De-embed Zone Audio at the HDMI Matrix Switcher, Not Per Display
Pull audio for amps and soundbars from the matrix outputs, not from an extractor box behind each screen. Fewer boxes, fewer handshakes to debug.
The problem
In a boardroom, a sanctuary tech booth, or a bar with screens on every wall, the displays are rarely all the same. A 4K60 front display sits alongside older 1080p confidence monitors, lobby screens, or a legacy kitchen set. A standard matrix passes the source resolution through unchanged, so the moment a 4K source lands on a 1080p panel, that screen goes dark — and the integrator is back to matching every display to every source by hand.
Audio is the second headache. Many of these rooms want program sound sent to a separate zone — a ceiling-speaker amp, a sanctuary DSP, a record encoder, or an existing whole-house amplifier — without buying an AVR just to break the audio out. And the smart-TV apps on the displays produce their own audio that has to get back to that amplifier somehow.
The usual answer is two or three boxes: a matrix, a scaler on the problem outputs, and an audio de-embedder. That is more rack space, more power, and more points of failure than a single shelf should need.
What changes with this product
The MMX-4X4AUD routes any of four HDMI 2.0 sources to four HDMI 2.0 displays and scales each output independently. It passes 4K2K 50/60Hz 4:4:4 at the full 18Gbps video bandwidth, is HDCP 2.2 and HDCP 1.4 compliant, and carries HDR10, HDR10+, Dolby Vision and HLG. At 4K60 YCbCr 4:4:4 it carries 8-bit color.
Each of the four outputs has its own scaler mode — Bypass, 4K→1080p, or Auto — so a 4K60 main and a downscaled 1080p overflow both run clean from the same box. Every output also de-embeds audio two ways: to a 3.5mm analog L/R jack carrying PCM 2.0CH, and to an RCA coaxial port carrying PCM 2.0, Dolby Digital/Plus and DTS 2.0/5.1. ARC returns a display's audio to the coaxial output only; when ARC is enabled on an output, that returned audio leaves the coaxial port and the L/R port is muted.
Control is by front panel, RS-232, IR remote, and TCP/IP, with a built-in Web GUI and advanced EDID management. The unit draws 10W maximum from a locking 12V/2.5A supply in a metal enclosure measuring 8.66" (W) × 4.13" (D) × 1.73" (H).
Where it fits
Corporate boardroom, 4K main plus 1080p overflow
Four sources — a room PC, a laptop HDMI feed, a video-bar output, and a cable box — route to a 4K front display and two 1080p side or confidence monitors. The per-output scaler feeds the 1080p screens a downscaled signal while the main output stays at 4K60 4:4:4, and the L/R jack breaks program audio out to the room's ceiling-speaker amp, so there is no AVR in the rack.
House of worship with recording feed
Camera, presentation PC, and playback route to a main IMAG display and lobby screens. The coaxial de-embed sends a Dolby Digital / DTS-capable bitstream to the sanctuary DSP while the analog L/R output feeds the stream and record encoder, and the whole matrix is switched from the built-in Web GUI at the tech booth.
Sports bar and QSR multi-display zone
Set-top and streaming sources fan out to four screens. The coaxial and L/R outputs on every display carry that display's own de-embedded audio, so whichever game a screen is showing plays from its own zone amp without a separate audio matrix, with source selection handled from the front panel or the IR remote behind the bar.
Residential great room with a legacy zone amp
A 4K media player and a game console feed the main 4K TV while an older 1080p kitchen TV takes the downscaled output. ARC on the coaxial path returns the smart-TV app audio to the existing whole-house amplifier, so the homeowner keeps the amp they have rather than adding an AVR.
Control and monitoring wall in an ops center
Four feeds route to four operator displays with independent scaling, so mismatched monitors all show a correct picture. RS-232 and TCP/IP put routing under the facility's control system, and the compact chassis fits a shallow console.
