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Dynaudio Acoustics Air Series

Integrated Digital Loudspeaker System
By Hugh Robjohns

Dynaudio Acoustics use cutting-edge digital signal processing, developed with TC Electronic, to increase the fidelity of their existing driver technology.

DYNAUDIO ACOUSTICS AIR SERIES DSP-based monitors.Photo: Mark EwingDynaudio Acoustics, closely associated with TC Electronic, manufacture a wide variety of professional monitoring loudspeakers, from compact nearfield to monster full-range systems. Indeed, a quick search of the SOS archives reveals a fairly comprehensive list of reviews of products from their roster in recent years.

The latest offering from this innovative company is the new Air series, currently comprising two near/midfield speaker designs with a pair of matching subwoofers. The main speakers are called the Air 6 and Air 15, with Air Base 1 and Air Base 2 subwoofers — as you might expect, the larger the number, the bigger the box. The Air 6 is the main focus of this review, auditioned in both 5.1 surround and stereo configurations, the former with the able assistance of the Air Base 1 subwoofer. However, the technology is virtually identical across the entire range, so much of my description and comments on the Air 6 will apply equally to the Air 15.

Although looking, initially at least, fairly conventional, the Air Series is anything but that. These active speakers employ state-of-the-art DSP hardware for the internal crossover and room-correction equalisation, and the individual components in the Air series are 'intelligent', communicating with each other and an optional remote control unit (the Air Remote) via a bespoke data network system. This networking allows an integrated approach to control, in terms of volume, speaker muting, bass management and so forth, as well as relatively simple system commissioning and in-room fine-tuning to compensate for room acoustics and placement.

Another feature of the use of DSP for the crossover functions is that each speaker can be matched at the factory to within ±0.2dB of the target frequency response, making every speaker fully interchangeable with any other. The time-domain output from the speaker is also optimised by this technique. When it comes to installation, a number of instant factory and user presets cater for most situations, including a free-standing position, wall or corner mounting, sitting on a console, and on a console near the wall or corner! From these generic starting points, further fine-tuning can be achieved by the user, and very elaborate tweakery is available to the installation engineer via custom commissioning software.

Most system configuration can be performed directly from the front panel of the speaker, but each system is also shipped with a special Air Soft program which runs on a PC or Mac connected to the speaker's network. This software provides much the same degree of control as the front panel, but in a somewhat more convenient and user-friendly way. It can also be used to update the speaker system's firmware, or to edit, store and recall system presets. A far more sophisticated software package — the one referred to above that is intended for the installation engineer — is called Air PC-IP and provides advanced calibration and alignment facilities. This PC-only software accesses such features as quad parametric equalisers and delay facilities in each monitor, to enable precise in-room integration. Not a toy for the novice!

The Air System Technology

If the drive units in the accompanying pictures of the Air series look familiar, it's probably because they are. The Air 6 uses exactly the same drivers as Dynaudio's BM6 and the Air 15 uses the same drivers as those in the BM15, which we reviewed in May 1998. They also have similarly (although not identically) proportioned reflex cabinets — at 12.1 litres of volume for the Air 6 and 27 litres for the Air 15. Just for the record, the Air 6 measures 382 x 216 x 345mm and the Air 15 is 432 x 275 x 395mm. If you were planning on carrying them about, the Air 6 weighs a solid 9.8kg and the Air 15 comes in at 15.5kg.

However, whereas the BM models both carry a port on the front baffle, the Air series vent to the rear, with their ports tuned to 45Hz (Air 6) and 40Hz (Air 15). One other very obvious and significant change in the MDF cabinet design, when compared to the BM series, is the large radius chamfering of the cabinet edges either side of the tweeter. This small modification is not just a styling tweak — it has improved stereo imaging dramatically, probably by reducing diffraction at the baffle edges which would act as sources of secondary radiation, thereby confusing the image.

