Event Layla

With an excellent audio specification and lots of inputs and outputs, Event's Layla looks an ideal candidate for many small computer‑based recording studios. Martin Walker gets plugged in.

All three Event soundcards (Darla, Gina, and Layla) are very popular, and it's not hard to see why. They boast excellent audio quality and are generally easy to install, each providing a minimum of eight outputs. Layla is the most professional of the Event family, with a total of eight analogue inputs and 10 analogue outputs, stereo S/PDIF input and output, and word clock In and Out. The audio electronics are entirely contained within an external rackmounting case to keep them well away from the inside of any computer.

Although it has now been available for several months, such was the success of the Event marketing machine that the backlog of advance orders initially made it difficult for a card to be spared for review purposes. However, this delay has provided an unexpected bonus, as we can now test the system in a configuration that many people have been waiting to try for a long time. With the recent release of the PC ASIO drivers to partner those for the Mac released a couple of months ago, Layla has finally come of age when used with Cubase VST. The resulting low latency, particularly when working with many simultaneous tracks, can make all the difference between a sluggish monster and a responsive dream machine.

Panel Games

With a total of 10 inputs and 12 outputs, Layla seems ideal for recording small live bands, as well as patching in racks of outboard processing during multitrack mixdown.

Initial impressions are certainly good — Layla's 1U‑high rackmounting case looks expensive and professional, and is surprisingly heavy. Most of the socketry is on the back, and there's quite a lot of it. All the analogue inputs and outputs use TRS balanced/unbalanced quarter‑inch jack sockets. From left to right, there are eight Line Input sockets, followed by 10 Line Output sockets. Channels 9 (L) and 10 (R) are marked 'Monitor', which suggests that Event expect most people to use Layla as an 8‑in/8‑out system with an additional stereo monitor output. A 25‑way D‑type Host socket connects to the PCI expansion card in the computer, and the remaining sockets are all digital. There's a pair of phono sockets for S/PDIF In and Out, a pair of BNC sockets for word clock In and Out, and 5‑pin DIN sockets for MIDI In, Out and Thru. These MIDI ports can be used for receiving MIDI time code (MTC), as well as an extra set for connecting synths.

The front panel is finished in two‑tone brushed aluminium, and is relatively uncluttered. On the left is an on/off mains rocker switch and a green LED power indicator, and on the right is a pair of duplicate inputs for channels 7 and 8, labelled Aux In. As you might expect, I carefully whipped off the top cover, and can confirm that the interface chips are identical to those of the Gina: Crystal CS5335 20‑bit A‑D converters, CS4327 20‑bit D‑A converters, and various other Crystal chips for the digital I/O. The two circuit boards are neatly laid out, and the only negative point I noticed was that the transformer produced a noticeable acoustic buzz in use, despite the case being clamped to it using a compliant rubber pad. I could still just hear this over the noise of my PC, but its level should drop once the Layla case is bolted into a rack, so I doubt that it would worry many people in practice.

The rack case connects to the PCI bus Master expansion card via a generous 4‑metre umbilical cable, which — unlike some others — should be long enough to actually stretch between a computer and rack in most cases. It uses the same 25‑way D‑type connectors as the Gina, but this time it's carrying digital signals, rather than audio ones. The PCI bus Master card itself is tiny and, at only 2.5 inches high, almost disappears once fitted in a suitable expansion slot. It also has two onboard connectors labelled RAM Expansion: no doubt these are to support some of the extra forthcoming features, such as DSP effects, that were mentioned a long, long time ago.

In Control

The Echo Console is a comprehensive utility that provides easy access to all aspects of analogue and digital control.

As far as Windows is concerned, Layla appears as the usual set of stereo pairs — six for playback and five for record. The analogue circuitry needs to be powered up to be recognised by the driver software, but a useful error message pops up during the boot procedure to warn you if the hardware can't be found. All three of the Event cards are supplied with the Echo Console software, which Event describe as a "virtual control surface". This utility lets you adjust input and output levels, select various monitor routings for each input, and choose between the various sync options. This can appear permanently on your Taskbar for quick access if you choose — a letter 'L' appears if a Layla card is detected by the driver, and 'D' or 'G' if the other cards in the range are detected.

There are three main areas in the Console (see screenshot on page 166). Inputs are on the upper right, with associated monitor options directly beneath each input, and the outputs are in two rows on the right‑hand side. The sync options are in a single row at the bottom of the panel. Various options in the menus allow you to launch multiple consoles (to control multiple cards, each from their own console), and to modify the colour scheme to your own taste. Input levels can also be globally or individually switched between –10dBV and +4dBu. Confusingly, this does not switch the input sensitivities, but simply alters the readout of fader gain level on the console. In fact, Layla can accommodate a wide range of input levels, although you are likely to get lower background noise levels when input signals are at the more professional +4dBu level.

