code to be used with interrupt protection and drift compensation. For example, with this feature multiple recorders in different areas of a venue could reliably use wireless receivers as a common time code source without the worry of drop outs, eliminating the drift concerns associated with jam-syncing.

There are a couple of time code features I would like to see included in subsequent software versions. Currently, when in the free-run mode, time code continues to be output while in stop. While this should certainly be an option, I would like to have the ability to not output time code while in the stop mode. Having this feature would allow the camera department to know when you are recording and when you are not simply by looking at the slate. With the Deva’s unique 10-second pre-record buffer it is not likely that you would miss a slate from a hyperactive camera clapping the sticks before hearing "speed", but it can be a reassuring feature that I have begun using with time code DATs.

The second feature I would like to see added is for time code to automatically be output from playback when in the playback mode and automatically return to generator when in the record mode. Currently, from the time code menu you select either "DISK" or "GEN", and that’s what you get on the output, regardless of recording or playing back. The problem is that it is too easy during playback to mistakenly send time code from the generator instead of from the playback track with no one being aware of the mistake until postproduction nightmares begin. Also, if set to "disk" time code and the machine is in the record mode, there is no time code output. This can often prompt a search for bad cables or placing new batteries in the Comtek system and allows very little way to cover up the fact that it was an operator error. So, my preference would be for time code to automatically follow the record and play mode unless another option is selected. This is the way the Nagra IV-STC operated for many years and I can’t think of an instance that it was a problem.

Finesse

Zaxcom has done an outstanding job building a machine that has the familiar features of the Nagra while adding some very nice ones that were
impossible in the analog domain. Any negative criticism from me would have to be put in what I’ll call "the finesse department", as is typical in any newly developed product, but worth mentioning.

The standard four pin XLR was already mentioned as being preferred over the 4 pin Lemo connector for power and charging. Along the same lines, since time code will be used every production day of this machine’s life, I think time code deserves to have a dedicated connector instead of only being available on the RS422 "D" connector. The 5 pin Lemo has been long established as the time code I/O standard with field recorders and film cameras and is certainly small enough to fit somewhere on the Deva.

The edges of the Deva chassis offer protection to the connectors and controls, but are subject to damage themselves, so some sort of protective edging is called for here.

Mic level signals are connected to panel mounted XLR’s, but line level inputs can only be made through a D connector shared by the analog outs. Instead, I would rather have the XLR inputs switchable mic or line level to eliminate at least one need for a D connector adapter and to clean up some of the spaghetti when mixing mic and line signals.

The input level controls do not have an infinity position (total mute) as the "(" labeling suggests, but instead only reduce the input signal by 57dB in their full counter clockwise position. This could be a big problem when an external mixer is not being used. For example, a slate mic could not be left plugged in to the recorder and opened only when needed unless it had a dedicated track on the hard drive. The small input knobs turn as smoothly as a P&G vertical fader; too smooth for this recorder because of the chance of accidental adjustment. This recorder has so much potential in documentary production that a little more friction on these controls would go a long way.

Summary

Well, let’s add it all up. The Deva is a very small battery powered four channel 24 bit recorder with record times of up to 8 hours, built in mixer, very good mic pre’s, 20dB of headroom, time code proficient, pull-up pull-down capable, records simultaneous backups, records 10 seconds before you push the button, impervious to motion, RS422 controllable for post production, and easy to use. That’s not all, but that should be enough. The wait may indeed be over. — Glen Trew

Audio Media always devotes a portion of their magazine to reviews and articles pertaining to sound for film and television production. Free subscriptions are available to industry professionals, by request, on-line, at:  www.audiomedia.com

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