This new HDMI switch was developed to connect a soundbar with HDMI eARC to HDMI sources directly. This doesn't work in the usual way because the HDMI ARC or eARC port of the soundbar is an HDMI output, not an HDMI input. However, the audio is transmitted in the opposite direction via the Audio Return Channel. The HDMI ARC interface has long been available on TVs. It allows TV audio to be played back from an HDMI input on the TV to the output of an AV receiver or soundbar. Note the signal direction: The audio is transmitted from the TV input to an HDMI output, i.e., opposite to the audio-video signal. ARC was originally limited to audio formats stereo, Dolby Digital, and DTS. For several years, LG and Samsung TVs have also been able to output Dolby Digital Plus via ARC, which also makes Dolby Atmos from streaming services possible.
Since 2020, there has been the HDMI eARC interface, which essentially works in the same way. eARC stands for enhanced Audio Return Channel, which is the improved version. eARC enables the transmission of additional audio formats such as Dolby TrueHD or DTS-HD.
HDMI ARC/eARC on TVs is not only used to transmit internal audio (cable TV, satellite TV, or smart TV) to the soundbar but also for external sources such as PCs or media players connected to the TV. This reduces the cabling effort. Unfortunately, there can be some limitations, and this is where the VAX04101 switch helps:
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Better Audio Formats:
Often, the TV does not support better audio formats. Many TVs do not pass through DTS audio, Dolby True-HD, or Dolby Atmos. The VAX04101 remedies this by bypassing the TV's limitations. -
No Audio Delay:
Or the audio is sent only after video processing and therefore arrives too late at the sound system. Lagging audio cannot be synchronized. The VAX04101 prevents such a delay because the soundbar no longer receives audio from external players from the TV. (For audio from Smart TV apps, nothing changes, only from external media players). -
Soundbar can be operated with a projector or monitor:
Video projectors or monitors do not have an HDMI ARC or eARC port. They cannot be operated with soundbars that require HDMI ARC.
How it works
The VAX04101 delivers audio and video signals from an HDMI source to the end device (TV, monitor, or video projector). It supports HDMI data rates up to 18 Gbps, so 4K 60Hz and HDR formats like Dolby Vision are possible. The EDID mode is set on the front of the device. This determines the maximum possible audio format – usually that of the soundbar. If a powerful sound system is connected, "7.1" should be set here. This signals to the player that all audio formats up to 7.1 audio are supported. If the soundbar does not support Dolby Atmos, DTS-HD, or Dolby TrueHD, "5.1" should be set. The "Auto" setting only corresponds to the TV's maximum audio format.
Please note: Some soundbars support high audio formats like Dolby Atmos and Dolby TrueHD but not the competing DTS formats (DTS-X and DTS-HD Masteraudio). DTS formats are often found on Blu-rays. However, there are no streaming videos with DTS sound. So if the soundbar remains silent when playing a Blu-ray, it's best to manually change the audio track.
In addition, media players often offer a selection or setting option for the audio format, which overrides automatic format negotiation. This allows for even better output customization.
The VAX04101 is compatible with most eARC soundbars, e.g., Sonos Arc, Sonos Beam Gen.2, Bose 900.
Everyday use
The desired HDMI source on the VAX04101 is selected via the remote control or the button on the front of the device. The soundbar is connected to HDMI input 1. So, if input 1 is selected, the soundbar's on-screen menu (if available) appears on the screen. If the soundbar has another HDMI port, additional players can be connected there.
The audio from the selected source is routed to the soundbar. The TV receives the video signal from the source. In most cases, the TV speakers will remain silent because ARC is activated or the audio format is not supported. However, it is fundamentally possible for the TV to also receive the audio. The same audio format as on the soundbar is used. Therefore, a TV headphone may remain silent because the TV does not convert the format. This depends on its capabilities.
If a TV is connected with its HDMI ARC port, the TV audio is also audible via the soundbar and the VAX04101. To do this, switch the TV to the receiver or Smart TV app. Then select HDMI input 1 on the VAX04101.
