Mobile Electronics Australia

There was a time when if you wanted serious bass performance you simply had to build a custom enclosure. Subwoofers would come with electro-mechanical specifications and you (or your trained installer) would plug these into a modeling software program, and spend endless time plotting, adjusting and comparing predicted results prior to breaking out an armada of tools and construction materials and making a hell of a mess of your garage. You needed computer skills, measuring skills, math skill, woodworking skills, wiring skills and even trimming skills to arrive at decent results – and that was if you got the design right in the first place. That is of course assuming you were able to emulate that design accurately from nothing more than a 1800x2400 sheet of raw MDF and a tube of Liquid Nails.

Thank goodness those days are all but a bygone memory. Yet while the choice of off the shelf enclosures has exploded in the past few years there’s always been a marked performance difference between the common sealed boxes made from chip board, and bespoke tuned enclosures design to compliment your subwoofer precisely. This is why companies like Pioneer have made advances in the design and manufacture or their pre-loaded subwoofer systems. The fruits of this labour include the 308D4SB I’m reviewing here, which is a tuned slot ported enclosure fitted with a single dual 4ohm 12-inch TS-W308D4 subwoofer that is ready to go out of the box.

Priced at $349RRP, the 308D4SB represents a $130 premium over and above that of the TS-W308D4 as sold in the raw. For that you get an all 18mm MDF wedge enclosure with the flat front wall acting as a baffle and the angled rear wall designed to butt up against the rear of your back seat. This encourages rear loading into the cabin which works best in most types of vehicles. Pioneer have dressed things up nicely with quality black carpet (complete with giant Pioneer embroidered logo on top), one pair of nice push-style binding posts, two steel bars acting as a grille to protect the subwoofer, and some fancy molded plastic fascia panels. You simply could not build a subwoofer enclosure of equivalent quality and finish yourself from $130 of raw materials, and a custom made enclosure from a decent installer would set you back twice this or more.

Alternatively, if you have the space and want the added output, a dual version of this system is available - the ‘308D2DB’. At just $549RRP it is only $200 more than the single sub version, making it a bit of a bargain given it affords 6dB more of output gain if you’ve got the amplifier power to feed to it. The single system is rated at 400WRMS of input power at a 2ohm load, and Pioneer have numerous mono amplifiers that are ideally suited to this task. The dual system offers two 2ohm loads, so you’ll need to choose amplifier wisely and the options abound here.

Road test

Punching the electro-mechanical specs of the raw TS-W308D4 subwoofer into BassBox Pro shows that the factory supplied slot-ported enclosure is certainly a compromise of size versus performance. With quite high Qts of 0.62 meant that the TS-W308D4 was never going to be optimized for tiny sealed or ported boxes, in fact BassBox reckons the optimum sealed and ported internal volume are 68 and 88-litres respectively. The factory ported enclosure meanwhile, is near half BassBox’s ‘optimum’ volume at 46.8-litres, while port tuning is a rather peaky 42Hz. This is required to offset the small chosen internal volume as you simply can’t tune low with compact box volumes and expect the same turbulence-free low frequency resolution you get from larger volume enclosures.

The fact is that these days most people simply don’t want to give up as much boot space for their enclosures, having been weaned onto ever smaller and smaller enclosure designs over the past decade. Yet buyers are demanding higher efficiency subwoofer systems which also offer prodigious output and good overall sound balance – which is diametrically opposed to the previous sentence in every way. So, while the BassBox math says the smaller ported box and higher tuning simply won’t perform as well as larger designs, the overall dimension of the 308D4SB are certainly compact enough for most people. The real question is does that large peak in response caused by the 42Hz tuning and 47-litre box volume still sound linear?

The answer is – yes it does. Actually, I did the sound quality and SPL auditions prior to plotting the subwoofer into BassBox this time around (since I didn’t actually have to build or even choose a box for this review) so given what my ears and internal organs were telling me I was quite surprised to see the peaky BassBox plot.

Sure, the 308D4SB certainly serves up enhanced output centered right on 50Hz, and yes this does mean that textbook linearity suffers, but I actually reckon Pioneer are smart enough to know that most buyers in this price point are after precisely this type of bass response. It certainly isn’t boomy and retains very good musicality and tonality throughout the pass band. Upper bass shows a hint of thickness common with ported designs like this, though I must admit that the very bottom octave performance was exemplary. Even though tuning was 42Hz the 308D4SB can stamp all the way down well below this without getting flustered. It certainly sounds like its tuned lower, but in truth very little music material reaches down to below 50Hz in any case.

All in all it’s a lively and vibrant sounding system with tons of efficiency and – thanks to the 10.5mm excursion – tons of output for a single, affordable 12-inch system. How loud? In my station wagon and when hammered with 850WRMS (twice rated power) I reckon it would stretch into the low 130dB range without too much drama. During my auditions I even upset the neighbors, and they are two storeys above through two layers of concrete! Yep, the 308D4SB can crank if required.

Conclusion

While the DIY guys will always want to design and build enclosures for themselves, the simple fact of the matter is that it’s becoming increasingly unnecessary to do so. Pioneer’s 308D4SB is built to a size and shape that will sit neatly into virtually any vehicle’s boot or cargo area, its ready to play straight out of the box, its affordable, and its tuned to a style of sound that 95% of people are going to love. You could build a custom box and get more linear results at the expense of boot space, but in all honesty there’s really no need to. The 308D4SB is a great sounding solution at a price anyone can afford.