It is an all-too common complaint from television viewers – you sit down to watch a gripping drama, only to find the dialogue inaudible.

Mumbling actors have been blamed, along with the design of flat screen televisions. But the UK’s leading sound technicians would like to highlight the major culprits – directors who think muttered conversations are more realistic.

“Mumbledom” is a deliberate choice by directors who have stolen the idea from cinema, they claim.

The BBC promised to address sound issues in 2016 after the drama Happy Valley attracted a slew of complaints. Yet its most recent detective drama, Shetland, suffered from the same issue, with some viewers turning off or resorting to subtitles.

‘Mumbledom’ is more realistic 

“There is an issue with enunciation by some modern actors but, in fairness to the acting profession, the great majority know how to speak and how to project,” said Malcolm Johnson, secretary of the Institute of Professional Sound.

“However, over the last 10 years there has been a trend within film production as well as drama for TV, of directors and producers going for a ‘natural’ performance – in other words, what we in the business refer to as ‘mumbledom’.

“Previously, a director would have said, ‘Sorry, I can’t hear you, can you pitch up a bit.’ Now directors are persuading actors to downplay their delivery, and almost throw their lines away, thinking that it is more realistic.

“Sadly, that’s become very fashionable over the last decade and that leads to a lot of issues.”

In decades past, Mr Johnson said, sound professionals worked in-house for the BBC or the ITV companies, and felt able to voice objections on set when the dialogue was muffled.

But he explained: “The majority of sound people now are freelance, so for obvious reasons they are biting their tongues when they know something is wrong unless they have a very good working relationship with a director and can say: ‘You know what, that line’s never going to get north of Watford.’”