Opening up some mp3's in Wavelab and checking them with the spectrum analyser yields something exactly the same in almost every song I open (from Korn to Metallica to Entombed...yeah metal tunes)

At 16,137Hz, the db's drop like there's some sort of brickwall at that frequency. Is this the case??

Whats the benefit? (I'm new to all this) Is it simply
an eq set to brickwall around that frequency? Side chain of some sort?

Just wondering. Thanks

What sample rates are these encoded at?

Devon

Judging by the value he posted, it's 192kbps. At 128 you're looking at a cutoff of everything above 13khz or so. Obviously the higher the bitrate, the less hifreq cutoff there is, but even at 320 you're still looking at losing freqs above 20khz.

I see. So it's not something intentional....

Thanks for the quick replies guys.

It's intentional in the MP3 compression codec. MP3s drop frequencies in order to compress wave data to smaller file sizes.

Yeah, I get it now. (<--- idiot)

I thought it was intentional by the mastering engineer or something.....OKAY, I'll stop talking now

I think it's because Bob Rock sucks as a producer.

Steven West wrote:

I think it's because Bob Rock sucks as a producer.

No comment...

Devon

ArneyS wrote:

Judging by the value he posted, it's 192kbps. At 128 you're looking at a cutoff of everything above 13khz or so.

Where did you get these values from? Doesn't it depend on the encoder?

I use LAME and iTunes to convert to 128kbps MP3 and I haven't noticed any high frequency loss... and I'm pretty sure I'm not deaf. I can hear up to 19kHz.

Forever,




Kim.

Talking of an nonintended brickwall, are there any good highpass brickwall filters out there, that say cut everything under 20hz, nothing over that treshold.

lame supposedly go to 19k, and with -q0 option it sounds more air, even 128k.