Onkyo LS-B50 Soundbar System

The Onkyo LS-B50 Soundbar System provides a compact, low-cost package with convenient Bluetooth functionality, but channel level mismatches limit the quality of its output.

CNET Rating

Onkyo's low-cost LS-B50 Soundbar System manages to fit within its purchase price a wireless subwoofer and remote control in addition to the main bar.

Nicely compact, the soundbar is only 909mm wide. It can be fixed to a wall using keyhole slots at its rear or sit on sturdy little legs, which are supplied with the unit.

Onkyo doesn't say a lot about what's doing the work in there. Without indicating their sizes, it says that the bar controls six "full range cone drivers" and two "ring tweeters". Peering through the grille over the drivers it appears that there two innermost of the larger drivers had tweeters built into them. No sizes are specified but they looked to be around 65mm. Each of the six full range drivers is supplied with 9 watts of power (presumably shared with the tweeters for two of them).

The subwoofer has a 160mm downwards firing driver in its base and uses a bass reflex enclosure with the port also pointing down in the base.

There are three — or is it five? — inputs on the soundbar. The unit will play back audio from a USB device (MP3 only), via Bluetooth, or from a 'TV'. There are three connections associated with this last: optical digital audio, coaxial digital audio and 3.5mm analogue stereo. But you only get input selections of "TV", USB and Bluetooth. Through experimentation I determined that the unit runs a hierarchy, with analog at the bottom. If you plug in coaxial digital audio, it will switch off the analog input and use the coax digital instead. If you plug in optical, it will override both coax and analog.

All of which is a pity. That means that for practical use you're going to have to plug your disc player into your TV and use its optical output to drive the soundbar. Many TVs convert surround sound to stereo and get rid of the low frequency effects channel. Had you been able to switch between these inputs, you'd be able to leave one plugged into the TV and one into a player, using the latter input for best performance in disc playback.

You can set the unit up so that basic controls on your TV's remote will control the soundbar. It comes with an IR "blaster", which can be plugged into an output on the unit to pass on remote control signals to other devices, most likely your TV if its remote receiver is obscured by the soundbar.

(Credit: Onkyo)

In use

The soundbar and wireless subwoofer were pre-paired, so as soon as everything was plugged in, they worked together. Indeed, the moment I paired the system via Bluetooth to an Android device and started playing some "Switched On Bach" (a 1960s recording with marvellous bass), the subwoofer was all too obvious. The remote has a subwoofer level control, so I wound it down, down, down to the minimum setting, and it was kind of in balance but with a rather resonant, woody-sounding mid-bass. The deeper notes on the Moog sounded fine, but as they went up an octave they rang out quite a bit.

This turned out to be the result of two characteristics of the system. First, the subwoofer level adjustment had insufficient range. Presumably, Onkyo figured that the average buyer would like strong bass. But that doesn't justify not providing a sufficient range of adjustment to bring it into balance with the rest of the sound.

Second, the bass response was peaky. At the minimum setting (with the subwoofer located in the corner of my office in which several hundred other subwoofers have done their work), the deep bass and the upper bass were in balance with the rest of the sound, but the mid bass — say around 60 hertz or so — was way, way above the rest.

I performed some measurements. Clearly there are limits to what a compact subwoofer can do, and the limits of this one were clear. Rather than providing a reasonably even band of output across an octave or more in the bass region, this unit produced a peak of output in the range of 60 to 83 hertz, falling away in output on both sides of the peak. Tones at 43 hertz were in balance with the mid-range sound. But tones around 70 hertz were 15 decibels higher.

That was with the subwoofer turned down to the minimum. I experimented with the subwoofer away from my favoured corner, but in the end, the slight smoothing effect on bass performance of the corner placement outweighed the slight reduction in output level, so I put it back. The result was not really overpowering bass so much as a boxy colouration of the sound.

The overall tonal balance of the system was a bias towards the bass, with it louder than the mid-range, and the mid-range louder than the treble. It wasn't altogether unpleasant but not particularly accurate.

There was another colouration to the sound due not to tone but to the levels of the channels when fed 5.1 sound. The centre channel was about 10 decibels higher than the left and right, while they were in turn much higher than the surround channels (it made little difference whether Music or Movie sound mode was selected). In fact, the surround channel test signals started off loud and rapidly diminished in level, the left side more quickly than the right. The surround processing was clearly doing something weird.

With program material, there was little surround effect but an extremely wide stereo sound stage. Content that was supposed to be directly behind the listener's head just muted away completely.

It was much, much better with stereo music because then the channel-level issue didn't come up (except for the bass, of course). There, the slight bass forwardness and recessed treble was easy on the ear. Movies were delivered with a strong bass underpinning and good clean dialogue but nothing much in the way of a surround effect.


The combination of strong bass, low cost and Bluetooth support may make the Onkyo LS-B50 an attractive proposition for many people, despite my reservations about aspects of the sound. I'd suggest having a listen yourself to decide whether it would suit you.

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