Ensoniq grew rapidly over the next few years with the success of the Mirage and the ESQ-1. The plant in Great Valley, Pennsylvania employed nearly 200 people and housed the manufacturing facility. A number of successful products followed which all included the full-custom ICs for music and effects which were developed in house. While the core keyboard products were generally successful, there were some quality problems and increasing competition from Asian companies. An attempt to diversify into hearing aids was unsuccessful and put the company in financial peril. In the mid-nineties, they developed a line of very cost-effective sound cards which sold millions of units.