[Richard Crowley]

If you had said you were interviewing ONE person (like you example of the visiting producer), my response would have been rather different. But, at least with the kind of people I typically see, in real life, and on the screen, trying to mic two people in an unscripted, unrehearsed situation with a single mic would make me very nervous.

[Richard Crowley]

First you say that your tracks “came out pretty good and the client has ordered many more to be done.” But then you say you “Want to update my game.” Is this just “free-floating anxiety”? Or are there specific things about the current performance that need improvement?

Do you have an experienced boom operator to handle aiming a single mic at two people? How do you plan on accommodating them when they speak simultaneously or rapidly back-and-forth? Experienced boom operators typically study the script in advance so they know who speaks when in order to have the microphone aimed properly at the right time. Of course, that is not possible for spontaneous interviews with amateurs.

From your brief description of your current production conditions, it doesn’t seem like a single boom mic is a very practical alternative for what you are doing. If you want to get away from lav mics (why?) perhaps what you need is a couple of decent hyper-cardioid mics. Of course, that assumes the subjects are stationary and don’t turn their heads much.

If I were in your situation, I might consider upgrading the lav mics, but boom mics would seem beyond the scope of what is reasonable.

[Richard Crowley]

Do you have the instructions for the Sennheiser G3 kit? If not, strongly suggest downloading it and studying it. The setting on the transmitter is based entirely on the sensitivity of the microphone and the loudness of the source. It is NOT “set at 40%”. NO! That setting MUST be optimized for whatever you are micing.

According to the manual PDF that I downloaded, both the transmitter and receiver have audio level indicators on the LCD screen. As I said before, FIRST set the transmitter level so that the indicator shows good movement, but not so high that it peaks/clips on loud sounds. And setting it too low is not good either because you leave the signal “down in the mud” of the noise floor.

The receiver level can be set for the default “40%” and then set the recorder level for optimal recording levels.

Proper “gain-staging” means that the audio level must be set at the optimal point at EACH AND EVERY STEP in the signal-chain and each step should be optimized before moving on to the next step. The transmitter level must be optimized FIRST before anything else. THEN the receiver level can be set.

Now, it is possible that the receiver level only adjusts the output level of the receiver, so there is some interaction with the input level of the next stage (the recorder). So if you set the receiver output on the high side, the input of the recorder could compensate by setting on the low side, and vice-versa. But even there, setting the receiver TOO HIGH means that the recorder is operating at a low input setting (to keep the audio levels proper) and that is not desirable. Nor is the converse (setting the receiver too low, and compensating by setting the recorder input higher than “normal”.

If you are unfamiliar with setting audio levels (or how to read the indicator on some new piece of gear), plan on spending an hour offline experimenting with your gear. Deliberately set the level of each stage too high and see what happens. And too low and see what happens. That will give you a feel for the “sweet spot” of each piece of gear. After you get some experience recording audio with your gear, you will get the “feel” for getting the levels set properly as indicated by the readings on the gear.

Generally if an adjustment is down in the lower 20% of its range, it makes me think that the incoming signal is “too hot” and should be adjusted down by the gear in the previous step in the chain. And if an adjustment is set in the upper 30% of its range, it makes me think that the incoming audio signal is too low and needs to be boosted by the previous stage. This applies to the receiver, the recorder, and the camera, but not necessarily to the transmitter.

The transmitter is a special case where there IS NO “previous step”, so if you have to adjust the transmitter level down really far because your source is very loud, beware of the microphone itself distorting from inability to handle very high sound pressure levels. And conversely, if you find that you have to adjust the transmitter level way up almost to the top of the range, then consider that you may need a more sensitive microphone, or you may need to get the microphone closer to the source, etc.

[Richard Crowley]

We generally do “gain staging” starting at the source and proceeding “downstream” to all the destinations.

Set the transmitter level so that it avoids clipping at the loudest sound levels you are expecting. THAT setting is completely independent of everything else in the audio chain. It only controls the operation between the transmitter and the receiver.

Typically we adjust levels at some “middle-of-the-road” setting to avoid operating at either “edge”: “down in the mud” of noise at the bottom end, or “clipping” at the top end.

This gets a little tricky with the wireless receiver, because often you must use that output level control also to create the proper signal level that the destination will be happy with.

You didn’t really make it clear what your signal path is, but I will assume that you are connecting the receiver output to the Tascam DR-70D recorder, and the output from the Tascam DR-70D to your 5D mark III.

If that is the case, then I would set the receiver to maybe around 40% of the total range (as a default setting) and next adjust the DR-70D level for proper recording levels. That means as high as you can get without clipping at the loudest sounds.

THEN, the very LAST step would be setting the level on the 5D camera input after everything UP-stream is set properly.

[Richard Crowley]

Virtually 100% of the time, voice (dialog, narration, VO, etc.) is recorded in MONAURAL unless you are recording a sleazy politician who talks out of both sides of their mouth. That single, mono, track is then mixed (and panned) into the proper place in the mix.

OTOH, if have (intentionally or accidentally) recorded some sort of “special effect” into your voice track, then don’t let “conventional wisdom” talk you out of it.

Remember, however, to check for monaural compatibility because you can’t always control how people play it back.

[Richard Crowley]

It sounds like chon teck is asking about bringing in HIS wireless mic and compatibility with the venue microphone (wireless or wired). I didn’t get the impression that he was going to use (or even have access to) BOTH signals.

Of course, Peter is correct that there may still be phasing/delay problems between chon teck’s own wireless mic and whatever might be picked up from the venue reinforcement system. However, with his wireless mic clipped right ON the subject, I would expect this to be minimal in practical application. Of course what is acceptable for a low-budget document of a live presentation would not be good enough for a big-budget feature film, etc.

But I think chon teck’s question was about that common belief that adjacent microphones somehow “interfere” with each other. (Which they do NOT except as maybe a minor 3rd-order effect.)

[Richard Crowley]

Yes it seems possible that it is clipping in the microphone, especially in a noisy ambient where the subject is likely speaking loudly. That is one of the reasons why it is popular to use a low-sensitivity dynamic microphone in a loud environment. Of course you MUST hold the microphone close to the subject’s mouth in order to hear them. This is not the kind of ambient where distant shotgun mics perform well for dialog capture.

[Richard Crowley]

I would take up the problem with Mr. Nemeth at GiantSquid. He is in a much better position to resolve your problem than we are.

[Richard Crowley]

The only issue is where BOTH mics are wireless and on the same (or adjacent) channels.
There is no acoustical issue with having two mics together. We have all seen press conferences where there are literally dozens of mics in a forest around the subject.

[Richard Crowley]

Yes, they have a boundary microphone between each two participants. But note there is a lot of room noise because the mics are so far away from the subjects’ mouths. That may be acceptable for some kinds of productions, and not for others.

And SOME of that could have been filtered out. It all depends on your acoustic conditions, your budget/resources, and what expectations you have of the quality of the audio track.

Shotgun microphones are typically unsuitable for indoor use around reflective surfaces like that because the reflections disrupt the directional operation of the mic, and render it just an ordinary mic too far away. OTOH, boundary mics like that DEPEND on those same reflective surfaces to operate properly.