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Hi,
I have completed testing of a couple of 192 x 24 DACS - both of which receive input via SPDIF optical. I have a NAS with my HD files on, so just need an Ethernet server with a spdif output to make my new digital system work. I guess I would like to use an IPAD for control. Is there anything circuit-board-like out there than can complete my system? I don't see the need to pay $5k for a commercial equivalent.
Thanks!
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I wouldn't build anything. I'd use a minimalist Linux box like Auraliti or a Mac Mini (I have both) and connect via SPDIF (optical or coax..optical via Mac Mini, coax via Auraliti). Either of them will use your NAS as its file server, the Mac Mini being a simple "point to it on the network". Then us any good 24/192 DAC.
Aha - so the mac mini "headphone jack" output socket must be a dual-purpose socket - it must have an optical output behind the analog stereo jack - so you can plug in either an optical cable (using the adapter) or a pair of regular old headphones. In fact I found this article about it: http://support.apple.com/kb/HT4806 which says The headphone / line output port accommodates digital optical audio output, analog audio output with a 24-bit, 44.1-192 kHz D/A converter, digital audio output up to 24-bit stereo and 44.1-192 kHz sampling rate and supporting encoded digital audio output (AC3 and DTS). For analog headphone / line output, use a standard audio cable with 3.5mm metal plug. For digital audio, you can use Apple iPhone headset with microphone or a standard TOSLINK cable with a TOSLINK mini-plug adapter.
Apple's mac mini info page doesn't have this info so I recommended they add this info to that page.
I had no idea the mac mini had an optical out and the whizzards at their store don't either so I appreciate you pointing me in that direction. Mac Mini running VLC, controlled remotely by an ipad - here I come!
Inexpensive system board, memory, and hard drive. System board with digital out running linux might save you a fair amount over the Mac Mini. A comparable speed system would be very reasonable.
PeterZ
Aha - so the mac mini "headphone jack" output socket must be a dual-purpose socket - it must have an optical output behind the analog stereo jack - so you can plug in either an optical cable (using the adapter) or a pair of regular old headphones. In fact I found this article about it: http://support.apple.com/kb/HT4806 which says The headphone / line output port accommodates digital optical audio output, analog audio output with a 24-bit, 44.1-192 kHz D/A converter, digital audio output up to 24-bit stereo and 44.1-192 kHz sampling rate and supporting encoded digital audio output (AC3 and DTS). For analog headphone / line output, use a standard audio cable with 3.5mm metal plug. For digital audio, you can use Apple iPhone headset with microphone or a standard TOSLINK cable with a TOSLINK mini-plug adapter.
Apple's mac mini info page doesn't have this info so I recommended they add this info to that page.
I had no idea the mac mini had an optical out and the whizzards at their store don't either so I appreciate you pointing me in that direction. Mac Mini running VLC, controlled remotely by an ipad - here I come!
.
Not sure what you mean by "circuit board like" but anything you find will basically be a computer. Why not a Mac Mini. It has optical out and works great with an iPad.
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bwb: Hi. What I meant by "circuit-board-like was a home-made type of thing as opposed to the $5k - $15k type ethernet DACS that are out there such as the Linn. I entered the realm of circuit-board DACS the first of which cost me nothing the second of which cost $65 from China.
So I am hoping to find a diy-type ethernet server to get the HD sound files I have into my DAC and thus into my stereo.
As far as I know the Mac Mini doesn't have a toslink output. I spent an hour in the local Apple store trying to concoct the required set up and they concluded they didn't have anything. We explored their new Thunderbolt interface, and found a 3rd party thunderbolt/toslink peripheral but the Whizard (or whatever they are called) couldn't say for sure I could do what I wanted to do.
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then all you need is an adapter like this or a cable with mini on one end and regular on the other
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Using the mini toslink optical output from the Mac Mini into the DAC section of my CD player is how I got started with my Mac based music server. Amazon is a great resource.
If he simply searches "mini toslink to toslink" while on Amazon.com, he will have several choices of suitable cables and/or adapters to pick from.
Get a Logitech Squeezebox Touch and you will have a nice streaming device that can be used as "transport only" with both digital coax and toslink. Now there is also an app that will permit to send out from the digital out files up to 24bit/192kHz and USB (default USB is input only).
With the Enhanced Digital Output applet the Touch can definitely output 192 S/PDIF coax or optical.
When using a squeezebox there are a few things you need to take into account, the SB gets the audio data from LMS, "Logitech Media Server", this has to be running on something, the Touch cannot directly read the NAS box. Some NAS boxes are powerful enough to run LMS, but many are not. If you don't run LMS on the NAS you will need to run it on another computer, anywhere from a $100 sheevaplug on up. The server can run on windows, OSX or linux so it can run on almost anything you can find to run it on. The server running on a different computer CAN read your NAS box and send the data to the Touch over the network. If you are going to be running hi res files it's highly recommendeed to run all this with wired ethernet. The controller (iPad, iPhone, android phone or tablet, web interface from a computer or several dedicated programs) can use wifi to get to the network.
