Spirit's 328 is a digital mixer designed to retain the intuitive feel of an analogue desk. Paul White takes the controls, while Hugh Robjohns explores the 328's comprehensive digital interfacing.
Since its announcement one and a half years ago, Spirit's long‑awaited 328 digital recording console has attracted a great deal of interest, not least due to its unique user interface. Other digital mixers have tended to cut down on the numbers of physical knobs and sliders, instead employing menu systems which can make them less than intuitive to those used to traditional analogue desks. Spirit, however, have tried to take a slightly different approach which emulates more closely the familiar in‑line analogue console paradigm. The 328, unlike most digital mixers, doesn't have a TV‑sized LCD window. Instead, there's the kind of two‑line display that would be more at home on an effects unit, but this isn't purely a cost saving — the designers say it's because so few functions need a display at all.
In addition to the friendly user interface, Spirit have also included as standard the sort of interfacing capabilities normally sold as optional add‑ons. For example, both Alesis ADAT and Tascam's TDIF connections are provided for use with 16 tracks of MDM (Modular Digital Multitrack) or any other recording system using a compatible interface, and there's also AES‑EBU and S/PDIF in and out, word clock in and out, and an RS422 port for connection to computers or other professional equipment that uses the Sony 9‑pin protocol. There's even an additional ADAT‑format aux output — see the 'Digital Facilities' box for more details on the digital I/O.
The mixer, which has an internal mains power supply, is around the same physical size as a small 16:8:16:2 analogue console, and indeed that's the configuration it emulates. The digital connections are located on the rear panel along with MIDI In, Out and Thru sockets. Because all the to and from tape connections are digital (I use the term tape in its generic sense here, as the mixer is equally at home with tapeless recorders), this isn't the obvious choice of mixer if you want to run an analogue open‑reel machine, but having the digital interfacing built in makes it quite cost‑effective for users of ADAT‑ and DA88/38‑compatible recording systems. For those who do need to use analogue machines, a sensibly priced 8‑channel analogue I/O to TDIF converter is on the cards.
The 328 is arranged as an in‑line mixer where channels 1 to 16 will normally be used to handle signals being recorded, though at mixdown, they can also be used to bring other sources into the mix. Channels 17 to 32 share the same channel strips and are fed from the digital inputs, so their normal function is as tape returns for monitoring during recording and for providing the main mix when mixing. As both sets of channels have essentially the same facilities, you don't end up sharing EQ and effects sends as you do with most analogue in‑line consoles, so there's no need for a 'flip' switch.
All the analogue connections are on the top panel to allow easy access for those users without patchbays, and all 16 channel strips have balanced mic and balanced line inputs as well as insert points. However, it is vitally important at this stage to clarify exactly what the insert point does on a digital console like this one. The inserts are analogue, on TRS jacks, and come after the input amplifier but before analogue‑to‑digital conversion. This means compressors, gates or equalisers can be used with any of the analogue inputs at any time, but when it comes to mixing from the digital inputs, you're restricted to using the onboard dynamic processors or to patching an external connection via an unused effect send and a spare analogue input channel.
Unlike the Yamaha range of mixers that provide dynamics on just about every channel, output and return, the 328 has just two dynamics processors, each of which can be configured to work in mono or stereo. Essentially, you pick a channel that will act as the side‑chain feed for the compressor or gate, then decide which channels need to be compressed or gated.
There are two digital effects units running Lexicon algorithms, plus full moving‑fader automation. Used in stand‑alone mode, the automation is limited to snapshots (up to 100), but in conjunction with a MIDI sequencer, the automation is fully dynamic. Snapshot automation can be locked to SMPTE or MTC and mixer maps have been produced for Cakewalk and Logic Audio, and will appear on the Spirit web site shortly.
All 32‑channels have a three‑band, fully parametric equaliser, four aux sends (switchable pre‑ or post‑fader) and two further sends feeding the internal effects processors.
Before moving on, there's one further important concept to introduce — the E‑Strip, a disarmingly simple but effective idea that is largely responsible for the 328's friendly interface. Leaving aside the big‑bucks megastudio digital consoles, it's quite impractical to provide a dedicated knob for every function on a digital mixer, which usually leaves us navigating via data wheels and cursor buttons. The 328 uses these familiar devices to access features and functions that aren't needed on a regular basis, but when it comes to setting up a channel, the E‑Strip is far more immediate.