Both Air units use the same 29mm soft-dome tweeter with ferrofluid cooling and a pure aluminium wire voice coil. The Air 6 couples this with a 175mm bass driver, again using pure aluminium, in a three-inch voice coil, while the Air 15 is equipped with a 240mm driver and a four-inch voice coil. The crossover in both systems is tuned relatively low at 1750Hz, with classic Linkwitz Riley 24dB/octave slopes. The Air series monitors are fully active but, as I have already mentioned, unlike virtually every other active loudspeaker system on the market these are digital through and through. The audio circuitry is designed to accept an AES-EBU digital input, which is then up-sampled to 96kHz and processed through a DSP to perform out-of-band filtering, a complex array of room-matching facilities, and the crossover. The outputs from the crossover are amplified by a pair of very efficient 200W PWM (pulse width modulation) amplifiers, one for the tweeter and the other for the woofer. The entire input, DSP and amplifier hardware is the same on both the Air 6 and Air 15 — only the firmware changes to suit the appropriate drivers.

The PWM amplifier design lends itself very well to integration into the digital environment of the Air Series, and the power efficiency of these amps becomes clear when the overall consumption of the Air series speaker is given as varying between 50W at idle and 375W at full throttle. The use of a switched-mode power supply adds further to the overall efficiency — indeed, the rear panel heatsink is remarkably small for such a powerful unit and rarely becomes anything more than warm.

The Air series units incorporate a low-power 'sleep mode' which is entered about 30 minutes after the last input signal has been detected. In this condition the speakers will 'wake up' again in less than half a second when signal is reapplied. However, after about two and a half hours of silence the speakers shut down to a proper standby mode, and only become active again if the volume wheel of the remote control or a button on the master controller speaker is touched.

Masters & Slaves

The Air speakers are provided in two forms — master and slave models — but are generally used in pairs. A simple stereo system requires a single master and slave, for example, whereas a 5.1 system employs three masters, two slaves and a subwoofer (which is effectively another slave). The master Air unit is fitted with a small backlit LCD panel at the bottom of the front baffle which carries system information and the various configuration menus. These are navigated and controlled by two rocker switches forming the curved side pieces at each end of the display. The left switch provides Exit and Enter functions, while the right provides up and down navigation and parameter adjustment.

The master Air unit is fitted with a small backlit LCD panel at the bottom of the front baffle which carries system information and the various configuration menus.The master Air unit is fitted with a small backlit LCD panel at the bottom of the front baffle which carries system information and the various configuration menus.The master speaker is also equipped with an AES-EBU digital input on the rear panel, but can be fitted with an optional analogue interface which accepts two audio channels. These analogue inputs are via XLR as well, and are converted to digital with 24-bit resolution in a very high quality delta-sigma converter. The dynamic range is claimed to exceed 113dB and the full-scale input level can be set between +9 and +27dBu, to accommodate pretty much every likely studio operating-level requirement. The 24-bit digital inputs are connected via an XLR too, and any input sampling rate between 31 and 97kHz can be accommodated. An external word-clock reference can also be provided via a BNC.

In addition to the audio and clock inputs, each master speaker is also fitted with three RJ45 sockets, like those used in standard Ethernet systems. The lower two are dedicated outputs, while the top one can be configured as either an input or an output by a small button. These sockets are used to connect the speakers together via a proprietary TC Link network interface, which carries a single 24-bit, 96kHz audio signal and bi-directional data communications.

The slave speakers have just two RJ45 sockets, one permanently configured as an input, the other as an output — there are no audio connectors at all. Slave units connect to the master only via the RJ45 network, using an eight-way cable provided with each speaker. In this way the appropriate audio channel is transferred from master to slave speaker, along with all the necessary control data. The maximum TC Link cable length is stated as 15 metres, although I gather that longer runs are possible with care.

This networking arrangement allows very complex multi-speaker setups to be created, with all speakers in a system being controlled as one. However, it is worth remembering that each slave receives audio only from its respective master, even though the Air Remote unit — included as standard with surround systems, and an optional accessory with smaller configurations — allows all speakers to be controlled simultaneously. The palm-sized Air Remote control panel connects to a spare TC Link output port, normally on the slave speaker, and provides a fully variable system volume control, with buttons to access three preset reference levels and four user presets. There are also mute and solo buttons for each speaker in a 5.1 configuration, allowing individual speakers, or combinations of speakers, to be auditioned or cut as required. This unit may seem a little gimmicky at first, and for a stereo system it probably is a little over the top, but in a surround setup the Air Remote solves, at a stroke, most of the operational problems associated with monitoring in surround from a conventional mixing desk.

