References

In the listening room, the AIA sub did whether onlyimpress withits outstanding level stability or its excessive depth, but above all did it convince with its self-confident laid-back attitude, with which itrendered the low frequencies. Regardless of whether itplankedthe electric bass and bass drum on "Away From the Sun" by 3 Doors Downinto the room, orlet the flying robot under the bridge knead your stomach wallsin "Terminator - Salvation": Itbehaves completely relaxed even at the highest levels, being entirely in charge of the situation. Distortions or even compression effects are alien to it, while performing at any time cool, extremely clean and incredibly impulsive. Anyone who thought that large, heavy woofer diaphragms used to be sluggish must be open to conviction: With resilient lightness and without the slightest delay, it projects double basses as well as massive low-frequency effects of action spectacles congenially into the room. Even for us, nothing remained to be desired. However, AIA is also offering a model with a 50-inched driver – this one, of course,will surelyfindits loyal advocates among professional cinema operators.
 

Complete Test

A subwoofer with a 60-centimeter driver and 6,000 watts of power - rarely did the key data of a component sound so promising. One and a half years ago, the SMSG15 managedto snag its place in our reference class relatively easy. Accordingly, we were very much looking forward to its bigger brother, the SMSG24 (the number stands for the driver diameter measured in inches), which,tagged at 10,900 euros, retails for more than twice the price. We therefore could hardly wait to live up to the power of this bombastic woofer first-hand.

First work, then play –how true this is, we had to experience while trying to manage the accident-freetransport into our editorial officesof an enclosure measuring half a cubic meter of volume and 110 kilosof weight. This finally worked out quite smoothly by letting someauxiliary equipment and some strong helpers join us in our task. Once having arrived in our listening room, the SMGS24 was marvelled at from all sides: With its height of 110 centimeters, its width of 75 centimeters and its depth of 50 centimeters, it outclasses many floor-standing speakers to look like toys. Especially being true because of its huge driver, who dominates the front panel with its diameter of 24 inches (62 centimeters).

Technology

In addition to its sheer size, this driver–a proprietary development by AIA – also impresses with further technical excellence: With a linear stroke of 90 millimeters, this XXL coneis able to move as much air as nine 18-inch drivers, if required. And moreover, a voice coil with a diameter of 13 centimeters gives it a helping hand - many speakers on the market even consider this to already be a veritable size for their entire woofer. In order to keep such a vibrating unit in linear and non-tumbling operation even under such extreme excursions, a spider of, believe it or not, 30 centimeters of diameter is an unavoidable obligation in addition to the voluminous neoprene surround.

To obtainthis excellent efficiency fromsuch a giant diaphragmand the gigantic magnet respectively, AIA backed the system withabundant amplifier power: The integrated switching power amplifier provides up to 6,000 watts. However, in order to push the envelope, the supply of power to the subwould be limited: Assigned for 16 ampere of current load, which corresponds to approx. 3,600 watts, the normal fuse of the house mains supply line would immediately shutdown if a higher load would be requested. For a short time, i.e. for a few milliseconds, the amplifier though would certainly be able to provide the 6,000 watts. The recessed connection terminalon the back of the SMGS24 reveals: Adjustment and operation is done by remote control only. There is not a single control element to be found except for the power switch, as well as two XLR inputs and three Ethernet network ports.

KleinerKasten

AIA SMSG 24

+ individually adjustable on system and room

+ extremelyaccurate, incredibly deep sound with gigantic reservesin volume level

- big, heavy, expensive

Space needed: With its lush dimensions, the SMGS24 is only suitable for large home theaters. The standard finish of the cabinet is black textured paint as used with PA speakers, but it is also available in high-gloss piano lacquer.

GrünerKasten

DIAPHRAGM SURFACE

The AIA SMGS24 is the ideal visual equivalent to the ancient wisdomgoing round within the worlds of loudspeaker design, namely that for lowbass you need big sized diaphragms and that for lower bass you need even bigger sized ones.This maximdefinitely has its physical background: To generate low frequencies, a driver needs to move as much air as possible during his movements. And you need two parameters to improve it: The stroke, which is the maximum distance that a cone can travel between its two maximum positions - and that as undistorted as possible. Here, the limits are set by the technology itself, although latest developments have already scored for several centimeters. But this requires specialist drivers who are intended to perform the deep bass range only. Limiting factor here is also the linearity of the motor, because it is a tricky task to combine magnet, air gap and voice coil in such a way that even with big excursions exorbitant distortions are avoided.