Essentially, the E‑Strip is a row of 16 rotary encoders located above the faders, and it can be used in one of two ways: you can either have it set to control a single parameter, such as an aux send level or pan setting, for 16 channels at a time, or you can rotate your mind through 90 degrees and have it provide all the EQ, aux sends, effects sends and pan controls for the currently selected channel. Simply hit a channel's select button and the E‑Strip functions just like the channel strip on a regular analogue console, with rings of LEDs around the controls to show the current settings. The equaliser Q controls display an arc of LEDs, the width of which corresponds to the bandwidth, and the EQ parameters are displayed numerically in the LCD window if you don't trust your ears. When the Q controls for the high and low EQ are turned to their widest settings, the LED patterns around the controls change and the response switches from bandpass to shelving.
There are two sets of Select buttons for each channel strip, one for the Mic/Line channel (1 to 16) and one for Tape (17 to 32). Similarly, three Fader Bank selector buttons are used to choose whether the 16 faders control the Mic/Line channels, the Tape channels or the bus and aux Masters. Each channel strip also incorporates a 10‑segment level meter, and three further select buttons allow these to monitor the Mix/Line, Tape or Master levels. Considering that most other low‑cost digital mixers have the meters set out only on one of the LCD display pages, having 16 meters constantly on view is quite a luxury. Two further meters monitor the stereo output level, and these also read gain reduction when setting up the dynamics processors. a fourth fader mode is being added to the software that allows the faders (motorised 100mm Panasonic devices) to be used to send MIDI data for controlling an external MIDI device or software package.
Aside from being easy to use, the sound quality is really very good, the EQ is reassuringly musical, and the provision of ADAT and TDIF (16 tracks, no less) plus AES‑EBU and S/PDIF digital interfacing as standard is excellent.
Inputs 1 to 16 are equipped with XLR mic inputs, balanced jack line inputs, a gain trim pot and a 100Hz low‑cut switch. Phase invert can be switched in for individual channels from the master section. The analogue controls are not programmable, but as a rule, if it lights up you can save it. All 32 channels have a three‑band, fully parametric equaliser, four aux sends (switchable pre‑ or post‑fader) and two further sends feeding the internal effects processors. Unlike my Yamaha 03D, which has a four‑band parametric on each channel, each band of which can be tuned over the entire audio frequency range, the 328's EQ section has been deliberately designed to emulate an analogue EQ, with the audio spectrum being divided into separate overlapping bands, and the high and low bands able to be set to parametric or shelving. This provides a more familiar feel to the controls, and the EQ algorithms have a surprisingly analogue sound which many will welcome.
At the bottom of each channel strip are the two Select buttons for Mic/Line and Tape, plus a Mute button and a Solo button which works in either PFL (pre‑fade listen) or SIP (solo‑in‑place) mode depending on how Solo is set up in the master section. a Solo Safe mode is also included which allows specified channels to remain on when another channel is soloed. This is useful for hearing a soloed channel complete with effects.
Each channel may be routed to 'tape' via the eight buses or via a direct output system where any channel can be made to feed the correspondingly numbered tape track. The 328 can accommodate up to 24 tracks of digital recording by using the Groups along with the direct channel outs, and though there are only 16 digital tape return channels, it would be possible to perform 24‑track mixdown (or even 32 come to that) by bringing additional tracks into the mixer via the analogue channels. This would also provide an opportunity to use the insert points on the analogue channels. Channel data can be copied to a different channel, but at the moment, there's no facility to link adjacent channels as stereo pairs, though I'm assured this has already been remedied and will be included in an imminent software revision.
Also located within the channel strip, but not strictly speaking a part of it, is an MMC record status LED. By using the Rec Arm button in the master section, individual channel Select buttons may be used to put up to 16 tracks of external MMC‑controlled recorder into record‑ready mode.