The Air Series Subwoofers

The Air Base 2 subwoofer.The Air Base 2 subwoofer.The smaller Air Base 1 subwoofer.The smaller Air Base 1 subwoofer.The Air system currently provides two dedicated subwoofers, the Air Base 1 and Air Base 2. The smaller unit measures a compact 290 x 480 x 447mm and weighs 18kg, whereas the larger is 900 x 290 x 447mm and weighs 29kg. Essentially, the Air Base 2 unit is a pair of Air Base 1 systems sharing a common cabinet and electronics chassis.

The Air Base 1 uses a single 240mm (nine-inch) bass driver with a four-inch voice coil, driven by a 200W PWM amplifier, installed in an MDF reflex cabinet which vents to the front. The Base 2 uses a pair of drivers with two ports, but the amplifier chassis is the same. All bass management functions are configured from the associated master speaker connected via the TC Link interface.

Installation & Configuration

As an example of a typical Air installation, consider a 5.1 surround system. This would comprise three master speakers, two slaves and a subwoofer. The first master becomes the 'system controller' and is placed as the front left speaker, with its slave as the front right speaker. The second master handles the front centre with a subwoofer as its slave, while the third master provides the left surround channel, with the right surround channel coming from its slave.

The system controller is set up with its top RJ45 socket designated as an output, so that it can send data to its own slave, plus the two subservient masters in the system. The Air Remote control is connected to the TC Link output on the slave speaker. The other two Air masters accept control data through their top TC Link connection switched as an input, and one of their network outputs is linked to communicate with their corresponding slaves.

The system controller's two audio inputs carry the main left and right signals, the right channel being passed over to the slave via the TC Link. The master speaker positioned as the centre channel is supplied with centre and LFE signals, the latter being passed on to the subwoofer, possibly with additional low frequency signals from the other channels if bass management is being used (these low-frequency audio signals are also routed around the system via the TC Link interface). The third master at the rear left position is provided with the left and rear surround signals, its slave supplying the rear right speaker channel.

Although this may sound a little complex it is entirely logical, and the manual provides comprehensive instructions and diagrams to aid in configuring the system correctly. Needless to say, this 5.1 arrangement is just one of many possible configurations — the manual details straight stereo, stereo plus subwoofer, stereo with two subs, 5.1, 5.3 and 6.1 arrangements.

Setting up and Air system is not something that can be rushed — the configuration menu is quite extensive and I found it surprisingly easy to get lost! Fortunately the manual provides a map, and as long as you remember to pick up the enchanted amulet in the last dungeon you can usually escape with all your life power intact! While it is perfectly possible to set the system up from the front panel of the system controller, I found plugging a laptop in and running the Air Soft program considerably quicker and easier. Before the system can be configured the complete monitoring setup has to be interfaced in the appropriate manner. This is because the system is intelligent and it won't let you try to assign functions to speakers that aren't connected. The system controller identifies each connected speaker by its serial number, but a pink-noise test tone can be generated to help the user to recognise which speaker is being addressed when configuring the system.

The first configuration menu function concerns bass management, with selectable crossover frequencies ranging from 50-120Hz, plus a mode which allows only the dedicated LFE signals to be reproduced by the sub. If bass management is used with a single subwoofer, the low frequencies from each satellite Air speaker are summed to mono and routed through to the subwoofer. The satellite's bass response is restricted by 12dB/octave high-pass filters at the appropriate frequency, while the subwoofer uses a 24dB/octave low-pass filter. The next menu accesses the bulk of the configuration facilities, starting with definition of each speaker's function within the system: front left, centre or right; surround left, centre, or right; subwoofer left, centre, or right; plus eight other functions which currently serve no purpose.

The rear panel of the master version of the Air 6 monitor, complete with the optional analogue interface. The slave version needs no analogue or digital signal connections and only has two RJ45 sockets for the necessary networking.The rear panel of the master version of the Air 6 monitor, complete with the optional analogue interface. The slave version needs no analogue or digital signal connections and only has two RJ45 sockets for the necessary networking.

The general monitoring configuration is then specified (custom, stereo, 5.1, 6.1 — with either analogue or digital inputs), as is the clocking arrangement (internal or external). If analogue input modules are fitted, the peak level calibration and nominal speaker level can also be set here. In the case of the Air Base subwoofers, this menu includes functions such as the internal generation of pink noise (for identification and line-up measurement purposes) and the setup of relative phase, polarity, LFE gain, low-pass filtering and relative level.

