Yamaha i88X

Photo: Mark Ewing

Yamaha's list of mLAN products continues to grow, and their rackmounting i88X offers high-quality mic preamps, analogue, digital and MIDI I/O in a 1U rack unit.

Regular SOS readers will be aware of an increasing number of Firewire-based audio/MIDI interfaces. These come in all sorts of shapes and sizes, with feature sets and prices to suit almost any budget. Yamaha have a long track record in this area through their mLAN technology, which uses specially designed chips to stream audio, MIDI and sync information via Firewire (IEEE 1394). This technology, which is now in its second generation, means that all the mLAN-compatible hardware within a studio can be linked to a computer hub (perhaps running the MIDI + Audio sequencing software that forms the heart of the studio) via a single cable. The result is that mLAN-based studios are easy to connect — devices can simply be daisy-chained together via Firewire cables with a single connection ultimately made to the computer.

As Firewire is either included, or can be very easily added, to almost all Mac and PC computers, the potential of mLAN is obvious and Yamaha have pushed the technology in their own product line. Perhaps the most significant recent release was the 01X, reviewed by Paul White in the SOS March 2004 issue. At a price around £1200, this combines the functions of digital mixer, hardware controller, audio I/O and MIDI interface into a single unit.

Yamaha have now introduced the mLAN-friendly i88X, a unit that contains much of the I/O functionality of the 01X, but minus the mixer/control surface elements (in much the same way that Digidesign introduced the Digi 002 Rack based upon the Digi 002). Housed in a 1U rack, the i88X boast an eight-in/eight-out analogue format with two high-quality mic preamps based upon those found in the top-of-the-range DM2000 mixer, plus optical and co-axial digital I/O, direct monitoring, MIDI I/O and, of course, mLAN connectivity. The eight channels of analogue I/O are available simultaneously with eight ADAT channels and stereo S/PDIF, offering a total of 18 channels of I/O at 44.1 and 48 kHz; at 88.2 and 96 kHz, the ADAT connection is multiplexed to offer four channels.

One obvious application for the i88X would be to expand the number of audio I/O channels available to an existing 01X user. However, even if you have no other mLAN devices in your studio, the i88X is a self-contained audio/MIDI interface in direct competition to other multi-I/O, Firewire interfaces. At this price point, the MOTU 828 MkII and the Digi 002 Rack would be two obvious examples. I have to declare that I'm a bit of a fan of Yamaha products (I've an 01V, DSP Factory and SW1000XG doing good work in my own studio) so, with or without mLAN, I was keen to see how the i88X fared against this competition.

Quick Tour

As can be seen from the photographs and the 'Specifications Summary' box above, the i88X packs a lot of connectivity into a 1U rack, although it is one of the deeper rack units I've seen at just over 37cm, so you will need plenty of room at the back of your rack to house it. With the exception of inputs 1 and 2, all the analogue and digital connectivity is housed on the rear panel. The front panel is dominated by the two XLR inputs. These both offer globally switched phantom power, and each also has a Mic/Line sensitivity switch, a Gain control and a peak LED, with channel 1 also offering a high-impedance setting for direct connection of an electric guitar or bass. The peak LED is pretty much the only metering available for setting input levels and some might find this a little limiting. Sensibly, however, it is set to activate at 3dB below clipping, so the occasionally flicker means a hot signal but, hopefully, not too hot. Input channels 3 and 4 (via the rear of the unit) have separate gain controls on the front panel, while inputs 5/6 and 7/8 are paired, each sharing a single gain control.

The Monitor section provides a Direct Monitoring function, avoiding the latency involved in sending the input signal to the computer and then back again to the i88X for output. The push button simply cycles the Direct Monitoring between off, the four analogue input pairs and the digital input. The appropriate LED lights up to indicate which input pair is selected. The Volume control can be used to balance the level of input signal being monitored to the rest of the mix coming back from the computer to the Master Output, making it easy to setup appropriate monitoring levels for the performer being recorded. Pressing and holding the push button causes one of LEDs to flash, indicating the sample rate in operation (44.1, 48, 88 or 96 kHz).

The front panel is rounded off by the Master Output volume control, a headphone output, a control to switch the optical I/O between stereo S/PDIF and eight-channel ADAT formats, LEDs indicating the master clock source, and a recessed power switch (which, unfortunately, leads to a wall-wart power supply).

