What would cause a lapel mic to sound like this? Can you help please?

L

LuckyProducer

Well-known member
Hey guys, I filmed myself speaking about my film for the DVD of my film but after it I saw that the lapel mic I used added a lot of hum noise. I don't know why it's giving me issues. Can someone listen to it and let me know what I can do? I have a Samson UHF Micro32. Also, if there are any free plugins I can use to get rid of it. I really don't have the time rerecord it. =(

Or maybe one of you guys would really like to help me out and fix it up for me. I can send you the complete wave file. I would definitely appreciate that. =D

Here is the file: Listen to me
 
It sounds like a combination of things, what did you record to?

one thing is that wireless and the mic that come with it is so so at best,
the other thing that it sounds like is your camera has AGC turned on as well as improper gain staging.

do you have a way to re-record it with a different mic directly to your computer or to camera (I hope youre not trying to use a Canon DSLR audio)
 
I am using a DVX-100A and yes, I am plugging it directly into the camera. And yes, I am using AGC. I was thinking that this was probably it because I think the level on my lapel is too loud so the DVX tries to turn it down. However, I don't know what to use to turn down the volume because I don't have those small screwdrivers to turn down the small little knob inside the receivers and such. The mic I am using actually doesn't come with it. I took a mic from another lapel system that fit this one. It used to work fine but come to think of it, ever since I began adjusting the volume, it started doing this. So maybe that could be it. What do you think?

I also uploaded another file. This happens once in a while and it's ticking me off. What do you think it is? Notice how it goes on and off as I speak. It's weird. Here is the file: Listen to the audio here
 
sounds like the AGC is doing the opposite of what you think its doing. it is limiting the peaks, but its also raising the nosie up when you stop speaking.

the crackling is actually RF interference on the wireless section of your rig (remember the best multi-thousand dollar wireless is not as good as a $15 mic cable). the background noise I believe i from improper gain staging.

do you have access to a wired lav? that would solve all your problems as well as disabling AGC.
 
1) There is no hum noise. Learn to properly identify the various kinds of audio artifacts. it will be very helpful in the future to use the common terms.
2) I do hear ambient noise. Record in a place that is more quiet. Also get the microphone as close the the mouth as practical without distortion, wind noise, etc. And don't use AGC.
3) I also hear distortion. Cause could be several different things. Using wireless when you don't really need it is NEVER recommended.
4) I also hear breath noise, perhaps because of the mic position and/or you weren't using a foam windscreen on the mic?
5) I also hear automatic-gain "pumping". You can turn off the AGC, you know. You almost NEVER hear professional video that used AGC.

If your father is pastor at a church consider borrowing a proper (wired) microphone for this kind of video shooting.
Experiment with microphones and recording so that you get better at it.
 
LuckyProducer said:
I also uploaded another file. This happens once in a while and it's ticking me off. What do you think it is? Notice how it goes on and off as I speak. It's weird. Here is the file: Listen to the audio here
Click to expand...
I hear a severe wireless microphone "hit". It is caused by the receiver losing the signal from the transmitter. There could be a dozen different reasons causing this.
Repeating: NEVER (NEVER!) use a wireless microphone unless you ABSOLUTELY need it, and then plan on things going bad.

As Recordingwhiz said: "the best multi-thousand dollar wireless is not as good as a $15 mic cable"

You have the opportunity of learning from the mistakes of others here so you don't have to repeat them.
 
Yes, I am actually using the lav from church. The receiver is my own. Recordingwhiz, how can I avoid RF interference? Actually, what is that?
 
Ok, I understand that. But I am trying to learn this now so that it won't happen when I go film a wedding because if this happens during the sermon, I am screwed. There must be something that can be causing it. Do you think it is the channel I picked? Do you think switching channels can help?
 
like mr crowley stated.. RF interference is when the receiver loses contact with the transmiter very much like when youre between radio stations on a radio, it is static. there are many reasons for this.

you can avoid it by using a wired mic.

one reason that arises recently is that alot of older wireless units are trying to share frequency ranges with new digital TV stations that obviously have way more powerful transmitters than your system.

you cant do much about that, if you read the FCC statement on the system it actually states that your system can be disrupted, but you cannot disrupt others.
 
its possible changing channels may help.

however if the system is older than say 6 months it is no longer working on FCC legal frequencies, do your research on the FCC frequency for wireless mics.

it depends on your city and how busy the frequency spectrum is, but if you must use wireless then you need to update your system to a system that is compatible with the new frequency range the FCC allows for wireless mics. its not just a good idea , its the law.
 
LuckyProducer said:
There must be something that can be causing it. Do you think it is the channel I picked? Do you think switching channels can help?
Click to expand...
As we said, there are probably over a dozen different thinks that could cause an RF "hit". That is one reason why they are far less reliable than wired microphones.
Maybe using a different channel might help, but frankly, the hit I heard in your example suggested a far more serious problem. I would certainly have ZERO confidence in using that wireless kit for something like a wedding.