Each of the inputs, outputs and monitor has a Mute and Solo button, and for stereo use the faders can be ganged together. Next to each fader is a peak‑reading meter, although these are a little conservative, moving 'into the red' at about 3dB below clipping. EasyTrim input gain adjustment is also provided, which automatically sets the input fader level to its optimum setting while monitoring a typical input level. On the output section, the EasyTrim 'T' buttons are replaced by output level switches; these do physically switch levels between –10dBV and +4dBu.

Monitoring is certainly comprehensive — you can route any input simultaneously to any or all of the output channels at differing levels (the console maintains 100 fader settings). There's also a switchable Group Mode, so that, for instance, clicking on the '3' button of any monitor channel will switch all monitors to display their settings for Outputs 3/4. This could be used to quickly set up a variety of output monitor mixes for different musicians. Although you can accidentally set up feedback, this system is ideal for monitoring inputs in real time through any output of the card, without the latency caused by the software application.

In Sync

The PC ASIO drivers a variable buffer size which, at its lowest setting of 1kb, gives a latency of 25ms.

At the most basic level, the Layla's MIDI In can be used to receive MIDI Timecode, and this is one of the five Input Clock options when you want Layla to act as a slave. The others are Internal (Layla provides the master clock, and you can use the word clock output to sync other equipment), S/PDIF (where Layla locks to the embedded clock in an incoming digital audio signal), and two forms of word clock. Standard word clock is the most widely used type of sync in digital audio, but much equipment (including Layla) uses a much higher‑frequency clock internally, known as Superclock. This runs 256 times faster than the sample rate, allowing other devices to sync more accurately and adjust more quickly to different sample rates. Layla uses a clock generated using direct digital synthesis (DDS) techniques, which normally have significantly lower jitter than clocks using PLL (Phase Locked Loop) circuits — Event mention a figure of less than 300pS (Picoseconds). Multiple Laylas are supported using Superclock; a short cable linking the word clock out of the first is connected to the word clock input of the second.

The S/PDIF mode (consumer or professional) can be switched from the Control Panel, which alters the implementation of the SCMS copy protection bit, although neither option prevents you making further copies. Also altered from within the Control Panel are MIDI Time Code Tolerance and Damping. Tolerance sets the amount by which the sync can wander before a correction is made. If the user is experiencing poor sync this is the first thing to adjust, but further control is provided by the three selectable Damping settings, which determine the speed at which the sync is adjusted.

Audio Performance

I first measured the RMS background noise of the Layla using Sound Forge. However, since Wavelab now has a Global Analysis option, performing the same function as 'Statistics' inside Sound Forge, but giving the option of measuring at 20 and 24 bits as well, I first double‑checked its 16‑bit figures with those of Sound Forge (they were within 0.01dB). I then moved over to Wavelab to measure A‑D background noise levels when recording with 20 and 24 bits.

The A‑D background noise of Layla with 16‑bit/44.1kHz files measured an excellent –93dB RMS. As I fully expected, given the 20‑bit converters, 20‑bit and 24‑bit results were identical to each other, and both at 44.1kHz (‑102.5dB) and 48kHz (‑99.8dB) were better than Event's quoted dynamic range figure of 98dB. The difference between the two may be due to a number of factors, including the wider bandwidth and behaviour of the converters at differing frequencies. Since both resolutions produce the same file sizes, the only advantage of recording at 20‑bit resolution is that the files will be recognised as such by applications such as Wavelab. However, bearing in mind that only 20 bits of a 24‑bit file can possibly contain valid information (and less in practice, since no converter is perfect), there seems little to choose between them — indeed, most applications capable of recording at higher than 16‑bit resolutions tend to default to 24‑bit saves.

Unlike the Darla and Gina cards (which, like most other soundcards, provide a fixed –10dBV output level), Layla can also be software‑switched to the higher +4dBu output levels used by much professional gear. With this +4dBu setting I measured 9.6 volts RMS when playing back a 0dBFS 1kHz sinewave, equating to +22dBu. You would be highly unlikely to achieve such a healthy level from an internal computer‑based soundcard. This is also the origin of Event's quoted 18dB of headroom: operating at a nominal +4dBu output level would still leave an additional 18dB before clipping. However, the software output faders affect the digital level, so Event advise leaving them at maximum if possible, to make sure you're using all of the available 20‑bit dynamic range.

