Gain Staging

Scooter B

Scooter B

New member
Questions on Gain Staging.
(Blue Bear you have been a good source so far and anyone else out there)

(Forgive me if this has been covered in a previous thread just point me in the right direction.)

If I understand gain staging properly you generally want your cleanest/purest signal boosted at the earliest point possible with you best pre-amp possible. Seems simple enough in theory and the goal here is to keep the noise floor to a minimum.

Now my question. My 4-track manual (Yamaha MT4X cassette) recomends keeping the input faders at the 7 - 8 range. With my various budget pre's; two Sans Amp Models and an ART Tube Pac I can easily get enough clean gain (for DI bass, guitar and drum machine) with my input faders at 4 - 6 and just start to peg the meters... or I can preset the input faders at the recomended 7 - 8 range and get the same level on my meters by backing off on;
1) the output of the preamp,
2) the pre gain,
3) and/or the output level on the drum machine.

I know the amout of pre gain will or can color the sound and is a matter of taste/ desired effect etc. And I am NOT using the built in pre's for anything.

But what is the best rule of thumb on priority between keeping your input faders at a recomended range (ie 7 - 8) versus using your preamp output with your input faders at a less than recomended (ie 4 - 6)? I do not hear an obvious diffrence between the two options when I am tracking but I have a feeling there will be a difference in the two options by time you bounce, add effects and mix.
:confused:
 
The 3/4 markings (usually marked 0 on the larger consoles) on a board is usually the best place for the faders. Manufacturers use that spot as the best balance between noise and headroom in the circuit design.

So you put the fader at 0 (or 3/4, or 7-8) whatver they suggest, then turn your mic trims all the way down (meaning little gain is added) - then play your source. If it's a Sansamp, you need to play a bit with the balance between increasing the output of the SansAmp, and reducing or increasing the trim level. Whichever gives you the least noise and best tone is what you want to use.

The problem with varying the fader from the specified range is the degree of linearity that's lost (especially below) the mark. If you were to measure the freq response of the signal at different fader levels, you would see the response vary from point to point with the best response usually within the nominal range around 0 (3/4, or 7-8, or whatever.)

This is also why there is some logic in setting recording levels according to normal instrument balances (ie, the drum track is recorded much hotter than the guitar track), so that the console fader levels at mixdown stay within their best operating range. This isn't as advisable with analog recording of course, 'cos you do want to maximize recording levels - the degradation due to linear irregularity is less of a problem than the noise introduced by poor recording levels!

Hope this helps...

Bruce
 
Thanks Bruce,

That sort of helps....except I am all analogue at this point and my 4-track's built in mixer faders go from 0 (off) to 10 (full on). For the input signal they recomend keeping the faders between 7 and 8 and adjusting the built in pre's (wich I don't use of course) to adjust your levels after setting the input faders between 7 and 8 (although I do bounce to a Sony Mini Disc).

So from what I gather so far;
1. Keeping the input faders at the recomended range promotes linearity of frequency response

2. With Analogue recording keeping the noise floor at a minimum takes precedence over maintaining the linear frequency response (especially if you are forced to bounce tracks).

3. If there is no benefit in noise reduction by increasing preamp output and dropping your faders below the "nominal range" then stay with the recomended or nominal range.

Let me know if I got this right Bruce. Thanks

Scott

:)
 
So from what I gather so far;
1. Keeping the input faders at the recomended range promotes linearity of frequency response
Click to expand...
"promotes" - semantics but I would say "maintains" the response linearity. This is the point where the manufacturer designs the linearity to be the best it ever will be!


2. With Analogue recording keeping the noise floor at a minimum takes precedence over maintaining the linear frequency response (especially if you are forced to bounce tracks).
Click to expand...
Yes - with digital too, just that there's more room to play with, especially at higher word sizes. Again, recording quality is a much bigger factor as far as sound quality, than the response aberrations of the board, but it's not quite so simple because the best-recorded tracks in the world will sound like crap through a bad board! So it's a question of doing what you can with what you got and choosing the sound quality trade-offs where you have to, especially when dealing with budget gear.


3. If there is no benefit in noise reduction by increasing preamp output and dropping your faders below the "nominal range" then stay with the recomended or nominal range.
Click to expand...
That's probably safe to say.... bottom line is - if it sounds good, it IS good! By the same token, if you can't HEAR the noise, does it matter? Probably the only absolute rule to recording - let your ears guide you!

Cheers! :)

Bruce
 
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