The other, much easier way for a developer is to simply increase the diaphragm size instead of extending thestroke. Because the more surface it has to offer, the more air it shifts at a given excursion. AIA really has gone to extremes here, using a chassis measuring 62 centimeters in diameter to achieve a surface area that is 2.6 times larger than that of the widespread 15-inch driver. And the manufacturer even managed to increase the maximum linear stroke by realizing a value of 9 centimeters, which defines the current state of the art. Both parameters together ensurethe incredibly relaxed, profound and in the truest sense of the word impressive performance of the SMGS24.

Calibration and operation of the SMSG24 are effectedusing a web browser on a PC. It offers the adjustment of all important settings, including an equalizer mode with 1/3 octave frequency spacing.

Adjustments on thecomputer

These portsare used, among other things, to connect a PC, which enables the subwooferto be completely set up and operated using a special software programoffering two options for calibration: Firstly, via a web browser after entering the respective IP address: On the first page of the shown web interface five presetscan be selected, as they are commonly known also from other manufacturers, for example "Rock" or "Cinema". More interesting it gets on the second page, where the low-pass cut-off frequency as well as their characteristics and slew rate can be set. In addition, the phase can be infinitely adjusted from 0 to 180 degrees. The equalizer controls in the middle section are used to adapt the subwoofer to the room, providing ten setting frequencies between 15 hertz and 120 hertz, that can be increased by up to six decibels or lowered by up to 18 decibels. With this diversity ofcontrollersyou can easily get a grip on even difficult room acoustics. However, the subwoofer lacks an automatic calibration mode, but that’s not necessary at all, as the price of the SMSG24 includes the installation and the calibration by the manufacturer on-site.

Secondly, the subwoofer can be even more flexibly - but also much more complexly - configured using the supplied Unos Creator software. This actually is intended for the setup of complex systems and clearly is subchallenged having to handle one subwooferonly. Nevertheless, the sub can be adjusted in all its relevant parameters.

The subwoofer can be fed with a music signal via its two XLR sockets, although it also processes signals via its Ethernet portsaccording to the AVB standard. AIA uses this protocol intensively in its own home theater installations, but otherwise this standard is still in its infancy.

Apart from the power switch, there is no control element to be seen on the SMGS24; music signals are processed via XLR sockets or via Ethernet AVB.

Sound quality

The tremendousdiaphragmsize and the huge amplifier power leave their marks already during our measurements: a lower limiting frequency of 14.5 hertz and a maximum level of 116 decibels at 200 hertz, as well as the 40 hertz low-pass frequency set thehitherto highest scores in our laboratory. In addition, the achievable maximum level was limited by our premises rather than by the SMGS24 itself: More deep bass energy, our room wasn’t capable of absorbing without suffering any damage. The software program allowed for the frequency response to be calibratedto extreme linearity, which of course also applies to measurements done at the listening position in any home theater.

In the listening room, the AIA sub did whether only impress with its outstanding level stability or its excessive depth, but above all did it convince with its self-confident laid-back attitude, with which it rendered the low frequencies. Regardless of whether it planked the electric bass and bass drum on "Away From the Sun" by 3 Doors Down into the room, or let the flying robot under the bridge knead your stomach walls in "Terminator - Salvation": It behaves completely relaxed even at the highest levels, being entirely in charge of the situation. Distortions or even compression effects are alien to it, while performing at any time cool, extremely clean and incredibly impulsive. Anyone who thought that large, heavy woofer diaphragms used to be sluggish must be open to conviction: With resilient lightness and without the slightest delay, it projects double basses as well as massive low-frequency effects of action spectacles congenially into the room. Even for us, nothing remained to be desired. However, AIA is also offering a model with a 50-inched driver – this one, of course, will surely find its loyal advocates among professional cinema operators.

AV CONCLUSION

For the first time in audiovision's history of test reviews, a subwoofer manages to knock down the maximum score of 100 points.

AIA SMSG24

Connections

Features

VALUATION
 

Sub minimum | medium | maximumcrossoverfrequency

The AIA subwoofer allows for perfectcalibration to the listening position. The irruptions characterize destructive room resonances that can be compensated. Here, the room does not transmit energy.