| Business | Phone |
| Usa Productions Audio 2406 Eugene St, Silver Spring 20902 | (301) 942-5555 |
| Entertainment Sound Production 2221 Kansas Ave, Silver Spring 20910 | (301) 608-2180 |
| Media Research Assoc Inc 502 Greenbrier Dr, Silver Spring 20910 | (301) 585-2400 |
| Indigo Communications 8115 Fenton St, Silver Spring 20910 | (301) 589-1325 |