[firedog]

Hi-

Do I have any way of knowing if a file from a a source like HDTracks, Linn, etc is truly hi-res (recorded in hi-res format) or just a standard 16/44.1 digital or old analogue tape that has been upsampled or  digitized to 96k or 176k or whatever high resolution format?

Obviously, if I'm going to pay good money for the files, I'd like them to be "native" hi-res files.

Thanks

[ted_b]

Firedog,
That is a very worthwhile question, and one that is not asked often enough.  I know that on HDTRACKS, HDTT (Hidef Tape TRansfers) and Linn, the large majority (95%+) of files either come from analog tapes, mastered then into hirez (i.e not 16/44 sources0 or are recorded in high rez to begin with.  Many HDTracks are actually sourced from higher rez SACD (DSD) files by the likes of Bruce Brown (Puget Sound Studios...had the pleasure of meeting and chatting with him last week at CES; he gave me some demo/promo music to try too).  But....it never hurts to ask the question.  David Chesky (HDTRacks) Bob Witrak (HDTT) and the Linn folks are all very approachable. 

By the way, I am gonna start a sticky thread called "HiRez files/websites that are not Hirez" to put a placeholder out there where people can report faux hirez.  Thanks for the idea! 

[firedog]

Hi-

I decided to write HDTracks and ask them the question. here's the answer I got:

Thank you for your email.  Regarding our high resolution 96/24 and 88.2/24 files (these are indicated with red text either below or above the album cover art that reads "Audiophile 88khz/24bit" or "Audiophile
96khz/24bit"), they are taken directly from the studio masters (either
digital or analogue tape) or direct from the DSD stream of the SACD.
They are all native high resolution recordings and are not up sampled.
If we find out that any of these albums are not native high resolution,
they are immediately taken off our site.

Pretty good answer I think.

[ted_b]

Yep, the Chesky brothers do a good job.  Bruce does their DSD transfers (to 24/88) and he's an expert too.

[Goosepond]

Is there a technical method of testing a random file to tell what rez it is besides taking someone's word for it? 

Gene

[newzooreview]

Is there a technical method of testing a random file to tell what rez it is besides taking someone's word for it? 

Gene

Well, one way is to open the file in iTunes and choose "Get Info" from the file menu. The bit depth and sampling rate are listed in the summary tab. There are probably other ways, but that's what I usually do. You can even add the sampling rate as a column in list view on iTunes. And you can make a smart playlist that shows only files above 44.1 for example.

[ksbruce]

Media Monkey displays the kbps.

[Mike Nomad]

~

[Goosepond]

So if you're using s/w to look at the file on your HD, that doesn't tell whether this is the native resolution of the file, right?

All you've got is the affidavit of whoever sold it to you. 

Does that make sense?

Gene

[ted_b]

Is there a technical method of testing a random file to tell what rez it is besides taking someone's word for it? 

Gene

Your question was about "what rez it is" Gene, not about what the original source file or master tape was done at.  Now later it seems you're asking for the original (i.e before any upsampling)...that is tough.  Any remnants are gone except for possible lack of very high end energy.  If through s/w you find that there is not a lot of energy above say, 24khz, then you can likely assume that the original file might not be hirez.....but it's detective work I'm not familiar with. 

[mgalusha]

You can do a frequency analysis with a tool like Audacity (http://audacity.sourceforge.net/) - it's a free, open source cross platform sound editor.

Example, first plot is the 24bit/96kHz original I bought from HD Tracks. Second plot is the same track converted to 16bit/44.1kHz. Third plot is the 16/44.1 upsampled to 24/96. Note that in the upsampled version there is no content above about 22kHz.



24bit/96kHz, content out to about 30kHz.



16bit/44.1kHz, content to Nyquist frequency of 22.05kHz



24bit/96kHz upsampled from 16/44.1. content does not extend past original sample rate.

[Goosepond]

Thanks Mike,

That's looks like it hits the nail right on the head. 

From those graphs it looks like upsampling a file isn't really buying you anything extra in terms of what you might be getting from an original hi-rez file. As they say, a graph is worth 1K words. 

Gene

[ted_b]

Thank you Mike.....an audio detective if there ever was one.   

[blackzarg]

Very nifty! I had a fun time comparing some tracks I bought on iTunes with some of my Apple Lossless files. Although not 24/96, the MP3/MP4 files all had frequencies above 20khz cut out.