Limited automatic switching
In principle, an HDMI switch can be switched via hotplug detection (Pin 19). Many devices only provide a signal here when connecting – not when switching on or off. A fully automatic switching of all inputs therefore often does not work. Especially devices without a power switch such as Apple TV, Fire TV, or Chromecast prevent automatic switching.
This is because a TV monitors its HDMI inputs and the players connected via HDMI handshake. As soon as a power-on command is sent here, the TV can switch to the respective HDMI input. A switch is transparent, and the connection between the HDMI source and the TV also takes place here. However, the TV or switch does not receive a control command from the inactive HDMI inputs because there is no connection to them.
If several HDMI sources are connected, and one of them does not have a power switch, manual switching is necessary. Switching on the VAX04101 is possible via button or with the infrared remote control. A programmable remote control can also be set up accordingly.
HDMI-CEC Control
Via HDMI-CEC, the player selected on the switch communicates with the TV. Therefore, the TV remote control can control the media player remotely. When the TV or media player is switched off, the connected device is also switched off, provided it supports this function. Players on inactive outputs, however, cannot be controlled via CEC because there is no active connection.
Alternative Use
The VAX04101 can also be used as a conventional 4x1 HDMI switch. In this case, 4 HDMI sources can be operated on one HDMI sink (TV, video projector, or sound system with a real HDMI input). To do this, switch off "eARC" on the switch.
Notes for Sonos App users
The Sonos App S2 allows the integration of additional audio services such as internet radio, Spotify, Amazon Music, etc. However, this app requires a connection to a TV with ARC (or an optical adapter). The app checks the connection when the installation or troubleshooting is started. But if a Sonos soundbar is not connected to a TV but to the VAX04101, the app reports an error and offers a new installation. This is very annoying. Sonos has not yet considered this case in the app.
Therefore, we recommend not starting the installation dialog. It is not necessary. If sound then comes through the soundbar, the app can be used as intended. All functions and settings such as sound, volume, and audio delay of the S2 app work as usual.
Update via USB
Since 2022, the VAX04101 has been equipped with a micro-USB port through which updates can be installed via a Windows PC if required. The update is described in this user manual. With some devices, you are used to ongoing updates and constant new features. This is not the case with an HDMI switch, as it merely passes signals through. If we make adjustments, it usually concerns necessary changes to the hardware (e.g., new chip due to component shortages) or improved compatibility, preferably with uncommon displays such as certain video projectors or laser TVs. Here, the old saying "never change a running system" applies. So do not perform an update in anticipation of new features, but only if we advise you to do so!
For installations with 2 displays, e.g., TV and video projector, we offer the VAX04201. This one also has a second HDMI output. It should be noted that CEC control cannot be used with such an HDMI matrix switch. This means that you have to use multiple remote controls to operate all connected devices. So, if there is only one screen, use the VAX04101.
Technical Specifications:
| Signal Input | 4 × HDMI (1× HDMI-eARC for Soundbar) |
| Supported Copy Protection | HDCP 1.x, HDCP 2.2 |
| Data Transfer Rate | maximum 18 Gbps |
| Supported Video Formats | up to 2160p @ 60Hz, 1080p/1440p @ 120Hz |
| Signal Outputs | 1 × HDMI, 1 × HDMI-eARC |
| Color Space | RGB, YCbCr 4:4:4, 4:2:2; 4:2:0 |
| Supported Color Depth | 3 × 8 Bit / 10 Bit / 12 Bit |
| HDR (High Dynamic Range) | HDR10, HDR10+, HLG, Dolby Vision |
| EDID Modes | 2.0 | 5.1 | 7.1 | Auto (corresponds to HDMI TV output) |
| Audio Formats HDMI | DTS-HD, Dolby True-HD (incl. Atmos), Dolby Digital Plus, AC3 (Dolby Digital 5.1), DTS, DTS-EX, DSD, LPCM 2.0 – 7.1, Dolby MAT |
| HDMI-CEC Control | yes |
| Recommended HDMI Cable Lengths | < 3 m at input, < 3 m at TV output (for 4K 60Hz) |
| Power Consumption | < 2W |
| Dimensions | 183 × 85 × 19 mm |
