Lexicon Studio

Combining the famous Lexicon reverb sound with the latest hard disk recording technology, the Lexicon Studio system should win many admirers. Martin Walker falls in love.

It is a sign of the importance now being given to audio recording systems based on computer soundcards that heavyweight industry professionals like Lexicon are joining the fray. A few years ago, soundcards were regarded by some companies as toys suitable only for games — and now look what they can do!

As you might expect, the Lexicon Studio is a fully professional recording system — all the audio circuitry is contained within an external rack‑mounting case for optimum fidelity, and the main analogue inputs and outputs are at +4dBu levels on balanced XLRs. However, when compared to other recent systems, there are two major differences in the approach that Lexicon have taken. Rather than moving their expertise to the software plug‑in market, Lexicon have incorporated their PCM90 reverb hardware into the new Studio recording system, and such is the desirability of the 'Lexicon sound' that many musicians have been eagerly awaiting the launch for this reason alone. We're not talking about a simulation either. The Lexicon Studio uses exactly the same core processing engine as the famous PCM90, taken out of its original rack housing and grafted on to a PCI soundcard.

The other major difference in the approach taken by Lexicon is that of software. Many hard disk audio systems have been launched over the last year or so, offering a wide range of features and capabilities. However, while most of these new systems are audio‑only, many also use proprietary software as the sole means of accessing the hardware. This is a significant area of concern for many people using MIDI keyboards, synth modules, or samplers, since it is vital for them to be able to record and play back MIDI tracks as part of the overall process of making music. Most such systems have options to sync a MIDI sequencer to the Audio software, but this is not an ideal solution. Not only does it involve running two pieces of software side by side on a single monitor screen, it also means possible conflicts when relying on the Audio software to supply tight timing for the MIDI software.

Lexicon have neatly side‑stepped this problem, as well as winning many people over in the process, by working closely with Steinberg to ensure that the Lexicon Studio integrates well with their Cubase VST software (which already supports both Audio and MIDI in a single package). Existing Cubase users will be very pleased to carry on using the same familiar package, rather than having to learn new software from scratch. The other benefit of working with Steinberg is that a dedicated ASIO (Audio Stream Input/Output) driver is available from day one. This should ensure good performance in VST, by minimising any latencies (those annoying time delays between doing something and getting a reaction from the hardware).

Lexicon are to be applauded for ensuring good performance with Cubase VST from the start, but initial shipments do not include a standard Win 95 Multimedia driver. This does mean that Cubase VST is the only application that can currently be used, although a standard driver is expected "in the near future" along with a driver for Apple Macintosh owners.

Installation

Figure 1: Main VST Screen. Both Lexicon reverb modules can be used as either Channel effects (as shown here) or as Channel inserts. Notice that the Buss Output has been set to 'PC‑90 1' and 'PC‑90 2' in the VST Effects window, to route Aux Sends 1 and 2 to the PC‑90 hardware. The VST Master window shows the two active buses.

For the purposes of this review, Stirling Audio supplied me with a Pentium II 300MHz PC containing 128Mb RAM, and an internal Ultra Fast Wide SCSI‑3 hard drive (see 'System Requirements' box). The Lexicon Studio was boxed separately, so I still got the chance to try out the installation procedure.

There are three main components to the Lexicon Studio 12T system: the Core‑32 System PCI buss card is common to all systems, and this has a daughterboard socket to attach the PC‑90 Processor card; two sockets on its back panel allow a couple of interfaces to be connected simultaneously. There is also a 24‑bit multi‑channel digital signal buss, which can communicate with other Lexicon cards to expand system processing power. Although nothing much is being said about this at the moment, "expanding system processing power" sounds suspiciously like a DSP farm to me. Who knows? The third part of the package is the LDI‑12T Interface, a 1U‑high rackmount box providing all the ins and outs.

The Lexicon Studio uses exactly the same core processing engine as the famous PCM90, taken out of the original rack housing and grafted on to a PCI soundcard.

The Core‑32 may be PCI, but unlike many such cards it is a full 14 inches long. The review PC was fitted with an ATX format motherboard, which allows every slot to be occupied by a full‑length card, but anyone contemplating installation onto a Baby‑AT format motherboard may not be so lucky — my own motherboard cannot accommodate PCI cards longer than about eight inches, due to the position of the processor heatsink.

