Very confusing audio situation

K

Kugar13

Well-known member
I borrowed a headphone amp from a buddy of mine for a weekend shoot. It is a personal amp for the boom operator. I have used it in the past and am quite pleased with it's performance. Over the weekend we discovered the headphones from the camera would pick up reverb from the boom operator between takes when he was adjusting the poles, but he (boom operator) could not hear the reverb through his headphones (they were working). This is baffling to me. Does anyone have any clue as to why this would occur?
 
If you are using the DVX100b, was this reverb perhaps the 2 frame audio delay? It would happen constantly, not just between shots, the effect would not be heard on external amps, and you will not hear it on the final tape playback.
 
wabbit said:
If you are using the DVX100b, was this reverb perhaps the 2 frame audio delay? It would happen constantly, not just between shots, the effect would not be heard on external amps, and you will not hear it on the final tape playback.
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I am using the DVX100A. During our sound test of the occurence the effect was recorded on the tape. It was clear how to avoid the effect, but not why one headphone would hear it and another would not.
 
Opps...I meant the 100a.

If this was an effect that was recorded to tape but not heard by the headphone amp then either the effect is occuring between the amp and camera or the amp/headphones are not of sufficient quality to pick it up. What type of headphones were used, what model was the headphone amp? How was everything specifically wired?

I have not heard of anything like this. Try swapping out headphones, cables, and amp one at a time to see if you can isolate the problem.

Good luck
 
It may very well depend on the headphone model. On one of my first shoots, the director was using AKG headphones (don't remember the model) and I was in Sony 7506's. We were shooting near an airport, and I was constantly calling for a hold for an airplane and holding until I could not hear it any more. Finally the director told me not to hold in silence for so long (he wasn't hearing the airplanes as long as I was on either the approach or departure). Finally, I traded headphones with him, and he heard what I was hearing, and after apologizing (a rare thing for most directors...this guy was a real mensch) he went out and bought a pair of 7506's. After that, we were in synch.

Phil
 
The old AKGs also leak like a sieve. Is it possible that the boom opperator's headphones were feeding back into the mic at a low level? When you factor in monitoring latency, that could sound a lot like reverb.
 
The boom operator was either monitoring pre-camera or using the RCA outs. The echo was coming from the headphone outs on the DVX100.
 
SMuir,

The AKG's were in my situation, not this original post. Just an example of when different headphones can cause problems on a set. And actually, these AKG's weren't too bad leakage-wise, just didn't have enough dynamic range to hear everything I was hearing.

Phil
 
Wow

Wow

Wow I am VERY thankful for the replies. We are using Sony MDR-7506 headphones only.

How the boom operator is wired: XLR to the amp on his hip. XLR from the amp to the boom XLR connector (K-tek boom pole w/ internal XLR).

The unwanted sound/effect is the sound of him adjusting the boom. For example when he grips and ungrips the boom it causes unwanted effect. I understand this is normal and you have to be careful with how you hold the boom. This is not the problem (it was happening between takes when he was adjusting the boom pole/etc).

I'll run a few tests tonight and see if I can isolate the problem. I have used the amp before with a friend who owns the same equipment (identical gear) and it worked fine.

During our tests over the weekend we gripped and even shook the boom pole and got the 'effect/unwanted sound'. We could hear it from the headphones on the camera (MDR 7506) but not the headphones (MDR 7506) attached to the amp.

Hopefully we can isolate this problem and fix it where the boom operator can monitor this. The concern is the camera operator who can hear the unwanted sound/effect may overlook it when under stressful conditions that demands his attention (stabilized shots, dolly, etc).

Thank you all for your effort to assist me with this issue!
 
Phil,

Sorry, I wasn't explaining myself very well. What I meant was that reminiscing of the AKG's tendency to leak audio out (rather than just in) made me think of the possibility that the reverby problem Kugar13 orriginally reported could be the result of a delayed headphone signal leaking out of incompletely sealed circumaural headphones and feeding back onto the mic.

I once had a simmilar problem when a novice boom-op with whom I was working insisted on using his own pair of open-backed Sennheiser Headphones rather than my beat-up backup 7506s. Sure, the Senn's were more comfortable with a more open and natural sound, but they would occasionally cause a subtle feedback loop when the mic picked up some of the audio spilling out the vents on the backs of the ear cups. If we had been using a confidence monitor or other delayed headphone return (I had rented a shiney new Nagra Ares), it could easily have sounded like a small ammount of reverb.
 
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SMuir said:
Phil,

Sorry, I wasn't explaining myself very well. What I meant was that reminiscing of the AKG's tendency to leak audio out (rather than just in) made me think of the possibility that the reverby problem Kugar13 orriginally reported could be the result of a delayed headphone signal leaking out of incompletely sealed circumaural headphones and feeding back onto the mic.

I once had a simmilar problem when a novice boom-op with whom I was working insisted on using his own pair of open-backed Sennheiser Headphones rather than my beat-up backup 7506s. Sure, the Senn's were more comfortable with a more open and natural sound, but they would occasionally cause a subtle feedback loop when the mic picked up some of the audio spilling out the vents on the backs of the ear cups. If we had been using a confidence monitor or other delayed headphone return (I had rented a shiney new Nagra Ares), it could easily have sounded like a small ammount of reverb.
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SMuir,

Thank you for the info! I wasn't even aware of that problem. We currently use Sony MDR-7506 headphones.... thankfully. Now that I know your personal experience I'll keep a close eye one the padding on the MDRs to make sure we don't end up with that problem in the future.... =)
 
The 7506s tend to keep their seal quite well, even when the pads are all worn and rattey. The feedback problem usually only occurs with other `phones, or if the `phones are worn improperly.

Some boom-ops (myself included in certain situations) like to wear only one earphone, positioning the other on the back of their head behind the ear. If your boom-op is doing this, it might be the source of the anomalous noise.
 
SMuir said:
The 7506s tend to keep their seal quite well, even when the pads are all worn and rattey. The feedback problem usually only occurs with other `phones, or if the `phones are worn improperly.

Some boom-ops (myself included in certain situations) like to wear only one earphone, positioning the other on the back of their head behind the ear. If your boom-op is doing this, it might be the source of the anomalous noise.
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Hey,

The anomalous noise is him b/t shots when he is adjusting the boom pole. Nothing to worry about between takes, but the idea of him not hearing it in his headphones (from the headphone amp on his hip) and I can (at the camera) bothers me.

Thank you again for you wisdom and experience.

Kugar
 
i dont understand - you saying that you can hear him adjusting the boom and he cant? is that what you mean?
 
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