Is this mp3?

[desert_rat]

I could use some more opinions on this show. I know this was an original cassette master, which at some generation was put to cd. Does anyone think this has mp3 lineage in it?

Thanks in advance.

[dorrcoq]

looks OK to me, maybe MiniDisc, but not MP3

[feralicious]

Doesn't look like mp3 to me either. FM? That black "line" of space in the top area I think indicates something, I think that it's an FM signal, but I could be wrong. Perhaps someone else will know what and if that's true that it even means anything.

On mp3s the freq will drop off at around 16khz. And the spectral view will show a hard line across the top where the sound cuts off, what is called a "haircut". Neither pic indicates these.

[Karst]

What show is that (Dublin?). I agree with Nina looks more like a FM.

[elguiri]

Doesnt FM radio normally show a spike at around 19khz? , might the missing black band 16-18khz be some sort of noise reduction ?

[RainDawg]

This is absolutely NOT mp3 by any means. Might not be FM, cass has similar fading of the upper end. I think that what I'm looking is perfectly normal for a Cass(x) > CDR, with no foul play suspected on my part.

[desert_rat]

Okay thanks everyone, this is a audience recording, not a great one by any means. At any rate, just wanted to get some second and third opinions.

[New Homebrew]

The straight, level blackness above 16kHz sure raises my suspicions.

[wazoo2u]

There's a 20db falloff at around 10k that doesn't look like the gradual freqency deterioration that you get from magnetic tape generations.

FM falloff is at the 15k carrier, so that's not it. If anything, it LOOKS like a normal analog gen that went through a REALLY FUBARED generation somewhere along the line. Doesn't look like great sounding audio, but certainly doesn't look like a "lossy encoded" product.

[Five]

I don't know what this is but is sure isn't mp3. I would love to check 2-second sample of this just for curiosity, either posted here as FLAC in a .zip or pm me for me my email.

[desert_rat]

Here's a 4 second sample of one of the songs.

Well stand by, the attachment pop up window doesn't like the .flac extension

[desert_rat]

Well I can't get the 2 second sample below the 97kb limitation. I'll send you a pm.

[Five]

OK, I got the sample and looked at it in CEP... This looks and sounds like 128kb/s cbr mp3. The classic indications are there: the fa drops off right at 16kHz, the sa shows a perfect straight cutoff at 16kHz with pure black above, and you can see some blocky black bits within the audio.

[dorrcoq]

well, that frequency analysis is a lot different than what he originally posted

[feralicious]

That's for sure. desert_rat are you sure you sent him the clips from the same tracks you got your fa and sa from? I don't see how those can be from the same track.

[Five]

Yeah, my fa looks totally different... I just double-checked to make sure that I got the right file. Maybe desert_rat mailed me the wrong clip??

[desert_rat]

Sent you the right clip. When I extract an entire song, and use EAC "process wav" I get the the same thing I posted originally. When I do a 2 second sample, which I sent to Five, it's the same sa and fa in EAC. However, when I bring the sample into Adobe Audition it matches what Five sees.

So apparently I just need to use a different program....

Either way, looks like I need to cull this from the collection. Thanks for the help and sorry for the confusion

[feralicious]

Just out of curiosity do either of you want to try Anal Frequency to see how it looks in a third program? It's not very comforting to have two programs show such different results.

[Five]

this is a revelation. it seems that EAC doesn't do a very good job at fa! where do I get analfreq these days? somebody got a link? I think they changed the name of the prog recently...

[Five]

oh, here it is: "SpectraScope" I'm surprised he didn't call it AnalScope lol Costs $30 these days

http://www.sharewaretools.com/audio/1145/

[Five]

Okay, I finally tracked down a copy of AnalFreq v1.80 still available on some ftp server in Sweeden:

http://ftp.sunet.se/pub/simtelnet/win95/sound/afreq18.zip

and a nice little guide is available here:
http://dislocateu2trade.webcindario.com/Analfreq.html

The results look more like the window in CEP:

[ffooky]

this is a revelation. it seems that EAC doesn't do a very good job at fa! where do I get analfreq these days? somebody got a link? I think they changed the name of the prog recently...

I've always thought the fa in Audacity is far superior to EAC's but not its sa.

[feralicious]

Five, did you also check those in EAC? Just to be certain there was no mix up?

[Five]

Five, did you also check those in EAC? Just to be certain there was no mix up?
Here's screenshots of the analysis using EAC... keep in mind I've got a 2-second sample, so the sa is "zoomed in" compared to desert_rat's sa. I also attached two screenshots of the fa, 1st one at 512 fft size, and the 2nd at 65536 fft size (maximum). You can see the dropoff a lot better with the fft size at maximum!

[RainDawg]

Holy shit Five....are those plots taken with EAC at the top of the page the same audio as the ones taken with analfreq at the bottom? The analfreq one is telling me, without a doubt, that this is mp3. The EAC one looks totally different.

