The KDL-40HX723's audio performance is acceptable, but nothing special. It sounds absolutely fine under relatively tame conditions, but when pushed by any sort of action scene, the speakers start to sound harsh and compressed, with dialogue sounding shrill or becoming overwhelmed.
There's not enough bass or enough dynamic range in the upper register to handle trebles convincingly at high volumes. At least the cabinet doesn't start to buzz when pushed hard, though.
The KDL-40HX723's £1,300 price tag makes it pretty expensive by 40-inch TV standards, especially when you consider that no 3D glasses or Wi-Fi USB dongles are bundled.
However, although it takes work to get the best out of it, the KDL-40HX723 is an excellent picture performer in both 2D and 3D mode, as well as being fearsomely well equipped with multimedia/online video streaming features and picture tweaking tools.
Ease of use
The KDL-40HX723 is a mixed bag where ease of use is concerned. One of its strongest points is its remote control, which uses an unusual curved fascia and mostly logical button layout to good effect.
The electronic programme guide for surfing the digital channel list is nicely done too. There are no adverts on it and a small version of the picture continues to play while you browse the listings.
The listings themselves are cleanly presented, well organised and respond quickly to commands.
The onscreen menus also have much to commend them. The way the picture shrinks to accommodate twin axes of menus focused around the screen's bottom right corner, for example, is clever, as it enables you to keep watching a full version of the picture while you look for the feature you're after.
The main problem with the menus is that they are difficult to navigate to get to the feature you're after. The icons along the screen's bottom aren't always particularly helpful in explaining what features they lead to and there are too many of them for comfort. Even getting to the basic picture adjustment options is a chore.
The KDL-40HX723 could do better when it comes to explaining its myriad features, too. There's no paper manual to speak of, yet the onscreen one is brief with its explanations, and – worse – it's seldom interactive. In other words, you seldom get an explanation of a feature when you highlight it as you do with recent TVs from Samsung and Panasonic. Instead, you have to manually find a feature in the onscreen i-Manual.