Pre-DVX Mic Mixing?

M

MikeGreen

Active member
Hi All,
Do you (or your audio guys) use portable mic mixers prior to the DVX-100, or do you send the mics into the DVX and mix in post? If external mixing is the way to go, what mixers do you favor?
Thanks,
Mike
 
If you only have 2 sources, and the volume doesn't change a lot, then just send it to the dvx. Otherwise, you'll need an external mixer. There are many mixers out there, but a good one would be a Sound Devices 442 or 302 (but I heard they are back ordered). A pretty good value is PSC DV Promix 3.
 
An external mixer also has the distinct advantage of giving your boom opperator a local monitor (eliminates the audio processing delay issue) and a set of level controls. Makes their job much easier and you can get better and more consistent audio. Just set the camera to a line level input, adjust the gain controls on the camera to match the headroom of the mixer and you are good to go. I have an Azden FMX-2 which works out great and just rides on the boom operators belt.
 
Thanks for the responses guys. The Sound Devices units look beautiful, but are a little out of the price range that I was looking at. I like the price on the FMX-2. It doesn't seem to supply phantom power, will it pass it from the DVX to the mic? Also, are the 3 LEDs enough for level monitoring? Can the Promix 3 be attached to a the boom op's belt, or some sort of harness? I like the specs on the Promix and could probably manage the cost. Has anyone used it? How do the Azden and the Promix compare?
Thanks,
Mike
 
The Azden does not supply phantom power for the mics (nor can it pass it from the camera). The FMX-2 lacks the 3 LED monitor level indicators, but does have a peak LED. The newer FMX-20 has 3 LEDs. As long as you have properly calibrated the mixer to the camera, then even the single peak LED is more than adequate to get proper levels to the camera.

The procedure that I used to calibrate the system was to apply a 1 kHz sinewave signal to the mixer and set its output level to where the peak LED just begins to illuminate. Then set the camera's levels to a point that you feel gives you adequate headroom (about -12 dB is a good point). I confirmed the DVXs metering by recording the signal and then later stripping out the audio portion of the captured segment and analyzing it on a DAW. After the camera levels are set, don't readjust them, only change your gain at the mixer (aiming for your peak indication point). I tested the mixer (Azden) and it still had plenty of headroom beyond that point (over 20 dB) so there was never any concern for the mixer clipping before the camera. This works out great and is a very simple and repeatable setup. The additional LEDs of the FMX-20 would give your boom op a little more information, but either will get you where you need to be. The local monitor at the mixer is a great tool for your opperator as it will give them the immediate feedback that they need to get the best mic placement at all times.
 
I've got a Promix, and it's worked fine for me. Haven't tried the Azden, though. Promix comes with a shoulder bag, but it's pretty much useless. Spend a little extra money on a Porta Brace bag. You won't regret it.

When I was shopping around, I compared the Promix and the Sound Devices. SD was great, but I couldn't justify spending the extra money. Jay Rose did a review on the Promix in DV magazine about a year ago, and gave it pretty good marks.
 
I always recommend people use some sort of mixer, or portable mic pre in front of any camera, no matter what anybody says, even if you are just using one mic. Here is why.

THE MIC PRES IN ANY CAMERA, AS WELL AS A/D CONVERTERS, SUCK.

No matter what anybody tells you, they suck, and suck hard. I've cut sound effects, and dialogue on lots of projects shot on several different kinds of mini dv cams, from the DVX100, to the XL2, and I can tell you that every single one where they plugged the mics directly into the camer, using the camera's mic pres, I have spent tons of time cleaning up the audio because of noisy mic pres. On projects where they put something like Sound Devices Mixpre in front of the camera, we were golden. I wouldn't go any lower in quality than the PSC DVPromix3, which is actually quite good for the money. You want your mixer to be as good as you can, because if you don't, you are going to use noisy mic pres, and putting your noisy audio through even noisier a/d converters. Mixers I'd recommend are:

Anything Sound Devices
Anything PSC
Anything Wendt


-Dave
 
i agree with dave, but don't misunderstand the post. none of the devices dave mentioned does anything about the camera's a/d conversion. just gets you around the crappy pre's (by giving you a cleaner line level signal than the camera's pres can.) personally, i think that the a/d conversion in better cameras is fine as long as they get a nice hot signal to work with.
 
hmmmm......... Anybody have any idea how the Sound Devices Mixpre and the PSC DV Promix 3 compare? The third input on the PSC would be nice, but if the Sound Devices are much better units.............
 
If you cannot afford a field mixer, and want to get better sound, I would bet that even something like a small Mackie mixer would be a fairly large improvement over the built in mic-pre's in a DVX. I am working on a short and I don't have a field mixer, but I do have several rackmount preamps so I am just going to drag those with me. I also like to use a little compression going to tape to even things out, so I will probably throw a couple of those in for good measure. I have not yet made a comparison of the built-in vs external preamps but it would probably make a nice test. I am pretty confident that my 1272's can take on the DVX :)
 
FYI. When recording production sound, NEVER use compression, and rarely used EQ. You are going to screw your re-recording mixers later on down the line.

-Dave
 
Dave_Fisk said:
FYI. When recording production sound, NEVER use compression, and rarely used EQ. You are going to screw your re-recording mixers later on down the line.

-Dave
Click to expand...

Probably good advice. Since I will be my re-recording mixer I will make sure to smack myself in the head later :)

I was actually kind of curious if production sound was laid down completely dry. It is quite common to record with at least some compression for music production. Almost unavoidable for some things, really. For what it is worth, I was only going to drop on a 2:1 or 4:1, so not too much danger there.


The only EQ I would consider is probably a low cut.
 
Gotta say, (and this is essentially a kinda dumb statement coming your way), Im looking at mics like an AT897 at the moment, trying to get the best quality for the least cash, but when it comes to a mixer, I dont think I would ever consider anything other than a Sound Devices (and nothing lower than the 302 at that).

Sound devices rocks. Period.
On the 302, input and output limiters allow you to send optimal signals to cam without distortion.
PFLs on all 3 channels let you check inputs.
You can actually configure the line level it sends out at for different cams.
Plus it has full scale tone for setting up exact metering on the mixer end.

I love Sound Devices. And no I dont sell em, I just wish I did so I could use the 442 for free.
Tim
 
Anyone used the Sound Devices Mixpre? How does it compare to the 302? I like the $600 price better than $1100. Do you guys find the need for 3 channels, or does 2 usually get it done? I'm presently comparing the AT4073 and the Sennheiser 416 for mics. If I can save $500 on the mixer to spend on the mic, it would help. Still, I want to make sure I get what I need for both.
 
IMHO 3 is the magic number. For some run-and-gun stuff a simple 2 channel mixer does the trick, but even then a 3rd channel becomes necessary: 2 wireless, 1 shotgun.

For narrative pieces 3 is an absolute minimum. If the 302 is out of your price range, try a used Shure 33 or 32a. You can get one for $600 or so on Ebay.

cheers
 
Thanks Wabbit. 302 it is then. Listening to the audio tests from DVFreelancer in the sticky post, I don't hear appreciable difference between the MKH416 and the AT4073a. I'll go with the 4073a and feel much better about spending the extra on the mixer.
Thanks again,
Mike
 
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