Subject:mp3 encoding clipping

Posted by: leedsquietman

Date:8/11/2006 12:42:50 PM

I've noticed that after mastering a wave file in Soundforge (with limiters to -0.3 db) and it working fine and never going above the -0.3 limit, that when I encode to mp3 using Soundforge that clipping is occurring.

Typically I encode mp3 at 192 Kbps on the highest quality setting and on 4 different songs it pushed the mp3 to 0.0 and several clips on 3 songs and to 0.0 (no clipping left channel) and -0.1 (no clipping right channel) on the other. In other words, the mp3 was adding gain of approximately -0.3 compared to the original .wav file.

When I encoded one of the same wave files, masterd to -0.3 db using CD Tag (which uses the Lame encoder as opposed to Fraunhofer in Soundforge) at 192 Kbps best quality, it pushed the ceiling up only to -0.2 db with no clipping.

Any suggestions/comments welcome !

Subject:RE: mp3 encoding clipping

Reply by: Geoff_Wood

Date:8/13/2006 6:17:44 PM

Suggestions ? Knock your level back a few dB, or use LAME.

geoff

Subject:RE: mp3 encoding clipping

Reply by: leedsquietman

Date:8/14/2006 10:26:39 AM

Thanks Geoff. I like the integration of using Soundforge for mp3 considering I master my recordings with it, so it's a pity that these problems are occuring, I will try using Cubase to rip the mp3 as it also has the fraunhofer mp3 codec and see if it occurs there too - if so, I guess the codec is the problem and will use Lame.

As for dropping off the dbs - well, most commercial CD's are limited at 0 db or -0.1 db, I think that -0.3 is fairly conservative and I need my mixes to not sound too weak - I accept that I don't have the tens of thousands of dollars of mastering room equipment to pump up levels to an average like the newer commercial CD's (like -6 average db) and I don't like them that hot anyway, dynamics are lost, but I do like my recordings to come in at -10 / -11 db average so they sound loud and clear without too much loss of dynamics. I have some great plug-ins and the the wave file for CD burning sounds great.

What I might have to do is render one file designed for 16 bit wave/44.1Khz for CD and then undo and drop off to -0.6 db limiting and use this for the mp3.

Subject:RE: mp3 encoding clipping

Reply by: Geoff_Wood

Date:8/15/2006 3:41:50 PM

Mixes sounding weak is nothing to do with the peak level. It is to do witth the average RMS level as you touch on. A file peaking at -1dB or less can easily sound just as loud or louder than one normalised to -0.3dB .

And it is the *resultant* file that you want to optimise the peaks to on, so adjust the source to whatever works !


geoff