Preamp - Compressor Relationship

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bdam123

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So I'm new to getting a quality vocal and just invested a good amount of money into a new chain. Its a Telefunken AK-47 -> a BAE 312a Pre -> API 527 Comp

My first question is about the gain knob on pre. What exactly is its function? I had to have it all the way down because having it up at all got the signal too hot.

For whatever reason I feel as if having the knob all the way down wasn't right so I turned it up and brought the output of my compressor down and balanced he signal that way. The only thing is that by doing this I'm actually bringing up any quiet stuff in the signal right? Super confused.

I understand that a lot of you are gonna give me the "use your ears" or "if it sounds right its right" thing but I would like a little more guidance into whats going on in terms the relationship between the gain knob on the pre and the output of the compressor. Does adjusting at each of these gain stages gonna make a significant difference in the signal.

Thanks for anyone that takes out time to help me out.
 
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In broad terms, the pre-amp is required to raise the low-level mic sound signal mic up to something closer to "line level". The gain knob controls the amount of amplification that the preamp applies to the input signal.

So, the hotter (higher) the signal coming from the mic, the less amplification required from the preamp.

If your signal is too hot even with preamp gain at lowest, then you might need to reduce the input signal with pad. I think that your pre-amp has a 20dB pad switch, or you can just get an in-line device. The pad just attenuates (reduces) the input signal by a nominal amount, say 20dB.

The compressor should (in my opinion) be used to control and shape signal dynamics, not tame an over-hot signal.

I'm curious to know what you are recording that produces such high SPL's.

Paul
 
So I checked my pre and the pad was engaged. That means that I'm attenuating the signal right? So even with pad engaged and the gain all the way down the vocal was still peaking at about -3db on my Pro Tools meter.

Is boosting the gain on my pre going to add more of its color as compared to having it all the way down? The way I can even begin to boost the gain knob is if I lower the compressor output a significant amount.
 
bdam123 said:
So I checked my pre and the pad was engaged. That means that I'm attenuating the signal right? So even with pad engaged and the gain all the way down the vocal was still peaking at about -3db on my Pro Tools meter.

Is boosting the gain on my pre going to add more of its color as compared to having it all the way down? The way I can even begin to boost the gain knob is if I lower the compressor output a significant amount.
Click to expand...

It's all part of your gain staging. Your Pre is going into the compressor, right? Where is the INPUT on your compressor? Where is the OUTPUT of your compressor?
 
RAMI said:
It's all part of your gain staging. Your Pre is going into the compressor, right? Where is the INPUT on your compressor? Where is the OUTPUT of your compressor?
Click to expand...

I dont understand what your're trying to get at? So is there no difference where I choose to boost or attenuate my gain?
 
This sentence...

The way I can even begin to boost the gain knob is if I lower the compressor output a significant amount.
Click to expand...

...would lead someone to believe you have the mic going into the compressor then out of the compressor into the mic pre. You should have this:

Mic> Mic pre> Comp> Converter> Computer

You should use the compressor sparingly if at all. Set the mic pre up as if you didn't have the compressor inline. The gain on the compressor is called Make-Up gain. It's meant to bring levels back up to normal after chopping them lower with dynamic reduction.

There's an article floating around somewhere about gain staging. It's a good read. Where was that thing again?? Try this link ....

peace,
 
Chili said:
...would lead someone to believe you have the mic going into the compressor then out of the compressor into the mic pre. You should have this:

Mic> Mic pre> Comp> Converter> Computer
Click to expand...

Yea thats how I have it, the only possibility is if the manufacturing of our housing unit mixed up the wiring for the mic inputs.

Yea thats what I thought about the "output" on my comp. Even at 0 on the comp I have to have the gain on my pre all the way down. So essentially I'm compressing lightly but can't bring the make up gain up.

Thats why I'm confused. Is there such a thing as using a pre with the gain all the way down? My pad is engaged too. This doesn't make sense to me.
 
bdam123 said:
Yea thats how I have it, the only possibility is if the manufacturing of our housing unit mixed up the wiring for the mic inputs.

Yea thats what I thought about the "output" on my comp. Even at 0 on the comp I have to have the gain on my pre all the way down. So essentially I'm compressing lightly but can't bring the make up gain up.

Thats why I'm confused. Is there such a thing as using a pre with the gain all the way down? My pad is engaged too. This doesn't make sense to me.
Click to expand...

It doesn't make sense. What are you sending the pre? That is what are you recording ..... voice, piano or cannon fire?







:cool:
 
Do you have a preamp on your converter? What is a "housing unit"? And what is your converter?

Try disconnecting the compressor completely, and just go mic -> pre -> converter -> PC.

And what other troubleshooting have you tried? For example, have you tried connecting equipment one at time to check response? Have you checked your software settings eg in protools, your converter's software mixer? Do you have other equipment that you can experiment with?

Normal vocals really should not overload a pre-amp with 20dB pad on and gain at minimum. Maybe if you were _firing_ an AK-47...
 
