manually wake up sonos arc from standbby?

Hi @riiiic 

Technically, there shouldn’t be a difference, at least in terms of the issue you initially described. However, technically, that shouldn’t be happening in the first place, so feel free to experiment.

I would not specify PCM, however, as that likely refers to PCM stereo, which is a downgrade from any other format. Passthrough is generally the best option - as long as other devices/apps are not configured to output a format that Arc does not support (DTS-HD, for example).

It may be worth trying things with eARC disabled. Standard ARC can still supply Dolby Digital + (Atmos), which is the best format you’re likely to get from streaming services. You would need to watch a BluRay to benefit from eARC being enabled at all.

I hope this helps.

Dear Corry, 

I found out something important.

I turned on the TV and the PC (PC was on but in sleep mode).

I started a game and checked the win audio output (dolby atmos).

Sonos app revealed that the sound was WMA not supported.

I check the LG and the setting was passthrough. So I changed it to PCM and the sound was stereo PCM, changed back to passthrough and “boom” the Arc recognized the sound as Dolby Atmos.

Now I am baffled:

1. PC must always transmit the same signal
2. TV must have interpreted as WMA and send it to the Arc which can’t reproduce?
3. Turning passthroughs to PCM and back to passthrough solved the issue

This is a f***cked up, I would say the fault is 100% the TV, but then how should I correct it?

Do the trick each time it doesn’t work and set itself to WMA for no reason ?

There is a lot of negotiation when an HDMI connection is established. Each end of each connection attempts to figure out what the other guy supports and they all attempt to find common ground. There’s no absolute standard regarding how this is done, Plus there can be timeouts where one device does not respond fast enough and another device makes a wrong assumption because of this. Restarting the negotiation might result in a different outcome. I know this can be an annoying mess, but this is the current state of the art.

A good plan of attack is to remove all HDMI connections from the TV, make sure that software is up to date, reboot everything, then connect only the TV and SONOS. Often the TV and SONOS will work out a good compromise at that time. Now, begin to connect other devices to the TV. Hopefully their negotiation will not corrupt the SONOS-TV compromise.

In some cases a device’s CEC is working against you. Unfortunately, turning OFF its CEC support might lock out certain audio formats on one or another device. There are HDMI inserts that will block CEC communication. This sometimes helps because it eliminates the negotiation and allows each device to assume that the other guy simply does not support CEC. This CEC blocker can have side effects, such as not allowing a remote control to adjust Volume because the Volume commands were being sent over the CEC bus. It is also common to send power and input selection data over CEC. When CEC works, CEC allows simply dropping a disc into a player and all appropriate devices switch ON and pass the disc through to the display.

Another dimension is EDID because it might influence the audio processing decision. This is another negotiation that occurs when the HDMI connection is established. There are also little ‘boxes’ that can fake the EDID data that is sent both ways.

Hi Buzz,

Thanks a lot.

I don’t think that would work, cause the PC randomly works immediately and randomly LG TV thinks is WMA audio. I would say the best would for the arc to support every format, ahahah

As other sound systems support almost everything, this might pass unnoticed.

For us that love the SONOS style, is a pain. But hey, at least now it would cost me only a couple of clicks, until LG figures it out.

Hi @riiiic 

That is most strange - I have never heard of a TV passing WMA before, so I can only presume that the TV was doing something incorrectly. Arc can play WMA files via the Music Library, but this format just isn’t used in Home Theatre and the Arc does not expect to see it coming via it’s HMDI socket. I suspect that the feed wasn’t actually WMA, but for some reason it was interpreted/labelled as such.

I recommend unplugging your TV from power for at least 2 minutes, if you haven’t already - this will make the TV’s software fully restart in a way that Standby just doesn’t achieve.

I hope this helps.

With respect to TV reboot, I’m not familiar with the LG detail, SAMSUNG TV’s need to be powered down for at least two minuets before they will reboot on power up.