Why is a mixer necessary or even practical

Rehdarh

Rehdarh

Active member
Hi,

I am looking to invest in a high quality sound system for my first film. By high I mean getting something like the NTG-3 ($700) for a microphone.

Given that I don't want to cheap out on sound, can someone tell me whether or not I should invest in a mixer? The reason why I am asking is because I simply cannot feel the pull of why one is necessary or even practical - this is largely because I still haven't figured out what exactly it does.

There are two things that I understand about it: It can cut out low frequencies noises like refrigerators (cannot a microphone or recorder do this as well?) and secondly it can adjust the volume of what's being recorded. So if one guy's voice is a lot louder than the other's, the sound-guy (I guess moving super fast so that the audience wouldn't notice the reduction in volume when he lowers the speakers level).

…. Here is another reason why I just don't "get it"…How is the mixer's role even practically possible?. The sound-person would surely have to be on their game to adjust the level of someone's voice the moment they started speaking…A more possible option to me is to listen to the recording, notice the sound difference, and re-adjust the mics accordingly for a second take. Or just reduce the volume in post.

I am sure I sound like a complete noob. But for what it's worth I've been doing a lot of reading into it and still can't grasp it so I thought I'd make an account and ask for help.

Thank-you very much
 
A mixer is only part of the system. A very important part of the picture is WHAT ARE YOU RECORDING ON?
Perhaps the number ONE reason for using a mixer is to get QUIET GAIN.
The mic preamp in virtually all camcorders is of rather low quality.
So you can get a better signal-to-noise-ratio (SNR) by using a mixer vs. connecting your mic directly to the camcorder.

Other reasons for using a mixer are that is a much more convenient way to...
1) Allow you to VIEW audio levels on the meters
2) Allow you to HEAR the audio through good headphones.
3) Allow you to ADJUST the audio levels for optimal recording level.
None of those things are very easy to do on a camcorder which is being used to shoot the video.
 
Context would help here. It depends on what kind of work you are doing. You mentioned takes, so I'm assuming you're making narrative films. It would also help to know what setup you have in mind. Are you recording to the camera or a separate audio recorder? Do you have an audio recorder that has mixer functions on it?

The sound person has to have something to control volume for an optimum level. There is a chain of gains/losses in the path from the speakers voice to the recorder. The type of mic and its sensitivity, the distance from the actor, and the levels at the mixer and recorder all affect what is being recorded. You are trying to achieve the best signal-to-noise ratio you can without clipping. So a mixer is needed to set a level that is the optimum for the setup. It's not like a mixing board for a TV show or for a concert. The sound person is not actively making adjustments during the take, or at least they shouldn't be under ordinary circumstances. That level is set before the take.

If you have a camera and you expect to set levels on the camera instead of a mixer, that's just not practical. It can be done for let's say interviews, but it is not advised.

If you don't get an optimum or adequate level recorded, then you have problems in post.
 
Hi,

Thank-you for your reply.

I imagine I will be investing in a recorder of some kind - as I've read numerous times that the audio recorders in cameras are poor.

It is my understanding that a normal recorder (that is, not a mixer) can do at least the first two things you mentioned. The third I have heard a number of times as being a benifit for mixers. But I do not understand why this is exclusive to mixers. If I have a boom mic, and I am moving it between two people during dialogue, could I not simply increase/decrease the volume of parts of the recording in post to compensate for a inconsistency in audio in the dialogue?

The best,

Reh
 
Yes, you can, but you generally do not want to increase the gain in post since that will also raise the noise floor that's set by your mixer's preamps. Your signal chain from the microphone is only as good as the weakest link. Once you add more gain after the preamp your also boosting the noise level.
 
Thank-you for your reply.

From my own research, I was planning on purchasing a recorder (one which is not a mixer) that has the ability to adjust the levels for optimum signal-ratio. However, I have heard about these mixers, so I am curious to understand the extent to which they go beyond the recorders that, from what I can tell, do at least some of these (important) things that mixers do for recording good audio.

Thank-you,

Reh
 
If you use a recorder with decent preamps, then you probably don't need an additional mixer.
Beware, however, that most inexpensive recorders have mic preamps that are no better than your camcorder.
There is also the argument that feeding nice clean audio (from a mixer) into the camcorder avoids all the extra trouble of recording "double system".

