I review a lot of wireless Bluetooth speakers, and the first question I tend to ask is, "Why would I buy this speaker over all the other Bluetooth speakers out there?" Or, to put it another way, "What makes it stand out from the rest of the pack?"
In the case of the Philips BT3500, the answer is pretty simple: it's got a decent design, feature set, and sound quality for a relatively affordable price (around $75 online). No, it won't blow you away in any one of those departments -- and it doesn't have great battery life -- but it's a likable portable speaker for the money.
Design and features
A lot of mini Bluetooth speakers have more of a canister design to them, but what helps set the BT3500 apart is its relatively flat design, which makes it easy to slip into a bag.
Though you can stand the speaker up vertically, it's meant to be laid down flat and propped up at a slight angle using the integrated flip-out kickstand. In that sense, it looks like a portable speakerphone and happens to offer that feature as well. I can't say the build quality or all-plastic design are all that swanky, but the speaker looks fairly attractive and has enough heft to it -- it weighs 17.6 ounces -- to steer it away from feeling cheap. However, there are more durable speakers available (I would avoiding dropping this one).
Like a lot of these little speakers, the 7.9-by-4.0-by-1.4-inch (201-by-101-by-35mm) BT3500 plays louder than its size would indicate, and I liked the analog volume knob, which gives the speaker a slightly retro look and, more importantly, makes it easy to raise and lower the speaker's volume.
That same volume knob can be found on the smaller BT2500, which costs around $30 less and is essentially the BT3500 cut in half. The BT3500 adds NFC tap-to-pair technology for devices that support it, but otherwise the two speakers have identical feature sets and include the standard audio input for non-Bluetooth devices. They both are equipped with Bluetooth 3.0.