Feeding the DAC

[little-endian]

Hi there,

After purchasing a decent external D/A-converter, the Benchmark DAC1 (the 'classic' one without USB), i had to discover that it is actually not too easy to get it fed with high-resolution material (exceeding 48kHz/16-Bit). Besides the required sources (in the form of commercial ones like DVD-Audio, DAD or HDAD for instance), the right transport system is needed to get the data properly to the DAC.

This is easier said than done since not too few devices aren't even capable to provide 44.1kHz/16-Bit without screwing it up - sad but true.

If one wants to use higher resolutions, it gets even more difficult since the requirements of the equipment are somewhat higher.

In general, this applies to all external DACs but in the case of the Benchmark DAC1 and its philosophy, i want to use the cheapest transport system i can get as long as the data remains intact (this is mandatory of course).

The problem is: Expensive players may provide me the required sample rates via the S/DPIF connector, but then you pay all other (higher quality) parts like the integrated DACs in addition which i'm not willing to to. Even worse, most players restrict the output to lower sample rates / bit depths due to stupid copyright issues.

So I looked for cheap sound cards which would do it for me. The ones based on VIA's Envy24-Chipset were reviewed pretty positive in this manner. However, the famous ESI Juli@ delivers 192 kHz only eletrically (cinch) and not optically which is limited to 96kHz. I personally prefer the optical signal path and besides that wanna try if my model of the DAC1 is really capable of doing so (the newer ones support this in general as far as i know).

Which equipment do you use to operate your DAC1? Suggestions of cheap transports, capable to output 192 kHz optically would be highly appreciated.

Cheers,

little-endian

 

[d-cee]

i think that the bigger issue is finding music that is encoded @ 192kHz/24bit - if your gear is capable of handling such high sample rates and word lengths, but the audio track isn't then it sort of defeats the purpose

the reason that most gear is 44.1kHz/16bit is that the audio CD format is limited to this

 

[infinitesymphony]

There are very few solutions to get unmolested DVD-Audio content to an external DAC, since as you say, the format has significant restrictions. There are three current solutions:

1. iLink-style connections that require a DVD player and receiver capable of iLink transmission. This obviously won't work because your DAC doesn't accept iLink.

2. High-res over HDMI. Newer DVD players and equipment that support the HDMI 1.2a standard (ex. new Oppo players) are capable of transmitting high-resolution audio via HDMI. This won't work because the DAC doesn't have a HDMI port.

2. X-Fi cards. They're the only ones to support software playback of the DVD-Audio format (specifically, MLP decoding). You might look into whether or not the Creative X-Fi or AuzenTech X-Fi cards will support 24/192 digital output. The Audigy 2 was the first line to support this feature, but it downsampled the digital output.

 

[audioengr]

Only a few PCI cards do 24/192. Even most USB converters are limited to 16/44.1 The Freeway and Off-Ramp will pass 24/96 as will the E-Mu 0404.

Most DAC's have problems with 24/192 and even if they work, the digital filters dont work as well, so they sound better with 24/96.

Steve N.

 

[Ori]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif Which equipment do you use to operate your DAC1? Suggestions of cheap transports, capable to output 192 kHz optically would be highly appreciated.

What software is recorded at 192 KHz?
If you're playing 96KHz software up-sampled to 192 then what's the point? Your DAC-1 probably uses the same ASRC chip and it would up-sample internally to 192. It's still a good question whether that's a good thing to do!
I checked the manuals of a few cheap DVD players. All of them will output the raw sample rate up to 96KHz, unless you choose to down-sample to 48 KHz - or if a protection scheme is employed with the software, in which case the digital output defaults to 48KHz.

 

[little-endian]

Thank you for your replies so far.

Quote:

Originally Posted by d-cee /img/forum/go_quote.gif i think that the bigger issue is finding music that is encoded @ 192kHz/24bit - if your gear is capable of handling such high sample rates and word lengths, but the audio track isn't then it sort of defeats the purpose

Yes, you're right. But there are even some recorded at this rate - refer to http://www.classicrecords.com for instance.

Quote:

Originally Posted by d-cee /img/forum/go_quote.gif the reason that most gear is 44.1kHz/16bit is that the audio CD format is limited to this

Sure - and if one is honest, even the performance of regular audio-cds is very seldom used if at all.

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif There are very few solutions to get unmolested DVD-Audio content to an external DAC, since as you say, the format has significant restrictions.

All these solutions are unfortunately rather expensive. That's the problem - i would pay for most i actually don't need. However i heard about some DVD-Audio players which don't resample. Maybe there are some cheap ones available. The best would be a USB 2.0 to S/PDIF device capable of up to 192/24. No included DACs, no gadgets, no fuss.

@audioengr & Ori

Of course, using 192kHz only makes sense (if at all due to filtering you mentioned) if the source uses that rate as well. Resampling with software before sending it to the DAC would be silly - especially in the case of the DAC1 which is going to resample everything to about 110kHz. That's why i would want to prevent resampling of given 192kHz-material down to 96kHz just to get it transfered out from the device (then i would have 192 --> 96 --> 110 - unprofessional).

