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View Full Version : freq. comparison: pre-fm | dfm | fm | pre-fm>mp3

pitchshifter.com
2008-04-05, 02:30 PM
Hi,
I wanted to test it by myself if there are any differences between shows which are: pre-fm | dfm | fm | pre-fm>mp3 ... -sourced!
The test is based on one track of a show which were seeded in different versions and I were so lucky to receive also the pre-fm track as reference.





1) preFM ... absolutely lossless (the version before it was broadcasted)
http://img378.imageshack.us/img378/6983/freqanaprefmqb3.th.gif (http://img378.imageshack.us/my.php?image=freqanaprefmqb3.gif)
http://img378.imageshack.us/my.php?image=freqanaprefmqb3.gif




2) FM ... (analogue, terrestrial ... a typical broadcast before everything went digital)
http://img169.imageshack.us/img169/3725/freqanafmiz3.th.gif (http://img169.imageshack.us/my.php?image=freqanafmiz3.gif)
http://img169.imageshack.us/my.php?image=freqanafmiz3.gif




3) preFM>mp3 ... (I used the preFM track to create a 192 kb/s cbr mp3 file - lame 3.97)
http://img384.imageshack.us/img384/6655/freqanaprefmtomp3yi0.th.gif (http://img384.imageshack.us/my.php?image=freqanaprefmtomp3yi0.gif)
http://img384.imageshack.us/my.php?image=freqanaprefmtomp3yi0.gif




4) dFM ... noticeable lossy shit (satellite, DAB, whatever)
http://img183.imageshack.us/img183/4996/freqanadfmen5.th.gif (http://img183.imageshack.us/my.php?image=freqanadfmen5.gif)
http://img183.imageshack.us/my.php?image=freqanadfmen5.gif





Conclusion: The thing is you don't only see the difference, you hear it CLEARLY. While the preFM version blows you away and goes under your skin, the dFM version sounds spongy like played next door and is even worse than a 192 kb/s mp3 file.
AAR.oner
2008-04-05, 02:43 PM
cheers for posting! :thumbsup
Five
2008-04-05, 07:20 PM
yessir I agree with that ranking :thumbsup
ameyer17
2008-04-05, 09:04 PM
Except that FM version doesn't seem to be FM. There's frequency response up to about 17 kHz (FM would be up to about 15 kHz), and there's no 19 kHz pilot tone.
rhinowing
2008-04-05, 11:57 PM
Except that FM version doesn't seem to be FM. There's frequency response up to about 17 kHz (FM would be up to about 15 kHz), and there's no 19 kHz pilot tone.

probably an analog broadcast of a digital source.
(my guess is that this is bjork glastonbury?)
ameyer17
2008-04-06, 01:58 AM
Except that FM version doesn't seem to be FM. There's frequency response up to about 17 kHz (FM would be up to about 15 kHz), and there's no 19 kHz pilot tone.

probably an analog broadcast of a digital source.
(my guess is that this is bjork glastonbury?)
Except FM broadcasts have to cut the high frequencies above 15 kHz for technical reasons, and you would still expect to see the 19 kHz pilot tone, although apparently some recievers filter out the 19kHz tone.
pitchshifter.com
2008-04-06, 05:55 AM
This is:
Nine Inch Nails / 2000-07-08 / Forestglade Festival / Wiesen, Austria

I'll check if I could find a different FM show (with the typical 19 kHz pilot tone) you mentioned. I remember that I've seen a small line once which I wondered about. I also want to post a cFM (cable FM) version soon.
ameyer17
2008-04-06, 07:20 PM
I'll check if I could find a different FM show (with the typical 19 kHz pilot tone) you mentioned. I remember that I've seen a small line once which I wondered about. I also want to post a cFM (cable FM) version soon.
Actually, it's not the lack of a pilot tone that suggests that's not a FM, I believe that FM tops off at 15 kHz (although upon further review, it's possible that the "FM" source could have come from a mono broadcast). Not from the same broadcast (and not a screenshot of the same program, but a typical US stereo FM broadcast would look something like this (http://www.binaryhermit.org/pictures/FM-analysis.png)