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unity gain

PostPosted: Mon Apr 07, 2014 2:37 pm
by garrett21allen
Crash or Peter

this may sound silly. when I play a CD that has been mastered and I have the gain
at unity and the channel faders and the left/right output at unity. it shows the channel
and the output level at around -15 . and I do the same thing with a mastered cassette
the reading is around -20 or -25. so what I am asking is when I do say a vocal with a
sing a long track without it being mastered should my levels be around the same
as the CD that has been mastered. seems like when I am around the same levels
as the Cd without mine being mastered mine just seems louder than the mastered CD
so without mastering why would mine be as loud as the mastered CD. I must be mixing
wrong after all these years. thanks for any thoughts please Peter or Crash Don't
be to hard on me.

Joe allen

Re: unity gain

PostPosted: Mon Apr 07, 2014 7:15 pm
by Casey_Pittman
What inputs are you using for for the CD track?

Re: unity gain

PostPosted: Mon Apr 07, 2014 9:57 pm
by Crash
Casey_Pittman wrote:What inputs are you using for for the CD track?


What he said..

Re: unity gain

PostPosted: Mon Apr 07, 2014 11:13 pm
by garrett21allen
Casey and Crash
I am using the line inputs on the CD track with channel gain at unity and
faders at unity and the master output at unity. on the mastered Cd it stays around -15
if I record say a vocal at -15 it sounds a little louder than the CD. I know I am doing
something wrong now because the mastered CD should be a lot louder than the vocal
I would think so anyway. thank you Crash and Casey

Joe Allen

Re: unity gain

PostPosted: Tue Apr 08, 2014 5:20 am
by Bruce Graham
Hey Joe;

So, without getting out my extended range meter and not having actually discovered where +4dbu is on the d8b as of yet, I would start by saying that "Unity" on the trim is around 0 or +4dbu.

So assuming you are going into the console at consumer level, and unbalanced (not that it matters), which is -10dbu, you would have to add 14 db of gain on the trim to equal "Unity" at the output. Again I haven't as of yet discovered what level the Mackie is set for.

According to the Manual, 0dbfs is +20dbu. So +4dbu should be -16 on the Meters. I will confirm that and get back to you.

I would hope that the CD you are using would maximize that 20db as most mastering processes do.

Long and short, as the CD is very much compressed and assuming you have know processing on the microphone you mentioned, I would guess, at this point, the difference is apparent loudness and not a real level difference.

I will attempt to measure the Mackie output level and determine where +4dbu sits and get back to you. It may take a couple of days but I'll do my best.

In the mean time, a good rule of thumb is to "fill the meters" with about 2 or 3db of headroom and soft compression will help you with that.

Hope that helps and back at you soon with the spec.

Regards
Bruce

Re: unity gain

PostPosted: Tue Apr 08, 2014 1:47 pm
by garrett21allen
Bruce thanks for the information

one thing I might not be understanding the right way is
that in the Mackie manual it says to stay around -15 so when I play the CD
in say channel 23/24 and I have gain at unity and channel and master faders
at unity its showing around -15 is this not what it should be showing I have always thought
this was the right way. now when I have the vocal singing around -15 on the channel
and showing around -15 on the masters meters the vocals alone sounds louder than the
mastered CD. could I be recording the vocal to loud

thanks for any help with this because I am sure I am not doing something the right way
I have always thought that -15 on everything was close to 0db

Joe allen

Re: unity gain

PostPosted: Tue Apr 08, 2014 2:23 pm
by Bruce Graham
H Joe;

I will check it out (-15dbfs = +4dbu), and let you know, but, the rest of the headroom (from -15dbfs to 0dbfs), is used for transient peaks. As long as your levels do not go above 0dbfs you are good to go, and to reduce the analog and digital noise (yes thee is digital noise), the more signal you have the more the noise is "masked". Hence "fill the meter".

It is possible that -15dbfs is 0dbu, but the international standard for most audio is +4dbu.

At this point it is very difficult to say why the vocal sounds louder than the CD, other than, as I mentioned, apparent loudness.

I use Unity Gain as a reference as to how much more or how much less gain do I need to adjust the trim to have the signal be at unity. In other words, what comes in is what goes out.

The Line inputs of the d8b are a range from -20dbu to +22dbu with a nominal level of +4dbu at the unity setting. So, if a signal of +4dbu is input into the console, the Unity setting on the trim would give you +4dbu at the putput assuming all faders are at "0" (which means Unity. Neither adding nor reducing the gain).

Mackie wants you stay at -15dbfs, when recording, so that you do not run the risk of having your levels go over 0dbfs as any signal over that, in the digital world, is pure, 100% distortion (clipping). They want you to keep the 15db (-15dbfs to 0dbfs) as a protection area or headroom). With compression and proper mixer technique that headroom and be used to achieve a "louder signal during mixing.

I know this doesn't answer your question but hopefully it gives you the basic idea.

I'll get that info and be back here with what I find.

Regards
Bruce

Re: unity gain

PostPosted: Tue Apr 08, 2014 7:01 pm
by garrett21allen
Hi Bruce

thank you for taking the time to respond and thanks for all your help
if anyone else can help with this it will be good because all the information
I can get will just help me to understand this better. something I should
already know. my lack of knowing these thing is bad.

thanks again for any help.

Joe allen

Re: unity gain

PostPosted: Tue Apr 08, 2014 10:28 pm
by garrett21allen
let me just ask this

if you was to run a CD into the line input
what would most of you set your gain or trim to if the CD was mastered
I know everyone if different.

Re: unity gain

PostPosted: Wed Apr 09, 2014 4:40 am
by Old School
Hi All,
Most of my customers record with sing along tracks and I can tell you from experience that all cd's are not mastered equally or even in the same ballpark, with most of the Gospel tracks being the most poorly mastered. Loudness, apparent and other wise, seems to vary greatly. My advice is to mix with your ears and take your meters with a grain of salt. Just my opinion however, so take it with a grain of salt also.

Have a Blessed Day,
Mike W.