holy crap shotgun audio distortion

B

booggerg2

Well-known member
Shot my first wedding with the HMC this past weekend.. half way into the reception, the audio starts distorting.. I've provided a link to the mp3 of the audio track.. I also faded to another clip with distorted speech.

I was recording thru an Azden SGM1X shotgun. Is it possible that the battery in the shotgun became so low that it started to distort?

Footage shoot later that night without the shot gun sounded fine. I just pulled out the shotgun (with the same battery) to test and it seems to be okay so I have no idea what caused this... (distortion starts about 10 seconds into it) I've confirmed that the SD card when played back in the camera also has this distortion.

audiodistortion.mp3 - 0.85MB

MediaFire link: http://www.mediafire.com/?sharekey=7adb9fd2e0e887b10dec85adfe0a530ae04e75f6e8ebb871

Please let me know if this kind of distortion sounds familiar to you.
 
Last edited:
Doesn't sound like it's overmodulating or running out of battery...sounds like bad audio compression, something digital...

At any rate, doesn't sound very good. Maybe you should try a reshoot :)

Sorry for the issue, real bummer, but I doubt it was battery-related.
 
Yeah I tested with a low battery, and the mic would generate static even with no audio pickup, in the case of the wedding footage, when there was low audio, the track was quiet.

I should also add that the distortion occurred across several clips after it started. I believe it stopped after I took off the shotgun and starting using only the on-board mic. However, I still think it's a digital audio compression issue but I'm hoping it was a mic power issue...
 
Last edited:
Sounds exactly like a 'bit crusher' effect to me. The effect is when you lower the bit rate of the audio.

Interesting... was the video blocky for the same portion? Would be a compelling result if the vid compression was overloaded and it dropped the audio bit rate to compensate.
 
ken: Video seems fine as far as I can tell.. I didn't watch all of the clips with audio distortion from start to finish so I can't say if there are NO breakage at all in the image. However, for the audio segment I uploaded, that's where the distortion started, and at that point, the video image remained solid and the scene did not get complex visually all of the sudden.

I did notice that just right before the distortion started, there were a couple of slight pops in the audio track. Again, this was my first wedding with the HMC so I'm not certain yet whether these small pops exist throughout all of the footage so it possible that these two pops were merely coincidence.

Also, I don't have the latest firmware installed on my HMC.... don't know if that fixes any bugs related to audio whether officially (or unofficially...)
 
Last edited:
I dont have the latest firmware either but I havent had any audio issues at all.

were you using a wireless system?
 
Nope.. Azden SGM1X shotgun routed to both inputs.. i think from now on, I will only route it to one of the inputs and dedicate the other input for the on-board mic.. until I'm sufficiently confident of what the cause was.. not that it would help if it was a camera compression issue. I do have audio recorded from the H2 but it was not placed in the ideal location...
 
That's an interesting thought...from what I understand, the camera uses VBR so I guess it's possible that as the camera needs more and more resources for the video compression that it takes those resources away from the audio compression. Would be a pretty crappy bug if that's the case.

I'm thinking of a wedding reception dance floor with lots of lights flashing and people moving around....not a compression-friendly scenario.

Interesting thought.
 
I played back the clip in question on my PS3 and I saw no abrupt change in bitrate when the distortion started.. This is going by the bitrate indicator in the PS3.. I don't know how accurate that is though.
 
Why did the mod feel the need to change thread title to insinuate it was distortion of the Azden shotgun mic? Do you have any information that it could be the mic? I kept the title generic but the mod felt the need to insinuate it was the mic? I would appreciate if you have any information you can shed on why you think it was the mic. Thanks.
 
This is nothing to do with bitrate.

Sounds like an external signal is screwing with your mic. Wouldnt surprise me at all being Azden, they arent renowned for quality.
 
Yeah, I honestly have no idea whether it's the Azden, your cable, the camera.....whatever. It "sounded" to me like a kind of sound you get on poorly compressed MP3 track, which is what led me to believe it was the camera. Interference usually sounds more like a buzz/hum, and usually phases in and out as you move in and out of the interference path (which I didn't seem to hear on your recording).

At any rate...yeah, Adobe polices their sites pretty well, sometimes I'll get a post update via e-mail and when I click through to the site it has magically disappeared :)

Still not sure why the mods decided your problem has to have something to do with your mic, but hopefully since someone has identified your problem so easily, they will give you more information about it soon........... :)
 
scapsinger said:
Still not sure why the mods decided your problem has to have something to do with your mic, but hopefully since someone has identified your problem so easily, they will give you more information about it soon........... :)
Click to expand...

I changed the title so that it would be different from the prior audio distortion threads. I didn't change it to say "audio distortion CAUSED BY Azden shotgun", I changed it to add "azden shotgun" to give the thread some identity. Prior threads were all about onboard mic audio distortion. We had a massive thread heavily attended by this same O.P., whereas this one is potentially very different, hence I clarified it.

We occasionally change thread titles here, usually when something is misspelled and that will make it more difficult for someone to find it in the future, or to add some bit of info so that someone browsing in the future will find it easier. Vague thread titles (like "please help me!!!") don't serve any purpose past the original poster's emotional state when posting the thread, yet these threads will be here for months or years, so future users can benefit.

We don't get them all, obviously. And sometimes we don't bother. But sometimes we do.

If the grand conspiracy theorists out there aren't through accusing us of everything in the world, perhaps you can suggest a better title? Perhaps "Audio distortion when using shotgun?" Or maybe some of you won't be happy unless we go directly to "All things Panasonic suck and I wish they would die?"
 
I had a sennheiser shotgun mic doing a similar problem (not even a month after buying it) i thought it was a battery problem source, soo i change to diferent ones with no improvement.
I just returned it for a new one (same mic) and all worked well

The noise was almost identical, it worked fine one shoot and 2 minutes later it went bye-bye

Azden is not known for great audio (on the low-end) but they're ok in the mid price... i have a 500UDR wireless kit (lapel trans, xlr trans, and true diversity receiver) and it has served me well
Maybe the same is true for the shootgun mics =)
 
You must log in or register to reply here.
Back
Top