I am stunned right now. I'll make sure to recommend people never use EAC for frequnecy analysis ever again if these two plots came from the same audio file! I always use and recommend analfreq anyway, but it looks like people will need to hold onto their old freeware versions.

[NINJA]

This is absolutely NOT mp3 by any means. Might not be FM, cass has similar fading of the upper end. I think that what I'm looking is perfectly normal for a Cass(x) > CDR, with no foul play suspected on my part.



NOISE REDUCTION AND DOLBY B/C CAN ALSO LOOK LIKE MP3

(ESPECIALLY MULTIPLE GENERATION OF DOLBY)

ALSO A LOT OF OLD CASSETTE DECKS AND REEL TO REELS FROM THE LATE

60'S AND EARLY 70'S ONLY RECORDED FROM 20 HZ -12.5 KHZ !

I STILL THINK IT IS BEST TO USE THE EARS !

JUST MY 2 CENTS ;)



AND JUST WANTED TO SAY THAT I LIKE THE LAYOUT OF THIS SITE

AND I HOPE ALL GOES WELL FOR YOU GUYS AND I REALIZE THAT YOUR

ONLY IN IT FOR THE MUSIC ! :clap:



DID I MENTION I WASHED MY HANDS BEFORE TRANSFERRING THE TAPE ? :lol:

[NINJA]

Holy shit Five....are those plots taken with EAC at the top of the page the same audio as the ones taken with analfreq at the bottom? The analfreq one is telling me, without a doubt, that this is mp3. The EAC one looks totally different.

I am stunned right now. I'll make sure to recommend people never use EAC for frequnecy analysis ever again if these two plots came from the same audio file! I always use and recommend analfreq anyway, but it looks like people will need to hold onto their old freeware versions.



IVE NOTICED THIS BEFORE ABOUT EAC

I USE SOUNDFORGE FOR FREQ. ANALYSIS

AND

THEY NEVER SEEM TO SHOW THE SAME RESULTS

:eek:

[NINJA]

Here's screenshots of the analysis using EAC... keep in mind I've got a 2-second sample, so the sa is "zoomed in" compared to desert_rat's sa. I also attached two screenshots of the fa, 1st one at 512 fft size, and the 2nd at 65536 fft size (maximum). You can see the dropoff a lot better with the fft size at maximum!


THAT BRINGS UP ANOTHER FACTOR

I THINK YOU REALLY NEED TO ANALYZE AN ENTIRE TRACK IF NOT HE ENTIRE SOURCE TO BE MOST ACCURATE ! :hmm:

[NINJA]

THIS IS WHAT IVE BEGUN TO USE

PAZ PSYCHOACOUSTIC ANALYZER


Realtime analyzer based on our hearing, shows 52 or 68 bands, with RMS, peak, weighting, variable integration time, and much more. Built on the math that the ear uses...See what you've been hearing.


More information
Perfect for mastering, trouble-shooting, environmental analysis and more.
See more of what your audio is really made of.
See peak or RMS frequency content and levels quickly.
Includes a Stereo Position Display for evaluating the 'spread' of the source.
PAZ uses wavelet techniques (as opposed to FFTs) to provide users with optimal graphic accuracy. Individual bands update independently for the fastest response and consequently increased accuracy and resolution. PAZ offers two distinctive real-time audio-analysis displays in addition to Peak/RMS metering:

A distinctive continuous-graph Frequency Display - showing 52 bands most closely resembling the ear's constant Q critical frequency bands.
A wavelet-based real-time analysis including RMS or Peak modes with dual channel or total-stereo-energy graphing from DC to Nyquist, and unweighted, C- and A- weighting modes.
Optional resolution in 10Hz steps can be shown for precise analysis below 250Hz for a total of 68 bands. The display can be zoomed into any area of the graph, all the way to -80dBFS. Level analysis can be saved to a text file. Level meters include L/R peak and summed average (RMS) display, with individually re-settable peak hold values. For fast operation, you can select just the meter you need from Analyzer, Pan, or VU - either all together, or each separately. The Stereo Position Display shows how energy is spread into the stereo field, including anti-phase information, all in an intuitive real-time vector display. This meter is unlike a phase meter, and can help you visualize the energy distributed in the stereo image.

[NINJA]

P.s I Do Not Work For Waves

In Fact I No Longer Work At All !

Retired

[desert_rat]

Holy shit Five....are those plots taken with EAC at the top of the page the same audio as the ones taken with analfreq at the bottom? The analfreq one is telling me, without a doubt, that this is mp3. The EAC one looks totally different.

I am stunned right now. I'll make sure to recommend people never use EAC for frequnecy analysis ever again if these two plots came from the same audio file! I always use and recommend analfreq anyway, but it looks like people will need to hold onto their old freeware versions.