Software Support

To get users off to a flying start, Event include some useful software in the bundle. There's the same 'special' version of Cool Edit Pro that came with the Gina and Darla, along with Sound Forge XP 4.0 (the simplified version of Sound Forge 4.0), and CD Architect, which is still one of the best Red Book audio CD‑writing packages available.

Mac ASIO drivers have been available for download from the Event web site for several months now, and should work with any genuine Apple Mac with a 604 processor or better (Mac clones are not supported). As most people now know, the long‑awaited PC ASIO drivers for use within Cubase VST are also now available. These give much lower time lags (latency) between an input signal and monitoring it during recording, as well as making many other controls feel far more responsive and immediate in use. (For a fuller account of the benefits, see my December '98 PC Notes.) A few working days before I finished this review, the 4.0.1 drivers also appeared, which finally support 20‑bit ASIO recording if you have Cubase VST/24 3.6.

Using the all‑purpose PC ASIO Multimedia Driver with Cubase VST, my latency measured 557 milliseconds, but changing to the 'ASIO Echo Gina/Darla/Layla' driver gives the option of selecting a variety of buffer sizes from 1Kb to 64Kb (see screenshot, above). At the default 8Kb setting the latency is 187 milliseconds, and at the lowest 1Kb setting this drops to an amazing 25 milliseconds. Whether or not your particular system will manage this without glitches or clicks is hard to say, but I had no such problems, apart from some audio 'chattering' when I pressed the Stop button. With the playback meters finally in sync with the sounds I was hearing, it became possible to relate meter movements to the relevant sounds, as long as the latency setting remained at under 100 milliseconds. I tried some 24‑bit recording as well, and this worked with no problems.

However, although audio recording and playback was a lot tighter, I had some timing problems with MIDI. Even with the lowest 1K ASIO buffer setting, MIDI playback consistently started 19mS earlier than the audio, and this offset increased with buffer size. I found that the problem could be fixed if the 'MIDI to Audio Delay' of the Audio System Setup was set to about ‑850 samples. Once this delay has been measured and corrected for, it ought to cause no more problems. Apparently, it only happens with the 4.0.1 PC drivers, and Event are already aware of the problem. A new driver is promised by the time you read this.

One disadvantage of using any device‑specific ASIO driver is that while Cubase is running you cannot use the same soundcard inside another application, such as Wavelab, for editing purposes (even with Background Audio disabled). This is nothing to do with Event, and of course doesn't apply to the internal Cubase wave editor, but it is a bit frustrating. Some people use a second, cheap soundcard for editing only, to get around this. You could also temporarily switch to the Multimedia drivers before editing.

Conclusion

Considering all the fuss about the merits of external converters, some people will be surprised that my measurements proved so similar to those of the Event Gina (see 'The External Enigma' box). However, given that both cards have identical converters, I see this more as a tribute to the design of Gina than a deficiency of Layla. Both cards have an excellent audio specification for their price, and Layla should be judged in terms of its greatly increased I/O capabilities. With six additional inputs, two more outputs, as well as word clock and Superclock facilities, this is a much more professional system. In addition, the analogue inputs and outputs are balanced, and it can operate at the higher +4dBu output level. Layla should integrate very easily into most setups with the minimum of fuss, and although I suspect that some people might have preferred XLR sockets to TRS jacks, you only have to make up a set of leads once.

Many people now use a large arsenal of real‑time DirectShow effects inside their MIDI + Audio sequencers, but those with external rackmounting effects will love the flexibility of patching the multiple analogue outputs into a mixing desk and adding lots of outboard effects (many of which still cannot be duplicated in software). Although this can be done with both Darla and Gina, Layla also allows simultaneous recording of up to 10 inputs (eight analogue and two digital), and this makes it far more suitable as the basis for a computer‑based studio where live bands are recorded as well as synths. Given that the Event drivers can run a pair of cards, you could also expand to a 16‑in, 20‑out system if your computer (and hard drive) were fast enough to cope. Layla is not really suitable for ADAT owners, due to the lack of any optical interfacing.

If Layla had appeared within a few months of Gina and Darla, it might have dominated the market at its price point. Although it is possible to find it at a street price of £799, Layla now has a lot more competition, including the Aardvark 20/20, reviewed in the August '98 SOS, and the MOTU 2408. However, Layla remains a solid and well‑designed system that should appeal to many people. If you want a generous complement of analogue I/O, it should be on your shortlist.