After attaching the PC‑90 daughterboard to the Core‑32, installing the combination into the review PC was quite easy. Such is Lexicon's attention to detail that disposable anti‑static wrist straps are provided for safe installation of the circuit boards, as well as a screw‑on bracket to support the far end of the card.

Once the cards are in place, rebooting the PC allowed Win 95 to detect the new hardware, and after inserting the appropriate floppy disk, the drivers were installed with no fuss — they take a single IRQ and one 64kb memory range. Once the Win 95 desktop appeared, the PC‑90 plug‑in software was installed from two further floppies, and that's all there was to it. A demo version of Cubase VST was also included in the packaging, but most people will want the full version, which will normally come already installed if you are buying a complete system.

The LDI‑12T Interface connects to the Core‑32 back panel via a single proprietary multi‑way cable, and thankfully this is a generous three metres in length, which is quite long enough for the interface to be fitted inside a 19‑inch rack. Its 1U rack casing is only four inches deep, and looks to be exactly the same as that used for the Lexicon Alex and Reflex, as does the supplied 'wall‑wart' external power supply. The front panel (from left to right) features an on/off switch, followed by a balanced female XLR socket for Timecode In, a pair of gold‑plated coaxial phono sockets for S/PDIF In and Out, and then the analogue I/O: a pair of male XLR (balanced) sockets for Left and Right outputs at +4dBu level, a pair of gold‑plated phono inputs (‑10dBV level), and a further pair of female XLR (balanced) inputs at +4dBu level.

On the back panel you will find a pair of 9‑pin D‑type connectors for ADAT Sync In and Sync Out, a pair of optical (Toslink) sockets for Audio In and Out (these can be used as either 8‑channel ADAT format, or stereo S/PDIF), the socket for the computer umbilical, a BNC Word Clock Input (with 75 ohm termination), another 9‑pin D‑type RS422 Comm Port (to connect to video and audio devices capable of Sony serial control), and finally the wall‑wart socket, along with a cable tidy to stop the plug being accidentally pulled out.

Initial Setup

Figure 2: Ctrl I/O window allows full access to the hardware, for selecting inputs and outputs, digital options, and for setting up gain structure.

Most of the external connection options are fairly obvious: digital connections can be made either using the rear‑panel Toslink sockets or the front‑panel coaxial ones, for easy connection to ADATs, DAT recorders, CD players or effects processors. Format conversion is also available, so that you can freely route between optical and coaxial devices. I did miss a pair of unbalanced outputs, but you can make up a special lead to achieve this, so it's not too much of a problem.

As far as interfacing with Cubase VST goes, you simply need to select 'ASIO Lexicon Studio' as your ASIO Device in the Cubase VST Audio System Setup window. This is my first experience of a hardware‑specific ASIO driver (there are very few yet available — notably the Korg 1212), and there are no buffers to set up — as soon as you select the driver, a latency value of 47 milliseconds appears, which is a factor of 10 better than with most recommended soundcard settings when using the ASIO Multimedia driver.

Adjustments to routing are made inside the Lexicon Studio Control Panel — to find this you need to select Audio System Setup, and then click on the ASIO Control Panel button. To be honest, you are likely to be using this Panel quite a lot initially, so it is useful to leave it open, ready to be used directly from the Win 95 Taskbar, rather than having to find it every time.

There are four main pages in the Control Panel. The first is Ctrl I/O, and this is fairly self‑explanatory, providing access to functions of the LDI‑12T Interface. There are two pairs of gain faders — one for the A‑D converters, and the other for the D‑A ones. These can be set at any value between ‑96dB and +12dB. The nominal position of 0dB represents unity gain between XLR input to XLR output, where +4dBu is 14dB below digital full scale. For the phono inputs 0dB corresponds to ‑10dBV, 14dB below digital full scale. These values are fairly standard and sensibly chosen to give you a useful amount of headroom. Each pair of faders can be ganged together, using a small button.

