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New Arc interfering w/Sennheiser RF headphones?


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I have a Sennheiser RS 185 RF wireless headphone system that I have enjoyed for years. As my wife and I are on different sleep schedules, this solution has saved my marriage.

Recently I added a new Sonos Arc, existing subwoofer and 2 Sonos One speakers to my TV. The TV and all Sonos components are working fine. However, except for a couple evenings(out of 2 weeks), I have been unable to get sound from my headphones. I installed and charged new batteries and added a new optical cord, but still no sound. Sonos support said that they cannot help because their components are working, and Sennheiser tells me there must be interference from the new changes that is causing the problem. Can anyone help? After buying the new Arc I can’t afford a divorce lawyer!

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Best answer by Airgetlam 19 June 2022, 22:49

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HURRAY!!! By fiddling around, I FINALLY came up with a workable solution that does not require me to unplug my Arc every time I want to use the headphones. In the TV settings, I changed the Digital Audio Out setting from Auto to Passthrough. This still allows Dolby or DTS to come through the Sonos unmodified from the source, AND most importantly for me, allows simultaneous sound from both the Sonos and the headphones(connected to Optical). That’s all it took, now everything works exactly as I wanted.

Amazed that I sent over an hour with TCL support and they told me the only solution was to unplug Sonos in order to listed through headphones.

Had also sent 45 minutes with Sonos help, and numerous emails with Sennheiser help, and both told me there was no solution either.

 

Special thanks to 106rallye for directing me to the appropriate page in the TCL manual. That didn’t fix the issue, but it put the idea in my head to try every potential setting.

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The manual of the TCL 6-series does mention CEC and Arc: https://www.tcl.com/usca/content/dam/tcl/product/home-theater/6-series/download/6series_Roku_User_Guide_US-CA-8.1_1.pdf

Page 123, could maybe help you.

I wouldn’t think so, but then the effort involved is rather low, so why not try it?
 

It really depends on the electronics in the TV set. It’s possible, albeit unlikely, that they’ve got an undocumented feature there. 

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As @ratty suggests, it’s likely to be the CEC system interfering.

CEC is explained here.

Sonos is just one company that uses this standard to do connection between TVs and speakers.

Unfortunately, CEC has a “one speaker sink” policy, so if you connect a CEC speaker, like the Sonos Arc, to the hub (your TV), and CEC is turned on,  it identifies itself as the only allowable sound device. Depending on how the TV manufacturer has implemented the hub for CEC, it’s possible that turning on CEC and connecting a CEC speaker sink turns off the optical port. It’s rare, I’ll grant you, but it appears to be the case in some TV sets. Turning off CEC on the TV set may or may not turn off the transmission of HDMI ARC that feeds the Sonos Arc, but it would ensure that the optical port is live, which you would be connecting the Sennheiser.

It’s indeed unfortunate that the CEC standard doesn’t really allow for optional headphones. 

As @ratty suggests, it’s likely to be the CEC system interfering.

CEC is explained here.

Sonos is just one company that uses this standard to do connection between TVs and speakers.

Unfortunately, CEC has a “one speaker sink” policy, so if you connect a CEC speaker, like the Sonos Arc, to the hub (your TV), and CEC is turned on,  it identifies itself as the only allowable sound device. Depending on how the TV manufacturer has implemented the hub for CEC, it’s possible that turning on CEC and connecting a CEC speaker sink turns off the optical port. It’s rare, I’ll grant you, but it appears to be the case in some TV sets. Turning off CEC on the TV set may or may not turn off the transmission of HDMI ARC that feeds the Sonos Arc, but it would ensure that the optical port is live, which you would be connecting the Sennheiser.

It’s indeed unfortunate that the CEC standard doesn’t really allow for optional headphones. 

Hi Bruce-

Really appreciate your detailed comments. After further discussion with the Sennheiser tech, it has become apparent that you are dead on about the cause of the issue being CEC once connecting Sonos to eARC. They suggested turning off the eARC on the tv as a potential solution.

My problem is the tv is a TLC R625, and the platform is Roku. Roku has many advantages, however the sound settings are very limited and basic. I see no option to manage the eARC or the other sound outputs on the tv, which are Optical and a headphone jack. My headphones only have Optical or analog connections for audio input, so it seems I am stymied when it comes to getting sound to both the Sonos and the headphones simultaneously.

I had the same issue previously when using my old Sonos Playbar, but was able to resolve it with an optical splitter. Unfortunately, with the only option for the Sonos Arc being eARC, I guess I am stuck.

 

Thanks to all for trying to help!

Bruce-

 

1 last question- would the Sonos work properly if I connected it to an HDMI port other than eARC?

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As @ratty suggests, it’s likely to be the CEC system interfering.

CEC is explained here.

Sonos is just one company that uses this standard to do connection between TVs and speakers.

