simple tip about levels

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Vurt

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With so much to always learn and improve upon, and because I'm my own worst critic, it's not often that I take notice of the baby steps and feel a real sense of accomplishment. One thing I learned over the summer, though, still has me doing just that, and it's something I should have picked up on a couple years ago when I started recording.

When beginning a mix, first crank the master fader/monitors, and then adjust the individual channels from their lowest position.

This must be common knowledge among a lot of you, but I thought I would mention it for anyone who may be in the habit of keeping the master somewhere in the middle and overdoing the channel faders.

I just mixed another set of songs, and still can't believe how much of a difference it makes.
 
Crank them?

Am I misunderstanding? I always try to keep the master faders consistent with the levels on the mastering source. For example, I put the master faders at 0 to 3db and make sure my DAT machine registers as close to that same range as possible. Then I bring the channel faders up. I found that keeping levels consistent ensured I was getting the most out of my recording source both in clarity and stereo imaging..

Are we talking the same thing, or am I doing something wrong?
:confused:

Cy
 
I keep my master fader at 0db until maybe until the very end if I notice I can get an extra .5 to 1 db on the mix..ill do that instead of going thru all the faders and pushing them up a tad.....if its more than 1db that i need, ill go thru the tracks individually....I dont know why I do it, I just do........maybe someone who knows what the hell they are doing will tell us what is best.......
 
On high-end console, fader linearity is not much of an issue, but on mixers in the budget to the project studio level, fader quality can vary and usually the frequency response is NOT linear for the entire path of the fader pot. This means that putting the fader at the say -20 mark results in a different response curve for the the signal than at it's intended range (near the 0db mark)......

Also... the idea is to keep your signal levels wihtin the intended design limits of headroom. Putting the faders too low means you underutilize the summing opamps and lose in the S/N department. Push the faders too high and you push the opamps too hard, causing harsh distortion and graininess.

Incidently, I recently discovered the answer to an inconsistency I've always wondered about - it usually came up when Ed would mention headroom issues with Mackie mixers versus other consoles... He knows what he's talking about as do I, and yet, I've never heard the problems he's encountered in my own gear.

A good part of that contradiction is related to gain structure and not so much any limitation on mixer design. The issue relates to the signal levels the mixer is designed to operate on (+4 dbU in this case) and the digital levels many of us are using.

We all know that for digital recording, we try to get maximum bit count in our recordings, meaning we keep signals as close as we can to 0dbFS to ensure max. resolution... fine... what is not immediately obvious is the correlation between what that means in terms of actual signal level between the mixer and the digital recorder.

A typical 8-buss project-studio board, say Mackie or Ghost is designed to operate at +4dbU.... which means the board's meters are calibrated so that 0db represents the +4dbu ratio 1 volt. And for the Mackie - it allows 28db of headroom above that - a significant amount, actually...

Great... so what, you say.... well - translating that to our digital recorders meters we might mistakenly assume that 0 dbFS on the digital recorder corresponds to 0VU on the mixer meters given that the +4dbU gain structure is maintained to connect between the 2. And unfortunately, we'd be wrong......

The fact is that digital meters have been calibrated in much the same way as analog meters were (for historical reasons and to allow engineers very familiar with analog metering to feel comfortable in a digital setting). This means that when we send a signal that reads 0VU on the mixer over to the recorder, it comes in at the -15dbFS reading on the recorder's meters.

That in itself isn't a problem, except for the fact that we all want to maintain maximum digital resolution, so we really want the signal level to be up a good 10dbFS more at least to make sure all the bits are getting used.......... So we boost the output level of our mic pres (or whatever we're using to track with) to get the level in the right digital ballpark.......

OK... great - we've got max. digital resolution and things are sounding great.... no digital overs - we're laughing! Until............

...we wanna mix... we set the master fader at 0db - its optimal point by design and convention... we set our channel faders as needed... and we notice the signal is generally above 0db on the mixer main meters... actually - it's peaking quite a bit between +2 and 4db.... and we're not even trying! OK... vocal needs to come up now we're peaking between +4 and +6db...

