Question On Bob Katz Mastering Book

[iangomes]

So I was doing a little educational reading last night and got a little confused in the whole calibrated monitor/k-system section. Here's what I remember...

So You have a VU meter to measure rms and a digital meter. You set the VU meter to be 0 db at -20 dbFS (because the crest factor of most recordings will never be over 20 db). Okay now I've just confused myself a little here.... because if your music is mastered at all, you'll pin the meter. Unless you have to turn music up until it is at 0 VU with your monitor control. That sort of makes sense. Except I thought you were supposed to set your monitor control to Odb.

Okay, onwards... So now I've got my music playing through. Now I beleive the next step was to turn down the monitor control and begin to add some compression. Is the idea that if you are at 0 VU, you turn the music down the same db as the loudness that you want to achieve?
For example:
If I want to make the crest factor of the material 12 db, I need to turn my monitor control down 8 db, then add processing until the VU is back at 0db. Right?

As you can see, I'm a little mixed up. Any help would be appreciated. Maybe I'll read it again.
Thanks!

[sinchi]

It's been a while since I read the book, but I'll try to answer anyway...

The crest factor will rarely be over 20 db. So, your VU shows 0 db (when it's calibrated like you mentioned) before it will digitally clip. If the rms is -12 dbFS the VU will show 0 db, if the rms is -24 dbFS the VU will show -4 db.

If I remember correctly the point wasn't achieving theoretically accurate readings. The point was that you'll never clip (digitally) even if you only read the VU's (and see that it won't go over 0). You have plenty of dynamic range in digital recording, so you don't really have to worry about losing a few dbs.

Hopefully that helps.

Cheers,
Ville

[iangomes]

Originally Posted by sinchi

It's been a while since I read the book, but I'll try to answer anyway...

The crest factor will rarely be over 20 db. So, your VU shows 0 db (when it's calibrated like you mentioned) before it will digitally clip. If the rms is -12 dbFS the VU will show 0 db, if the rms is -24 dbFS the VU will show -4 db.

If I remember correctly the point wasn't achieving theoretically accurate readings. The point was that you'll never clip (digitally) even if you only read the VU's (and see that it won't go over 0). You have plenty of dynamic range in digital recording, so you don't really have to worry about losing a few dbs.

Hopefully that helps.

Cheers,
Ville

do you mean if the rms is -20dbFS the VU is 0? -12dbfs would be -8db on the VU.
so how does the K system work then? Is it a system to make sure you decrease the crest factor by a certain amount?

Thanks for the help!

[sinchi]

-12 dbFS would be 0 db in the VU, and it would very possibly be clipping digitally.
-18dbFS would also be 0 db in the VU, and it might clip digitally.
-20dbFS would also be 0 in the VU, but it will not clip digitally.
-24dbFS would be -4 db in the VU.
-28dbFS would be -8 db in the VU.

So, the point is that if you are only looking at the VU and you make sure it's not hitting 0 db, you wont have digital clipping.

Sorry for the unclear explanation...

I don't remember k-system well enough (and I cant read the book in the next few days), so I'll let somebody else answer...

Cheers,
Ville