Power From The Deep
Powered subwoofers have been around for many years. Technological improvements have made them smaller, more powerful and above all, more musical. Here we look at a few prime specimens.
Hertz Deici DBA 200 - £299.99
Just a sloping face away from being cuboid in shape, the DBA 200 from Hertz is somewhat unique in that it features not only an 8” subwoofer with large motor assembly, but also two 8” passive radiators. With a 140 Watt RMS amplifier rebated into the sloping face and four “standoff” spacers, the box can be mounted soundly against the rear seat bulkhead of a car without the risk of overheating.
Passive radiators have been around for many years in home hi-fi but are less common in cars. They allow a single box to move more air as the radiators move with the main driver albeit out of phase. However as they are driven by air rather than electrical impulses, this is not the same as being electrically out of phase. The result is a dramatic and pleasing enhancement of low frequencies.
Claiming a frequency response from 32 – 400 Hz and with a sensitivity of 92dB/W/m, Hertz manage to squeeze impressive level out of this compact box. As with most powered subwoofers, the DBA 200 will accept either low or high-level inputs. A 24 dB/octave subsonic filter fixed at 35 Hz is provided as is a 50 – 120 Hz adjustable 12 dB/octave low-pass filter and a 0 – 180-degree phase adjustment. All connections are made via a single connector for quick and easy removal if extra luggage space is temporarily required.
Eton UG RES 11 - £419.99
This innovatively constructed powered subwoofer comes from UPGRADE by Eton. A German company with a long heritage for great home and car hi-fi, the team at Eton is a master of precision engineering, as this product demonstrates. Using an empty spare wheel well to hide a subwoofer enclosure in is fairly common practice, however, the UG RES 11 exploits the space in the centre of the spare wheel itself. The solid die-cast chassis protects two dual voice coil 2 ohm elliptical speakers (12.5 X 20 cm) that are driven by the on-board amplifier rated at 200 Watts RMS. A 24dB/octave subsonic filter keeps power focussed on the 30 – 160Hz frequency range. A wired remote control allows for level adjustment on the move. Once again, the amplifier accepts both low- and high-level inputs and all connections at the subwoofer are on plugs for simple removal.
Eton UG USB 6, 8 and 10 - £229.99 - £349.99
This popular range of under-seat, powered subwoofers are amongst the market’s top performers. Squeezing low bass from a small enclosure has challenged manufacturers for many years. These particular subs are helped enormously by the development of shallow, long-throw drive units and super efficient D-class amplification. Available in the UK are the UG USB 6, 8 and 10. The number denotes the cone diameter in inches. Power on each is provided by two 80 Watt RMS amplifiers and the cones all carry dual 2 ohm voice coils. The low impedance exploits the ability of D-class amplifiers to happily run into extremely low impedances with ease and without excessive heat.
18 dB/octave subsonic filters ensure that energy is not wasted driving frequencies easily reproduced by woofers and full range speakers. All three products are delivered with a wired remote level control, as even the exciting bass delivered by this range needs to be tempered when listening to some acoustic music and of course, boosted when the mood takes you.
The usual rules of science prevail as reflected in the frequency range of each product. The 10 providing a frequency range of 75 – 150 Hz, the 8, 90 – 170Hz.
Rugged case construction offers protection against misplaced feet although bulkhead and vertical surface mounting is an option. Level control and crossover frequency (50 – 100 Hz) are mounted on the side of the unit, as is a variable phase control with up to 180 degrees of adjustment.
Audison Prima APBX 8 AS and 10 AS - £399.99 - £449.99
Audison continues to lead the world in continuous development of speakers and amplifiers. The Prima range is developed with OEM integration and ease of installation in mind. In this instance D-class low impedance is taken to extremes with dual voice coils running in parallel offering a load of just 0.12 ohms. This breakthrough means that the on-board Audison amplifiers are able to run directly from the nominal input voltage without the need for an energy-sapping DC to DC convertor. This results in an incredibly efficient speaker/amplifier combination. The compact, sturdy enclosures can be mounted with the subwoofer firing upwards or downwards or in the case of mounting to a vertical surface, inwards or outwards. This enables your installer to offer two different types of bass due to the mechanical loading on the cone. Of course, personal preference is everything when it comes to bass. Some prefer musical enhancement while others insist on vertebrae-crunching, filling-loosening bass. These boxes are guaranteed to offer both in abundance with the 8” version equipped with a 250 Watt RMS amplifier and the 10” capable of 400 Watts, power is not a problem.
Both 8 and 10 feature water-repellent pressed paper cones. A 12dB/octave Butterworth filter with cut-off frequency from 50 - 200 Hz sits alongside a 0 – 180-degree phase control and both models come with a wired remote level control. A single quick-release connector is provided for convenience.
We have yet to test-drive these new Audison units but if they perform at anywhere near the level of the passive versions we are certain that price-to-performance ratio will be unbeatable. Check the Driving Sounds website (www.drivingsounds.co.uk) or sign up for the Driving Sounds Club to get the inside track on these and all new Audison Prima products.
The decision to go for a subwoofer with integrated amplifier or a passive sub with a suitable discrete amplifier will depend largely on your starting point. If you already have all of the channels of your amplifier dedicated to the speakers in your car then one of the solutions above could be the simplest option and keep installation cost to a minimum.
For a dedicated bespoke system design, contact enquiries@fourmasterscaraudio.co.uk
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