I'm not really sure what it means when you say "I am using the lav from the church but the receiver is my own."?
When you say "receiver" do you mean literally only the receiver, and the transmitter is from some other set?
Using a mis-matched transmitter and receiver will practically guarantee you a 100% chance of failure.

It is probably pointless to continue any discussion of wireless microphones unless you identify exactly the brand and model number of the microphone, the transmitter, the receiver, exactly what channel you are using (MHz), what frequency band(s) you have available, and what antennas you are using. Talking about this in generic terms is helpful for nobody including yourself.
 
If your wireless system is in the 700 mhz range you should replace it with a system in a legal range. We had to do this at Ithaca College recently, we replaced our 700 mhz sennheisers with shure ULX. Love the beta 87a capsule.
 
A couple of things jump out at me here:

1) The DVX-100A does not have AGC. It has ALC, which is Automatic Limiting Control. This is merely a tool to try and tame sudden peaks, but it won't cause nasty compression that we're hearing.

2) There are multiple audio settings in the camera that can affect your signal's integrity. Mic/Line setting on the inputs, input sensitivity, input gain control pots... get to know them and how they interplay.

3) Richard asked for specific makes/models of all pieces of the puzzle: lavaliere mic, transmitter, and receiver. Those are important bits of information here. The breathing/pumping I hear in your sample could be from a really, really crappy compander in a cheap wireless system... but without knowing specifics, that's just a wild guess.

Also:

recordingwhiz said:
however if the system is older than say 6 months it is no longer working on FCC legal frequencies, do your research on the FCC frequency for wireless mics.
Click to expand...

That's a bit inaccurate. There are many systems that are several years old and operate in the 500MHz or 600MHz range. Many manufacturers started phasing out 700MHz systems some time ago in preparation for the FCC reallocation. Merely being older than 6 months does not mean it runs in the illegal 700MHz zone, but knowledge of which frequency block you're running is a requirement.

LuckyProducer said:
Updating my system would require me to buy a whole new lapel mic system??
Click to expand...

Again, there are a lot of questions you've not answered yet. That said, making sure you have a matched and compatible transmitter/receiver system, along with a lav that is properly wired for the transmitter, will save you lots of headaches. Having a system that isn't running in the 700MHz band is also a must in North America.
 
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I will definitely want to get deeper in this conversation but right now I'm on a tight schedule and was wondering if there is a plugin to fix this now because rerecording this is out the window for me right now. =T I used a demo of a plugin and it worked nice...so are there any free ones? Or maybe one of you guys could do me a quick favor? Sorry for being such a pain. =T
 
I am using the following:

Receiver: Samson UHF Micro32 M32 Diversity Receiver (Model M32M). It says "Tested to comply with FCC standards for home or office". It has 32 channels (currently using channel 4)

Transmitter: Samson Model T32M

Not sure how to find out what frequency bands I have available. Also, they both work together. Meaning, they are meant to work together. The only thing that is not with the "system" is the mic itself. The original mic broke and I needed something desperately so I used the mic from church. I saw that the cable fit so I used it and it worked beautifully. But after a while, it started giving me interference problems and that "room noise". I think the room noise has to do with the volume because I can hear that it's too loud and the ALC is indeed trying to bring it down. I have no screwdriver small enough to make the volume on the receiver lower.

I'm not sure how a different mic would help the interference problem. All I know is that this used to work beautifully. It's frustrating cause I spent money on this (bought it from a friend). So now I feel like I just wasted money. But maybe you guys can help me through this now that I told you all the information I know. It comes with a handheld mic also (Samson Model H32M). I used this before and I get the room noise too but that must be a volume issue. I don't think it has a problem with interference however. I don't remember it ever having problems with that. Maybe that should clue us in?
 
read again:

Richard Crowley said:
1) There is no hum noise. Learn to properly identify the various kinds of audio artifacts. it will be very helpful in the future to use the common terms.
2) I do hear ambient noise. Record in a place that is more quiet. Also get the microphone as close the the mouth as practical without distortion, wind noise, etc. And don't use AGC.
3) I also hear distortion. Cause could be several different things. Using wireless when you don't really need it is NEVER recommended.
4) I also hear breath noise, perhaps because of the mic position and/or you weren't using a foam windscreen on the mic?
5) I also hear automatic-gain "pumping". You can turn off the AGC, you know. You almost NEVER hear professional video that used AGC.

If your father is pastor at a church consider borrowing a proper (wired) microphone for this kind of video shooting.
Experiment with microphones and recording so that you get better at it.
Click to expand...

plus:

As Recordingwhiz said: "the best multi-thousand dollar wireless is not as good as a $15 mic cable"

and just forget anything but a retake with a wired mic and properly balanced levels. There is no plugin to cure the mistakes you made, laws of physics apply. you could filter out a groundloop hum, de-ess some sharp esses but you can not un-pump a pumping limiter and you can not recuperate radio mic drop outs. its a fact like: at night its colder than outside :-)
 
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