Ok... it's still sounding good... until we look at our digital 2-track (oh, let's say a Masterlink for example) -- digital meters again, and our hot signal is only hitting between -15 and -12dbFS on the 2-track! Gotta watch that digital resolution again........ bring those levels up some more! (and incidently, we're not even close to commercial cd levels at this point!)

Well... need more level out of the board, so we bring the faders up more, bring the master up more and get ourselves up another 4-6 db....

But what's really happening at the board at this point? We are already a good 10db above the nominal design of the the input channel level due to our getting the signals to tape at the requisite hot digital level... so our input channels now have only maybe 12-14db of headroom left... the summing opamps of the master buss is starting to feel the push, because the combined signal level of all those already hot tracks is really eating into its headroom, so that last 4db we want to get out of the board to send a hot mix to the 2-track really grinds the output headroom right down... and suddenly, your mix sounds like crap - distortion, graininess, muddiness.... all the characteristics that we attribute to lowly gear, when in fact, we're simply using it beyond it's intended usable signal range! (mainly because the although our mixer/recorder inputs are matched, the metering is not calibrated the same way, and desired digital levels do not corrolate to the design levels of the mixer!)

So what do we get out of this??? Since the scenario I described will not apply to everyone - it amounts to you really having to know and understand the signal levels that you're dealing with between recorder and mixer and to compensate or adjust accordingly in every phase of the recording process (tracking, mixing) -- otherwise, you're basically shooting in the dark as to what output level you're ending up with.

As a matter of fact, you not only need to know and understand your signal levels, you also need to have a good understanding of the levels your mixer and recorders are designed to handle and adjust your methods to get the best use out of them......

Sorry to interrupt your thread Vurt, but this was kind of related to your question.......

Now back to your regularly scheduled program.....

:)

Bruce
 
More bad news

Bruce,

And with the Mackie the direct outs on each channel are not balanced resulting in a 6dB drop in output to ADAT requireing us to reduce headroom even further on each channel.

I am building some balancing boxes to fix this. About 900$ per 8 channels. Wish Mackie would have done it for me. :)

Kirk
 
Some quoted material from the Artist Pro website...




" Some mixers have a suggested setting for input faders and track
assignment bus faders. This setting, referred to as the point of unity
gain, is typically indicated by a grayed area near the top of the fader’s
throw, by the letter "U", or numerically by a zero. Try placing the input
and track assignment bus faders to their ideal settings. Then adjust the
input preamp for proper recording level. This is a safe approach and
often works very well."

"Experiment with different approaches to find what works best with your
setup. No approach works every time, so remember to trust your ears. If
your sound is clean and punchy but the settings don’t seem to be by the
book, you're better off than if you have textbook settings on your mixer
with substandard sound."

"Confidence in your control of the gain structure can take time and
experience, so start practicing. See what happens when you try a new
approach."

" Peak meters are necessary for recording digitally, since our primary goal,
using a digital recorder, is to not record above a certain level with any
signal. When recording digitally, always try to obtain the highest meter
reading without going past 0. If digital recordings are made with levels
too low, the full resolution of the digital recording process isn't realized.
Low level digital recordings can sound grainy and harsh."

By Bill Gibson

Peace,
Dennis
 
Yes but you missed the point of my long diatribe above.... O VU as indicated in the mixer meters DOES NOT EQUAL 0 dbFS on a digital recorder's meters. Many people are not aware of this, and run into gain-matching/level issues...

Bruce
 
Absolutely right! In my rig, the various meters (on the board, on the various converter boxes, the input meters on the multitrack, the meters on the Masterlink, the inputs to the reverbs and other outboard gear) disagree _dramatically_, even when they claim to be calibrated to the same reference level. 0dB VU indicated on a meter somewhere is meaningless on its own, until a context is established.

The first thing I did was to set up my lineup oscillator, and calibrate _all_ the meters. Until you know what indicated signal levels correspond to actual behaviors, you're exposed to some seriously gnarly behaviors.

