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View Full Version : SBD? Um.. only if blocky spectrums are included.


taygan
2006-02-03, 01:23 AM
Yeah, this one just came to me. Does everyone get these beauties or what?

Soundboard. Um, looks like a strange FM or something. Lossy except for the FM-like spikes, or am I making this all up? I guess the line at 16kHz could be at the venue..

Ideas?

Could it actually be a soundboard recorded as ?something?

http://img136.imageshack.us/img136/5738/sau2secspec1hn.th.png (http://img136.imageshack.us/my.php?image=sau2secspec1hn.png)

http://img139.imageshack.us/img139/6615/saufreq0dg.th.png (http://img139.imageshack.us/my.php?image=saufreq0dg.png)

And I must say I'm really enjoying learning this stuff from you folks. I've sent a number of people to this forum, and have walked a few folks through what I've gleaned.

Thanks.

taygan.

Five
2006-02-03, 06:14 PM
looks like radio encoded to lossy sometime before it made it to FLAC. lots of static going on there. the carrier (or whatever) is broken up all over the place, so something happened to this recording (and then there's the visible blocks).

taygan
2006-02-03, 07:53 PM
I was thinking radio encoded mp3, but the carrier seems low and there's no pops or clicks to explain the high spikes. I thought mp3 would wipe out those spikes.

Five
2006-02-03, 11:48 PM
the high spikes could be static introduced by cdr gens and/or bad extraction, certainly some kind of distortion. some other places it doesn't look like static... perhaps a post-lossy remastering effort?

the carrier does look kind of low, but whatever that steady sound is caused by something has happened to it or else it would be continuous.

ssamadhi97
2006-02-05, 10:22 PM
I'd guess the "spikes" are just caused by some kind of distortion (clipping?).

As for the tone you called "carrier", I suspect we're simply looking at some kind of TV source here (remember, horizontal scanning frequency is ~15750Hz for NTSC)

taygan
2006-02-07, 03:26 PM
I'd guess the "spikes" are just caused by some kind of distortion (clipping?).

As for the tone you called "carrier", I suspect we're simply looking at some kind of TV source here (remember, horizontal scanning frequency is ~15750Hz for NTSC)

CLIPPING! yes, thank you. take a look at the spectrum matching the waveform where it would clip.

So, broadcast FM or PAL > WAV file? > encoded mp3 > WAV (recorded too high introducing clipping spikes) > flac.

I assume this is the progression, since the mp3 would remove the clips if they were in the original WAV file.

http://img202.imageshack.us/img202/8214/sau042secspectrum7fv.th.png (http://img202.imageshack.us/my.php?image=sau042secspectrum7fv.png)

http://img203.imageshack.us/img203/2586/sau042secwaveform3cu.th.png (http://img203.imageshack.us/my.php?image=sau042secwaveform3cu.png)


taygan.

ssamadhi97
2006-02-07, 04:27 PM
So, broadcast FM or PAL > WAV file? > encoded mp3 > WAV (recorded too high introducing clipping spikes) > flac.

I assume this is the progression, since the mp3 would remove the clips if they were in the original WAV file.
Actually if the volume is not altered upon decoding, mp3 compression is actually much more likely to make a recording clip more.

Either way, mp3 encoding of a clipped broadcast recording seems to be what we're looking at.

guygee
2006-03-20, 10:52 PM
Just curious, is this that pulled Neil Young 1-20-01 Rio De Janeiro show that is being discussed here? If not, that one sure looks similar.

guygee
2006-03-20, 10:55 PM
I guess not quite the same, since the carrier is not apparent but the clipping is there.

guygee
2006-03-20, 11:27 PM
I was looking in this forum to see who "outed" that show, but I see it got busted in the original thread, sorry for the intrusion.