Sky "considering" adding Dolby Digital 5.1 via HDMI to Sky+ HD boxes

At the moment, Sky+ HD owners have to use an HDMI cable to transmit the picture from the box to the TV or projector, and a separate optical digital connection to their home cinema amplifier to output 5.1 surround sound.

"When we launched Sky HD, lots of users weren't using HDMI [for sound], but we're aware this is becoming more of an issue for some of our customers," says a Sky spokeswoman.

There's no timescale for when the change may be introduced, but Sky's technical team is looking into it.

It's become more of an issue recently, with some new-model multichannel amps and receivers automatically defaulting to HDMI for surround sound and bypassing the optical connection.

This means that in certain configurations current Sky+ HD boxes will only output stereo sound (via HDMI) to the amp or receiver, not Dolby Digital 5.1.

Sky is not alone in this regard, with other set-top boxes from companies such as Tiscali and BT Vision also outputting Dolby Digital 5.1 via the optical, not HDMI connection.

Last year Sony had to fix its STR-DG820 and STR-DA2400ES receivers so you could use the HDMI and optical inputs simultaneously, and this year Yamaha has run into the same problem with four of its 2009 models.

Even if Sky does decide to add surround sound via HDMI to its future set-top boxes, there are still one million or more existing Sky+ HD boxes in UK homes that need the dual HDMI/optical connection.