Rap mogul Dr Dre and Interscope Geffen label boss Jimmy Iovine have joined forces to sue the bosses of a Delaware headphones firm after they allegedly failed to deliver on a manufacturing deal. Dre and Iovine are upset that plans to "manufacture, market and distribute" a line of industry-quality headphones, Beats By Dr Dre, fell flat - and they're going after the brains behind the idea. In the lawsuit, filed in Los Angeles County Superior Court and obtained by website TMZ.com, the plaintiffs allege that SLS International, Pentgram Design, Inc. and Jibe Audio "failed and refused to perform under the contract." The suit also claims the defendants went forward with a plan to sell the Beats headphones through a separate company. Iovine and Dre are seeking damages upwards of $1 million (GBP555,500) and an injunction that prevents the defendants from manufacturing and selling headphones using the Beats trademark and design.