The Air 6 and 15 speakers are also equipped with internal pink noise generators, calibration and relative level adjustments, position compensation (for wall, corner, console and other placements), and bass and treble equalisation. Although the system is capable of introducing delay to provide distance compensation — for example in a 5.1 system where the centre speaker has to be positioned on a line with the left and right speakers rather than at an equal distance — this can only be accessed through the Air PC-IP installer's program, which seems unnecessarily restrictive to me.

The Air satellite speakers are also provided with facilities to adopt X-curve frequency compensation. This is a standard equalisation curve often employed in the monitoring chain of small dubbing theatres when mixing a product which is to be listened to in large rooms — feature films or advertisements destined for cinema release, for example. The reason for this compensation is that when mixing in a small room, the listener and speakers are relatively close to each other and the full signal bandwidth is preserved more or less intact between speaker and listener. However, in a large theatre the sound has to travel much further between speaker and audience, and the level of high frequencies is reduced, relative to low frequencies, because of absorption along the way. The X-curve introduces a 1.5dB/octave high cut above 2kHz (or a 3dB/octave cut above 4kHz) forcing the mixer to produce a slightly brighter balance to compensate for the inherent reproduction losses.

The third and fourth menus concern the selection and storing of preset configurations — there are 16 factory presets, plus 16 user memories. It is vital, though, to use the correct wiring between speakers if the presets are to work as expected. The system may have intelligence, but it doesn't know where you have placed the speakers relative to one another, nor what signals are being fed to each speaker.

The Air Soft Configuration Utility

Every Air system is supplied with the Air Soft software editor, which provides full system control and configuration from a PC or Mac computer. A dedicated cable is provided with the software to connect between the computer's serial port and the TC Link network interface, but this is not just a simple wiring job, as some bespoke electronics have been built into the serial plug! For systems where a serial port is not available, an optional extension cable is available which interfaces between USB and the serial plug of the standard cable.

Once the program is installed and the serial link established, a very attractive GUI allows the system configuration to be determined, speaker functions allocated, and parameters set up as required. Once the system is running as desired, the screen provides a virtual volume control, complete with three preset level buttons. User setups can be recalled and each speaker muted or soloed — all in real time. There is also provision to update the firmware in the Air speakers from this program, using files downloaded from the Internet.

Listening Tests

Dynaudio Acoustics monitors have built up a very good reputation over the years, both in terms of reference-quality monitoring and in offering respectable value for money. As a starting point for comparison, it therefore makes sense to consider the equivalent active BM series monitors (equivalent in terms of driver complement, at least, since the new Air series are considerably more expensive than their active BM siblings — a stereo pair of Air 15s costs roughly 40 percent more in the UK than a pair of BM15As, for example).

However, despite using the same drivers, the difference in price is reflected in a clear quality advantage too. A friend happened to have a set of BM6As in his studio, and a brief comparison with the Air 6 left the impression that the new model was tighter and cleaner, with a more detailed, extended and tuneful bass, much more stable and explicit stereo imaging (and the originals weren't bad!), and a clearer, more neutral mid-range, especially through the vocal region. As with any monitor speaker, at this level of performance we are into diminishing returns, and it is very hard to quantify perceived quality against price. Nevertheless, it is clear that the Air series' DSP technology has extracted a lot more resolution from the original drivers, and incremental cabinet improvements have brought further benefits. There is therefore a significant step up from the BM products, easily justifying the price difference, to my mind.

The Air Remote hardware remote controller.The Air Remote hardware remote controller.

Considering the Air 6 in a simple stereo system, the competition includes models such as the ATC SCM20 Pro, Genelec 1031, and Harbeth Monitor 30 Pro — distinguished company indeed. The accuracy and neutrality of the Air 6 is certainly comparable, and in comparing them to my own reference PMC IB1s (three-way passive loudspeakers) I found them to give surprisingly little away. The stereo imaging was similar, with excellent depth, and the sweet spot was also generously broad and stable. Suitable material, such as simply recorded acoustic music, was portrayed with lifelike dynamics, and the monitors were quite happy to go very loud when required, without any hint of strain or change in character. The mid-range was very honest and clear, reproducing subtle details very nearly as well as the three-way design. The bass end was obviously limited to an extent by the relatively small cabinet size, but even so the Air 6 produced well-controlled, accurate bass well beyond expectations. Although the Air series have a ported design, the port resonance did not seem to colour the lower mid-range, and the typical hump in frequency response didn't become noticeable.

