BSX Allegro 4 Electric Upright

If the thought of transporting an upright bass fills you with dread, the BSX Allegro may be the answer to your prayers. Mike Brooks dons his overalls for some bass DIY

We can fully appreciate why the bass tones of an upright instrument are so popular and still very firmly in demand. However, the daunting size, restrictive dimensions and pain in the posterior involved in transporting your beloved upright from home to rehearsals, recording sessions and live engagements is more than enough to put a lot of bassists off the idea. For those reasons, this Allegro electric upright might just tickle your fancy – but the only thing is, you have to assemble it yourself! Now before you baulk at the idea, this reviewer thought the same thing when faced with the large brown packing box. However, with the various elements laid out on the floor and the instructions at hand, I quickly assembled an electric upright bass. And before you ask – no, there weren’t any surplus parts!

Build Quality

I’ll be honest, I had my doubts as to the quality of the components when I first read about this instrument – but I needn’t have worried, and on putting the instrument together, I was surprised by the quality and sturdiness of the parts. The maple neck, with its rich, dark ebony fingerboard, is easily attached using a single large bolt and once tightly seated in the neck pocket, the fit is very snug: the neck isn’t going to shift. A stomach rest is also fitted to the rear of the instrument to make resting the bass against the player’s body a relatively comfortable experience.

The antique-like tobacco burst finish gives the spruce top, maple sides and baltic birch body a traditional look, as do the F-holes in the front facing of the body, although other colours and finishes are available if you prefer a more modern look. Although the handmade curvaceous body is sizeable, with a bass bar and sound post fitted internally, it obviously isn’t as domineering as a traditional upright instrument and in terms of weight, it is manageable, weighing in at a respectable 6.8 kilos. The D’Addario Helicore Hybrid strings are partially fitted at the headstock requiring the player to install them at the bridge and bring them up to concert pitch or to whichever tuning you prefer.

The controls sit alongside the side edge facing the player, and provide a master volume and three-band EQ with cut and boost courtesy of the Bartolini active circuit and multi-sensor piezo bridge. Additionally, the volume of each string can be adjusted individually by a set of controls housed in the rear of the instrument in a separate control cavity. Once the output level is set to a suitably even response across all four strings, the master volume determines the overall output.

Sounds And Playability

You’ll be pleased to know that this bass didn’t disintegrate the moment I started playing it. In fact, it felt reassuringly sturdy. Even before amplifying the Allegro, its natural sustain and thick, woody tone stands out a mile. It’s incredibly resonant and vibrant, as it should be, and in a very pleasing way – which is a good indicator that, despite the self-assembly nature of this bass, the sum of the parts works and performs without any underlying issues.

With the EQ set flat, I plugged the Allegro in and was deeply impressed by its tonal display. The bass tone is rich and warm but solid; the midrange provides some projection and presence; and the top end is smooth and clear without sounding nasal. It sounds as if the instrument has its own voice: as you become familiar with how it plays, manipulating the tones to your requirements allows the instrument to breathe. The Bartolini EQ gives the player plenty of room to manoeuvre in most musical contexts. As the bass is well shielded to prevent unwanted noise and feedback, some care should be taken when boosting the lows and highs: a little adjustment across all three EQ bands goes a long way. Thankfully, the Bartolini circuit complements the piezo system, maintaining the organic tones very well.


The Allegro concept seems like a very good idea to me, and a welcome solution to the intrinsic problems with most upright instruments. Although the optional tripod stand and thigh rest are additional purchases, the components you are provided with are more than enough to get you up and running quickly. If the action isn’t to your liking, the angle of the neck can be adjusted to suit your preference by way of a pivot system. This is very much an intelligent design and clearly, much thought has gone into it. It’s both interesting and impressive, and we suggest you check one out if a venture into the upright world is calling you. 


Price | £2499

Made In | USA

Colour | Tobacco burst

Body | Five-ply baltic birch, spruce top, formed maple sides

Neck | Maple, 41.5” scale

Neck Joint | Bolt-on, one-bolt attachment

Nut Width | 41mm

Fingerboard | Ebony

Frets | 24

Pickups | Multi-sensor piezo bridge

Electronics | Active Bartolini 3-band EQ, individual string volumes

Controls | Master volume, 3-band EQ (bass/middle/treble cut/boost), individual volume control for each string

Hardware | Black Hipshot elephant-ear machine heads

Weight | 6.8 kg

Case/gig bag included | Custom gig bag

Left-hand option available | Yes

What We Think

Plus | Works very well, sounds very good and is easily transported

Minus | At a snip under £2500, it isn’t cheap

Overall | Impressive, with a flexible array of upright tones, easily built and broken down and very well thought out

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