Thanks again Five and everyone for taking a look at this. Fortunately I have a friend who has this show on 2nd gen cassette. I think I'll bug him for a copy and redo this transfer.

Looks like I'll stick to analfreq and Adobe Audition from here on out.

[feralicious]

Here's screenshots of the analysis using EAC... keep in mind I've got a 2-second sample, so the sa is "zoomed in" compared to desert_rat's sa. I also attached two screenshots of the fa, 1st one at 512 fft size, and the 2nd at 65536 fft size (maximum). You can see the dropoff a lot better with the fft size at maximum!
Sheesh! Just the discrepancy between the two EAC fas is astounding. Glad I have AnalFreq. And I guess I'll load up CEP or Audition after I reformat and use that as well. Crazy.

[Lou]

Everything but that very first EAC screenshot is mp3.

With EAC you really have to look at the frequency and spectral analysis in conjunction with each other. The one thing that EAC will trip you up with is if there was noise reduction.

[dorrcoq]

My EAC no longer performs FA or SA for some reason, so I have been using Nero Wave Editor for analysis. Anyone have any comments about it?

[Beleaguered]

Someone should mention these discrepencies over at the EAC forums (http://www.digital-inn.de/forumdisplay.php?f=14). The EAC developer posts there and might be able to clear up these issues.

[New Homebrew]

The spectral view generated by EAC in the first post says mp3 to me, as I posted above... the program did its job.

Remember that these things could have been sampled from different parts of a song or show.

[dorrcoq]

Remember that these things could have been sampled from different parts of a song or show.

I'm a little confused by that statement - wouldn't the MP3 compression be consistent throught the whole song or show?

[New Homebrew]

I'm a little confused by that statement - wouldn't the MP3 compression be consistent throught the whole song or show?

Yes but differences in the relative levels in the frequencies below 16kHz can affect your perception or recognition of various patterns. Try sampling many different points in a song or show and see what you get.

[buzzy]

You've reached the wrong conclusion here, now that you all have a lot more experience with these, you ought to revisit this issue. EAC is a very good tool for this, if used at all correctly.

Look at the images in this post, I added the bold:Here's screenshots of the analysis using EAC... keep in mind I've got a 2-second sample, so the sa is "zoomed in" compared to desert_rat's sa. I also attached two screenshots of the fa, 1st one at 512 fft size, and the 2nd at 65536 fft size (maximum). You can see the dropoff a lot better with the fft size at maximum!This post (about halfway through the thread) has analyses with a much shorter time frame than the first ones posted; and the FA presumably has only music in it, not all the other stuff that can be on a track. I'm betting the first FA and SA were whole track (clapping, voice, etc.), not just music. EAC looks to be working just fine to me, as a few others have noted here.

I think what you've proved in this thread is:

- don't look at whole-track analyses. When you look at music-only, shorter time frames, the results in any program are much clearer.
- in particular, the first FA posted here was probably for the whole track. That's not going to be effective all of the time, especially in unusual cases.

The comments also show the tendency to read too much into too little info, though now that everyone has more experience with this it probably wouldn't happen again. But people were making all kinds of conclusions based on an odd example and too little info. Wehn you get something that seems a bit off the wall, like the first post here, you really have to say, let's look closer.

This analysis is best done when you actually have the tracks. But if you're going to do it with screenshots, you really need about 3-4 views, over the right time frames, to analyze a track. (Though by the time someone gets done doing those, you'd hope they'd have a good idea themselves, except on the odd cases.) Some info here:

http://wiki.etree.org/index.php?page=SourceAnalysis

As far as the FFT size - that graph at 65k is unreadable to me. It's probably a matter of personal preference; and it may be worth trying a few options; but I find something around 1-2k works for me.

[Five]

EAC is one of my favorite programs on my computer. Its perfect in so many ways it makes us want it to be perfect in every way.

So far it looks to me like EAC is weak for source analysis. The clip being discussed earlier in this thread is a classic 128kbps CBR mp3 source, the most common lossy source. EAC has to be able to spot this and more to be of any use for our purposes. I don't think it was designed for this. I mean no disrespect to the author.

The next "interesting" source I get I'll post pics from EAC, CEP & Audacity side by side. I'd love to be wrong about this.

[ssamadhi97]

EAC is uninteresting for spectral analysis thanks to artifact orgy from hell in treble range whenever there's something of considerable intensity is going on in the lower ranges.

Even if there's actually no treble content in the signal, EAC output still looks like a weaker version of the spectrum has been flipped and superimposed on the actual spectrum. (some kind of weird aliasing effect, I guess)

It's just too misleading (see: this thread)

[Five]

http://wiki.etree.org/index.php?page=SourceAnalysis
This Page Last Changed: Dec 9, 2004 13:46:01 :eek2: