Freesound Forums

Hi,
So I just got a new mixpre, and had some VERY silly mistakes when using it for the first time:

* I have a stereo x/y mic but had the panning for chan 1 and chan 2 on the mix pre set to center
* I forgot to turn on the limiter

So I won't do that again, but the reason I'm putting this post here is because I was very suprised by the gains on the mixpre. I heard elsewhere on here someone usually starts their gains at 12 o'clock and adjusts from there. But for me, things were so hot I couldn't even have the gains set to the first tick mark on their gauges. So this really gave me very little room to work with. It was kinda annoying and I'm wondering if there is any idea why this is?

When I mean little room, I'm talking about on the mix pre alone. I realize "unity" gain (i.e. no gain or attenuation?) on the R-09 is about 8? So I had it set there. But then on the mixpre, It seemed like the tiniest touch would put the peaks way down on maybe just the first green meter light, or the other way would put it easily into clipping area (since again I forgot to turn on limiting).

On the NT4, I removed the 9v battery and went with 48V phantom. Not sure which is better, so I figured I would try using 48V phantom cause I think I saw someone once say on here that was better. But I did turn on the "on/off" switch on the NT4 since it seemed like without turning that on nothing really comes out.

The other thing that was annoying was that in the dark (and probably I assume even in the light), making sure I turn the gains equally on chan 1 and chan 2 seems harder than I thought. I thought they would be distinct positions but they are 100% analog dials. I assume there's not much I can do there but I'll take any suggestions...

Thanks for any tips,
Justin

Hi,
What were you recording that the levels were that hot?

After my first post about the Mixpre, R09, NT4 set-up I have made a quite a few recordings . The levels on the mixpre have been right up to -12 (well into the red!!) and it all sounds fine to me. The gain pots have been all over their rotation, depending on what I was recording and at what range. I discovered may years ago that location is not studio and that faders cannot be preset to any level. After over a decade doing location recording for TV the most important device that you have is your ears. If you use them in conjunction with your meters you will get great recordings.

So what were you recording and at what range?

Cheers,

Euan

I have no knowlwedge of the equipment you're using, but the symptoms about the gain control being either virtual mute or fully open sounds like a broken track in the potentiometer: the knob acts more like a switch than an attenuator, however if the same symptoms occur in two different controls then it is either an extreme coincidence, or a broken PCB trace/wire or a short circuit that is common to both bits of circuitry is responsible. Of the top of my head I can't think of a common schematic arrangement where this could occur, but if somebody could point me to the circuit diagram of the mixpre (if it's on line) I will gladly check to see if the possible cause I describe could be responsible.

Location Guy
Hi,
What were you recording that the levels were that hot?

I was recording a rock show in a small bar. It was definitely loud (I always wear earplugs ) but I guess I was hoping that the mixpre would give me some range to work with. What I mean by that is, on the R-09, I can go up from unity (so > or I can go down (<= . 0 is still "off", but I think what the NT4 is putting out into the mix pre was so high that not very far off of "off" was already going to clip.

Maybe it's just that I need to reset my expectations on the gain knobs, but also I think what *may* have been the issue was that I was on "center" for both channels? Because it was summing both channels together, could that have caused it to be even hotter than normal (as well as of course making it essentially mono recording)? An easy experiment should help me figure this out tonight when I get home.

Here was the recording just FYI:

http://www.archive.org/details/RCPM2009-05-28.aud.flac16

Justin

Sounds like a really loud gig!
You could try putting a couple of attenuators between the NT4 and the Mixpre, that would make your levels more manageable.
You can make your own if you are good with a solder iron or there are a couple of companies out there make them. Some are reasonably priced and some are just outrageous!
I had a listen to some of the tracks and once you got the levels sorted they were ok.
How far up the meter were you letting the levels go?

Cheers,
Euan

Location Guy
Sounds like a really loud gig!
You could try putting a couple of attenuators between the NT4 and the Mixpre, that would make your levels more manageable.
You can make your own if you are good with a solder iron or there are a couple of companies out there make them. Some are reasonably priced and some are just outrageous!
I had a listen to some of the tracks and once you got the levels sorted they were ok.
How far up the meter were you letting the levels go?

Cheers,
Euan

I emailed the MixPre support also, and they said that the summing of the two would simply make the output louder, so my hope is once I put the panning right, I'll have much more room to play around with the gains. If not, I'll check out some attenuators like you said. I have a nice soldering iron.

The levels were going all they way up to 2 out of 3 reds, and a lot of times the bass kick drum was giving red peak lights over the two gain knobs. Again, I forgot to turn on my limiter. Doh! LOL. Anyway, I think I'll test around with it tonight and next time it will be much better I think. That's what I get for having it come 1 day before the show and not having time to play around.

Cheers,
Justin

Ah the learning curve can be steep!
Stick the limiters on, pan the pots and have fun. The day you stop learning is the day that you get carried out in a box.
Know your gear, use your ear.

Enjoy,

Euan

Location Guy's idea of attenuators not only brings the controls into a more usable range, it reduces the potential for distortion from saturating the input transformers. (-10dbu according to mixpro's specs)

I worked out the values for a 20dB Mic Pad taking into account the 2K input load of the mixpro and the values turned out to be very convenient. The circuit I uploaded here http://www.fonehome.demon.co.uk/extlink/mic_pad.jpg is exactly the same as in any pro console and can easily be built into the XLR shells. If cable length is more than a foot or two put the resistors into the output (mixpro) end. If the cable is short it might be less cramped to put the 2 x 620R's into the mic XLR shell and the 150R into the other.

Before you start adding attenuation, let me ask a dumb question. Are you sure you're connecting the output if the Mixpre to LINE level inputs of your recorder, and not MIC level inputs? The Mixpre is a mic preamp; it takes (two) mic level inputs and produces two line level outputs. Line level is MUCH hotter than mic level (that's why it's called a pre-AMPLIFIER), so if you connect a line level signal into something expecting the raw un-amplified output of a mic, you'll saturate the input even with the gain set very low. What you described sounds like that's what might be happening here.

On some recorders, the line level inputs is on the same physical jacks as the mic inputs and which level it is is selected with a switch or menu setting; on others, they're different jacks (and you also have to set a switch). (I have an NT4 and a Mixpre, but not an Edriol E-09, so I'm not sure how your particular recorder works).

And about the 48V phantom powering: in general, most mics that can use either battery or phantom power will perform better (with lower self-noise and/or higher dynamic range) when used with phantom power than with internal battery. So use phantom with your NT4.

Matt