Digital tracking levels question

[copperx]

Hi, I've seen multiple threads on "optimal" recording
levels when recording digitally in 24-bits. Many of the posts
say "calibrate your converters to -18dBFS". What does
that mean on a project-studio level converters that
can't be calibrated? That is, when tracking stuff, should I
watch the meters in my DAW so that the average
level does not exceed -18dB? or should I watch
peaks not to exceed -18dBs? ... I've made several recordings
with lower levels (previously I was hitting almost -3dB on
all tracks) and they sound significantly better, especially
when using some plug-in processing after the fact.

Basically I want to record with lower levels to leave more
headroom to the plugins and to not distort my preamps,
and I want to do this without losing resolution. Is the approach
I mentioned sound?

[Harley-OIART]

As this thread is very technical please I ask do not post an answer unless you really do know what you are talking about. Please for the sake of everyone here keep to facts only, and don't turn this into a 20 page thread.

With Respect,
-Scott

[prismtheory]

Peaks can safely be between -20 and -3 in a 24 bit system. It's fine. Use your ears...different preamps sound magical hot, and some you don't have to push...quiter levels are safer, especially when doing projects with large track counts. There's lots of discussion of this. Digital is NOT analog.

-Christopher

[copperx]

Originally Posted by prismtheory

different preamps sound magical hot, and some you don't have to push

Hmm ... I don't have any Neve 1073s yet ... just theoretically, do you think cheapo preamps would sound better at a low gain or cranked up? common sense tells me probably at low gain they will operate better ... that's probably why I'm hearing lower tracking levels = better recordings with my gear.

[pan]

Even cheapo preamps have a sweet spot between noisy and distorted;-)

Gain stageing is the answer:

Where's your 0VU? How much headroom does your system have? Will your system sound better at "lower levels" with more headroom? Will you raise the noisefloor (noticeably) by keeping more headroom? Where do you really peak in the analog domain?

It is certainly a fine line, but the line is not within the last dB of your converter!!!
Who runs his board within the last +20dB???

A good analog desk has a headroom of 25dB? (haha!) -18dbFS for 0dBVU seems allright.

Your low end mixer has 18dB headroom? OK: -14dB seems alright for that board!


Even ITB mixes should relate to some kind of "0dBVU":

The higher you set your "virtual zero", the more dynamics you lose...
so there is an analogy (is this the word what I mean?) between analog and digital.

Christopher, digital is NOT analog, but there are similar rules.

No Flames, please! I'm with you, Scott. Lets make this a good thread!


Ohh, and pushing a Neve is something totally different, than pushing your rosetta!

Niko

[copperx]

Thanks for the responses!

I think I'll make my question a little more specific ... I am using a Yamaha i88x interface, which has a Gain (!) knob on the A/D inputs (yes, these are not the preamps, I don't get it, but well...).

I don't know where to set that gain knob when I connect an external preamp to the interface's A/D inputs. Should I crank the preamp and set the A/D gain as low as possible? or should I set the A/D gain as high as possible and then set the preamp level so that my DAW peaks at -18dBFS?

Probably there will be a middle ground, but I don't know what to look for ...

[DigitMus]

Originally Posted by copperx

Should I crank the preamp and set the A/D gain as low as possible? or should I set the A/D gain as high as possible and then set the preamp level so that my DAW peaks at -18dBFS? ...

You should adjust the gain on the preamp to get the sound you want, then adjust the A/D, if you need to, to get within a few dbs of your -18dbfs target.


Just my 2¢...
Scott

[bmsander]

Originally Posted by copperx

Basically I want to record with lower levels to leave more
headroom to the plugins and to not distort my preamps,
and I want to do this without losing resolution. Is the approach
I mentioned sound?

yes. This is the right idea!

[Gomez]

There's a very interesting chapter on a book called "mastering Audio" by Bob Katz about this. I wish I could explain the concep to you right now, but I kind of forgot about it... Mr. Katz calls this recording level "the Cushion" as far as I remeber.

Try PSW, he writes there a lot. do a search on it....

Maybr I'll read it for tomorrow and post here again.

[ticohans]

Hey guys, I really don't want to muddy up this thread, but a quick question for the newbies like me that are reading "-18dbFS for 0dBVU seems all right" and thinking "-18dbFS... dbVU... what the HELL does that mean?!"

What kinds of things should I be searching for to learn about headroom, what headroom means in the digital domain, what the different units and abbreviations mean, and why I would ever want to calibrate my A/D converter?

Links, books, websites, any and all info is welcome.

And if people think it would be better for me to start an independent thread and delete this post, I'd be happy to. I just wouldn't have any clue what to call it!

[pan]

dBFS - dB Full Sample (0 dBFS is digital max) - digital dB

dBVU - reading on the VU-meter on your console or outboard (this is not a standard unit)


there's some more dB units like dBV, dBU but there's info out on the net...as a start:

http://www.digido.com/portal/pmodule...er_page_id=36/