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HDMI Audio De-embedder

post #1 of 12
Thread Starter 
Currently I am using my Receiver as a networked Audio player using its DLNA features. The FLAC files are streamed to the receiver via ethernet. This means that I am using the receiver's internal DAC . I would like to use an external DAC . There are several devices that claim to be able to de-embbed the audio signals from the HDMI output so they are available through the devices's Toslink output . What quality of digital Audio signals would I be getting from these devices?

Thanks
post #2 of 12
I use the FC-46XL for my at work jobs when I need to strip the audio and send it to another DAC and path. It does a very good job and I haven't received any negative comments...only wows. Please use a well known and tested manufacturer, because they are not all created equally. I have too many friends who have found out the hard way.
Edited by enthuzist - 7/10/12 at 7:24pm
post #3 of 12
Quote:
Originally Posted by enthuzist View Post

I use the FC-46XL for my at work jobs when I need to strip the audio and send it to another DAC and path. It does a very good job and I haven't received any negative comments...only wows. Please use a well known and tested manufacturer, because they are not all created equally. I have too many friends who have found out the hard way.

Interesting device. It handles both TrueHD and DTS-HD. It also allows a passthru of the original HDMI signal as well as setting the EDID for multichannel.

To the OP, in terms of sound quality the output of the Toslink will be core DTS or Dolby Digital. In other words, S/PDIF can't handle the higher bitrate of the high-resolution audio codecs and therefore down-converts to something it can handle. Other than that, the quality should be equal to what you would get over HDMI with Dolby Digital and DTS.
post #4 of 12
Thread Starter 
FC 46xl seems to be able to do what I want but its pretty expensive.

I just thought of a new idea : My Panasonic TV has a Optical Return output. Would that function in the same way ? ie strips the Audio from the HDMI signals so I can send that signal to the external DAC input?

A straightforward solution is not to use the HDMI for audio at all but to install a Squeezebox Touch to handle the Audio Stream directly from my computer.
post #5 of 12
Quote:
Originally Posted by sportflyer View Post

FC 46xl seems to be able to do what I want but its pretty expensive.
I just thought of a new idea : My Panasonic TV has a Optical Return output. Would that function in the same way ? ie strips the Audio from the HDMI signals so I can send that signal to the external DAC input?
A straightforward solution is not to use the HDMI for audio at all but to install a Squeezebox Touch to handle the Audio Stream directly from my computer.

Don't know. Without knowing which Panasonic TV you have, it is not possible to figure out whether the optical return will support AC3 or DTS (doubtful).

When asking a question here, it is helpful if we know what components you are talking about.

For the SB Touch, it will depend upon what O/S you're running and wether it supports sending multichannel audio.

There may be cheaper alternatives but not knowing how you plan to use this (Blu-Ray, DD, DTS, wave, flac), it's impossible to provide much help. For instance the old Roku HD1000 could take streaming audio and convert to DD and DTS but couldn't handle DD+, DTS-HD, Dolby TrueHD. There are boxes from Gefen that will take optical output Dolby Digital and convert to 2-channel. You could simply use the analog outputs of your computer. Tons of solutions but I don't know which one is suitable for you.
post #6 of 12
Thread Starter 
For this discussion , the Ext DAC is only for 2 Ch Music .

Here are the audio components I have:

TV: Panasonic TC-P50ST30
Receiver: Onkyo NR3007
DVD Player: Oppo 980H
Blu Ray Player: Panasonic ( dont remember the model number off hand, but its their most basic one )
Media Player : WDTV Live
Preamp: Jolida Fusion
Power amp: Odyssey Khartago SE ++

The Ext DAC will only be used for 2 ch Music either from streamed FLAC files or from the OPPO CD player. so there is no need for multichannel , just a good quality digital stereo signal is needed.

I use the Onkyo Receiver for Movies in 5.1 mode.

Thanks
post #7 of 12
Quote:
Originally Posted by sportflyer View Post

For this discussion , the Ext DAC is only for 2 Ch Music .
Here are the audio components I have:
TV: Panasonic TC-P50ST30
Receiver: Onkyo NR3007
DVD Player: Oppo 980H
Blu Ray Player: Panasonic ( dont remember the model number off hand, but its their most basic one )
Media Player : WDTV Live
Preamp: Jolida Fusion
Power amp: Odyssey Khartago SE ++
The Ext DAC will only be used for 2 ch Music either from streamed FLAC files or from the OPPO CD player. so there is no need for multichannel , just a good quality digital stereo signal is needed.
I use the Onkyo Receiver for Movies in 5.1 mode.
Thanks

OK, I think I understand now. Your toughest job will be not making things worse. Your Onkyo DAC is actually a good DAC. So, anything that you do has to result in something "better" (at least better spec).

