DSA
| Federal Signal DSA | |
 A Federal Signal DSA4x2, as depicted on Federal Signal's website. | |
| Company | Federal Signal Corporation |
|---|---|
| Produced | 1990-Present |
| Type | Directional Electronic |
| Sound output | 111-121 dB @ 100 feet |
| Wattage | 200-600 |
| Voltage | 24/48 V DC |
| Preceded by | Federal Signal EOWS |
| Documentation | Manual Product sheet |
The DSA, (Directional Speaker Array), is an electronic siren produced by Federal Signal Corporation. It it comprised of speaker modules that vertically hold two to six speakers with projectors. Up to four can be installed on a mount, and at different angles, depending on coverage requirements. The DSA can be mounted on 3 different pole mount models, the DSAMK1 which holds 1 module, the DSAMK2 which holds 2 and the DSAMK4 which holds 4.[1]
History and Design
The DSA was released alongside the Modulator in 1990, and directly replaced the older omnidirectional EOWS*115 and EOWS*1212. The DSA is essentially a directional Modulator, using the exact same 100 W speaker compression drivers to produce sound. Each DSA array is made of 2-6 fibreglass Atlas CJ46 speakers attached to an aluminum rear housing which contains the speaker drivers. This makes it very similar in appearance to sirens such as the Whelen WS-2000 and ACA's Alertronic sirens. Each array can support up to 6 speakers/drivers, for a total of 600 W. Up to 4 arrays are supported on one controller, and the DSA is compatible with the SiraTone, MC, MCP and UltraVoice controllers produced by Federal Signal. These arrays do not appear to be made by Federal Signal themselves, instead being bought from elsewhere, as early ATI HPSS-16 units used identical arrays.
Different sized arrays can be used in the same installation according to needs, such as if extra sound output is needed in a particular direction. Each DSA array comes with 4 stainless steel mounting brackets, which can be attached directly to a pole or wall, depending on installation needs. The arrays can be swiveled downwards up to 15 degrees. The DSA can be mounted on 3 different pole mount models, the DSAMK1 which holds 1 module, the DSAMK2 which holds 2 and the DSAMK4 which holds 4.
The DSA arrays are named as follows:
| Model | dB @ 100ft | Number of drivers/speakers per array |
|---|---|---|
| DSA2 | 111 dB | 2 |
| DSA3 | 115 dB | 3 |
| DSA4 | 117 dB | 4 |
| DSA5 | 119 dB | 5 |
| DSA6 | 121 dB | 6 |
DSA arrays are often named by both the number of speakers per array, and the number of arrays attached to the controller. As an example, an installation of 4 arrays with 6 speakers is known as a DSA6x4. Installations with multiple sizes of arrays are simply known as DSAs.
The DSA is still sold by Federal Signal today, and competes with other directional electronic sirens such as the ASC E-Class, ATI HPSS, and Whelen WS400H. It is a common find as a campus or industrial siren due to its wall mounting capabilities, cost, and versatility.