View Full Version : How to I get a full bandwidth MP3?

10-26-2006, 07:50 AM
I've been listening to some 320k MP3s I acquired that I did not personally rip, and using a spectrum analyser the frequencies go right up to 20Khz, sometimes beyond.

I am stunned and puzzled by this, I am ripping all my original CDs on Alt Present Insane (which I assume is the best quality) and I only get response to around 18Khz before the frequencies beyond this start to roll off.

How on earth are people managing to encode such high quality files? I would really like to know, I have tried every preset and my MP3s never go that high.

Thanks, and if anyone can give me a reason how this is possible I'd be most interested since I work with audio a lot on the technical sound (sound mixing films, DTS CDs, etc).

Great forum, guys!

10-26-2006, 09:57 AM
How about not using any presets so you can manipulate individual settings separately?

10-26-2006, 10:53 AM
Well I assume some presets in LAME do cut off's on certain frequencies. There are switches in LAME to stop this sort of thing, but you would have to access them by the command line (such as -y). 320kbps is -preset-insane as far as I know, unless it does something else, but I didn't think it would.

The main thing is though, could you even tell the difference if those frequencies are there in the first place? Do you desparately need frequencies so high? I'm pretty sure my ears couldn't pick up frequencies over 20khz...

If it bothers you that much, why aren't you using a lossless format?

11-06-2006, 09:53 AM
I use preset insane but it still cuts off frequencies.

This is a mystery no one seems to be able to answer, and I cant see any LAME command lines that would trigger this either.

12-03-2006, 08:07 PM

Full Bandwidth

Tells the encoder to use full bandwidth and to disable all filters. By default, the encoder uses some lowpass filtering at lower bitrates, in order to keep a good quality by giving more bits to more important frequencies. Increasing the bandwidth from the default setting might produce ringing artefacts at low bitrates. Use with care!

12-04-2006, 03:11 PM
It also depends on what frequencies are present on the original recording!