FORUMS: list search recent posts

Kino Flo Diva Light audio problem

COW Forums : Lighting Design

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Bob Cole
Kino Flo Diva Light audio problem
on May 2, 2009 at 3:06:42 am

I had my Diva Light right over the camera (about three feet higher than camera); camera had a teleprompter LCD and was taking wireless audio in.

The audio had a very obvious buzz. I finally had to feed the audio to a second camera which was handheld and further from the Diva Light.

There were many electrons floating around the room - it was a demo room for some electronic equipment; we had about ten lights, etc. But the Diva was clearly responsible for the buzz.

Is this a bad ballast? I've heard or imagined very faint audio problems on subsequent shoots (when the Diva was about 4-5 feet away from the camera), but the sound recordist has waved them off as inconsequential.

If it's a bad ballast, what can I do about it? The light is a couple years old.

Bob C


Return to posts index

Michael Palmer
Re: Kino Flo Diva Light audio problem
on May 2, 2009 at 3:17:08 am

It is not a ballast issue. I would bet a cell phone may have been the problem. These Kino's have electronic ballasts and they DON'T cause audio issues.

Good Luck
Michael Palmer


Return to posts index

john sharaf
Re: Kino Flo Diva Light audio problem
on May 2, 2009 at 5:26:45 am

Bob,

I've got to agree with Michael, Kinos are used hundreds of times a day on motion picture and tv sets around the world with no audio problems. After getting spurious noise on tracks which we isolated to be AT&T cell phones (all iPhones + others) we ask people to turn them off when we can. In public places, obviously we can not have control and suffer with occasional noise.

JS





Return to posts index


Bob Cole
thanks
on May 2, 2009 at 11:54:16 am

Thanks guys. I want to believe, but I'll have to test further. All I know is that the fixed camera which was right under the Kino had a buzz, and the camera which was handheld and went everywhere else in the room did not.

Could it have been a bad or improperly seated lamp?

Bob C




Return to posts index

Michael Palmer
Re: thanks
on May 2, 2009 at 3:18:10 pm

Most of the Kino's I'm use to working with have remote ballast and have a head feeder cable to the head. The Diva light has the ballast on the back of the head and perhaps you are getting sound issues from this unit.

Were you using wireless audio gear?

Good Luck
Michael Palmer


Return to posts index

Bob Cole
Re: thanks
on May 4, 2009 at 3:56:46 am

[Michael Palmer] "Were you using wireless audio gear? "

We were using the Kino Flo Diva with the built-in ballast.

Yes to the wireless question, but I quickly ran a hard wired mic to the talent and had the same issues. I'm also suspicious that there was some interaction between the Kino and the teleprompter's LCD screen.

I needed the Kino's output, & over the camera, right where it was, and there simply wasn't time to do more than some quick AC recabling. When that didn't work, and the other camera's audio was clear, we just went ahead with running the audio to the handheld camera. Sometimes you just have to get the job done. I haven't been able to replicate the problem since then, but I'm planning to set up the Kino and a teleprompter and see if I can make it happen again.

Bob C


Return to posts index


Dennis Size
Re: thanks
on May 2, 2009 at 5:48:56 pm

Did you test your theory by shooting with that handheld camera right up next to the Diva? ....or by moving the Diva close to the hand-held?

DS



Return to posts index

Bill Davis
Re: thanks
on May 2, 2009 at 8:37:41 pm

Bob,

Probably not, but while tedious, it's not particularly hard to figure out the TYPE of noise you're facing.

Ground loop hum (common mode hum, more accurately) has a characterisitc sound. So does inductive RF noise. they're similar since they can both be related to the 60hz carrier cycle of US alternating current. (our oveseas bretheren have their OWN set of sounds to understand) But over time you'll learn to tell the diference. Ground loops tend to be stable in loudness regardless of what you move or do. Inductive RF will change depending on how the cables/antenna/lousy ground solder joint - changes.

Cel phone noise, however, tends to be totally different - not like ground related noise at all.

The key is learning basic step-by-step audio system problem solving - which is always the same. You start by identifying the signal inputs and outputs that are in use. Then you eliminate/decouple each signal in turn until you find the circuit that's injecting the noise. Once you have the circuit isolated, you check every connection, device, power feed and cable involved in that circuit until changing something makes it go away.

If someone banged the Kino Flo and a cold solder joint cracked in the ground circuit, that doesn't mean that brand or even that instrument sucks at ALL. It's just an acknowledgment that over time, stuff happens to even the best of gear.

Our job is often to make it UN happen. So if your gut is telling you it's the Kino, UNPLUG it. if the problem disappers, it's something realate to the Kino. If the problem persists, move on.

Over time, you'll learn the "sound" of various common problems, and that will shorten your problem solving time.

Also, you'll learn that a lot of common mode grounding problems are caused by plugging different pieces of equipment into different AC feeds. Sometimes moving plug A from outlet A to outlet B will make everything go away. Or make things worse.

Welcome to audio. It's NEVER boring!



Return to posts index

Bob Cole
Re: thanks
on May 4, 2009 at 3:38:48 am

Thanks for the very informative reply. It would be neat if some audio guy would put up samples of the various types of hum, along with a description of their usual sources.

I didn't say that the Kino "sucks" - only that I traced a buzz to it. But as I think you are saying, it could have been the power lines we tried to it.


Return to posts index


Craig Kauffman
Re: Kino Flo Diva Light audio problem
on Jun 2, 2009 at 8:45:33 pm

Hi, Bob. I have 2-Diva400s and have run across the same issue more than a couple of times. For me it was a lamp seating issue. Sometimes the buzz (60 cycle hum) is also faintly audible at the ballast. The loudness of the hum will be affected by how loose the lamp is, the amount of dimming, and how close any part of the fixture is to any part of your audio system, and grounding. After transporting reseat the lamps, especially after air transportation or long vehicle trips.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]