Radio Design Labs ST-UMX3
Universal Audio Mixer

OUR PART #  STUMX3


Radio Design Labs' ST-UMX3 is a three-channel audio mixer for combining mic-level or line-level signals to a single output. A MIC / LINE switch is provided for each input. A separate MIC / LINE switch selects the output level. Each input features a separate preamplifier circuit, which isolates it from the other inputs. An audio taper single turn gain adjustment is provided for each of the three input preamps. Signals from the three preamps are actively summed and fed to the output amplifier which includes an RDL Dual-LED VU meter.

NOTE: Radio Design Labs' PS-24AS power supply is NOT included but is required in order to power this product.  Please see the "Accessories" tab or click here for more information on the PS-24AS power supply.

Each input level is set while observing the LED output level meter. The Dual-LED output meter follows standard VU ballistics. The intensity of the green LED progresses from minimum at -11 dBu to full intensity at +4 dBu.

The flexibility of switching each input and the output between MIC or LINE allows installers to address a wide variety of mixing solutions with only one product type.

NOTE: Mic inputs on the ST-UMX3 are not protected against phantom voltage. Use the ST-MPA2 Mic Phantom Adapter.

Rackmount System for 12 Stick-On Units
Radio Design Labs STR-19A Rackmount System for 12 Stick-On Units
Radio Design Labs' STR-19A Racking System holds up to 12 STICK-ONs in a 19" rack and only occupies two rack spaces.
24 VDC 500mA Switching Power Supply, North American Model
Radio Design Labs PS-24AS 24 VDC 500mA Switching Power Supply, North American Model
Radio Design Labs' PS-24AS is a 24 VDC/500 mA switching power supply with a North American AC plug. Compatible with various RDL products.Radio Design Labs PS-24AS Specifications: Input: 100 to 240 VAC Output: 24 Vdc, 500 mA (UL, ...
Din Rail Adaptor for STICK-ON
Radio Design Labs DRA-35S Din Rail Adaptor for STICK-ON
The DRA-35S is a 35 mm DIN rail mounting bracket that provides positive mounting for any RDL STICK-ON® module. The oblique mounting angle of the DRA-35S allows an installer to mount several STICK-ON modules to a single DIN rail. Access to ...
Mounting Kit for STICK-ON, TX, or Rack-Up module
Radio Design Labs MB1-RDL Mounting Kit for STICK-ON, TX, or Rack-Up module
Two mounting brackets mounts a STICK-ON, TX, or Rack-Up module to a flat surface.
Rackmount Kit for 10 Stick-On Units
Radio Design Labs STR-19B Rackmount Kit for 10 Stick-On Units
Radio Design Labs' STR-19B Racking System holds up to 10 STICK-ON unitss in a 19 inch rack and only occupies two rack spaces. The STR-19B holds STICK-ONs at an angle allowing for control adjustment from either the edge of a STICK-ON, or ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Frame for Stick/TX
Radio Design Labs SR-4 Mounting Frame for Stick/TX
Radio Design Labs' SR-4 is a universal module chassis that can mount to a backboard, wall or nearly any other support. It provides mounting for 4 STICK-ON power amplifiers or 7 standard STICK-ON modules. TX ™ modules may also be mounted. ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
Stick-On Mounting Rack for 10 Units
Radio Design Labs SR-10 Stick-On Mounting Rack for 10 Units
Radio Design Labs' STR-10 Racking System holds up to 10 STICK-ON units.  It holds STICK-ONs at an angle allowing for control adjustment from either the edge of a STICK-ON, or the top (depending on where the adjustment is located on ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
STICK-ON Series 19"W Mounting Rack for up to12 Modules
Radio Design Labs SR-12A STICK-ON Series 19"W Mounting Rack for up to12 Modules
Radio Design Labs' SR-12A chassis can be mounted in a rack or on a backboard to provide mounting of 12 STICK-ONs.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Strip for STICK-ON Units
Radio Design Labs Smk 12 Mounting Strip for STICK-ON Units
The SMK-12 allows removable surface (up to 6 units) or edge (typically 12, max. 16) mounting of STICK-ON units. They can be fastened to its surface using screws or adhesive foam pads.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Bracket for STICK-ON Modules
Radio Design Labs ST-RRB1 Mounting Bracket for STICK-ON Modules
Radio Design Labs' ST-RRB1 mounting kit contains a bracket to attach a STICK-ON module to a rear rack rail or to any flat surface. The module slides into the holder and snaps into position. The module may easily be removed.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Detachable Terminal Block
Radio Design Labs Dtb Rdl Detachable Terminal Block
Use DTB's to quickly detach and reattach wiring harness to STICK-ON units.

Usually ships in 7-14 business days.
Need it sooner? Call us!

