Why do I hear a 'burbling' or 'bubbling' sound when listening to some DAB stations?

This is almost certainly due to poor reception.

Although DAB is excellent at providing quality audio from very little signal, the quality can suffer if the signal strength is too low and if that happens a ‘burbling’ or 'bubbling' broken type sound can be sometimes heard. To reduce the possibility of poor reception, check that your aerial is extended and vertical. Optimum DAB aerial length is around 40cm to 45cm, so you may need to lower the height of your aerial.

Its worth noting that you may be trying to tune to a station that is actually out of range of the radio. Check your postcode in our post code checker here http://www.getdigitalradio.com/whats-on-dab/in-your-area/ to make sure the station you are trying to tune to is clearly available in your area.