Wiibo String 15 - bookshelf loudspeakers

[Wiibo String 15 - bookshelf loudspeakers]

Definitely, not my cup of tea!

[Italian version here]

Product: Wiibo String 15 bookshelf loudspeakers
Manufacturer: Wiibo - Spain
Approx. price: 70-120€ depending on special offers
Reviewer: Lucio Cadeddu - TNT Italy
Reviewed: November, 2022

In my recent comparative test of three inexpensive bookshelf loudspeakers there was a clear winner, the diminutive Lonpoo LP42. Since then, I've been looking for better alternatives, those best kept secrets that might help any audiophile on a highly restricted budget. The price tag is always the same: 50-100€/pair. Trust me, it is not an easy task to outperform the Lonpoo LP42, as they punch way above their weight, and a better cap on the tweeter makes their performance reach even higher levels, as discovered during our recent crossover recapping experience.

The first speaker in line (others will follow, your suggestions welcomed!) to try to defeat the Lonpoo LP42 is this Wiibo String 15 two-way bookshelf. Since many audiophiles seem to prefer a front firing bass reflex, I've decided to focus my attention on speakers with this feature.

I admit I wasn't aware of the existence of this Spanish loudspeaker company, Wiibo. This name apparently belongs to Panarrecord s.a., a Madrid-based company, though I'm pretty sure they just resell Chinese-made loudspeakers.

[Wiibo String 15 - woofer]
[Wiibo String 15 - woofer rear]

A closer look

The String 15 is a small two-way bookshelf loudspeaker, with a front firing reflex port, equipped with a 13cm woofer and a 1" silk dome tweeter. The crossover is as minimal as it gets, with just a cap and a resistor on the tweeter. Quite surprisingly, considering the price tag, the cap is a metallized polypropylene component, made by JMX. The two drivers seem of good quality, and the woofer sports a massive magnet. The inside of the cabinet is partially stuffed with acoustic synthetic wool. The downside is the cabinet itself, an extremely thin (few millimeters, see pic below!) and light box that resonates even if you speak at it. Moreover, the bass reflex ducts are not perfectly aligned with the cabinet baffle, and pushing them inside didn't cure the problem. It seems the hole in the baffle is slightly narrower than the duct itself.

On the official website these speakers appear listed at 129€/pair, on temporary sale at 99€. I've found them at 70€ shipping included, on Amazon. For this reason they are direct competitors for the Lonpoo LP42. The package also includes a set of speaker cables, eight rubber/felt feet and a thin owner's manual.

Claimed tech specs

[Wiibo String 15 - cabinet]
[Wiibo String 15 - cap]

Definitely, not my cup of tea!

[Wiibo String 15 - rear]

Considering their size, the size of the woofer, the apparently good quality of the drivers and of the crossover cap, my expectations were quite high. Unfortunately, I've quite soon realized they couldn't beat the Lonpoo LP42. Indeed, they don't even come close to those terrific mini-monitors.

Overall, the sound of the Wiibo String 15 is dull, lifeless, confused and even slightly distorted. The bass range is quite powerful, but less extended than expected, so the LP42 outperform them quite easily. There's no depth, no control, no real punch and, what's worse, there's no sense of speed. Moreover, with certain bass heavy tracks, a rattling noise can be heard from the inside of the speakers. I assume the cables vibrate and hit against the cabinet walls, but trying to place them differently didn't help. Perhaps it is a resonance of the extremely thin cabinet walls. With a better cabinet I'm pretty sure these woofers can perform much better.

The mid and the high range are sadly uninvolving, lacking precision and harmonic content. Moving the speaker far/close to the rear wall didn't help much. Voices and instruments sound like they are made out of cardboard. Again, I think this is mainly due to the poor, resonant cabinet. The tonal balance is, overall, on the neutral side, but the speakers fail to reproduce the lowest and the highest frequencies. You'd say this is normal, considering the price, but a quick comparison with a pair of LP42's shows all the weaknessess of these speakers.

The bigger difference between these two speakers is the size of the soundscape they create: wide and deep that of the LP42's, extremely narrow and compressed that of the String 15's. The difference, in each and every parameter, is astonishing. And, if that's not enough, the LP42's sound louder, in the sense that they have a clearly higher sensitivity. Considering the LP42's are smaller, with a smaller woofer, this came as a complete surprise to me. Hence, the 86dB claimed sensitivity datum is utterly optimistic, as is the frequency response. Playing them louder didn't help, as confusion and distortion increase, up to an almost unbearable level.

Need I add more? Perhaps these speakers have some potential hidden somewhere, but - first of all - a better cabinet is mandatory, a neat internal layout comes in second place and finally, I believe the reflex frequency is wrong, because these woofers shouldn't perform so badly. They are well made and have a big magnet. Probably they won't outperform the high-quality carbon fiber woofers of the LP42's, but they could come close in performance.

This review proves that Amazon buyers' opinions must be taken with a grain of salt, since the 53% of opinions are rated 5 stars! Unbelievable.


The String 15 not only fail to beat the Lonpoo LP42's, and by a huge margin, but also sound in a way that I consider not adequate to their price, to say the least. Considering what the market offers in this price range, I believe these speakers need to be redesigned, as explained. For these reasons I can't recommend them, not even if you can find them at a sale for 50€ or so.

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© Copyright 2022 Lucio Cadeddu - editor@tnt-audio.com - www.tnt-audio.com