The meters that truly matter are the input meters on the digital recorders: you have to be able to believe them. 0dBFS is not just a good idea, it's the law (;-). I found that an honest 0dBFS on the Masterlink corresponds to +12dB VU indicated on my board's master out. Fine. And 0dBFS on a track input to my multitrack corresponds to a +10dB VU indication with the channel soloed on the 8 internal converters in the D1624, and +8dB VU on the 8 external channels in the AC2496 (even though they are set for the same "reference level", there's a perverse difference in the gain structure somewhere). The input levels for the outboard gear are all over the map, despite the fact that they all _claim_ to be built with +4dBu (ref) balanced inputs. And so on. Now that I know that, I can compensate for it.

The important thing here is not the exact relationship between 0dBFS and 0dB VU on any particular meter on any particular piece of gear in someone else's room. It is that you need to completely understand what the relationships are on _your_ meters, on _your_ gear, in _your_ room. What you find will suprise you in some cases, and dismay you in others. But once you _know_ what you're looking at, you can meter with much more meaning.

And in some degenerate cases, you may find that you actually need to add an external gain stage to allow that "supposedly" +4dBu gear to actually _drive_ a real +4dBu input with any headroom left over. Pretty much every pro studio has one or two bump boxes pasted in between pieces of Really Expensive Gear to handle this exact problem...

Until you do a lineup pass on the gear, the meters on anything but the recorders themselves are basically just Tokyo-by-night moving wallpaper. And if you're an analog guy, you know that even the recorder meters are meaningless until you line up the machine for the tape you're using that day. At least digital recorders do provide an _absolute_ reference: that's one good thing they've done for us all to simplify life...

The next step beyond that is to hook up your distortion analyzer and figure out what the headroom actually is inside a given box (with respect to a certain level of distortion) to see if the VU meters on the box even mean anything in _that_ context. Many don't, you know: maybe the thing is throwing 2% THD at an indicated -6dB VU... In that case, you just cover up the meters with black tape and ignore them, to keepsome helpful soul from seeing that the meters read low, and cranking the bejeezus out of the send to "compensate". But that's the advanced course.... (;-)
 
Im sorry Bruce,
I read your "diatribe" and found it useful for future reference when I have a Mackie high end console combined with ADAT digital recorders.

I read Vurt's post and I never made the assumption he was using digital recorders, maybe its because Im a newbie. I thought the post was simpler than metering discontinuities between analog high end consoles, digital recorders and other equipment.


Peace,
Dennis
 
Dennis, my initial post was much simpler and more along the lines of your follow-up. I don't have the experience and knowledge of many people around here like Bruce to convert my process to technical explanations, I just know that it's been working for me. Although I'm tracking to ADAT now, I still use my 4trk all the time and use the same approach - apply a heavy dose of Master fader, and then bring up the channels slowly. The scenerio Bruce went through could apply to analog as well as digital.

To be honest, I'm oblivious to all meters on all equipment with the exception of the recorder. Didn't start out this way, but I've found that trying to get perfect meter readings on effects boxes, pres, mixers, etc is just a fruitless and frustrating waste of time (probably b/c of the explanations of Bruce & Skippy) When mixing, I actually try to look at the equipment as little as possible to keep my head clear. Once I HEAR what I want, I ensure I'm not peaking out on the multitrack and I hit it. Usually takes a long time, but that's basically it.

I'm not about to go out and buy distortion analyzers and oscillators, but I may read the specs on my gear to see what is said about the meters, if anything.
 
Ouch! Get a handle on the signal chain meters, this is where it all happens! Go read one of my threads in the Newbies section titled Tip-o-the-week a few months back... good stuff, and good comments afterwards...
 
Good tips, TD.. thanks. I actually know most of what you mentioned in both, but have been burned so many times as a result of putting faith in meters vs. my ears that I just don't trust them much anymore. Except for the recorder, anyway. Could have something to do with shit gear, but more likely it's user error. Regardless, I'm able to get good, hot signals just by keeping my ears in the chain and my eyes on the last link of it - the recorder. I have no doubt that having more knowledge of what Bruce was talking about would help me out and enable me to effectively do the things you mention in your posts, but until then, I'll just keep doing the best I can.
 
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