The i88X's analogue and digital I/O can all be used simultaneously, for a total of up to 18 audio inputs and outputs.Photo: Mark Ewing

Also included in the box are two CDs and two printed manuals. The first CD provides installers for both the PC and Mac mLAN tools and drivers. The second CD contains four plug-in effects: Pitch Fix, Vocal Rack, Final Master and 01X Channel Module. These are bundled with the i88X but are also available separately. The first three of these were reviewed by Paul White in the February 2004 issue of SOS (www.soundonsound.com/sos/feb04/articles/yamahaplugins.htm) so I won't cover them in detail here, but 01X Channel Module is described more fully below. All four plug-ins are host-powered rather than running on any DSP in the i88X itself, and are provided in VST (Windows, Mac OS 9 and OS X) and Audio Units (OS X) formats. Two manuals cover the i88X hardware and the mLAN software/effects plug-ins separately.

In Use

On the test PC, installation of the mLAN tools, drivers and the bundled plug-ins was straightforward. Given that the 01X driver set includes both ASIO and WDM drivers, I was a little surprised that for the WDM drivers supplied with the i88X, only playback is supported. Yamaha's Nick Howes explained to me that this is a result of how Windows 2000/XP deals with dynamically adding channels on the fly if a new mLAN device is hot-plugged. While this works fine under ASIO, it is problematic under WDM. Nick also said that Yamaha expect this to be resolved when Microsoft release Longhorn — but as this currently has a target release in 2006, users requiring full WDM support have a long time to hold their breath.

One further software issue is worth noting. When using the mLAN Manager software to change the configuration of the hardware, pressing the Connect button to confirm the changes resulted in a very long pause (well over a minute) while the i88X and the test PC implemented the required changes. In testing on the PC as part of Paul White's 01X review, Martin Walker reported the same issue. While the length of time taken is rather surprising, it is not a major inconvenience, as most users will probably 'set and forget' most of these options.The mLAN Manager Auto Connector dialogue allows the sample rate, driver and channel configurations of the i88X to be set.Photo: Mark Ewing

All this said, the performance of the ASIO drivers with Cubase SX (v3.0.0) was faultless. I was able to achieve latencies of less than 4ms for both input and output with a moderately busy song featuring a few soft synths and a variety of effects plug-ins. Configuring SX to feed a 5.1 surround monitoring system via the i88X also operated exactly as would be expected. Acid Pro (v4.0f) also gave the same excellent performance under the ASIO drivers, both with stereo and surround projects.

As ASIO support is still in development in the current version of Right Mark's Audio Analyser (v5.4), I concentrated on some less formal subjective listening tests of the audio performance of the i88X. Frankly, having listened to a few commercial recordings (from classical through to hip-hop), I'm not sure I would have worried too much about the exact numbers anyway — the i88X sounds very good indeed, reproducing well at both the bottom and top end of a mix.

Within SX, I carried out a range of typical recording tasks. These included vocals (both sung and spoken) and acoustic guitar (strummed and plucked), all recorded using a mid-priced condenser microphone via the i88X's very well specified mic preamps. The results were uniformly good, faithfully capturing the detail of both voice and instrument. With line-level signals such as my Line 6 PodXT and Roland synth module, the results were equally good. In terms of audio quality, the bottom line is simple — even in a well appointed home or project-studio environment, it is highly unlikely that the i88X is going to be the weak link in the audio signal chain.

Both the MIDI and the digital I/O worked very much as advertised. Given the number of analogue inputs and outputs, there is plenty of flexibility. This is further enhanced as the channel 1 and 2 TRS jacks on the rear can also function as channel inserts, allowing an external effects processor to be patched in if required. Channel inserts can be a little hard to come by in rack-based audio I/O units and budget digital mixers, so their inclusion here is most welcome. With a mic or guitar feeding the front-panel input of channel 1, a stereo-to-paired-mono patch cable can be used to insert a favourite compressor, EQ or similar.

Conclusions

As an audio and MIDI interface, the performance of the i88X is certainly competitive with that of the other leading Firewire-based rack units such as the MOTU 828 MkII and Digi 002 Rack. While all provide multi-channel I/O connectivity, each of these units does offer something different in terms of specific features or the included software. With the i88X, the distinctive selling points are the mLAN support, the high-spec mic preamps, the ability to patch in an external effects unit and the bundled plug-ins.

The latter in particular are a useful extra, and would certainly appeal to users developing a new computer-based system. However, if you already have your quota of pitch-correction, mastering and voice channel plug-ins, they may be less of an incentive. In addition, if the i88X is your only mLAN product, then some of the hot-plugging/connectivity advantages of that protocol may be of less relevance. This said, whether you buy into the mLAN concept or not, there is no doubting the quality of the audio hardware on offer. As the central in/out hub of a project or mobile recording system, it would do an excellent job — providing, as a PC user, you are happy to work with the ASIO drivers until the long haul for Longhorn is over.