unity gain

[garrett21allen]

Hi mike

thanks for your input. since you record a lot of vocals with sing alone track
and I too think there all not mastered the same. do you mine telling me
about how you do record your sing a lone track with the vocals and how you use
unity gain. do you ad or take away or leave your gain at unity. I know everyone
is different but I would like to be close to the ball park of what most people are doing
I have always thought that anything you run at unity with all channel faders /master faders
at unity or 0 that's how loud it was post to be. boy I need to read a lot about this I think
I am thinking the wrong way about unity. I just hope I don't get raged out about not
knowing this already. thanks for any help Mike If you need to send any information to my in box
instead of hear that will be okay any kind of help is good

Joe Allen

[csp]

I am quite prepared to be shot down with the following posting:

When I did my audio/electronics training many years ago (we were still using valves, as ICs had not been invented) we were taught the following:

On a professional console the optimal input level was when everything was at about 75% of the fader's/pot's travel, so if you set the input trim control at about 75% of its travel (assuming that the input source was out-putting at a professional level -- today +4) and you then set the channel fader at about 75% of its travel, then the channel Vu meter should have read 0Vu (or in the old days the join of the red/black line). Now if you sent this to the master fader and set this to its 75% mark, then the output Vu on the console should have read 0Vu.

Have a look at the D8b and measure where the zero line is on the fader, you will notice that it is 75% up the fader's slot.

We were also taught that if you set up a channel this way and got the 0Vu reading then muted the channel and did the same for another channel and got its 0Vu reading, then muted this channel and continued in the same process with other channels, then you wnt back to the first channel and un-muted it (getting the 0Vu reading on the console's output Vu meter), then for each channel you un-muted to keep the 0vu reading on the main output Vu meter, you would have to reduce the level of the output fader by 3db.

Applying this principle to Joe's initial question, we were also told that you should always keep the signal for each channel as high as possible without having to lower the main output fader by more than about 6 - 10db, because if you have to bring it down lower than this to keep the output Vu at arround the 0Vu position, then you were overloading the input stage of the output section and distortion could occur.

The important part being, not to really be concerned with exactly what input level was being received, provided the gain structure was in the general 75% region and that when every channel was combined (ie mixed together) the end result on the output Vu meter, was as near to the 75% level as possible and it (ie the mix) sounded as you wanted it to sound.

Now, if you consider that on a digital desk, at the 0Vu reading of a Vu meter you are going to get the dreaded "digital distortion", whereas as on (say) the older analogue consoles there was always the "red" (ie +Vu) section above the join of the black/red point (ie 0Vu) and this was at about 75% of the Vu meter's travel, having the zero line on the faders on consoles such as the D8b where it is (ie at the 75% mark), this point being effectively at about -12 to -15db below the 0Vu point, allows for the equalivelent the "red" section on an old professional analogue console, where you could place peak signals above the black/red 0Vu point without getting any real distortion.

It should also be considered that although we are now working in the digital age, all our audio recording/mixing standards, processes and procedures, were set up and designed at least 50 - 60 years ago, by organisations such as the BBC, RCA, etc who were all designing and using very professional analogue consoles, recorders and outboard equipment and they had to ensure that all the equipment used had the exact same level gain structure.

As a result of the above, if everything was exactly correct, then the CD being played when the console is set to the correct gain structure, should sound exactly the same volume as the live recording you are doing, BUT having said that and all before it, in my case I go from my D8b to an Alesis Masterlink with all levels set at the correct input/output/Vu levels, but if I burn a redbook CD on the Masterlink (even if I fully normalise the material before burning) and play this CD back through my home Hi-Fi system, the level through the speakers is considerably lower than that on a commercially bought fully mastered CD, but playing back the song recorded from the D8b onto the Masterlink's hard drive back into the D8b's digital inputs, the level is the same as it was during the recording process --- go figure!!!!!

Sorry the posting is a bit long (!!!) but I hope it gives something to think about.

David

[garrett21allen]

Hi David

thanks for explaining that. now I have ten guys with ten guns
ready to shoot you down LOL. for some reason I have always thought
that when ever you put a channel At unity that what ever come in is how
loud it was recorded because at unity is not adding or taking away
anything what goes in is what comes out at unity. so the way I have been thinking
is the wrong way. I am a slow learner but with the help of the good people on this
forum it will sink in I am just slow. thanks for everyone's help

Joe Allen

[Bruce Graham]

Hi David;

Spot on with the Techy info. I was a CBC TV Audio Engineer and that 75% mark you speak of is the RMS (Root, Mean, Square) value of an audio signal, which 0, on a VU meter, represents your reference level. Regardless of what your reference is (+4dbu, + 8dbm, etc). It is understood that all meters (VU & PPM's) within your system are all calibrated to your reference standard.

It is all about understanding reference levels (whatever they may be) and adjusting the gain of your source to match your reference level, then unity gain there after. Taking into account headroom. The more headroom one leaves not filled, the quitter the loudness will be. With compression, one can utilize that headroom and make the apparent loudness more, without altering your reference level.

The d8b has a reference level of about -15dfs to be +4dbu, giving one 15db of headroom. (I'm working on proving this).

With CD's, I believe, the secret to achieving maximum level without distortion, thus the apparent loudness lies in the Mastering process.

Regards
Bruce

Regards
Bruce

[garrett21allen]

Hi Bruce
thanks for the information it helps a lot
anything I can learn about this will be good

Joe Allen

[Bruce Graham]

Hey Joe;

I should have mentioned it on my first post, but Yamaha has a great book about Audio called "The Sound Reinforcement Handbook". It has a very good section on "audio levels" and gain "structure through" the audio path as well as a wealth of information about all thing audio.

Forth the investment for the curious mind.

Bruce

[garrett21allen]

Hi Bruce
thanks for the information on that book
I will see if I can get one by next week
because I do need to wrap my head around this thing
some people can learn stuff like this real fast I am one that's just a slow
learner its always been that way for me in life. but I do try

Joe Allen

[doktor1360]

Hi Bruce
thanks for the information on that book
I will see if I can get one by next week
because I do need to wrap my head around this thing
some people can learn stuff like this real fast I am one that's just a slow
learner its always been that way for me in life. but I do try

Joe Allen

Joe... as long as you take one step everyday toward your goal, whatever it is in Life, you're making Progress, man...

Respect, Brutha!

Peace

[garrett21allen]

Hi Dok

thanks man