Gabriel, better known as a singer songwriter, and Engelke completed the deal for the 36-year-old company on 15 June. The company, which was partly owned by media investment company 3i, was put up for sale at the beginning of February.
Engelke, who heads Broadcast Devices in the US, and Peter Gabriel, who owns the Real World Group, are believed to be equal partners in the deal.
A new management team has been brought in to replace former managing director Colin Pringle and former financial director Graham Longton.
Gabriel and Engelke have appointed Antony David, formerly head of pro audio at Sony Broadcast & Professional Europe, as managing director, while Piers Plaskitt, president of sales and marketing at Euphonix, has been appointed group commercial director. Chris Smith is now group finance director.
It is not thought that SSL will be moved into either Gabriel's Real World Group or the Engelke business. Gabriel's companies have won awards for technological innovations such as OD2 (On Demand Distribution), which is a European platform provider for online music. The Real World Studios already has three SSL consoles.
SSL consoles have recently been sold to ABC and NEP - which recently bought outside broadcast company Visions.