[Lord Chaos]

Thank you, Elias. That corroborates my experience, but I was curious.

 

[joijwall]

Thanks, Elias!
Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif First of all, we do not suggest removing the headphone-mute-function. Where did you hear that?

Page 13 Rev D of the Manual:
"TIP: If the DAC1 USB is being used in a critical signal chain (...) the headphone mute switch should be defeated using the internal jumpers."
Maybe I shouldn't have used "removing"? Or am I wrong to understand the passage to refer to some kind of bypassing?
/Joachim

 

[Ross MacGregor]

Quote:

Originally Posted by joijwall /img/forum/go_quote.gif Page 13 Rev D of the Manual: "TIP: If the DAC1 USB is being used in a critical signal chain"

That's a really odd tip. I wouldn't expect the headphone out to be part of a critical signal chain in the first place. For example, you are recording or broadcasting a live event. IE: we don't want Aslee Simpsons "mic" to go dead!

 

[Ross MacGregor]

Quote:

Originally Posted by Wavelength /img/forum/go_quote.gif Here are some of the things that I would consider variables for errors on the USB link:

Gordon,
Thank you for the wealth of information on the subject. This is exactly what I was looking for. It's great to hear from someone who has actually tested the hardware under real operating conditions.

Great USB tips for DAC owners, this should be on a Web page or stickied somewhere more permanent. I might have used my front panel USB ports without thinking they would be more prone to error.

Quote:

Originally Posted by Wavelength /img/forum/go_quote.gif The good thing is this... you follow these rules and really you may never have a problem.

 

[Wavelength]

Quote:

Originally Posted by Ross MacGregor /img/forum/go_quote.gif Gordon, Thank you for the wealth of information on the subject. This is exactly what I was looking for. It's great to hear from someone who has actually tested the hardware under real operating conditions. Great USB tips for DAC owners, this should be on a Web page or stickied somewhere more permanent. I might have used my front panel USB ports without thinking they would be more prone to error.

Ross,

I talked to my web guy yesterday about this. We are going to rework our concept page into a white paper kind of format. I have written a ton of these little things for my dealers and I will make up seperate pages for these.

You can keep in touch on usbdacs.com. None of this stuff is dac specific. all of the setup information can be used by most products.

Thanks
Gordon

 

[EliasGwinn]

Quote:

Originally Posted by joijwall /img/forum/go_quote.gif Page 13 Rev D of the Manual: "TIP: If the DAC1 USB is being used in a critical signal chain (...) the headphone mute switch should be defeated using the internal jumpers."

Ahh, I see where your concern comes from. This is only referring to situations where the DAC1 USB should never be muted. This tip is for critical signal chains that cannot be disrupted. In other words, if the DAC1 USB is being used in a television or radio broadcast, the audio cannot be disrupted under any circumstances.

The left-most headphone jack has an internal switch that mutes the main outputs when the headphone plug is inserted. However, this has no affect on the sonic performance of the unit. It will, however, be a bit "OOPS!!" if a radio DJ plugged in his headphones and the radio station was muted!!

 

[vergefio]

Hello all

this is my first post in this forum...

I've recently bought a dac1 usb to connect with my laptop (just amazing quality); i'm using foobar 0.9.5.1 and i wanted to check if i'm going bit-perfect playing some track downloaded from:

Multichannel Sound 5.1 - sr.se

I can hear oly static from output:benchmark1, so i made some research and i tried asio4all and kernel streaming to see if i could go bit-perfect (even if as far as i read from Elias foobar can play bit-perfect just through DS). Choosing asio4all under output tab (setted up like in the first page of the guide in this forum) turned back in static again. I tried then with KS but i can't choose dac1 from the menu so i assume it doensn't work.

Now, what's going on here? What does i have to check in my system and what to do?

Thx in advance
Simone

 

[furball]

Those are DTS or Dolby Digital signals right?

Your software player has to decode the DTS or Dolby Digital signals, and then transfer the decoded PCM signal to an external DAC, only then can you hear the music.

Sounds like your software player is either not decoding the DTS/Dolby Digital signals, or your software player is outputting the DTS/Dolby Digital signals directly out to the external DAC.

Benchmark DAC1 cannot decode DTS/Dolby digital signals.

 

[vergefio]

Thx furball for your reply, those files are .WAV file 44Khz/16bit encoded from a .DTS source and they should be readable by the dac1 only in bit-perfect scenario and they should prove the bit-perfect chain; in the case we hear a static it means the playback it's somewhat managed by kmixer or whatever and it's not bit-perfect.

(This is what i've understood reading through the forum though, i'd be happy if someone can shed some light on it)

 

[furball]

Benchmark DAC1 does not decode DTS/Dolby Digital signals. And Benchmark DAC1 does not have digital output. It only has analog output. In order to test to see Benchmark DAC1 outputs a bit perfect digital output, you need to open up the case and do some mucking around with the internal components.

How is your setup hooked up?


That wave file is still a DTS encoded file. You need a DTS decoder to decode that file. This can only be done in the following ways,
1) Your software player
2) Your software player outputs the digital signal to an external DTS decoder (such as your receiver)


Because the Benchmark DAC1 does not have a DTS decoder, all you hear is pink noise.

And because Benchmark DAC1 does not have a digital output (pass through), you cannot hook up your DTS decoder to the Benchmark DAC1 to test to see if the bit perfect digital output is extracted from the USB port.

 

[infinitesymphony]

But more importantly, the DAC1 does not accept multi-channel signals because it's a two-channel DAC. You'll have to decode the DTS stream in software, then downmix it to 2.0 stereo, and by that point, it won't be bit-perfect.

 

[eweitzman]

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif But more importantly, the DAC1 does not accept multi-channel signals because it's a two-channel DAC. You'll have to decode the DTS stream in software, then downmix it to 2.0 stereo, and by that point, it won't be bit-perfect.

Or use three DAC1s

- Eric

 

[furball]

No, this still would not work.

DTS, Dolby Digital, and their variants are a compression scheme designed to compress multichannel audio signals into one encoded digital signal.

A decoder, such as the one that exists in your receiver, decodes the DTS, Dolby Digital and other such formats, decodes the encoded digital signal into into 5 or 7 channels of analog signals.

There is only one encoded digital stream that carries the encoded DTS/Dolby Digital signal. The DTS/Dolby Digital decoder decodes that one encoded digital stream into the respective 5 or 7 channels of analog signal.


Benchmark DAC1 only decodes PCM style (2 channel) digital signals. It cannot decode DTS, Dolby Digital signals. You need your receiver to do that.


Quote:

Originally Posted by eweitzman /img/forum/go_quote.gif Or use three DAC1s - Eric

 

[eweitzman]

I don't have a multichannel setup (computer or otherwise) so it's just academic for me....

I just figured the single six channel digital stream (DTS or DD) would be decoded/demuxed into six independent, uncompressed digital channels before D to A conversion in a PC. This is how mp3 is played back. The multiple frequency-based and scaled channels are reconstructed and merged into plain old PCM by software before hitting the DAC chip.

- Eric

 

[furball]

Really? I always thought that DTS/Dolby Digital signals are outputted in one digital signal.

The DTS/Dolby Digital decoder inside your receiver only outputs 5 or 7 channel analog outputs, it does not output 5 or 7 channel PCM style digital signals.

As far as I know this also applies to computer soundcards. That one coaxial cable or optical cable carries the entire multichannel digital stream. Those 5 or 7 channel outputs are analog outputs.