Click to download

Radio Design Labs ST-UMX3
Universal Audio Mixer

OUR PART #  STUMX3

Product Information:

Radio Design Labs' ST-UMX3 is a three-channel audio mixer for combining mic-level or line-level signals to a single output. A MIC / LINE switch is provided for each input. A separate MIC / LINE switch selects the output level. Each input features a separate preamplifier circuit, which isolates it from the other inputs. An audio taper single turn gain adjustment is provided for each of the three input preamps. Signals from the three preamps are actively summed and fed to the output amplifier which includes an RDL Dual-LED VU meter.

NOTE: Radio Design Labs' PS-24AS power supply is NOT included but is required in order to power this product.  Please see the "Accessories" tab or click here for more information on the PS-24AS power supply.

Each input level is set while observing the LED output level meter. The Dual-LED output meter follows standard VU ballistics. The intensity of the green LED progresses from minimum at -11 dBu to full intensity at +4 dBu.

The flexibility of switching each input and the output between MIC or LINE allows installers to address a wide variety of mixing solutions with only one product type.

NOTE: Mic inputs on the ST-UMX3 are not protected against phantom voltage. Use the ST-MPA2 Mic Phantom Adapter.

Rackmount System for 12 Stick-On Units
Radio Design Labs STR-19A Rackmount System for 12 Stick-On Units
Radio Design Labs' STR-19A Racking System holds up to 12 STICK-ONs in a 19" rack and only occupies two rack spaces.
24 VDC 500mA Switching Power Supply, North American Model
Radio Design Labs PS-24AS 24 VDC 500mA Switching Power Supply, North American Model
Radio Design Labs' PS-24AS is a 24 VDC/500 mA switching power supply with a North American AC plug. Compatible with various RDL products.Radio Design Labs PS-24AS Specifications: Input: 100 to 240 VAC Output: 24 Vdc, 500 mA (UL, ...
Din Rail Adaptor for STICK-ON
Radio Design Labs DRA-35S Din Rail Adaptor for STICK-ON
The DRA-35S is a 35 mm DIN rail mounting bracket that provides positive mounting for any RDL STICK-ON® module. The oblique mounting angle of the DRA-35S allows an installer to mount several STICK-ON modules to a single DIN rail. Access to ...
Mounting Kit for STICK-ON, TX, or Rack-Up module
Radio Design Labs MB1-RDL Mounting Kit for STICK-ON, TX, or Rack-Up module
Two mounting brackets mounts a STICK-ON, TX, or Rack-Up module to a flat surface.
Rackmount Kit for 10 Stick-On Units
Radio Design Labs STR-19B Rackmount Kit for 10 Stick-On Units
Radio Design Labs' STR-19B Racking System holds up to 10 STICK-ON unitss in a 19 inch rack and only occupies two rack spaces. The STR-19B holds STICK-ONs at an angle allowing for control adjustment from either the edge of a STICK-ON, or ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Frame for Stick/TX
Radio Design Labs SR-4 Mounting Frame for Stick/TX
Radio Design Labs' SR-4 is a universal module chassis that can mount to a backboard, wall or nearly any other support. It provides mounting for 4 STICK-ON power amplifiers or 7 standard STICK-ON modules. TX ™ modules may also be mounted. ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
Stick-On Mounting Rack for 10 Units
Radio Design Labs SR-10 Stick-On Mounting Rack for 10 Units
Radio Design Labs' STR-10 Racking System holds up to 10 STICK-ON units.  It holds STICK-ONs at an angle allowing for control adjustment from either the edge of a STICK-ON, or the top (depending on where the adjustment is located on ...

Usually ships in 7-14 business days.
Need it sooner? Call us!
STICK-ON Series 19"W Mounting Rack for up to12 Modules
Radio Design Labs SR-12A STICK-ON Series 19"W Mounting Rack for up to12 Modules
Radio Design Labs' SR-12A chassis can be mounted in a rack or on a backboard to provide mounting of 12 STICK-ONs.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Strip for STICK-ON Units
Radio Design Labs Smk 12 Mounting Strip for STICK-ON Units
The SMK-12 allows removable surface (up to 6 units) or edge (typically 12, max. 16) mounting of STICK-ON units. They can be fastened to its surface using screws or adhesive foam pads.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Mounting Bracket for STICK-ON Modules
Radio Design Labs ST-RRB1 Mounting Bracket for STICK-ON Modules
Radio Design Labs' ST-RRB1 mounting kit contains a bracket to attach a STICK-ON module to a rear rack rail or to any flat surface. The module slides into the holder and snaps into position. The module may easily be removed.

Usually ships in 7-14 business days.
Need it sooner? Call us!
Detachable Terminal Block
Radio Design Labs Dtb Rdl Detachable Terminal Block
Use DTB's to quickly detach and reattach wiring harness to STICK-ON units.

Usually ships in 7-14 business days.
Need it sooner? Call us!

Click to download

Add to Cart

We're sorry, only of this item available



Call a Sales Pro at for more information

Serving Contractors, Dealers, and Installers Since 1977

Contact: 1-800-828-0509 / Hours: Mon - Fri 7:00AM - 7:00PM