Having said all that, while the Air 6 — and by implication the Air 15 — are extremely competent players, I don't feel that the technological advances of the Air series really come to the fore in a simple stereo system. There is no doubting that the DSP has allowed far more to be achieved with these drivers than was possible under the conventional approach, and in difficult control room situations the comprehensive room-tuning capabilities could well prove a godsend, more than justifying any price differential. However, part of the high cost must also be ascribed to the networking technology, which serves little purpose in a stereo setup, and perhaps makes the system slightly less competitive than other monitors of equivalent performance.

Where the Air series really comes into its own is in a surround monitoring context. Here, above and beyond the precise room-tuning facilities, the Air series offers integrated bass management and comprehensive remote control facilities which really make this an attractive and much more cost-effective proposition. In many situations the inclusion of the Air Remote control alone could obviate over £1500 of expenditure on an outboard surround monitoring controller.

Something In The Air?

One fact that may concern some potential purchasers is that this is a 'digital speaker' — probably with the most complete digital signal path available in a commercial product to date. This may well scare some prospective users, and I know some interested studios have banished the Air series from the premises the moment they realised it was 'digital', presumably fearing that the internal digital processing would interfere in some way with the quality of the monitored signal. As far as I can hear, those fears are wholly unfounded. These speakers are magnificently revealing, detailed, precise and neutral, and I could find no quality limitation that could be pegged to the use of the DSP. Clearly, though, they will give of their best when fed with a digital signal, since additional stages of A-D conversion are unlikely to be a good thing, no matter how good the converter design.

Indeed, I went to some trouble to try and discover any weaknesses in the digital signal path and failed completely. I ran the stereo output of a SADiE workstation replaying a live concert recording at 44.1kHz/24-bit, straight into the Air 6 monitors and also into my conventional monitoring chain. The latter consists of an Apogee PSX100 D-A converter, routed through a Meridian hi-fi preamp, Bryston 4B power amplifier and the PMC IB1 speakers. Once I had matched levels, switching between the two revealed no loss of clarity or detail beyond that which might be expected in such a comparison of a small two-way and large three-way system. Indeed, the Air 6 performed astonishingly well, given its price compared to that of the assembled analogue components rallied against it.

These days, most recordings and virtually all consumer releases are in a digital format of one sort or another, and it makes sense, to me, to monitor the signal in this domain. The Air series comes the closest yet to making this a reality, and in this context becomes very attractive indeed, since top-flight D-A converters, a monitoring controller and a set of similar-quality active speakers would cost rather more in the UK. I think that is really the key — the Air series offers an integrated solution for the digital studio, capable of reproducing a digital source with precision and accuracy beyond that which might be expected at the price. In a surround environment, the integrated network control functions make managing and controlling the system a dream. I was very impressed with the Air 6 system and enjoyed working with it on a number of small mastering projects. I look forward to seeing how Dynaudio Acoustics develop this technology in the future.

Air Series Prices

  • Air 6 £2079; with digital in only, £1974
  • Air 15 £2702; with digital in only, £2596
  • Air Base 1 subwoofer £1045; Air Base 2 subwoofer, £1586.
  • Air Remote remote controller £106
  • Air PC-IP Advanced Installer £423
  • Analogue interface £423

SURROUND SYSTEMS (inc. remote control)

  • Air 6 & Base 1 system £6421; Air 6 (digital in only) & Base 1 system £6110
  • Air 15 & Base 2 System £8518; Air 15 (digital in only) & Base 2 System £8166.

All Air systems come with Air Soft configuration software. Prices include VAT.

Pros

  • Integrated remote control facilities.
  • Superb quality at realistic prices.
  • Sophisticated room-tuning facilities.
  • Closest approach yet to the all-digital ideal.
  • Remote control software provided as standard.
  • Remote control hardware supplied with surround systems.

Cons

  • Benefits more obvious in surround than in stereo.
  • Delay only adjustable with expensive installer software.

Summary

DSP technology provides a step up in performance and resolution from existing cost-effective drivers, while the introduction of innovative data networking between monitors in surround arrays enables integrated remote control and system setup.

information

See 'Prices' box.

Unity Audio +44 (0)1440 785843.

www.unityaudio.co.uk

www.dynaudioacoustics.com

Published September 2002