Currently there is a limitation that if you want to play 192 files you have to send them as flac data over the network. The server can transcode anything you have into flac for sending over the wire so you don't actually need flac FILES, BUT that transcoding takes some horsepower on the server computer, so if your hi res files are not flac a wimpy little computer will probably not be good enough. An Atom based computer shoulf be fine, but anything less than that may not be good enough. If your hi res files are already flac then they don't need to be transcoded so a somewhat lesser computer may work fine. Remember this restriction ONLY applies to 192/176 files, anything less does not have this issue.
John S.
Thanks for the input so far - I am excited about the Squeezebox and found a related product called a Sonos. I have questions in to their respective Support lines as to whether they will handle 192 khz x 24 bit (the Squeezebox apparently goes up to 96k x 24 and the Sonos doesn't describe it's resolution. But this is very cool - and I am in pursuit! Thanks Again! btb
You might find this thread from the pc audio asylum interesting, especially John Swensons input. It talks about a 3rd party app so dont be surprised if Logitech says it isnt possible when it is.
Afterwards we discovered faith; it's all you need
The other alternative is to transcode the 24/192 at the server end. While the Squeezebox Touch itself does not directly support anything past 24/96 at factory settings, the server software is capable of converting so you can play the files with no modifications needed to the Touch.
Hmmm - you mean up-convert from 96 to 192? I have native 192 khz 24 bit sound files so don't really want to down-convert then up-convert those.
Or does it pass the 192 khz 24 bit data through unscathed?
No, it would down-convert from 24/192 to 24/96 at the server software side. If that is unacceptable to you, then you'll either need to hack the Touch or find a different device.
Of course, that brings up the whole issue of what is truly audible at the consumer level (studios often need to mix multitracks where the level of volume disparity between tracks is significant - end users don't do that) but I understand that many subscribe to the theory that if "X" is good, then twice "X" must be better.
Good luck with your search. Hope you find what you need.
mls-stl - thanks for your info. I am definitely going to avoid getting into that whole "can you hear the difference" debate - we would never get to the end of that one!
I find 24 x 96 khz significantly better than CD so I would class it as adequate for now if that's all I can do. I am also exploring the SONOS but have the same question for that gadget - I have a question into their support line to find out if it supports 192 x 24.
"Of course, that brings up the whole issue of what is truly audible at the consumer level"
192/24 downconversion to 96/24 is likely to be audible on recordings that derive from original 192/24 digitization of analog sources (e.g. 15 IPS tape, live microphone feeds, analog mixing console output, etc.) The reason is probably not high frequency response, it's probably filter smoothness. To hear the difference it may be necessary to have amplifiers and speakers suitable for the music being played and a decent DAC. However, moderately priced DACs may benefit more than high-end DACs from being run at the higher sampling rate as many aberrations of mediocre DSP are less annoying when moved up the F-scale.
Some sites, such as Linn, are selling 192/24 downloads at the same price as 96/24 downloads, so the only cost involved in purchasing the higher resolution format is a few cents worth of disk space, rather cheap insurance even if one doesn't hear a difference today.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Hi Tony - there are so many variables in the whole music chain that it boggles the mind. I recently had some super-brains (Phds in a to d and d to a) in for a listen and found that the issues we were listening to were attributable to the D to A converters used to make the CD/digital music files.
I have HD files from both Linn and HDTracks which are "native" 192 x 24, and I also have some of the same recordings in 96 x 24. There are clearly differences in the same recording between 192 and 96 but I am not sure that is due to the sample rate - I think someone has modified the eq between the two. But other than the eq, I found the 96 x 24 to be a huge step forward over CD but am still exploring whether its worth the disk space for 192 (over 96 k)
HDtracks sells 96/24 and 192/24 versions of "Waltz for Debbie". According to available information, the only difference between the two versions is that between the two transfers the ADC converter speed was switched and the tape was rewound. (No DSP other than what was inside the converter.) Some of the Acousense recordings on Linn are made similarly, i.e. by capturing the output of an analog mixing desk at various sample rates. In some cases the source tracks fed into the mixer were only 96/24 but capturing at 192/24 still sounded better than 96/24 according to the recording engineer.
Another way of evaluating formats is to do conversions yourself, e.g. start with a high sampling rate and produce different versions file to file using a sample rate converter. In this case, you can be certain that there is no extra "EQ" involved, other than the particular settings used for the SRC software. The operation of the SRC is transparent, i.e. it's not magic. One can actually inspect the numeric values of the input and output samples if one is so inclined, measure frequency response and transient response of the SRC's filters, etc. (One will need at least an audio editing program and some knowledge of DSP.)
In general, the step from 44/16 to 48/24 is the largest step up in sound quality from CD, the bigger step up from 48/24 to 96/24 is not proportionally greater. From then on, diminishing returns definitely set in.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Check out the Vortexbox web site below. They have a line of SOTM devices that can do what you want. (Edited to change the reference to the one digital interface - not sure it does ethernet, but their other servers do.)
Edits: 05/05/12
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