 

[Dept_of_Alchemy]

I think of the 192/24 feature in the DAC1 as more of a carry-over technology from its studio roots as a pro-recording tool. For us consumers, the vast majority of music that we'll encounter is going to be 44.1/16 and maybe some HDCD at '20 bits'. Perhaps this will change with ultra high-res downloads through the internet and soundcards capable of properly outputting the digital signal but I don't think the 192/24 capability in the DAC1 was intended for consumer use for now.

Besides, why let the DAC dictate what music you listen to?

 

[little-endian]

Hi Dept_of_Alchemy,

i agree with you in what you write. I just want to experiment and learn new things.

In this regard, the fact that no decent little device seems to exist with outputs 192/24 annoys me a bit because it would be definately possible - and i'm pretty sure without too much cost. I suppose the market is simply too small for that.

Ah, and don't worry. I don't go so far to choose the music i listen to on the basis of the used sample rate As written before, it is even difficult enough to find well-mastered audio-cds. In most cases, i go for movie scores beyond the loudness war. I would appreciate scores like 'Memoirs of a geisha' or 'Speed' to have them as DVD-audio (just for comparison) but - of course - none of them is available. Just the old (noisy) Jazz / Blues / Classic stuff. Grrrrrr.

 

[joe_cool]

IMO the only economical way to get high-resolution data to your DAC is to use a computer.

I have no problem playing 96/24 DVD-A tracks with my M-Audio equipment, using WINDVD-6.

If I use the FW Audiophile I can output 96/24 SPDIF (coax) and physically loop back to SPDIF input and send to the PC (via firewire) for recording and conversion to FLAC.

If I use the Revo-5 I can output 192/24 but in analog only.

<edit> Oh yeah, the Toshiba optical SPDIF is not specified for data rates over 96kHz.<edit>

 

[infinitesymphony]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif However i heard about some DVD-Audio players which don't resample. Maybe there are some cheap ones available.

There are a lot of players that don't resample, as long as the disc is not copyrighted (unlike all commercially-released DVD-A discs). You could burn your own non-copyrighted DVD-A from 24/192 source files and it would play back over the digital outputs.

Quote:

Originally Posted by little-endian The best would be a USB 2.0 to S/PDIF device capable of up to 192/24. No included DACs, no gadgets, no fuss.

Except then the question becomes, how do you decode the MLP stream on your computer?

joe_cool, you can play back the MLP streams of DVD-Audio discs on a M-Audio device? I'd read that the X-Fi cards were the only ones to officially (and legally) support this.

 

[joe_cool]

<quote>I'd read that the X-Fi cards were the only ones to officially (and legally) support this.<quote>

Yes, I read the same and so was surprised that "WinDVD Player 6 Platinum" was so cooperative.

 

[infinitesymphony]

Very interesting... I'll have to give it a try with an E-MU 1212M.

 

[joe_cool]

I bought a new legal copy of WinDVD Player 6 Platinum on eBay for $9.99 plus shipping.

 

[little-endian]

Quote:

Originally Posted by joe_cool /img/forum/go_quote.gif IMO the only economical way to get high-resolution data to your DAC is to use a computer. I have no problem playing 96/24 DVD-A tracks with my M-Audio equipment, using WINDVD-6. If I use the FW Audiophile I can output 96/24 SPDIF (coax) and physically loop back to SPDIF input and send to the PC (via firewire) for recording and conversion to FLAC.

Nice setup. Unfortunately, i could never get it to work to loop the s/pdif output of my "M-Audio Transit" to its input. When i even try (not connect properly, yet), awful distortions occur. When it is connected, there's no output (via s/pdif and analog 3,5 mm connector) anymore, at all. This really sucks because this way i can't verify if it is bit-perfect or not. I have a Envy24-HTS based sound card as well but this seems not to be able to record higher than 44.1kHz/16-Bit. Argh!

Quote:

Originally Posted by joe_cool /img/forum/go_quote.gif <edit> Oh yeah, the Toshiba optical SPDIF is not specified for data rates over 96kHz.<edit>

It's not the first time i read that statement. But as far as i know, the standard just limits the bit depth while the sample rate is rather determined by the timing capabilities of the hardware. At least the later versions of the DAC1 definately support 192kHz optically so there must be sources which provide this optically, too.

Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif There are a lot of players that don't resample, as long as the disc is not copyrighted (unlike all commercially-released DVD-A discs). You could burn your own non-copyrighted DVD-A from 24/192 source files and it would play back over the digital outputs.

Yes, my DVD-player Yamaha DVD-S540 doesn't have any problems to output 96/24 via s/pdif if the DVD is not encrypted, either. It would be a possible way to "free" the commercial discs and rewrite them thus the player will output the data without resampling.

Do you know players that are able to output 192kHz optically, by chance?

Quote:

Originally Posted by joe_cool /img/forum/go_quote.gif Yes, I read the same and so was surprised that "WinDVD Player 6 Platinum" was so cooperative.

It wouldn't be the first time that commercial players would allow sometime that isn't too official.

 

[infinitesymphony]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif Do you know players that are able to output 192kHz optically, by chance?

I figured that any player with a 24-bit/192kHz spec and an optical output would be capable. I hadn't heard about any limitations until today.

Of course, testing that assumption would be difficult. I'd guess that the easiest way would be to take a DVD-Audio disc with a 24-bit/192kHz stereo track, rip it using dubious methods that essentially strip the watermark / copyright, and re-author the MLP stream to a new DVD using a program like Minnetonka discWelder.