If I understand correctly you are primarily concerned with going from a FLAC file to the DAC. In that case the toughest part will be finding a device that converts FLAC to wave (or PCM) and then send that to the external DAC, since your DAC does not support native FLAC. The easiest way I can think of is to convert the FLAC file to WAV (no loss that way). The files will be bigger but hard drives are cheap these days (even after the Thailand floods).

The problem then is how to get the PCM file out of the computer. My first thought is to burn a DVD-Audio disc (up to 192kHz, 24-bit) or Blu-Ray disc. The Blu-Ray has the advantage that you already have a player. DVD-Audio is a little easier to work with for music-only disc creation but you would need a player.

Can you give me an idea of what types of digital inputs your DAC accepts? If it is only Toslink (or S/PDIF) you are probably limited to 96/16 anyway (at best). If it is a different type of interface then that would change the answer. Going into analog to go back to digital for the DAC doesn't make sense to me, so I'm trying to make sure we stay digital until you reach the DAC.
post #8 of 12
Thread Starter 
The new target DAC will have both Toslink and Coax S/pdif . It should be able to accept 24 bit/192 khz . I totally agree we should stay with digital right up to the DAC

If I limit the resolution to what Toslink can support , could I not use the TV's HDMI Toslink audio return to feed the DAC like so:

Computer>Receiver ( via ethernet) >Receiver HDMI out>TV Audio Return( Toslink) >Ext Dac >Preamp etc

BTW what is the format of the signal in the Toslink HDMA audio return path ?

If the above signal chain works , it would save me having to buy more hardware.
post #9 of 12
Quote:
Originally Posted by sportflyer View Post

The new target DAC will have both Toslink and Coax S/pdif . It should be able to accept 24 bit/192 khz . I totally agree we should stay with digital right up to the DAC
If I limit the resolution to what Toslink can support , could I not use the TV's HDMI Toslink audio return to feed the DAC like so:
Computer>Receiver ( via ethernet) >Receiver HDMI out>TV Audio Return( Toslink) >Ext Dac >Preamp etc
BTW what is the format of the signal in the Toslink HDMA audio return path ?
If the above signal chain works , it would save me having to buy more hardware.

HDMI would have up to 192/24 PCM.

The S/PDIF is interesting. I had always been taught that the maximum clock was 48kHz on both optical and coax S/PDIF. I just did a look-up and there are DACs (probably like yours) that support 192/24 over S/PDIF. However, that doesn't mean that all S/PDIF sources/sinks can support the higher clock rates. Just ones that were designed for it. It's a non-standard standard.

So what that means is that I think it is highly unlikely that a TV would be able to support that rate. You would have to try a specific TV model first to be sure with 192/24 audio. I would also be surprised if the HDMI overlords allow 192/24 output from HDMI as anything but HDMI. I suspect there is a downconversion that would occur. My other concern is that I wonder if a standard TV wouldn't convert to analog first (have to add bass, treble, volume) before converting back to digital and sending out over S/PDIF?

I don't hold out much hope of your plan working, but then again, I haven't tried it.

The best methods for doing what you are trying to do seem to involve USB or IEEE-1394, both of which can handle the higher clocks.

Now, if you are willing to accept that you are running 48/24 then it should work (may be 48/16). However, at that point I'd say the Onkyo at 192/24 should provide you better quality than any DAC running 48/24 (or 48/16). Of course to my ears, once you get to 48/24, anything above that I really can't hear a difference (actually 48/20, but that has become non-standard). After 48/24, the recording/mixing/mastering chain introduces much more noise than anything in the playback chain.
Edited by alk3997 - 7/12/12 at 4:04pm
post #10 of 12
Thread Starter 
I am afraid you are right about down conversion by the TV's de embeddment hardware.

The only way is to try it out . But how to measure what I am really getting over the toslink? I dont trust my ears that much smile.gif

The sure way is to get a network music player like the Touch then send its output to the DAC

Tks
post #11 of 12
Quote:
Originally Posted by sportflyer View Post

I am afraid you are right about down conversion by the TV's de embeddment hardware.
The only way is to try it out . But how to measure what I am really getting over the toslink? I dont trust my ears that much smile.gif
The sure way is to get a network music player like the Touch then send its output to the DAC
Tks

The way I'd do it is to use an audio card that has a S/PDIF input and record the input. Then compare source (or converted to wave source) against the Toslink output. The audio card clock should lock into the Toslink frequency and you'll know right away what the output frequency is. Then line up the two waveforms and subtract (invert the output and add). If you have any resulting waveform then they aren't the same. Of course, the most difficult part of that is lining up the two waveforms exactly.

Not easy but it can be done.
post #12 of 12
Thread Starter 
I'll think about it. Tks for the suggestion.
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