One potential problem with mixing consoles is that you never seem to have enough stereo inputs to cope with all those odd external effects returns or synths you want to run into the mix. Spirit have got around this quite neatly by building what is in effect an analogue 'levels only' submixer into the 328's master section, combining four stereo analogue inputs into one before digitisation. In addition, a second stereo analogue input path is provided, this time with just one pair of input jacks, and again with its own level control. I imagine the idea of separating the first group of four inputs is to make them available as effects returns to handle anything that might be connected to the four aux sends, but in reality, any line‑level input signal can be fed into the mix via any of these analogue inputs. All the tape returns and the two sets of stereo inputs have the same routing facilities as the main input channels, as well as access to EQ and aux sends.
The analogue paradigm has been carried over to the master section, where there are inputs for two separate 2‑track recorders and monitor selection between Mix and 2 Trk, as well as a monitor Dim button. At the top of the section are rotary controls for all the analogue ins and outs, for the 2‑track tape returns, control room, aux sends and the stereo inputs. Stereo input STE 1 has four stereo inputs that are mixed into one stereo pair with a level control for each, while STE 2 has a single pair of inputs. Either of these stereo ins may be fed from the AES‑EBU digital interface, if required, and the stereo mix can also be sent out over AES‑EBU. In the present software version, it isn't possible to use the AES‑EBU input as the 2‑track return, which seems a little remiss given the number of DAT machines out there, but this is due to be remedied in the imminent software revision.
The centre panel contains the two‑line backlit liquid crystal display, below which are four cursor buttons and a rotary encoder for parameter editing. a Confirm/Yes button functions as an enter key, and there are Undo and Redo buttons that allow you to go back one step if you've made a mistake. a clear SMPTE readout is used to monitor the incoming timecode when the automation is being sync'ed to an outside source (MTC or SMPTE), and a set of five MMC transport and locate buttons are provided for remote control of any MMC‑compatible device. These work in conjunction with the 'record arm' LEDs in the channel strips, and include two locate memories.
Most of the smaller digital consoles I've looked at make really heavy weather of signal routing, but again Spirit's designers have really thought the problem through. Instead of having to visit menu‑land, they've provided eight Group routing buttons. Holding down one of these allows you to use the channel Select buttons to route or unroute any channels to that destination. Pressing and holding the routing button again puts the console into Query mode, which causes the Select buttons of any routed channels to light up, so you can interrogate the routing at a glance. In fact, this same philosophy has been carried over to the Phase, Direct Out, EQ In, SIP Safe, Route to Mix, Rec Arm, Mute and Solo functions, so that pressing a single button in the master section can show the status of the entire mixer for the selected function. There are also buttons for setting up the Solo status and for storing, recalling and stepping through (Next) snapshots.
Both effects generators have rotary level encoders plus Select buttons, and may be routed to the same destinations as the channels, though not to themselves. a library of effects and dynamics treatments is included, and these may be edited very easily using the data wheel, display and cursor buttons. Pressing and holding the Dynamics button by the main stereo meters allows the dynamics processor to be assigned to one or more channels (including the stereo inputs and effects returns), while the side‑chain source is selected using the display, cursors and data wheel. It's also possible to assign a dynamics processor to the stereo output, but not the the group outputs.
The dynamics section provides a choice of gate, compressor, compressor/gate, limiter or limiter/gate, where the compressor may be set to hard‑ or soft‑knee. All the usual parameters are editable including attack and release times, threshold, gate depth, gate hold, compression ratio, makeup gain and so on. These parameters are accessible as a simple list in the display window. Selecting the Dynamics button next to the main meters changes them to gain‑reduction meters with the gate open/closed status being registered by the red LED at the top of the meter Pressed the button again exits this mode.
The effects section comes with 112 editable presets ranging from straight reverbs and delays to combination delay/chorus and multi‑echo effects. The amount of editing is reasonably comprehensive (it goes beyond the usual decay time, pre‑delay, HF roll‑off), and edited patches can be stored in one of 128 user memories.
There's a lot to like about the 328, and I believe the design of the user interface sets the standard for ease of use in the small digital mixer market.