Higher-ed active-learning classroom
An instructor PC, a document camera, and two BYOD inputs route to a projector plus three group monitors. The scaler protects the projector's native rate while the group screens take 1080p, and the analog L/R output feeds the room's program-audio amplifier for reinforcement.
Typical setup
- Up to four HDMI sources — Blu-ray, PC, media box — connect to the four HDMI input ports.
- A 4K60 4:4:4 main display and a 1080p overflow display (scaled to 1080p) connect to the HDMI OUT 1/2/3/4 ports.
- A zone amplifier takes coaxial de-embed or ARC return from the Coaxial Audio OUT ports.
- Powered speakers take analog de-embed from the L/R Audio OUT ports.
- A control system connects to the RS-232 port; a control PC reaches the Web GUI and IP control over the TCP/IP port.
The manual's connection order is: HDMI sources first, then HDMI displays, then the control device (TCP/IP, RS-232, or IR IN), then audio devices to the coaxial or L/R outputs, and finally the 12V DC power supply.
What to check before you specify
The manual recommends Premium High Speed HDMI cable and specifies shorter maximum cable runs at higher resolutions — the highest-bandwidth 4K60 4:4:4 mode supports the shortest run, and 1080p supports the longest. Specify the cable run for the resolution the output actually carries, and check the manual for the exact limit at each resolution you plan to use — an overflow output scaled to 1080p is not held to the shorter 4K60 limit.
For power, the included locking adapter takes AC 100–240V at 50/60Hz and outputs DC 12V/2.5A; the matrix draws 10W maximum and 1.56W in standby, and surge protection is recommended. For control, the default IP address is 192.168.1.100 and the default RS-232 baud rate is 115200. A 38kHz IR receiver cable is supplied, 1.5 m long, for use when the front IR window is blocked or out of line of sight.
Questions integrators ask
Can one output stay 4K while another goes to 1080p?
Yes. Each of the four outputs has an independent scaler mode — Bypass, 4K→1080p, or Auto. Set the main output to Bypass to follow the 4K source and set the overflow output to 4K→1080p or Auto so a 1080p display shows a picture; Bypass passes the source resolution through unchanged.
Which audio comes out of each de-embed port?
The coaxial (RCA) outputs carry PCM 2.0, Dolby Digital/Plus, and DTS 2.0/5.1. The analog L/R (3.5mm) outputs carry PCM 2.0CH. Note that ARC returns a display's audio on the coaxial output only, and when ARC is enabled on an output the L/R port on that output is muted.
How do I control and configure it?
There are four control methods — front panel, RS-232, IR remote, and TCP/IP — plus a built-in Web GUI reached by entering the matrix's IP in a browser. The GUI's Output page sets scaler mode and toggles ARC per port, the Input page handles advanced EDID management, and the Video page saves up to four routing presets.
What color depth does it carry at 4K60 4:4:4?
At 4K60Hz YCbCr 4:4:4 it carries 8-bit color.
Where it sits in the line
- MMX-8X8AUD — 18Gbps 8×8 HDMI Matrix with ARC Function; choose it when you need eight sources and eight displays.
- MMX-16X16AUD — 18Gbps 16×16 HDMI Matrix with ARC Function; choose it for the largest source-and-display counts.
- HDMX44A-18G — 4×4 HDMI 2.0 Matrix Switcher with Independent Analog Audio Outputs; choose it when you need analog audio break-out but not coaxial.
- SW-HDMX44DS — 4×4 HDMI Matrix Switcher with Independent 4K Downscaling & HDR Support; choose it when downscaling and HDR are the priority.
- HDMX42A-18G — 4×2 HDMI 2.0 Matrix Switcher with Optical & Analog Audio Extraction; choose it for four sources to two displays with optical extraction.
- HDMX42-18G — 4×2 HDMI 2.0 Matrix Switcher with WebGUI, Telnet & RS-232 Control; choose it for a four-in, two-out switch with networked control.
