Is there a need for 5.1 signal (LPCM, DD, DTS) for 2.1 Soundbar?

cassper

Standard Member
Hi all, I am seeking an answer to one dilemma:

I have a Yamaha YAS 207 soundbar, it is a 2.1 soundbar configuration. As a source I use Apple TV 4k with Infuse, Netflix, Prime Video etc., Apple TV outputs 5.1 LPCM. The soundbar does not support Dolby Vision pass-through, so I had to hook up Apple TV 4k directly to a TV (LG OLED CX) and the sound to a soundbar is from the TV via HDMI Arc. However, HDMI Arc can only output 2ch LPCM. Do I need to worry abou not being able to feed multichannel LPCM into YAS 207 if the soundbar is only 2.1 anyway? Or should I connect Apple TV directly into a soundbar and feed 5.1 LPCM into it, but sacrifice Dolby Vision? Will I be able to hear a difference in sound from 2.1 YAS 207 when I feed it 5.1 LPCM vs 2ch LPCM?

All help is appreciated, thanks.
 
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x6461

Member
I set my Apple TV to Dolby Atmos and my Fire TV Cube to best available the TV to Auto (not PCM) and the soundbar I leave in surround mode the TV sorts out what to send to the soundbar.

But I do find I have had to reduce the volume on the subwoofer to get crystal clear sound.

For Dolby Atmos content I the use DTS Virtual X even though the soundbar does not have Dolby Atmos support itself this seems to work for me. Just press the surround button on the remote to enable DTS Virtual X and vice verse to get get back to surround as and when needed.

Forgot to say I just connect all to the TV and use ARC to the soundbar.
 
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cassper

Standard Member
As YAS 207 is not an Atmos soundbar, I do not need to go this way. However, Apple TV 4k can output uncompressed multichannel LPCM, so why should I force it to output into a compressed DD 5.1 format? The problem I am talking about is that even though I get multichannel LPCM from Apple TV into an LG TV, via HDMI Arc from LG TV to a soundbar I am only able to get downmixed 2ch LPCM. My question is: will I be able to hear a difference from the soundbar when I feed it directly from Apple TV 4k by HDMI multichannel LPCM vs when I feed it 2ch LPCM from LG TV over HDMI Arc.
 

x6461

Member
If you use the passthrough option on your TV (I think the CX has this option my TV does not) to the soundbar then I would think the results would be similar as you say the soundbar is only a 2.1 unit but perhaps try both and see which you prefer.
 

cassper

Standard Member
If you use the passthrough option on your TV (I think the CX has this option my TV does not) to the soundbar then I would think the results would be similar as you say the soundbar is only a 2.1 unit but perhaps try both and see which you prefer.
Well, thank you for your input - but that exactly does not answer my question :D It is not about my perception...I need to know, from the technical point of view, whether there is a difference, if I feed a 2.1ch soundbar with a 5.1ch signal vs 2ch signal. Whether a virtual surround YAS 207 is capable of will be different when created from 2ch input sound vs created from downmixed 5.1 channel sound.
 

x6461

Member
No there is no need for a 5.1 signal with a 2.1 soundbar, stereo is surely optimal.
Apple TV to stereo,TV to PCM and soundbar to stereo is technically all that is required, 2 for the stereo signal and the 1 for the low frequency taken from the stereo signal.
That is how I see it, perhaps I am wrong :)
 
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Enex

Standard Member
Hi all, I am seeking an answer to one dilemma:

I have a Yamaha YAS 207 soundbar, it is a 2.1 soundbar configuration. As a source I use Apple TV 4k with Infuse, Netflix, Prime Video etc., Apple TV outputs 5.1 LPCM. The soundbar does not support Dolby Vision pass-through, so I had to hook up Apple TV 4k directly to a TV (LG OLED CX) and the sound to a soundbar is from the TV via HDMI Arc. However, HDMI Arc can only output 2ch LPCM. Do I need to worry abou not being able to feed multichannel LPCM into YAS 207 if the soundbar is only 2.1 anyway? Or should I connect Apple TV directly into a soundbar and feed 5.1 LPCM into it, but sacrifice Dolby Vision? Will I be able to hear a difference in sound from 2.1 YAS 207 when I feed it 5.1 LPCM vs 2ch LPCM?

All help is appreciated, thanks.
No, simply because your soundbar will convert to stereo anyway before apply any effects. The dts virtual x and all other modes are post processing
Just set you ATV to stereo so that enconding could be done near source and avoid cuttings done by TV.
 

cassper

Standard Member
Many thanks, I thought it was going to be something like that. How it would be for a 3.1 soundbar? Is the centre channel also generated from a stereo signal or would I need to bitstream compressed multichannel signal?
 

Enex

Standard Member
Many thanks, I thought it was going to be something like that. How it would be for a 3.1 soundbar? Is the centre channel also generated from a stereo signal or would I need to bitstream compressed multichannel signal?
Center channel can be generated from a stereo source, my 18 years sony AV does that and is indeed efective. I presume that depends on what soundbar but is perfectly possible.

I had an Q60T 5.1 soundbar and i prefer the phantom center channel generated by my yamaha 107 2.2 in stereo source vs 5.1 source on Samsung. Could be diferent for other soundbars of course.
 

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