Automation is what digital desks are really all about, and the simplest level of automation is the snapshot. a snapshot records all the console settings, with exception of the analogue input gain controls and the high‑pass filter status — anything that shows up on the E‑Strip is saved as part of a snapshot along with routing and the currently selected effects and dynamics processors. To store the current state of the console as a snapshot in the current memory location, it's necessary only to press the Store key in the Snapshots section of the console. If memory mode is selected in the display, the data wheel can be used to scroll to any snapshot location prior to saving. The same data wheel is used to select snapshots for recall using the Recall button. Snapshots may be named with up to 12 characters, and recall can beautomated against SMPTE, MTC, MIDI Clock or MIDI Program Changes. In a simple mix, where all you need is a change of mix between verses or between versus and choruses, snapshot automation may be all that's required. Master console settings such as sample‑rate and tape‑machine selection are not stored within a snapshot, though there are 27 user setup memories that can be used to store this information.
Dynamic automation is more useful when you have a mix that involves constant balance changes or fades. Once Automation Setup is selected in the LCD window, MIDI information (NRPNs) is sent on a single MIDI channel via the console's MIDI Out whenever a fader or rotary encoder control is moved. This data may be recorded directly into a MIDI sequencer, and a full listing of the data is provided in the manual. This way of working only records changes to the console setup — no MIDI data other than the least significant bit (LSB) is sent until a change is made (to keep the MIDI data stream density under control) and, for this reason, a starting snapshot must be created for each song. Subsequent automation moves effectively modify this snapshot. If the song is not always going to be played from the beginning, this method of working means you'll have to create other snapshots throughout the song so that if you stop the mix, you only have to wind back as far as the previous snapshot. Clearly this isn't quite as convenient as having built‑in dynamic automation that lets you start and stop anywhere you like during a mix, but it works.
The 328 currently has four dynamic automation modes, the first three of which are Read, Write and Update. Read mode allows automation data to be played back from a sequencer, while Write is selected when you're recording automation data. Update mode is used to modify mix data — in this mode, the external MIDI information controls the mix (Read mode) until a fader or control is moved, at which point those controls are switched into Write and remain there until the pass is finished. Any unmoved controls remain in Read mode. In practice, the automation is still a little clumsy as you have to switch between Read and Write modes via the LCD window, and fast fader moves tended to gum up the data stream, at least with my budget MIDI interface. Spirit are aware of this and are planning extensive improvements in this area via free software upgrades. Fortunately, the 328 can be updated from floppy using a Mac or PC — there's no need to send it away or to pull it apart.
Finally comes Remote mode, in which MIDI data is accepted from a remote controlling device such as a MIDI sequencer with a mixer map. This is similar to Read mode except that no MIDI data is sent from the 328. This mode would be the one to use when controlling the 328 entirely from a sequencer mixer map.
Once you've switched on, seen the light show and waited a minute for the operating system to load, finding your way around the 328 is largely intuitive, not least because of the excellent E‑Strip and the rings of LEDs around the rotary encoders. Even so, the brief manual could be more helpful by working through examples of procedures you're likely to want to do. Routing, recording and EQ'ing is almost as simple as on an analogue desk, so no complaints there, and the 24‑bit converters are extremely quiet and transparent. Noise‑shaped dither can be applied when reducing the output signal for 16‑bit in order to preserve the greatest possible dynamic range. The EQ section has a positive character but still sounds nicely analogue, and though the effects are arguably less sophisticated than those found on the Yamaha 01V and 03D, they're still perfectly adequate for the majority of applications. The dynamic processors are generally good and tend to have more 'attitude' than most digital compressors I've heard. However, having only two can be limiting (no pun intended), especially as you can't insert external signal processors.
Finding your way around the 328 is largely intuitive, not least because of the excellent E‑Strip and the rings of LEDs around the rotary encoders.
Snapshot automation is straightforward and effective, and when the snapshot memory gets full, you can dump it to a sequencer or data filer via MIDI SysEx. The ease of use of the dynamic automation dependslargely on which sequencer you're using, as is invariably the case when it relies on an external MIDI sequencer. Mix edits have to be dealt with in the sequencer, and I also found that moving multiple faders or making fast moves tended to produce more data than my system could comfortably handle, so some automation events got lost. Apparently this is because Spirit use a very high‑resolution logarithmic mapping system which produces a lot of data, but they've already sussed that many sequencers can't deal with it and they're providing a less data‑intensive linear alternative in the next software revision. Operationally, I didn't like having to switch from Write to Read mode manually using the display section every time I made an automation pass. Hopefully the next software revision will enable the software to automatically drop back into Read mode from Write whenever the timecode is stopped. I'd also welcome some means of using the channel Select buttons to put individual channels into Write mode from Read — a methodology that's familiar to most people who've already used desk automation.
