Acland, who joined Emap from Capital Radio in 2001, is to start at Tulchan in June as a consultant.
Tulchan founder Andrew Grant said: 'Miranda's expertise in investor and media relations, internal and external comms and the media industry in general will significantly strengthen our team of consultants and add another dimension to our advisory capacity.'
She will become Tulchan's 11th consultant.
Emap is to recruit a replacement for Acland, who resigned last Friday.
Acland oversaw the appointment of Emap's retained financial communications agency Brunswick in 2002. But an Emap spokeswoman ruled out a review of Brunswick's account.
Acland has more than 20 years' experience of working in the media sector, having joined Capital Radio as head of communications in 1997, after five years in various sales and development roles at Thames Television.
She said she was making the move to Tulchan because she wanted to be 'part of an independent business' with 'variety and expertise'.
News of her departure comes in the same week that Emap finance director Gary Hughes quit to spend more time with his family.
Hughes was a major figure in the group's purchase of a 27 per cent stake in Scottish Radio Holdings from his previous employer, Scottish Media Group.