Yamaha NS-SW050: Small box, big bass

Yamaha’s diminutive NS-SW050 is so unassuming that it’s easy to consider it inferior to those big, bad-ass subs. After, all bigger should be better in subwoofer terms, right? Well, the little Yamaha might surprise you …

By Deon Schoeman

In home theatre systems, a subwoofer is de rigeur. But as living spaces shrink, a 2.1 stereo system linking a pair of compact bookshelf speakers to a subwoofer is becoming a popular alternative to traditional floorstanders.

However, accommodating a large subwoofer in restricted space is even more difficult than living with floorstanders. So, in a compact room , the speaker system needs to be equally compact – and that suggests the use of a small subwoofer.

The Yamaha NS-SW050 is certainly compact, making it much easier to locate than those big-box subs that make the eyes of low-frequency fans light up. It’s also very basic in control set terms. And it comes with a fixed, twin prong plug-terminated power cord.

The execution and finishes are durable and utilitarian rather than fancy, with a matt black veneer that looks long-lasting and easy to clean. The front-firing driver is protected by a non-removable black cloth grille.

In some markets, the SW050 is offered with faux wood or white veneer finishes. However, it looks as if you can have the sub in any colour in SA – as long as, in the words of Henry Ford, that colour is black!

Those limited control aspects don’t augur well for the Yamaha’s capabilities. And yet, my attention was drawn to the side-firing port, which has an unusual execution that its maker describes as a twisted flare port.

As you’ll have seen on the image, the exit aperture has an almost floral shape, as a result of the port tube having a twisted inner surface. The resulting irregular port aperture is meant to diffuse the air being pumped out of the port, as well as the vortex created at the exit point.

By smoothing the air’s passage, the SW050 addresses the chuffing noise typical of more conventional port designs, allowing the full impact of the bass  to be delivered without any attenuating noise.

Another key technology is Yamaha’s Active Servo Technology (deployed here in Mk II guise), which makes the most of the amp’s power output by dynamically optimising actual speaker impedance using what Yamaha calls a negative-impedance converter.

According to the marque, this allows the on-board Class D amplifier to operate at maximum efficiency, and to make full use of the modest output power, while also benefiting overall control and stability. Does it work?

To find out, I linked the sub to our Marantz SR-6011 AV receiver. Later, I also roped in a more powerful Yamaha RX-A3080 Aventage home theatre receiver (review pending) to validate my initial review impressions.

As mentioned earlier, the SW050 isn’t exactly well endowed as far as facilities and features are concerned. In that sense it’s a stripped out, budget-saving design – but it also makes the subwoofer very easy to link up.

All it takes is connecting up the sub to the AVR via a suitably long RCA-terminated subwoofer cable, and plugging in the power cord. There’s an on/off switch, but there’s no auto-sensing sensor that will wake up the Yamaha from standby when the input starts receiving signal.

So, if it’s on it’s on. And if it’s off, it’s off. No half measures. And there isn’t any phase adjustment, either.

Notable purely by its absence is any form of frequency cut-off adjustment, which is fine in the home theatre context, where the receiver’s bass management will determine what the high-pass point will be.

However, in a 2.1 stereo application you’ll need to either find a stereo amp with a subwoofer output, or perhaps opt for active speakers, which typically include low-frequency management.

Either way, it’s vital to ensure a seamless handover from sub to speaker if any semblance of sonic unity is to be achieved.

Remember too that the SW-050 doesn’t have a high-output, speaker cable-based input set. The line-level RCA input is the only option.

I used the SW-050 in both a surround system and a stereo system context. The latter was achieved by setting up the receiver in a 2.1 stereo mode, and running in straight mode, which still allowed the AVR to determine the high-pass crossover point – 80 kHz in the case of the Atlantic Technology satellites used in left front/right front role.

With no adjustable phase, I located the sub in the right front of the room, behind the satellites, but in a free-standing position about 50 cm away from the rear and side walls, as well as the corner.

The sub arrived brand new, and I allowed for about 50 hours of playing in time, before settling in to listen.

The biggest surprise is how big the small Yamaha sounds. Once the levels had been suitably adjusted, it not only integrated seamlessly into the overall sound picture, but delivered its low-frequency wares with real punch and precision.

Let’s face it: nothing moves air quite as well as a big driver. And the SW-050 certainly isn’t the big-boy league in that respect. But it projected sub-bass notes with loads of impetus and control.

Those big notes never sounded constrained, and while it probably didn’t reach down much more than 30 Hz or so, the Yamaha created a solid, weighty and precise bass foundation that added real substance and texture to the sound.

White finish unlikely to be offered in SA

Movie special effects were delivered with a succinct assurance that made explosions and gun shots come alive. Thus, the action sequences from White House Down were rendered with power and a confidence, as well as an agility that never allowed the bass notes to lose their pace or become flabby.

If anything, the Yamaha sub shone even brighter in a 2.1 role. Be it the soundtrack from Eric Clapton’s Crossroads Guitar Festival 2013, or Melody Gardot’s live set in the Paris Olympia Stadium, I enjoyed the way the sub added presence and weight to the music, without becoming overbearing.

Indeed, in this installation, the lack of adjustable frequency cut-off was never an issue, as it could be effectively managed by the AVRs used for the review. And let’s face it, in space-constrained environment, using an AVR-based system for both movies and stereo music makes space and economic sense.

If I wanted to nit-pick, I could point to a slight regression in transparency of the left/right monitors when paired with the Yamaha sub. But the benefits overrode that criticism: the music sounded bold and confident, while never getting in the way of the finely focused music image, nor the airy backdrop of a generous soundstage.

For this kind of money, you can forget about any of the concerns raised above. The NS-SW050 doesn’t try to be fancy or sophisticated, but it rolls up its sleeves and gets the job done.

While there are definitely better, bigger and more versatile subs, this little Yamaha offers huge bang (and bass) for the buck.


Enclosure type: Side-ported, Helmholtz resonator
Drive unit: 200mm cone subwoofer
Inputs: Single-ended RCA
Outputs: None
Amplifier rating: 50 watts (100 Hz, 5 ohms, 10% THD)
Controls: Adjustable level
Dimensions (WxHxD): 291 x 292 x 341 mm
R3 280
Balanced Audio

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