There's a lot to like about the 328 and I believe the design of the user interface sets the standard for ease of use in the small digital mixer market. For me, the weakest areas are the the limited number of dynamics processors (though they actually perform very well), and the reliance on an external sequencer for dynamic automation. My own view is that there's little excuse not to bring the automation on board apart perhaps from on the very cheapest digital mixers. These criticisms aside, the 328 is largely good news, and the ease with which the software can be updated means it can only get better in the future — v1.004 should be fitted to all shipping models by the time you read this review and v1.1 is in development. Aside from being easy to use, the sound quality is really very good, the EQ is reassuringly musical, and the provision of ADAT and TDIF (16 tracks, no less) plus AES‑EBU and S/PDIF digital interfacing as standard is excellent. The inclusion of MMC control with track arming is also very welcome and there's a nice, clear timecode display. I'm also impressed by the generous number of analogue returns/line ins and the fact that two stereo machines are catered for as standard. Professionals will be impressed by the word clock in and out as well as Sony 9‑pin compatibility, while the clear metering should win friends in all areas. Once Spirit have tightened up the automation side of this mixer (as v1.1 promises to do further), they should have a real winner in the 328.
|Frequency Response:||10Hz to 22kHz +/‑ 0.5dB.|
|Dynamic Range:||Mic In 109dB, Stereo inputs 112dB.|
|A to D and D to a Converters:
||24‑bit with 128‑times oversampling.|
|Internal Processing:||24‑bit, 56‑bit.|
|LF Parametric EQ:
||Sweep/shelf 40Hz to 800Hz, Q 0.7 to 2.8, +/‑15dB range.|
|MID Parametric EQ:
||Sweep 200Hz to 8kHz, Q 0.7 to 2.8, +/‑15dB range.|
|HF Parametric EQ:
||Sweep/shelf 1kHz to 20kHz, Q 0.7 to 2.8, +/‑15dB range.|
||2 x Lexicon processors, up to 10 editable parameters per effect.|
||Two assignable mono or stereo processors offering compressor, limiter and gate.|
||16 mono mic/line channels, five stereo line inputs and two stereo tape machine inputs.|
||2 x 8‑track ADAT and TDIF connectors, plus one ADAT aux input. AES‑EBU (XLR) and S/PDIF (phono) in and out. See 'Digital Facilities' box for more information.|
|Sync:||SMPTE or MTC.|
||In, Out and Thru, plus MIDI Machine Control (MMC).|
The digital processing and interfacing side of the Spirit 328 is extremely well specified. For example, all of the analogue‑to‑digital and digital‑to‑analogue converters use 24‑bit delta‑sigma designs operating with 128 times oversampling. The internal signal processing hardware provides full 24‑bit resolution, with 56‑bit buses.
Interfacing the console digitally to tape or disk recorders is pretty flexible — in fact I would suggest that the 328 is the present market leader in this respect. Facilities are provided for two simultaneous 8‑track digital recorders with full send and return connectivity normalled to channels 17‑24 and 25‑32. The 328 is one of the few digital desks which provides both ADAT optical and TDIF interfaces as standard — not as plug‑in options — and the provision of both interfaces permits easy format conversion. The software menu system determines which I/O port format is in use as well as providing a very useful +/‑ 10dB return level trim for each channel.
A very unusual facility is the menu option to adjust the phase of the audio data on the TDIF port relative to the desk's word clock output. The phase adjust in the Clock Source menu addresses issues raised when working with two Tascam units, where one is fitted with an old sync card and the other with a new sync card. The ability to adjust the phase guarantees that both units are stably synchronised when transferring data to and from the Digital 328. Spirit have developed a special sync cable that will be available to those users whose setup contains two of the older Tascam units.
The TDIF output can send 16, 20 or 24 bits, the appropriate option being determined automatically to match the number of bits received on the corresponding TDIF input port. Although the clock signal within the TDIF connector is checked to ascertain whether synchronisation has been achieved, the desk relies on separate word clock signals to operate correctly with DTRS machines.