Unfortunately, CEC has a “one speaker sink” policy, so if you connect a CEC speaker, like the Sonos Arc, to the hub (your TV), and CEC is turned on,  it identifies itself as the only allowable sound device. Depending on how the TV manufacturer has implemented the hub for CEC, it’s possible that turning on CEC and connecting a CEC speaker sink turns off the optical port. It’s rare, I’ll grant you, but it appears to be the case in some TV sets. Turning off CEC on the TV set may or may not turn off the transmission of HDMI ARC that feeds the Sonos Arc, but it would ensure that the optical port is live, which you would be connecting the Sennheiser.

It’s indeed unfortunate that the CEC standard doesn’t really allow for optional headphones. 

Hi Bruce-

Really appreciate your detailed comments. After further discussion with the Sennheiser tech, it has become apparent that you are dead on about the cause of the issue being CEC once connecting Sonos to eARC. They suggested turning off the eARC on the tv as a potential solution.

My problem is the tv is a TLC R625, and the platform is Roku. Roku has many advantages, however the sound settings are very limited and basic. I see no option to manage the eARC or the other sound outputs on the tv, which are Optical and a headphone jack. My headphones only have Optical or analog connections for audio input, so it seems I am stymied when it comes to getting sound to both the Sonos and the headphones simultaneously.

I had the same issue previously when using my old Sonos Playbar, but was able to resolve it with an optical splitter. Unfortunately, with the only option for the Sonos Arc being eARC, I guess I am stuck.

 

Thanks to all for trying to help!

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I have moved the Sennheiser transmitter several feet from the Arc- as far as the optical cord allows- but still no sound 90% of the time. 

As an experiment, power the Arc off temporarily. See if the headphones start working again. 

Yes- when I unplug the Arc, headphones work. I noticed on the Sonos app it say Audio in is Dolby Multichannel PCM 5.1. I have disabled Dolby on both my Dish Network settings and on the tv. By experimentation, my headphones only work when the Audio in is Stereo PCM, but I can’t remember what I did to get that result. My tv is a TCL Roku R625, I cannot find any sound setting for PCM on it.

Am I going to have to unplug the Arc every time I want to use my headphones?? 

As @ratty suggests, it’s likely to be the CEC system interfering.

CEC is explained here.

Sonos is just one company that uses this standard to do connection between TVs and speakers.

Unfortunately, CEC has a “one speaker sink” policy, so if you connect a CEC speaker, like the Sonos Arc, to the hub (your TV), and CEC is turned on,  it identifies itself as the only allowable sound device. Depending on how the TV manufacturer has implemented the hub for CEC, it’s possible that turning on CEC and connecting a CEC speaker sink turns off the optical port. It’s rare, I’ll grant you, but it appears to be the case in some TV sets. Turning off CEC on the TV set may or may not turn off the transmission of HDMI ARC that feeds the Sonos Arc, but it would ensure that the optical port is live, which you would be connecting the Sennheiser.

It’s indeed unfortunate that the CEC standard doesn’t really allow for optional headphones. 

I have moved the Sennheiser transmitter several feet from the Arc- as far as the optical cord allows- but still no sound 90% of the time. 

As an experiment, power the Arc off temporarily. See if the headphones start working again. 

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It’s not really the Arc, per se, but the fact that CEC only allows a single system to be an audio sink (speakers). 
 

I would suggest turning off ARC (HDMI CEC) on your television, and make sure the optical port is active. 

Can you please elaborate, not sure I understand your solution. Are you referring to turning off the eARC port on the tv? That’s where Sonos is connected. Goal is to have sound available from both Sonos and headphones when needed.

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I have moved the Sennheiser transmitter several feet from the Arc- as far as the optical cord allows- but still no sound 90% of the time. 

Assuming the Arc is the cause, then any increase in the separation will be welcome. The interference follows the inverse-square law, so doubling the distance reduces the intensity by a factor of four. 

Presumably the Arc is presently on a TV stand of some kind, or similar furniture. Is it not possible to simply move the RS185 transmitter further away? Optical cables can extend up to 5m if necessary.

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Yes, it’s the headphones that were cutting out, sorry I didn’t make that clear. I moved them as far as I could, which was only a few inches, from the center of the Arc and they actually worked OK for the rest of the evening. Hopefully that was the fix, but it’s been an intermittent issue and I’m not counting on it being permanent.

 

Does anyone out there know if wall-mounting the Arc(which would increase the distance between Arc and headphone receiver from 15” to 3’) would be a permanent fix?

Which sound cuts out? If it's the headphones there's little you can do other than try and reduce the interference they're seeing. They maintain a low latency (delay) by minimising the amount of buffering, making them more susceptible to interruptions. 

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Thanks for the help so far! They are working now but sound keeps cutting out(very briefly) every few seconds. Am somewhat limited with how far I can separate the Sennheiser transmitter from the Arc. If I was certain it would fix the problem permanently, I would hire someone to wall mount tv and Arc. Would that definitely fix the problem?

Assuming the Arc is wireless you’d also want to keep the RS185 transmitter as far away from it as possible. Those headphones use a proprietary wireless in the 2.4GHz band which can interfere with WiFi/SonosNet in the same band. 

It’s not really the Arc, per se, but the fact that CEC only allows a single system to be an audio sink (speakers). 
 

I would suggest turning off ARC (HDMI CEC) on your television, and make sure the optical port is active. 

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