Gain Staging

[music293]

I am currently trying to explain why proper gain staging is so important at all points through out a mix, and why you would want to leave about -10db of headroom on your final mixdown before mastering to a friend and I am apparently not doing a very good job.

I was wondering if anyone could explain this in a better fashion, or if anyone can point me in the direction of some good reading material on this subject?

Thanks in advance!

-Matt

[Link555]

So how are you explaining it?

[Codemonkey]

Errr..... make them read this blog post by the guy from Massive Mastering.
Aha! found it.

HEADROOM
You cannot get enough of it

[music293]

So how are you explaining it?

Well, simply put, I am explaining that if you record a track as hot as you can and begin adding your compression and e.q. to (generally) increase the db output all while constantly lowering the fader on a track is in the end sonically squishing your track.

Also, that when you reach your master fader with your main mix, you want to be peaking (again, generally) at about -10db. This will leave you with enough headroom to send over to a mastering house, or apply your own in house master technique without distorting/clipping, or otherwise ruining your mix sonically.

[music293]

Errr..... make them read this blog post by the guy from Massive Mastering.
Aha! found it.

HEADROOM
You cannot get enough of it

This is good material, thank you.

Though I'm not sure it fully explains the importance of proper gain staging? It focuses more on the actual input, which is great, but I am also trying to explain when you bus your signal over to another channel or use compression/eq.

But thanks for the link!!

[Codemonkey]

Input is a gain stage.

Bussing, and every plugin, is also a gain stage. ;)

[Link555]

Well, simply put, I am explaining that if you record a track as hot as you can and begin adding your compression and e.q. to (generally) increase the db output all while constantly lowering the fader on a track is in the end sonically squishing your track.

Ok a few things to expand on here is:
The pre-amp- What is it function? It takes the lower voltage output of your mic and amplifies it essential to a line level. In gain staging it is important to put the main amplification as close to the orginal signal possible.

Here is why:
Say your noise in a given system is 10mV, and say your mics output is 20mV-100mV. When the mic transduces quiet sources at 20mV the 10mv noise will add in and be 1/3 of the total signal!

Now if you amplify the input signal as soon as it enters the system, by say 40dB (100:1) the input becomes 2 vollts. Now 2 Volts with 10mV on noise on it is 0.5% noise. This is not a real world example but it gives you the idea. Gain up front improves your signal to noise ratio.

Your Daw ADC input, after your mic pre, expects a line level signal. So as long as your average input signal is about -15dBfs your ok. Too hot and you may clip your ADC with transient peaks. To low and your noise floor gets closer. However in most ADC's these days the noise floor is very low. In the world of tape your have more noise and a higher noise floor to deal with.

In your DAW each insert, send and bus your send your signal too can be clipped. Maintaining a bit of headroom in each stage is a requirement, again -15dbFS is a healthy signal.

For mastering the ME need the Headroom to work in as well, the same all over again.

[music293]

Input is a gain stage.

Bussing, and every plugin, is also a gain stage. ;)

Of course! But that is my point.

Sonically speaking, taking a low input level track (say -12db) and compressing the heck out of it to +3db and then lowering the post fader by -3db before bussing it over to another channel is not the same as a high input level track (say +3db) and compressing/limiting it down to -6db and then raising the post fader +6db before bussing it over to another channel.

Maybe I'm way off base here, but this was my understanding?

[music293]

Well, simply put, I am explaining that if you record a track as hot as you can and begin adding your compression and e.q. to (generally) increase the db output all while constantly lowering the fader on a track is in the end sonically squishing your track.

Ok a few things to expand on here is:
The pre-amp- What is it function? It takes the lower voltage output of your mic and amplifies it essential to a line level. In gain staging it is important to put the main amplification as close to the orginal signal possible.

Here is why:
Say your noise in a given system is 10mV, and say your mics output is 20mV-100mV. When the mic transduces quiet sources at 20mV the 10mv noise will add in and be 1/3 of the total signal!

Now if you amplify the input signal as soon as it enters the system, by say 40dB (100:1) the input becomes 2 vollts. Now 2 Volts with 10mV on noise on it is 0.5% noise. This is not a real world example but it gives you the idea. Gain up front improves your signal to noise ratio.

Your Daw ADC input, after your mic pre, expects a line level signal. So as long as your average input signal is about -15dBfs your ok. Too hot and you may clip your ADC with transient peaks. To low and your noise floor gets closer. However in most ADC's these days the noise floor is very low. In the world of tape your have more noise and a higher noise floor to deal with.

In your DAW each insert, send and bus your send your signal too can be clipped. Maintaining a bit of headroom in each stage is a requirement, again -15dbFS is a healthy signal.

For mastering the ME need the Headroom to work in as well, the same all over again.

Link555, thank you, this is good advice, although I'm not great with some of the technical terms, the concept still applies.

[TheJackAttack]

snip ...high input level track (say +3db) and compressing/limiting it down to -6db and then raising the post fader +6db before bussing it over to another channel.

Hold on there cowboy. If you are tracking at +3dB then you are WAY TOO HOT. All your tracks should be peaking in the -15 to -6 dB maximum range. Period. Even if you were just throwing out numbers you should conceptually understand you don't track with peaks even at -1dB.

There is an active thread right now over in the mastering forum that says straight up if the peaks are at least -25dB (peaks not RMS) then you have enough gain for recording.

Even if we are speaking of a hypothetical live sound situation, you do not want any individual stick to get hotter than -10dB or so otherwise you will overload your sub mixes and main bus when everything sums out.