The relative phase between the ADAT port and the word clock is not adjustable, but the output word length can be manually configured for 16 (default), 20 or 24 bits (with appropriate dithering on the shorter word lengths). The ADAT input receives 24 bits and relies on the source machine to set unused bits to zero. a third extra ADAT optical output provides menu‑selectable feeds of auxiliaries 1‑4, FX 1 and 2, the stereo mix bus, or the group buses.
Both flavours of stereo digital I/O are present: an AES‑EBU input and output pair on XLRs is complemented by an S/PDIF input and output pair on phono sockets (although either connector actually accepts data in both formats). The only apparent limitation in the implementation of these I/Os is that pre‑emphasised audio data cannot be accommodated, so bad news for those still using Casio and TEAC portable DAT machines, or CDs which employ pre‑emphasis. Perhaps a future software update can correct this anomaly?
The output ports can be independently selected to provide a mute signal, the stereo mix bus (default selection), auxiliaries 1 and 2, aux 3 and 4, or FX 1 and 2. It is a shame that specific channels' direct outputs cannot be selected (to provide a feed of specific sources without having to tie up the aux sends), but according to Spirit the facility could easily be added should there be a demand for it — the benefits of DSP‑based consoles! The output word length for each of the stereo I/Os is individually selectable between 16 (default), 20, or 24 bits, with appropriate dithering on the shorter lengths.
On the review machine (running v1.0 software), the stereo digital input is of limited use though the v1.1 revision should remedy the problem I'm about to describe. Both of the stereo digital inputs can be independently routed through various signal paths within the desk: nowhere; STE‑1 or ‑2 (ie. in place of the analogue stereo effects returns); or FX‑1 or ‑2 (ie. in place of the internal FX processor returns). By default, the AES‑EBU input is routed to FX‑1 and S/PDIF to FX‑2, but all of the available routings end up on the main stereo mix bus. In a recording application, the DAT return is needed as a source to the control‑room monitoring to check the recording, but currently there is no way either stereo digital input can be auditioned without going through the mix bus. Apparently v1.1 will provide a 'two‑track monitor' option in the list of destinations!
Clocking options are as comprehensive as most other aspects of the 328 with internal options of 44.1 or 48kHz, plus external word clock inputs via a standard BNC socket, the AES‑EBU or the S/PDIF inputs. The desk will lock to an external clock between 40 and 48kHz and the selected clock is available at the word clock output socket. The specifications for the desk don't mention internal clock accuracy, but subcode on the S/PDIF output indicates the clock as Level II (50ppm).
The S/PDIF data stream is inevitably burdened with SCMS codes, but Spirit have provided three category code options as well as both copyright modes. By default, the desk declares itself as a 'Digital Mixer' in the category code flags, but as many SCMS‑equipped DAT machines don't recognise this identification, the desk menu system provides alternative categories of 'DAT Recorder' (for systems that simply don't recognise the mixer code), or 'General'. There are also two copyright settings: 'asserted' means no further copies of the recording are allowed; and 'not asserted' which permits unlimited copies. Incoming category codes and copyright status from the S/PDIF input can be displayed, but are ignored.
Spirit say that the next software upgrade will include, in addition to the improvements already mentioned, dithering to the Optical Outputs and MIDI control of the FX and Dynamics processors, and they're looking into the possibility of synchronisation to Digidesign Superclock. Hugh Robjohns
- 8‑Channel I/O: this connects to the TDIF port to provide eight unbalanced analogue group or direct outputs and inputs.
- AES‑EBU Interface: four pairs of AES‑EBU digital ins and outs on XLRs. Connection is via the TDIF sockets.
- Mic Preamp Interface: provides eight additional mic inputs using the same low noise Ultramic preamps as in the 328. Each input has a gain control, high‑pass filter, insert point, phase button and pad switch; connection is via the TDIF sockets.
- Excellent digital I/O implementation.
- Generous number of analogue inputs.
- Extremely intuitive user interface with long faders.
- Good sound quality with very analogue‑like EQ.
- Dynamic automation relies on an external sequencer.
- Only two onboard dynamics processors.
- No insert points in the tape return path.
This is one digital console that shouldn't frighten away those brought up on analogue mixers. Though there are some problems with the dynamic automation, the imminent software revision should improve matters significantly.