Riding levels up and down in "real-time" is NOT the primary job of the sound recordist.
The sound recordist sets the optimal recording level for the shot during rehearsal and records at a constant gain.
Making "real-time" adjustments is typically left to the post-production editing process.
 
If you are using a separate audio recorder, then that may suffice for your needs. They are adding more and more features to recorders to behave like mixers. One important feature of a mixer is that it will send audio to the camera and to the audio recorder so that there are two copies and the video has a reference audio. The mixer also has a feature that the sound person can either listen to the mix at the mixer or they can flip a switch and listen to what was recorded on the camera/recorder. This is a way to confirm that the take was good and ensure mistakes were not made.
 
If you only have one microphone, and you want the cleanest signal to noise ratio you can get a single channel preamp such as the Sound Devices MP-1 (Or a Shure FP23, which is basically the same thing since it's designed by Sound Devices). This will give you phantom power to your mic, and very clean gain you can feed to your camera, or a separate recorder (preferred).

The idea is to get the cleanest, loudest signal into your recorder with the lowest noise floor to get the best sound quality.

Of course, going this route, like I did, will leave you very limited once you want to start adding a second, third, or fourth mic. Something like the Zoom F8 is appealing but it's not really necessary if you don't use more than one audio source.
 
Thank-you for the information. What I am getting from this is that for the most part a mixer is not required for properly recording audio. I imagine that once I start making some recordings I may begin to appreciate some of the benefits a mixer has to offer. As it stands now, I think I will just look into a recorder.

The best

Reh
 
Since you say this is for your first film, there are a few other things that need to be addressed.

First, are you also going to be directing and shooting this yourself? If so, you're going to need someone on set who knows what they're doing in terms of sound, and can focus on getting you the best results possible.

Second, what's your anticipated budget for sound?

Also, have you accounted for all the other stuff you'll need to,complete an audio rig? The NTG-3 is also going to require proper shock mounting and wind protection ($299), a boom pole ($200), good headphones ($100). You'll also need cables. Add in the recorder and you're in at least the $1500-2000 range, maybe more if you're looking at a better recorder.

Add a good mixer and you're looking at another $930 (MixPre-D) to $1650 (SD 302) at minimum. Then, you'll also need a bag to keep all this stuff together ($300). Now you're over $3000.

Last, you may consider that the same +/-$2000 (or more woth a mixer) could be better spent on hiring a more experienced sound person, who will bring with him/her all the necessary gear.

There's a lot - and I do mean a lot - to learn with sound to get it right. Which do you think will be a better ROI for you, especially for your first film? A good-quality audio kit will last, but is it going to pay for itself?

There's a sale this weekend on the Sound for Film and Television tutorial video that David Jimerson and Barry Green produced a few years ago. You might want to make that your first investment, as it will give you a better understanding of the sound world... and why you may or may not need a mixer.
 
Personally I would suggest not buying a bunch of $$$ gear.

You haven't explained more that your "first film" so it's hard to tell if you have a bunch of experience in general but this is the first film you a producing, or if this is literally the first film you are going to work on. In the former case maybe buying is wort it, in the later it most certainly isn't. In both cases your film is better off with you getting a sound person to do the production recording. Depending on your budget maybe you buy something they get to keep as payment. I'm assuming a really low budget.

Getting gear doesn't get you good sound.

Specifically to your mixer question. There are really two things that are referred to as a "mixer", one you definitely need. The first, that everyone is talking about often comes when you get the second. The title for the person doing production recording is "mixer". That is a person you need, even if it's a mixer in training. Any mixer with a touch of experience will also have gear that will probably include some version of the other mixer.

The reason for the hardware mixer is that it's a better interface with the user and the mic. Recorders vary in how user friendly the levels and other set up options are. Mixers are generally much more user friendly. They also are important if you use a lot of mics. Something like the MixPre is more of a mic pre than a mixer but has many of the bonuses of a mixer. Really good meters, test tone, slate mic, flexibility in ins and outs, good quiet gain.

You don't want your mixer (person) to be doing a lot of gain riding unless they are very experienced, and maybe not then. Riding gain was very important with analog to stay above the noise floor. Digital has basically a nonexistent noise floor so there isn't a lot of benefit. If you set levels correctly and have a good limiter to protect against surprises then not changing level while recording is a plus for post. 1) because the noise floor is constant and a lot easier to use NR on and 2) we don't have to play around undoing gain changes that don't work.

