Gain staging- just to be sure.

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dreib

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Even though Ive been recording awhile I always question myself when gain staging with my mixer to my interface. Here's my scenario-

Mixer DDA- I like these pre's and the eq is useful- subed to my interface

Tascam US-1641- This interface has been rock solid for me except I find the pre's brittle and unpleasant when turned up.

I only have so many line in's on my interface so Im stuck with using a pre into a pre if that makes sense.

So I leave the pre's on my interface left all the way down and gain stage from the mixer but I never really get where I should start with the level from each channel strip as far as the gain and the fader are concerned.

I just wanna make sure im getting the most out of my board signal wise, I know its not the best in the world but I can tell you its a lot better than just running straight into my interface, to my ears anyway.

Hope this makes sense!?
 
Hey dreib.
I'd recommend upgrading your interface to something with more line inputs.
Usually when people say they're running a pre into a pre, they mean a preamp line output into a line input on an interface, but one that uses pad-before-pre rather than true bypass.

As far as I can can tell you're literally just running a preamp line output straight into another preamp.
Whether it works or not, it's far from ideal.

Presumably this means you can't use phantom power should you choose to plug a mic or two direct into the interface?

Not really what you asked, but my $0.02
 
dreib said:
Even though Ive been recording awhile I always question myself when gain staging with my mixer to my interface. Here's my scenario-

Mixer DDA- I like these pre's and the eq is useful- subed to my interface

Tascam US-1641- This interface has been rock solid for me except I find the pre's brittle and unpleasant when turned up.

I only have so many line in's on my interface so Im stuck with using a pre into a pre if that makes sense.

So I leave the pre's on my interface left all the way down and gain stage from the mixer but I never really get where I should start with the level from each channel strip as far as the gain and the fader are concerned.

I just wanna make sure im getting the most out of my board signal wise, I know its not the best in the world but I can tell you its a lot better than just running straight into my interface, to my ears anyway.

Hope this makes sense!?
Click to expand...

Well if it sounds better to you, then so be it, but let me warn you about the way you are using that Tascam product... I have what I believe is considered an updated version of the 1641, the Tascam US-1800. You can not bypass the pre's on the face of the unit. Meaning even if you turn the pre's trim pot all the way down on the interface, and plugging your external pre into the pre's jack on the interface, your signal is still passing through that circuitry. No way around it unless you took it apart and rewired it, which I am not about to try. So, it is likely all you are doing with the above procedure is, yes perhaps adding the "colour" you admire from your external pre, but then also adding more noise floor to the overall signal. Of course, when you add outboard to the equation, you're always going to get more noise, but this may be a little too much noise doing it this way - I don't know, I haven't tried.

Perhaps that saturation is what you desire but with this signal flow, it's likely not adding anything musical that benefits the signal. But at the end of the day, who am I to judge, do what you like - just a heads up.

Here's what I do when I am plugging in an external mixer into one of my Tascam's 1/4 LINE IN JACKS on the rear panel. Mind you, this only work to get 2 channels from my mixer since it has no direct outs, just main outs.

Mic>XLR Cable>Mixer channel input>channel volume pot/fader at unity gain "0" (in the middle) and output (master) volume pot/fader at unity gain "0">pan pot all the way to the left or right>1/4" TRS cable from either Left or Right main output jack (depending on which side I hard-panned the track)>into Tascam 1/4" Line in jack on rear.

^^Keeping everything set as outlined above, I use the track's Gain knob (on mixer) and only the gain knob to get up to the proper recording level in my DAW. That's your pre-amp gain. Look down at your mixer while adjusting/tracking and make sure you're not clipping the mixer's input or output (your mixer should have meters for this). If you're clipping the front end (the gain knob) turn it down until it's not clipping on the mixer meter. But then if your DAW's level is now not as loud as you need it anymore, use the mixer's master output fader to get you a few more db until it's at the level you need.

Keep in mind, this is the hacked up way of doing it, but I manage to get good clean recording when going this route (not often). Using both my ears, and eyes analyzing a noise meter, there is barely any noise this way and in side by side comparison with the same track going through the cheap digital pre's on the Tascam, this method yields more sonically pleasing results to my ears. Less harsh in the top end and a little more bottom.

I hope this all made sense and helps you out in some way. Thanks.
 
and another point you didn't ask about but I think is relevant ...... turning gain all the way down on a mic pre isn't always the best way to go.
I use a Mackie mixer in my studio and live also and I've found that the Mackie pres sound MUCH better when they're turned up as high as they'll go before clipping. No, I don't want them to clip but when you turn them down too much they sound thin and sterile comparatively.

So while you want minimum noise and distortion ....... you're not always gonna get minimum noise at the very lowest settings and you definitely won't always get the best sound outta a pre at the very lowest setting.

All this stuff be's interactive and complex ......... what fun!!

:)
 
First off I know what I am doing isnt ideal, and I know I need an interface that has more line in's.

I know im still running thru the circuitry of the tascam, but if I leave the gain all the way down on the 1641, but increase the gain or fader from the mixer in my mind I should be getting more of the channel strip than the 1641 yes?, I mean thats what I have been doing and it seems fine, I just never know if I should set my gain at 12 o'clock and then use the fader to get my level or do like Recordmaster said, have everything at unity and then adjust the gain to get my recording level.

A new interface is in my future for sure.
 
You don't get any "less" of the Tascam pre by turning it down. The signal still goes all the way through. What you get is all of whatever the Tascam pre does when turned all the way down. That may well be different from what the Tascam does when all the way up, but its not any less of anything really.

RM's method is technically correct. You want to get as much gain as early in the signal path as possible without clipping anything along the way. The question is can your mixer give you enough clean gain to get a good level after being knocked down at the US1641? I don't know how much that Tascam attenuates (but I really need to figure it out for my own application) but it is at least possible that it's way too much, and you'll never get a decent level into the computer without distorting something (pre or mix bus or both) on the mixer. But wait! Are you actually routing through a bus for this, or just taking direct/tape outs from each channel?

You could run a test. Run a test tone of some sort into the mixer. First plug the mixer output into a line in on the Tascam and adjust the gain on the mixer to get its meter showing 0dbVU and record a little bit, or at least make note of the level in your software. It should be somewhere around -20db give or take a few. Now plug it back the way you had it and compare the new level. If you actually do get the chance, please report the results because I want to know.

Edit - OK, I checked the manual. It doesn't directly answer the question, but I used some deduction and think I figured it out. It says that for the Line inputs a +4dbu singal (should be 0dbVU on your mixer) gives 16db headroom. I'm guessing that means it will hit the DAW at -16dbfs. For the mic pres with the gain all the way down -2dbu signal will give the same 16db headroom. That tells me that there is the equivalent of 6db GAIN as a minimum on those pres. No attenuation at all. I take that to mean that you shouldn't have any trouble with getting healthy clean levels from the mixer. In fact, optimum levels on the mixer may be a little too hot for the Tascam. So, not exactly the best gain staging in the world (we'd rather get that 6db gain on the other side of the noise antenna we call a cable), but not far enough off to be a deal breaker. I haven't quite worked out what it means for my situation...
 
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Ok thanks, and not to be a smart ass, I know it works because Ive been doing this way for 2 years, but im glad you gave me all the details concerning the actual db's and stuff. I just know its not the best scenario to have so I was putting it out there to reassure myself and maybe get some better knowledge as far how to stage my levels.

Its awesome all the people here who are willing to help and to go even further with info that helps even more!

Thanks again guys!
 
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