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Spirit 324

Live Digital Mixing Console By Hugh Robjohns
Published July 2000

Spirit 324

Combining their vast live sound experience with the success of their 328 digital mixer, Spirit have launched a specialised version of the desk, intended for live sound work. The new 324 model, however, is also well adapted to recording, so Hugh Robjohns checks it out in both applications.

The Spirit 328 console came to the market relatively late compared with the other familiar mid‑priced digital consoles, appearing first in early 1998 (previewed in SOS June 1998 and reviewed in SOS December 1998). However, instead of being disadvantaged by their late entry to the fray, Spirit were able to capitalise on the situation by developing a refined and distinctive user interface which is claimed to offer a number of advantages over the more conventional assignable techniques employed by the likes of Yamaha, Tascam and Panasonic, to name but three.

The key feature of Spirit's user interface is the 'E‑strip' — an approach to assignability which presents a complete channel strip of controls along a horizontal row of encoder knobs, one above each fader. This gives access to all the EQ controls, aux and FX sends and the pan control for a selected channel all at the same time. However, the flexibility of the system also permits one specific control to be displayed for all channels — Aux send 4, for example. The E‑strip is both intuitive and fast to use and is one of the 328's major strengths.

The Spirit Lives On...

Spirit 324

The latest development from the Spirit factory is a specialised version of the original 328 digital console, designated the Spirit 324 Live — a dedicated live sound digital console based closely on th e 328, but with a collection of new features and facilities optimised specifically for theatre and music front‑of‑house duties. Spirit's sister company, Soundcraft have already developed considerable experience in the requirements of live sound with their high‑end Broadway digital console, which has been used on many major West End and Broadway shows, and I would imagine that some of the features on the Spirit 324 Live may have benefitted directly from this.

The 324 Live is, currently, one of the most affordable live sound desks able to offer the real strength of digital consoles in this application, which is the ability to instantly recall and reset the complete console. This is immeasurably useful, for example, for rapidly changing stage acts, or for different scenes of a play. The new Spirit 324 also provides the multiple output flexibility so essential in live sound applications, and finds itself with few direct few rivals in its field, and with those that are there all considerably more expensive (the closest perhaps being the Roland VM7100 and VM7200, although these are marketed more as general purpose digital‑consoles). Yamaha too have used their vast experience of both live sound and digital consoles in producing their new flagship PM1d console, but that product is clearly aimed at the top end of the pro touring and theatre markets!

For this review Spirit supplied a console running version 1.0 software. although I am told that V1.1 (currently on beta test) should be available at around the time this magazine is on sale in the high street. This new software issue makes a few worthwhile improvements on some of the features of the original system, but only in half a dozen areas, and there is nothing radical about it (see 'Version 1.1 Upgrade' on page 180 for more information). The core of the DSP and operating software is ported directly from the 328 console (which is now running Version 1.601) and the two internal Lexicon effects and dynamics algorithms are also identical to the 328.

Spirit Guide

Many of the unique functions of the Spirit 324 Live can be accessed via dedicated buttons in the Master section.Many of the unique functions of the Spirit 324 Live can be accessed via dedicated buttons in the Master section.

The appearance of the 324 Live is, at first glance, virtually indistinguishable from that of its elder sibling. However, closer inspection quickly reveals a range of subtle differences in the connectivity and button legends. As the majority of the console and its operation remain unchanged from the 328 I'll only give an outline of the system here, using this review to concentrate on the new features. Paul White's review of the 328 can be found both on the SOS web site and 1998 CD‑ROM.

As already mentioned, the fundamental layout of the new mixer is identical to that of its antecedent and the analogue input and insert facilities are unchanged. However, the analogue outputs, digital I/O and master section have all been extensively reworked, including a few tweaks intended to make working on live sound easier. A major result of this reworking is the substantially simplified digital I/O section, the benefit of which is a price reduction of around £300 compared with its stable mate's list price. However, the only multichannel interface is now TDIF: the ADAT light‑pipe connections have been dropped as Spirit believe TDIF is more robust for the live sound environment.

Unlike the 328, this new console operates only at a 44.1kHz sample rate and although there is a wordclock output BNC socket there is no provision for an external clock input. Devices connected to the TDIF ports must synchronise to the console either via the clock supplied over the TDIF cable or through the BNC connector. Routeable AES‑EBU and S/PDIF inputs (on XLRs and phonos as usual) are accommodated at 44.1 or 48kHz rates via internal sample rate converters, obviating the need for synchronisation completely.

Entrances And Exits

The flexible controls of the mic/line interface.The flexible controls of the mic/line interface.

A quick run down of the 324 Live's facilities must start with the 16 mic or line inputs on XLR and quarter‑inch TRS sockets respectively. Each channel is provided with an insert point (pre‑EQ), switchable high pass filter (100Hz, 18dB/octave) and a gain control covering the range from +6dB to ‑60dB. These are the only controls not recorded and set as part of the snapshot memory. If sixteen analogue inputs are insufficient, as is likely in many live sound situations, two optional 2U rackmount digital mic/line Interface units can be connected to the mixer via the TDIF digital ports, increasing its capacity to 32 analogue inputs. Each unit provides eight additional analogue mic or line inputs, the circuitry being based very closely on the input stage of the console itself (see box on page 178).

Two separate stereo inputs can be accommodated (for the obligatory background music feed, for example), of which one is analogue and the other digital (AES‑EBU or S/PDIF) — both with full EQ, Aux and FX facilities. The analogue input is catered for by a pair of quarter‑inch TRS sockets (with gain control and activation switch) and both inputs have their own mix level controls.

The internal talkback system provides an XLR socket to connect an external mic, along with a gain control and six push buttons to route the signal to either the four auxes, four matrix and two floating outputs in pairs, or to the main mix.

It is the output side of the console where the most obvious differences between the 328 and 324 Live occur. The 324 retains the four auxiliaries of its sibling (all on TRS sockets) but the five sub‑mixed analogue stereo returns of the 328 have been reduced to just one and in their place are XLR sockets for four matrix outputs and a pair of 'Floating Outputs' — the latter can be fed from the mono output buss, from the FX1 or FX2 internal effect sends, or from any of the four groups. The four matrix outputs are derived from a user‑defined mix of any or all of the four groups, the mono output and the stereo mix buss — typically these would be used to drive secondary speaker arrays, backstage foldback speakers and so forth, although they could also be used as group aux sends or stage foldback feeds.

The control room speaker outputs have been repurposed as a local monitor check feed. The selected monitoring source also appears at the headphones outlet and defaults to being either the stereo mix bus or the mono output (determined via the menus) unless a Solo button is pressed.

Since the two TDIF ports are bi‑directional, the sixteen digital outputs made available through them can be selected to provide either direct outputs from the first sixteen (analogue) inputs, or the four group outputs (repeated four times to fill up the sixteen channels and intended to simplify routing to multitrack recorders). In the interests of flexibility, particularly as the Mic/Line Interface units are used to extend the connectivity of the 324 Live, it is a shame that all the other busses cannot access this option too, but perhaps this will come with a future software update.

New Functions For Old

The I/O of the mic/line interface.The I/O of the mic/line interface.

Although most of the buttons in the master section of the console remain in the same physical positions as those of the 328, many have acquired completely different functions more appropriate to live sound applications. For example, the 324 Live boasts four Mute Group buttons which can be configured to kill specific sets of channels, and an Isolate function to prevent nominated channels from being updated when a new snapshot memory is recalled.

There is also a new lockout facility which disables selectable console parameters, the intention being to prevent inebriated punters from messing up your carefully crafted mix half way through the gig! You can set this up to disable the faders, to prevent snapshot memories from being recalled, or to disable everything except the faders or everything but the snapshots — these last two would be very useful in theatrical situations where a sound designer may wish to protect the settings from the show operators. The final mode is to lock out every control on the entire console and to turn off all the illuminated switches so that it all looks pretty dead, apart from the flickering bar graph meters!

As befits a live sound console, the integral automation is principally concerned with the snapshot memories. The section of the console which was given over to recorder time display and transport controls on the 328 has been completely repurposed for the management of the snapshot automation. There are also dedicated Next and Last buttons, along with Recall, Store and Home keys — this last allowing the user to get back to the currently active snapshot page instantly. The clear LED numeric display leaves no doubt as to which is the currently selected cue and whether it has been altered from the stored setting, or as to which cue is about to be selected.

There are several other elegant features in this section which demonstrate just how well Spirit understand the requirements of live sound. For example, there are two Function buttons which can be quickly programmed to recall any previously identified menu page to the LCD, making it possible to access frequently used parameters very quickly indeed.

One other significant alteration from the 328 recording console is that its track arming buttons, located under each of the channel meters, have been replaced with additional peak overload LEDs. One of the problems inherent in consoles which employ fader paging, as most digital boards do, is that overloads on channels not displayed on the current fader page can be missed and are, consequently, often very hard to track down. Spirit have solved this by providing 'Alt Pk' LEDs which illuminate when peak levels are detected in the corresponding input channels on the invisible input fader page. In other words, when Bank A is active the 'Alt Pk' LEDs represent the Bank B channels, and vice versa.

Crowd Pleaser?

The 324 Live retains the fine analogue and digital performance of the 328 console on which it is based and will be welcomed by the live sound community for its excellent combination of features, usability and affordability. Although intended for live sound applications it can, of course, also be used in a studio recording role or, indeed, for recording a live sound event! In fact, some users may actually prefer the primarily analogue I/O arrangements of the 324 Live over its more digitally capable 328 sibling.

There are very few shortcomings in the 324, but one obvious one is that the otherwise freely assignable dynamics processors can't be allocated to the groups, as would be useful in some applications. Overall, however, this is a very impressive console, well designed for its target market and offering significant benefits over the familiar Japanese consoles which have previously dominated this sector.

The Digital Mic/Line Interface

With the increasing number of digital systems, the need for decent but affordable analogue front ends continues to grow rapidly. For example, there are many eight‑channel PCI cards now offering only digital I/O, such as the Korg 1212, and in many applications the paltry number of analogue channels provided on many digital mixers is simply not enough. Spirit clearly had their own 328 and 324 consoles in mind when they designed the mic/line interface, but it has already found its way into all manner of other applications too!

The converter technology employed in the Interface is based on 128‑times oversampling chips providing 24‑bit resolution, and the input circuitry is based around the UltraMic+ design used in many Spirit products including the 328 and 324 consoles. This elegant topology provides up to 28dB of headroom with a 66dB gain range and an equivalent input noise figure of ‑127dBu (with a 150Ω source). These numbers translate into a quiet and very usable input stage which does not require a pad to accommodate loud mic or line inputs — the whole range is covered by the turn of a single control from +6 to ‑60dBu.

However, unlike the console implementation of the UltraMic+ circuit, the mic/line Interface provides each of its eight channels with individual phantom power buttons and associated LED indicators (the consoles have a single switch which applies phantom to all mic inputs simultaneously). Also provided on each channel is an 18dB/octave high‑pass filter turning over at 100Hz, and a button to switch the insert point into the circuit path (also with an LED indicator).

Although the console input stage provides a switch to reverse the signal polarity for each channel, this is sadly missing from the stand‑alone interface unit. Level setting is courtesy of four LEDs, which form a miniature bar graph meter along the bottom of each input section. These are calibrated ‑30, ‑20, ‑10, and ‑2dBFS, relating to the digital full scale.

Completing the front panel facilities, a ninth group of four LEDs indicates the presence of the interface's three power rails (phantom +48V, ±15V audio rails, and +5V logic supply). A fourth LED illuminates when an acceptable clock signal is being received — the machine cannot operate on an internal clock, but will happily synchronise to 44.1 or 48kHz when wordclock is received from connected equipment via the TDIF port.

The physical input connectors are all neatly arranged on the rear panel with XLR sockets for the mic inputs and ground‑compensated quarter‑inch TRS sockets for the line inputs. The insert points are unbalanced and also use TRS sockets. Since the TDIF interface is bi‑directional, Spirit have very sensibly also included eight line level outputs on the Interface unit to carry whatever signals might be allocated to those channels of the interface. These outputs are 'impedance balanced' on quarter‑inch TRS sockets and can output peak levels of up to +18dBu.

The bottom line is that the mic/line Interface, like the console, is quiet and clean sounding, easy to use and extends the flexibility of whatever it is attached to considerably, without fuss. The only minor limitations are the restriction to TDIF interfacing only, and the requirement for an external clock via this connection.

Version 1.1 Upgrade

One of the strengths of the 328, and now the 324 Live, is the facility to update the operating software via either a Mac or a PC, downloading the latest software over the Internet. The process is a little long winded but not too taxing and should be within the capabilities of any reasonably literate computer user.

The forthcoming v1.1 upgrade for the 324 Live introduces a range of small but important additions and amendments to the console. However, as this was in beta testing at the time of this review, I can only comment on the claims for it rather than on its results. I can say, however, that the v1.0 installed in the review console functioned faultlessly and has clearly benefited from the development of the 328's software, which is now very capable and robust.

Of the new features added in v1.1, the Isolate function (which prevents the isolated audio path from being inadvertently changed when a new snapshot is recalled) has been extended to the Main Mix, the two FX Processors, and the two Dynamics Processors too. The dynamic automation via MIDI has also been updated to use Continuous Controller messages rather than NRPN messages, which should simplify the process of recording and editing Dynamic parameters from a MIDI sequencer.

A useful new reset feature has also been added where holding down all four cursor keys during start‑up resets everything to the original Factory defaults, but leaves all the snapshot memories intact — a clean start mode without losing important user‑memories. The original facility to reset and clear everything is retained when holding down just the Left and Right cursors during start‑up.

To avoid potential confusion or embarrassment when recalling snapshot memories, a new MIDI symbol has been added to the Numeric Cue number display to warn of MIDI content in the selected cue. MIDI data stored as part of the snapshot memories can be used to trigger external FX or Events, and so recalling an incorrect cue could be a tad embarrassing! Finally, the Channel Copy system which allows parameters to be cloned from one channel to another has been modified to include the status of the Direct Output routing (ON, GRP or PRE).

Pros

  • Excellent sounding console with very usable internal effects and good EQ.
  • Cleverly optimised facilities for live sound and theatre use.
  • Intuitive user interface with the E‑Strip assignable controls.

Cons

  • Dynamics processing not assignable to groups.
  • Restricted to 44.1kHz sampling only.

Summary

The Spirit 324 Live console is a clever reinvention of the 328 for live music and theatre work. Key areas of the control surface have been redesigned to better suit the intended applications and the digital connectivity of the console simplified, bringing a worthwhile reduction in price compared to its antecedent.