Phantoms and home cinema

[JohnnySix]

Unfortunately most AV receivers can only delay the sound. We need the video delayed! That would need a frame buffer. However, if watching from a Media PC, it is usually possible to achieve this shift. JRiver Media Centre allows me to watch movies from hard disk with sound and picture in sync. If only a TiVo would provide the same facility...

[fgueho]

Indeed, I can only delay the sound with my AV Receiver. Not the video.
So it means my video feed from my TV source will not be synchronised with the audio... very frustrating.
I can sell my external bluray player and use only my PCHC (with an integrated bluray player). And I will be able to sync the video.
But not with my TV source... I don't see any solution.

[fgueho]

As another post put it, you need the DIALOG box to control and delay the video image as processing the audio takes time (As Sonos demonstrates).
I think it will all be sorted when we see a DIALOG box with an HDMI input.

I don't think an HDMI input will be the solution.
Because :
1 - It would also need an HDMI output to send the video feed in sync.
2 - It would need multiple HDMI inputs, because people have multiple sources (bluray, tv, playstation, etc.)
3 - It would (sort of) replace an AV Reciver but with far less options, and far less power

What I don't understand is that my AV Receiver use an optical input for the sound. And there is no delay with the video feed (which doesn't go through my AV Receiver but directly link to my TV).

I have multiple sources :
Playstation (video) => HDMI link to my TV
Playstation (audio) => optical link to my AV receiver
TV (video) => HDMI link to my TV
TV (audio) => optical link to my AV receiver
PCHC (video) => HDMI link to my TV
PCHC (audio) => optical link to my AV receiver

So in all cases, the audio and video go separate ways. The video always goes directly to the TV, the audio always goes directly to my AV Receiver.
And I don't have any delay.

So how come my AV Receiver is capable of processing the optical audio source without delay, and not the phantoms?

[stonedragon]

I watch all my TV/Films through a PS3 and have not experienced any kind of delay. Works perfectly.

[road rebel]

Because there is an additional synchronisation step needed between multiple phantoms (network speakers) that doesn't exist in a traditional AV setup with active/passive speakers.

For the record: how do you guys achieve home theater (=surround) with phantoms (stereo)? And how do you set phantoms as surroundspeakers from an optical (toslink) sending 5.1 (AV receiver) or 2.0 (TV) where, I suppose, phantoms only take the front signal?!

hdmi would be an important evolution as from then you will not need an AV receiver/ processor anymore for surround and you will be able to use the phantoms as stand alone option. + All modern sources are hdmi and all modern formats require hdmi + hdmi is more appropriate to achieve a correct AV sync.

[Phs]

Because there is an additional synchronisation step needed between multiple phantoms (network speakers) that doesn't exist in a traditional AV setup with active/passive speakers.

For the record: how do you guys achieve home theater (=surround) with phantoms (stereo)? And how do you set phantoms as surroundspeakers from an optical (toslink) sending 5.1 (AV receiver) or 2.0 (TV) where, I suppose, phantoms only take the front signal?!

hdmi would be an important evolution as from then you will not need an AV receiver/ processor anymore for surround and you will be able to use the phantoms as stand alone option. + All modern sources are hdmi and all modern formats require hdmi + hdmi is more appropriate to achieve a correct AV sync.

I agree with you. The fact that you can input optical on one Phantom doesn't mean the signal goes as straight and fast to the speaker as it does with an AV receiver, because streaming to multiple Phantoms needs buffering to synchronize them together.
On top of this, Phantom uses a lot of DSP processing which also takes a bit of time (but less)

So IMO I hardly see how the situation could improve to perfect A/V sync ( I mean here one frame max = 40ms )

Our best options are :
- hope that Devialet code and buffer optimization reduces the delay
- compare different setups. What I mean here is to test for example if using ethernet between Dialog and Phantoms reduces the delay compared to using WIFI, and also test wether the delay is the same when using optical input on Phantom vs Dialog

[fgueho]

I plan to use ethernet between phantmons and dialog. No wifi.
Is anybody can tell us if the delay is okay with ethernet compared to wifi?

[JohnnySix]

I'd like to beg Devialet to implement a mode where each Phantom can take a full Optical signal and extract one allocated sound channel from the stream, bypassing the Dialog entirely. Synchronisation wouldn't be required, and it would be practically zero latency. It would require extra optical cable and splitters, but those would still have less visual impact than most audiophile speaker cables.

[f1eng]

I'd like to beg Devialet to implement a mode where each Phantom can take a full Optical signal and extract one allocated sound channel from the stream, bypassing the Dialog entirely. Synchronisation wouldn't be required, and it would be practically zero latency. It would require extra optical cable and splitters, but those would still have less visual impact than most audiophile speaker cables.

What makes you think there would be no latency?
The latency will always equal the length of time it takes to fill the buffer. A smaller buffer = less latency but less resilience against streaming errors.
There may also be latency associated with the DSP correction of frequency response and timing error inherent in getting full range performance from such a small unit.
A simple DAC would have minimal latency, but a Phantom is not a simple DAC.

[JohnnySix]

There is very little buffering when the Dialog is taken out of the equation. If you set up a phantom without it, and put a TV sound signal into the Optical input, that Phantom is perfectly in sync with the picture. I believe in that situation, the Phantom IS much like a regular DAC.