With todays gear (good level and above) almost all of the "noise floor" is coming from stuff in front of the mic pre so there isn't a big difference between turning it up on the mixer and turning it up in post, providing you are recording at a decent level. Getting the mic closer on the other hand is a BIG plus.

If you are stuck in the "I must do it all myself" mode remember that film is a team sport so you are trying to field a football team with only one player. If you go to festivals you will be competing with some teams with a full squad.

But if OMB is your thing then don't buy expensive sound gear, it's a low bang for your buck. A much more new user friendly shotgun like the AT875R will exceed your needs and save you a bundle.
 
Noiz2 said:
Really good meters, test tone, slate mic, flexibility in ins and outs, good quiet gain.
Click to expand...

And... really good limiters. Newbies tend to discount the value of limiters, I know I did. But once limiters have saved the day a time or two, one really begins to appreciate them.
 
We can all pretty much agree that good limiters START with a device like the Sound Devices MixPre. Perhaps if you are one man banding it or really want to own you may be better off starting with something like an AR875 and DR60.
 
There are a lot of good points from everybody here.

I am curious about the saying I've heard a number of times that your audio system is only as good as the weakest link. Not being educated about this stuff, I find that hard to fully believe - I would think that someone could clearly recognize a difference in sound quality between an NTG-3 and NTG-2, both recorded on a cheap H4N. But I'm not an expert on this stuff. So...would it be stupid to spend a fortune (for me anyway) on an NTG-3, and then purchase an H4N recorder? Or if I just got an H4N, should I might have well just got a cheaper mic?

Throughout this thread there's been talk about pre-amps to boost the signal; but maybe this has only been mentioned because I brought up what mixers do. What I'm getting at is the question of whether or not you're really getting your money's worth if you buy a higher end mic without a high end pre-amp/recorder.

To clarify, for my first film I don't mean anything serious. I just mean producing something amateur, but as best I can for practice and with the idea of eventually producing something more serious...and I'm serious about producing something more serious haha. And so it seems reasonable to spend more money if need be on more advanced equipment than a typical entry level filmmaker may do.

BTW - I am seriously considering buying the DVD. Thank-you for pointing it out to me!

The best,

Reh
 
Film making is 'story telling' my suggestion is pick a simple subject and produce a 2-3 minute 'story' use just a smart phone ( which you will probably have) perfect your skills before you spend anything serious.
If you can't do that a million $$$$ on gear won't help.
 
Rehdarh said:
I am curious about the saying I've heard a number of times that your audio system is only as good as the weakest link. Not being educated about this stuff, I find that hard to fully believe - I would think that someone could clearly recognize a difference in sound quality between an NTG-3 and NTG-2, both recorded on a cheap H4N.
Click to expand...

Think about picture. You can have a $50k camera with the most repected imaging quality, but put a piece-of-crap lens on it and the picture won't be that good. Same with audio: put a cheap mic in front of the best mixer and the signal can be only as good as the mic will allow. Put a great mic through a terrible pre-amp and the signal will be only as good as the pre-amp will allow. Once damage is done to a signal, there's really no fixing it downstream.

As for your example: yes, the NTG-2 and NTG-3 sound different, and the 3 is a much better mic. Put the 2 in the hands of a pro and the 3 in the hands of a newbie and I guarantee the better results will be from the 2. Why? The weakest link here is the user, an inexperienced beginner who doesn't know how properly to use a shotgun mic.

Rehdarh said:
To clarify, for my first film I don't mean anything serious. I just mean producing something amateur, but as best I can for practice and with the idea of eventually producing something more serious...and I'm serious about producing something more serious haha. And so it seems reasonable to spend more money if need be on more advanced equipment than a typical entry level filmmaker may do.

BTW - I am seriously considering buying the DVD. Thank-you for pointing it out to me!
Click to expand...

Okay, ao there is absolutely no point in you spending thousands on a sound kit. The AT-875r that Scott mentioned is a good place to start as it is less expensive but still a decent mic. It also has a hotter output, which helps with cheap recorders sicne they all have fairly weak pre-amps. I'd also take a DR-60D over a Zoom H-anything, any day, for a kit like this.

But how much do you really want to spend at this point for something you're just starting to explore as a hobby?

And yes, the tutorial is helpful (I think it's only available in download now, no more DVDs). If you really, really want to do this, it is worth learning some of the intricacies of sound. Of course, if you do want to do something more serious, hire a sound pro.
 
You must log in or register to reply here.
Back
Top