At first glance, it's hard to tell the difference betweenBluetooth wireless speaker and its successor, the SRS-X33 (reviewed here). In pictures, they feature the same attractively minimalist rectangular design and come in a variety of colors. But place one model next to the other -- or just look at the specs closely -- and you realize the new X33 is considerably smaller, weighing 1.54 pounds (730 grams) instead of 1.75 (795 grams). It also features better battery life -- 12 hours instead of 7, a significant upgrade.
Like its predecessor, the X33 carries a list price of $150 (UK £109, AU $230), although it can be had for less online. While lighter than the X3, it still feels sturdy in hand, with two 10-watt drivers (20 watts total power) and dual passive bass radiators. Its design is straightforward and elegant and the speaker itself has a nice, smooth-to-the-touch finish. I'm a fan of the design, though others might find it a tad dull.
In terms of features, it's got everything you need but no real extras like waterproofing, the ability to charge up other USB devices or the ability to wirelessly join two X33s together to make a stereo pair (withand speakers, for instance, you can pair multiple speakers).
It offers the standard Bluetooth range of about 30 feet (10m), has a built-in speakerphone for taking cell-phone calls (it works pretty well), and offers NFC tap-to-pair technology for smartphones and tablets that support it. You also get support for Sony's LDAC codec, which, like, is supposed to make Bluetooth audio streaming sound slightly better. However, you'll need a LDAC-compatible device to actually to take advantage of it. Not too many of those devices exist at this point.
The speaker charges via Micro-USB -- a charger is included, though no protective carrying case -- and around back you'll also find a standard minijack audio input for connecting audio devices without Bluetooth.
Typically in the speaker world, going smaller isn't usually the best recipe for getting better sound. But Sony's engineers appear to have worked some magic on the inside of this speaker because the new X33 sounds better, with a slightly improved bass performance at higher volumes and a bit more balanced sound overall.
As with many of these small Bluetooth speakers, your first reaction to it will be that it plays quite loud for its size, delivers a decent amount of bass, and can fill a small room with sound. However, the fight with a speaker such as this is how much volume you can get out of it before it distorts. And every compact Bluetooth speaker I've ever listened to distorts. It's just a matter of raising the volume and feeding it material it just can't handle.
For the most part, the X33 sounds really good for a speaker in its size and price class, particularly at more moderate sound levels. Where it runs into some trouble is when you hit it with more complicated tracks with lots of instruments or just bass-heavy material.