Rolls DB228 In-wall impedance-matching interface
Best wall-mounted interface for integrating consumer audio into professional sound systems.
This passive in-wall interface seamlessly integrates consumer audio devices into commercial sound systems. It converts unbalanced stereo sources, such as phones or microphones, into a professional, low-impedance balanced output. The unit features convenient front-panel connections including an XLR input and a 3.5mm TRS jack, with a single rotary knob for simultaneous level adjustment. Designed for discreet installation, it fits within a standard single-gang junction box and is compatible with Decora wall plates, offering a clean and professional setup.
$99.00
Owner Satisfaction
4.7
/ 5
Category Rank
34
/ 184
#34 in Direct Boxes
Price vs Category Average
-63%
Below average
DI Box Type
Passive
/ Passive
Who it's for
- Venue managers needing versatile connections for consumer media devices
- Audio engineers managing long cable runs in noisy environments
- System integrators building clean, permanent commercial audio installations
Who should skip it
- Mobile technicians needing portable gear for temporary event setups
- Renters or users avoiding permanent modifications to their walls
- Engineers requiring active gain stages for low-output audio sources
Performance breakdown
Installation Versatility
Standard Decora plate compatibility makes mounting into existing wall boxes effortless.
Signal Integrity
Passive circuitry maintains clean signal paths without introducing unwanted electrical noise.
Input Flexibility
Dual-input design handles both microphones and mobile devices with ease.
Build Durability
Compact metal chassis provides necessary ruggedness for permanent in-wall placement.
Operational Simplicity
Single-knob control streamlines volume adjustments for non-technical end users.
Frequency Fidelity
Reliable performance for voice and background music within standard commercial ranges.
Key Specs
DI Box Type
Passive
Input Channels
2
Output Channels
1
Input Connector Type
XLR, 3.5mm TRS
Output Connector Type
XLR
XLR Input Impedance
600 Ohms
1/8" Input Impedance
20k Ohms
Frequency Response
50Hz-20kHz (± 3dB)
Know before you buy
No, the DB228 is a passive device and does not require external power, batteries, or phantom power to operate.
Yes, the unit is designed to mix these inputs. However, keep in mind that the single rotary knob controls the level for both inputs simultaneously, so you cannot adjust their volumes independently.
Yes, the DB228 is designed to fit into a standard single-gang junction box and is compatible with standard Decora-style wall plates for a clean, professional finish.
The output uses a 3-pin Euroblock (pluggable barrier strip) connector. You will need to wire your balanced audio cable directly into this terminal block.
No, the DB228 is designed for dynamic microphones. It does not provide the phantom power required to operate condenser microphones.
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