Subject:Surely this must be an easy one...

Posted by: JoeTesora

Date:8/12/2003 1:25:06 PM

I am using Sound Forge Deluxe which came pre-installed with my Sony Vaio. Right now, I am trying to transfer all of my CD tracks to MP3 to upload into an MP3 jukebox for my family room.

At first, I was unhappy with the results since (obviously) every CD is mastered differently and the resulting MP3s were all over the place in terms of volume level. Then I studied the program a bit and learned about Normalizing. I thought this was my magic solution. However, I am still having problems.

For instance, I "caught" a CD track and Normalized it. I "Saved As" an MP3 (with CD Quality Audio and so forth) and was generally satisfied with the result - however when I proceeded to "capture" the next track (from the same CD) and repeated the process (exactly) THIS track is getting Clipped all over the place after it is converted to MP3.

I guess my questions are: is there (please) a digital equivalent of the old "Record Level" switch on an analog tape recorder (where the user can augment and control the level of each track as needed to create a standardized OVERALL volume level on the finished compilation) and if not, what is it I am doing wrong?

The reason I am also confused is when making MP3s of tracks from very old CDs (when the mastering was low and dodgy) I conversely want the volume INCREASED to match current mastering standards, also without clipping. While this is something that a baby could do on analog circa 1985, I for some reason am an adult failing to do so digitally in the 21st century.

All I want is for them to all sound about the same coming from the jukebox, without Clipping. Help.

Joe

Subject:RE: Surely this must be an easy one...

Reply by: kbruff

Date:8/12/2003 1:42:41 PM

well - first of all the Normalizing routine is done on a file by file basis. What you need to do is this....
(1) Record all the tracks from your cd, into a single wave file (I know it will be a rather large file).
(2) Insert regions where you would mark the start and end of the tracks
(3) Then apply the dynamic compressor
(4) this tool will boost and reduce the volume accordingly
(5) it will also prevent clipping and distortion will be at a minimum
(6) export the resulting regions as separate files and then you are done
(7) If you have batch converter - use to batch process the wave files into mp3's

You see SF6 is awesome tool, but you just need to go through additional steps -- that is why it works so well - You can do whatever you want if you know how

Let me know --- how it goes

Subject:RE: Surely this must be an easy one...

Reply by: msterlin

Date:8/12/2003 3:44:21 PM

There are complications when converting to mp3 that you might find interesting. I've just completed ripping 450 CDs and there are some things i've discovered along the way...

1. As you said, there is wide variation in mastering among CDs. CDs recorded in the 80's up till about 1995 are generally conservative and have average RMS power of between -16dB and -18db. These also generally have good dynamic range. CDs mastered in the late 90s till today are compressed to death, have little to no dynamic range and have average RMS power levels between -10dB and -12dB (there are exceptions of course).

2. The mp3 conversion process will alter the RMS power somewhat. Conservatively mastered tracks will often go DOWN slightly. For the heavily compressed tracks, if it looks like a solid rectangle at the normal zoom ratio of 4096:1 it will almost certainly clip when converted to mp3 unless you peak normalize to -1db or lower (and even then it will sometimes clip as the conversion to mp3 will raise the peaks right back to zero).
These tracks can't be 'uncompressed' (as far as i know anyway) so you would have to use them as the reference level for the quieter tracks which might make those quieter tracks unbearable when they are raised to the same level.

So you can normalize all tracks to the same/similar RMS power value or use dynamics as suggested but you still may get clipping. The only real way to avoid clipping altogether is to normalize, convert to mp3, and play the file - if it clips and you don't like it, do it again with a lower peak value. Personally, I've given up on the idea of having all tracks at the same volume level due to these problems. It would be nice to have a dynamic compressor that compresses during playback like the radio stations use so we wouldn't have to worry about the loudness issue.

Subject:RE: Surely this must be an easy one...

Reply by: Geoff_Wood

Date:8/12/2003 3:51:37 PM

Joe,

The clipped track - chances are it was clipped before (the recording) and now it is noticable because it's louder. Unless you've slected normalising to an RMS level rather than 'peak'. The RMS option needs care to avoid clipping.

What you want do do with the 'mastering levels' is evil and not musically valid. Check out this article on the current trend towards 'hypercompression' , but if you can listen to mp3s, well, what the heck...

http://www.prorec.com/prorec/articles.nsf/files/8A133F52D0FD71AB86256C2E005DAF1C


geoff

Subject:RE: Surely this must be an easy one...

Reply by: JoeTesora

Date:8/12/2003 5:34:37 PM

Pardon my misuse of the term Mastering. I don't wish to change or subvert the intention of the original composer/arranger/producer. I just want everything to be of equal volume during playback.

J

Subject:RE: Surely this must be an easy one...

Reply by: drbam

Date:8/12/2003 6:25:07 PM

>>I just want everything to be of equal volume during playback.<<

Due to the sometimes radically different dynamic range and sonic character within various CDs, even if you worked hard to get the volume equal, they won't necessarily *sound* equal. However, with some work you can probably create an acceptable compromise.

drbam

Subject:This is in the wish list....

Reply by: JTelles

Date:8/12/2003 8:20:36 PM

>>I just want everything to be of equal volume during playback.<<

In order to get that you need an edit operation like the "GROUP WAVEFORM NORMALIZE" that is found in Cool Edit Pro. There have been a good number of months since I first suggested Sound Forge could have a similar edit operation.
Roughly, it calculates the RMS average of all files and AUTOMATICALLY runs a certain RMS normalization (with a little limitting if needed) for each file. The desired result is ending with a perceived (it also puts emphasis on the mid frequencies to achieve this) equal volume for the whole batch of songs. It works great for a complete set of songs you want to burn in a CD.

JTelles