It's not unusual to have 10, 15+ db gain at min on pres, plus the mics (condensors) start with a strong signal to boot. Sometimes folks will use a pad after the pre to allow driving them harder (assuming soft clip/saturate.
I often have to use pads on the Precision8 (+15 min, no saturate but the 7602 does but has an output trim..
This was easy to find-
http://www.gearslutz.com/board/so-much-gear-so-little-time/450025-brent-averill-312a-mic-pre.html
Check out down around post 10--12.. +30? :p;)
 
PRHunt said:
Do you have a preamp on your converter? What is a "housing unit"? And what is your converter?

Try disconnecting the compressor completely, and just go mic -> pre -> converter -> PC.

And what other troubleshooting have you tried? For example, have you tried connecting equipment one at time to check response? Have you checked your software settings eg in protools, your converter's software mixer? Do you have other equipment that you can experiment with?

Normal vocals really should not overload a pre-amp with 20dB pad on and gain at minimum. Maybe if you were _firing_ an AK-47...
Click to expand...

I'm using an MBox mini for my converters. I have it going in DI so I'm pretty sure that means the pres on it are bypassed.

The housing unit is the rack unit with slots that the pre and comp slide into. API makes one called the Lunch Box I believe. We have one called the 500 HR made by A designs. I'm guessing the correct term for it would be a "frame".

Yea we made sure each component worked before we connected it all together. We're in the middle of recording someone right now and it sounds pretty good to me. I just have a feeling its not totally functioning as it should. I'm gonna wait til these sessions are over and get back on here. Any more info would be awesome.

Mixsit, thanks for the link btw.
 
BTW, what is your DAW, recording medium's input level set to.? ( ie..-10 or +4)
 
snatchman said:
BTW, what is your DAW, recording medium's input level set to.? ( ie..-10 or +4)
Click to expand...

I have to apologize cause I'm a complete newbie but if we're talking about the pads on on my Mbox mini and having it engaged means -10 and unengaged means +4, than we have it at +4. Should that be engaged? I guess that makes sense. Even if though, the -20db pad on my pre is engaged.
 
So i've been reading around and the consensus is the BAE 312a is pretty hot. There are more people saying that even with the gain all the way down they are still getting a healthy level out of this pre.

My only solution is to engage every pad I have and bring the output down on my comp. My concern now is with using the comp's output to bring everything down. By doing this I know I'm not bringing any of the lower passages up in the vocal. This has to be a bad thing but I can't think of any other way to bring the signal down besides keeping the gain on the BAE all the way down. Still confused.
 
bdam123 said:
I'm using an MBox mini for my converters. I have it going in DI so I'm pretty sure that means the pres on it are bypassed.

The housing unit is the rack unit with slots that the pre and comp slide into. API makes one called the Lunch Box I believe. We have one called the 500 HR made by A designs. I'm guessing the correct term for it would be a "frame".

Yea we made sure each component worked before we connected it all together. We're in the middle of recording someone right now and it sounds pretty good to me. I just have a feeling its not totally functioning as it should. I'm gonna wait til these sessions are over and get back on here. Any more info would be awesome.

Mixsit, thanks for the link btw.
Click to expand...

Hello..When you say you are going into the DI on the M-Box, is this a " real" instrument level DI ..? If so, this maybe some of your problem as instrument level is different than line-level..Also, is the DI input balanced..?..Do you have a " true" balanced line-level input on the M-Box..?..As the signal chain you have has a very hot output and I think you are fine until you come out of the API because these have all balanced in/out levels..It's that DI input on the M-Box that concerns me..!.
 
bdam123 said:
So i've been reading around and the consensus is the BAE 312a is pretty hot. There are more people saying that even with the gain all the way down they are still getting a healthy level out of this pre.

My only solution is to engage every pad I have and bring the output down on my comp. My concern now is with using the comp's output to bring everything down. By doing this I know I'm not bringing any of the lower passages up in the vocal. This has to be a bad thing but I can't think of any other way to bring the signal down besides keeping the gain on the BAE all the way down. Still confused.
Click to expand...

I would presume the output fader on the comp would be after compression and you'd be able to trim the whole thing there(?) Your threshold and point of gain reduction sould be a decent indication of the the level out of the pre.
 
bdam123 said:
I have to apologize cause I'm a complete newbie but if we're talking about the pads on on my Mbox mini and having it engaged means -10 and unengaged means +4, than we have it at +4. Should that be engaged? I guess that makes sense. Even if though, the -20db pad on my pre is engaged.
Click to expand...

+4 and -10 are almost certainly operating levels, not a pad. If you set it to -10 it will expect a much lower level than if you set it to +4.
 
snatchman said:
Hello..When you say you are going into the DI on the M-Box, is this a " real" instrument level DI ..? If so, this maybe some of your problem as instrument level is different than line-level..Also, is the DI input balanced..?..Do you have a " true" balanced line-level input on the M-Box..?..As the signal chain you have has a very hot output and I think you are fine until you come out of the API because these have all balanced in/out levels..It's that DI input on the M-Box that concerns me..!.
Click to expand...

So I checked the specs for the Mbox and the 1/4' DI ARE meant for instruments.
Also the inputs are unbalanced. So I'm guessing that means it doesn't have a true balanced line level input.

I've also discovered that there is no way to bypass the internal pres of the mbox. Is this also presented a problem for me?
 
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