The deal could be worth up to 拢3.7m, depending on Smooth's performance over the next two years.
Smooth Operations was set up in 1996 with offices in Cambridge and Manchester and is the largest independent radio producer outside London.
The business provides a number of shows for BBC Radio including the nightly 'Mark Radcliffe Show' and country and folk music for BBC Radio 2 as well as documentary programmes for BBC Radio 4 and music output for digital TV channel BBC Four.
Simon Cole, UBC chief executive, said: "This is an important acquisition for UBC. With the growing commitment of the BBC both to independent radio production and to regional production, we believe that this is the right time to acquire a leading regional producer to broaden our offering."
He added: "We anticipate that the acquisition of Smooth Operations will bring much to UBC, not least positioning us as the clear market leader in independent radio production and assisting in our progress to profitability."
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