Heartland

One for all you sound studio merchants.I have some Bootlegs and dont know weather they are mp3 sourced or not;Could one of you who has experience walk me through what i should be looking for.Currently using the spectrum analizer thingy on Soundforge 7.

From what i have been able to figure out so far the frequency range runs Horizontally and the decibel range , vertically.......so far so good .When i load up a sample of the boot i can then get various graphs , representing the sound.what i need to know is how to interpret the graphs?

Thanks in advance...........

The only way I know how to tell if a cd is burned from mp3 is if the person didn't convert the mp3 to wav first. Some cd burners can burn mp3 straight to cd, and converts as it writes. If this is the case there should be a very tiny gap between each track which is usually audible when you listen to the cd.

At the end of the day, if it sounds good then it doesn't matter - it's a boot recorded on a dodgy tape recorder, not the Royal Philharmonic.

So, here we go...

I made an MP3 128 KBPS from an original WAV-file (Sekhmet by belgian trashband Grinning Ghoul, hail guyz!)

What you see below, is the spectrum analysis (abbr. SA hereafter) using SoundForge.




The left channel on the SA (the 'top' image) is the original left channel of the WAV-file.

The right channel on the SA (the 'bottom' image) is the left channel of the MP3-file.

You can see clearly that the top image on the SA is much 'darker' in the upper frequencies than the bottom image.

The darker the area, the more data on that frequency.

The bottom image (the MP3, remember?) shows that there is lots of data loss above the 16 kHz (the numbers on the left of the graph are the frequencies).
Most people do not notice data loss above 20 kHz, so when you make an MP3 at 128 KBPS, a lot of people will notice the difference (for data loss already starts at 16 kHz).

It gets less audible at 192 KBPS and as good as obsolete at 256 KBPS.

Hope to be of some help,

IZ.