Also on this page are switches to select which of the various Input and Output sockets on the Interface are to be used, along with SCMS settings (copy‑protection can be used or ignored), and a De‑Emphasis switch for the analogue output. Finally, clicking the Turbo Mode box enables full 32 channel capability (this setting defaults to off, with 24 channels available at 44.1kHz and 21 at 48kHz sample rates, and will give higher quality, glitch‑free audio with slower machines such as 166/200MHz Pentiums).

The second page is Reverb, and this allows a wide variety of sources and destinations to be routed to each of the two PC‑90 DSP engines. These include 12 inputs from the LDI‑12T (two analogue, two S/PDIF, and eight Toslink), 12 outputs of the same persuasion, along with four Aux sends (Aux Send 1 L and R, and Aux Send 2 L and R), and four Aux returns of the same variety. This versatility allows the PC‑90 to be patched directly to an input or output signal, as well as within Cubase VST in the normal manner of plug‑ins. It is even possible to create a cascaded reverb using both PC‑90 engines in series. However, although comprehensive, this is one area in which some sort of graphic patchbay would help — it can initially be confusing until you get your head around the alternatives. Thankfully, a default routing is set for Lexicon Studio (shown in Figure 3), allowing you to use the PC‑90 straight away, as an Aux effect in Cubase VST.

...controlling VST using the Lexicon Studio felt much more like using an analogue machine — no wonder that Steinberg are so keen for other soundcard manufacturers to develop ASIO drivers.

The third page is for Punch Record (with its own Mix level fader). This is a very useful feature that allows you to bypass the normal Cubase monitoring, and directly patch any selected combination of Lexicon Studio input signals through to one of the Lexicon Studio hardware outputs during recording (you will need to select Global Disable for Cubase monitoring in its System Setup window). This overcomes an annoying problem with all Win 95 audio recording packages — that there is inevitably a latency between the input signal and the playback of previously recorded tracks during recording. On playback every track will be perfectly in sync, but if you listen to an input signal after it has passed through the software buffers, it will sound delayed, and even the low latency figure of 47ms can be tricky to work with. Of course, you could achieve the same end by monitoring the input using an external mixer, but Punch Record allows you to do it with direct connections.

The final Control Panel page is Timecode, and here you can enable timecode reading, select the timecode source, as well as displaying its current type, validity, and value. The LDI‑12T uses a MIDI driver to convert the LTC (Longitudinal TimeCode) supplied by its front‑panel XLR socket into MTC (MIDI TimeCode).

In Use

Figure 3: The Reverb window is where the routing of the two PC‑90 modules takes place, and the options are comprehensive, to say the least! These are the default settings, which routes both PC‑90 machines as Aux effects through to the hardware analogue outputs for monitoring.

Given the number of inputs and outputs on offer, it takes a short while to get to grips with audio recording, but I soon had some tracks recorded. I couldn't measure noise figures using my normal software of choice due to the lack of a Win 95 driver, but audio quality was subjectively excellent. The main signs of the dedicated ASIO driver were the almost immediate Play/Stop response (the Multimedia driver, in comparison, typically takes half a second to fill up its buffers before anything happens) and the snappy response of recording and playback level meters (which reflected the actual signals much more closely). In fact, controlling VST using the Lexicon Studio felt much more like using an analogue machine — no wonder that Steinberg are so keen for other soundcard manufacturers to develop ASIO drivers.

To check that multitrack recording was working correctly, an ADAT was patched in using optical cables, and an existing 8‑track ADAT tape recorded directly onto the PC's hard drive using Cubase VST. Once the routing was configured, and the ADAT data selected as the word clock source within VST, this worked very well, although some clicks were noticed during the transfer process. However, this didn't happen during further tests with a different ADAT machine, so the problem seems unlikely to be due to the Lexicon Studio. When employed in a larger digital system, using a mixer such as the Yamaha 02R or 03D, you could use its word clock output connected to the rear panel BNC word clock input of the LDI‑12T, and select this as the word clock source, to provide centralised clocking for everything.

PC‑90 Software

Figure 4: PC‑90 reverb module. This familiar‑looking PC‑90 plug‑in is modelled on its hardware equivalent, and should make a lot of people happy.

OK, so I've left the best bit till last. Since the PC‑90 uses exactly the same core processing engine as the PCM90, the reverbs and effects sound just as good, and its front‑panel display will look very familiar to any Lexicon owner. There are two reverb plug‑ins available from within Cubase VST (Machine 1 and Machine 2), and there are five algorithms available for each: Ambience (to add space around the sound), Chamber (particularly useful with voice), Concert (very clean halls), Room, and Inverse (for gate and special effects). Two new banks, each of 50 presets, have been created for the PC‑90, although I suspect that many libraries of other effects will be quickly transported to the computer format.

Using the PC‑90 was a revelation. Switching it into circuit took no more overhead than the simple Wunderverb3 plug‑in supplied free with Cubase VST, and for all practical purposes you have simply connected your VST channels to a piece of external hardware. For anyone who has not used a Lexicon reverb before, the overwhelming feeling is of clarity — a 100% wet signal sounds just as clear as the direct one, with no metallic colouration during long decays, and it was a treat to have such a variety of quality reverbs on tap inside a PC. The other thing to note is the sheer variety of sounds on offer. Most reverbs only offer a handful of controls, but here there are up to 24 (depending on the algorithm). Scrolling through the two new banks of 50 presets created for the PC‑90 shows its versatility. There are the standard rooms, halls, and churches, and beautifully clean they are too, but other special effects like Synth Hall (with pitch modulation) and CyberVerb (using the Inverse algorithm with staggered delays) show just what can be achieved. Mind you, I doubt that I need to convince anyone of the benefits of using a Lexicon reverb!

Lexicon are to be applauded for ensuring good performance with Cubase VST from the start.

The hardware PCM90 does provide access to many more parameters than the PC‑90, but Lexicon told me that future PC‑90 software updates may well add more if users demand it. The current interface only has three parameters visible at any one time, so some algorithms need eight display pages in total. I can't help thinking that here is a missed opportunity to provide an alternative software interface which shows more (or all) of the controls simultaneously, as well as using a graphic approach, with a flowchart for each algorithm. Yes, I know it's the sound that is important and that most people will tweak the presets, but here's the chance to make existing Lexicon owners green with envy, and possibly gain some more potential customers.

Summary

Lexicon seem to have designed a system that has a very useful balance of features. For many people who work with tape‑based 8‑track recorders such as the ADAT or DA88, moving the data to a computer‑based system for editing and mixdown is ideal, and for nearly all such applications a couple of high‑quality reverbs will always be needed. Implementing reverb functions in software demands a great deal of processing power, and the better the quality of the reverb, the more DSP power it normally consumes. By building in a pair of hardware reverbs, offering the legendary quality of the PCM90, Lexicon have created a winning combination, since all of your computer power remains free to run more channels of audio, or a wider selection of other less intensive plug‑in effects.

By opting to integrate their system with Cubase VST, many people who have already devoted a large amount of time learning the Steinberg software can immediately achieve useful work, without starting at the bottom of yet another software learning curve. The people who grumble about timing and latency problems with VST are unlikely to have used a powerful PC with hardware‑specific ASIO drivers and built‑in reverb hardware, such as the Lexicon Studio. If they did, they would find a system with huge power and few compromises, which should win over the majority of doubters.

Lexicon's audio hardware is also well thought out. By providing 24‑bit A‑D converters, as well as internal 24‑bit resolution, you are assured of high audio quality recordings. The fact that the D‑A converters are only 20‑bit is less important, since the majority of audio ends up as 16‑bit in the final master, and you are normally using these converters for monitoring, rather than as part of the recording chain. However, when using Cubase VST v3.55, recording is currently restricted to 16‑bit resolution. The forthcoming Cubase 4.0/24 (initially for the Mac from June 98, and then later in 98 for PC) will remove this restriction, allowing full 24‑bit recording, as well as a host of new features.

The main limitation of this version is the lack of standard Win 95 drivers (and Mac ones). Both of these are promised within a few months, and then the Lexicon Studio could be used with any Audio+MIDI sequencer, albeit with greater latency. Lexicon intend to specifically support other sequencers, to provide optimum results a package at a time. Personally, I think their approach is sensible, given the many potential problems when using a universal driver. Overall, I think Lexicon have a definite winner on their hands in the Lexicon Studio 12T, and I suspect that they may be initially hard‑pressed to keep up with demand.