PDA

View Full Version : An Audio Accident-- what happened??



Stacey
01-28-2009, 02:06 PM
I was hired as the videographer on a small doc shoot last week and just about everything was wrong.* I kind of panicked and rushed through it.

I was running a uni condenser mic (HTDZ HT-81) off the camera 6' away from the subject. I did a quick sound check and everything sounded fine. 15 minutes later, I was interviewing the subject (in lieu of the director) and the levels looked slightly high, but not in the red.

When I'm playing the footage back in Premiere, however, it's about the worst thing I've ever heard. It sounds like a windy day on a tarmac and not a word of the subject is audible/intelligible. I am almost sure that I turned off the second input, the XLR connection seemed secure... so I'm scratching my head as to what happened.

Any ideas on what could have created this? I posted a 4 second sample on Vimeo; the first 2 seconds are the audio from the built-in mic on the second camera (15' away from subject) and the last 2 seconds are the audio from the uni about 6' away from the subject. Link here. (http://www.vimeo.com/2989513)

Any suggestions on how to put lipstick on the piggish built-in mic audio track would be wonderful as well. Thank you!

-Stacey


(*The Defensive Asterisk: The director/interviewer left to "run an errand" and never came back, the assistant never materialized and the interview subjects were told to show up an hour earlier than they should have been and were "in a hurry." I know this doesn't make it less my problem, but I feel some need to defend my blunder. I'm pretty embarrassed about this.)

JordanBlock
01-28-2009, 02:40 PM
Is this (http://www.htdz.com.cn/en/productsDisplay.asp?id=940) the mic in question?

What happened?
1 - You used a garbage microphone. (If it says 'PRO' in the product name, chances are it's not.)
2 - You placed said microphone too far from the talent.

Steve House
01-28-2009, 02:41 PM
I was hired as the videographer on a small doc shoot last week and just about everything was wrong.* I kind of panicked and rushed through it.

I was running a uni condenser mic (HTDZ HT-81) off the camera 6' away from the subject. I did a quick sound check and everything sounded fine. 15 minutes later, I was interviewing the subject (in lieu of the director) and the levels looked slightly high, but not in the red.

When I'm playing the footage back in Premiere, however, it's about the worst thing I've ever heard. It sounds like a windy day on a tarmac and not a word of the subject is audible/intelligible. I am almost sure that I turned off the second input, the XLR connection seemed secure... so I'm scratching my head as to what happened.

Any ideas on what could have created this? I posted a 4 second sample on Vimeo; the first 2 seconds are the audio from the built-in mic on the second camera (15' away from subject) and the last 2 seconds are the audio from the uni about 6' away from the subject. Link here. (http://www.vimeo.com/2989513)

Any suggestions on how to put lipstick on the piggish built-in mic audio track would be wonderful as well. Thank you!

-Stacey


(*The Defensive Asterisk: The director/interviewer left to "run an errand" and never came back, the assistant never materialized and the interview subjects were told to show up an hour earlier than they should have been and were "in a hurry." I know this doesn't make it less my problem, but I feel some need to defend my blunder. I'm pretty embarrassed about this.)

Don't have a clue what caused the "windy" noise (dead battery or phantom off? phantom on if it's a dynamic mic? bad cable? faulty mic? - Can't locate any info at all on the web about that mic so have nothing to go on even to make a guess). I'm afraid there's nothing to be done about the reverb in the sound from the camera mic other than reshoot it. Once reverb is there it's pretty much locked in stone.

If it's any consolation about the mic failure, putting any mic 6 feet away from the subject is doomed to failure anyway. Even if whatever caused the noise you recorded didn't happen, at that distance your results most likely wouldn't have been substantially better than what yoiu got with the in-camera mic anyway. Like I said, can't find a thing about that mic to even tell me what kind of mic it is, but even a high quality shotgun needs to be within around 36 inches max of the subject to give high quality results.

JordanBlock
01-28-2009, 02:53 PM
I'm pretty sure a decent chunk of blame for the bad shoot should be on the vanishing director and non-existent AD. You at least stepped up and made sure the shoot happened.

Theres really nothing you can do to fix the poor result other than learning from it and making sure it doesn't happen next time. If you don't generally monitor the sound during the shoot, start doing so. Thats your primary defense against bad audio.

Steve House
01-28-2009, 03:04 PM
What Jordan said!

Looked at that link you posted, Jordan. Man, that is one WEIRD microphone and set of specs! First mic I've ever seen whose impedance varies with the distance ("Output Impedance: Near :1KΩ; Far: 2.3KΩ") ... sheesh! I notice it says it needs 1.5 volt power - a dead battery could account for the failure .

JordanBlock
01-28-2009, 03:15 PM
The mic looks very similar to the Apex "shotgun" (http://www.apexelectronics.com/products.asp?type=6&cat=2&id=27) mic that I've seen in a couple local music stores. I think it's two seperate mics stuffed in a shotgun-like tube. A single mic element wouldn't have two different sets of specs.

From looking at this page (http://www.quarkr.com/dropship/14_37_inch_Professional_Shotgun_Microphone_p2741.h tml) that HT-81 comes with a really cheap looking cable which is probably not helping matters.

phoric
01-28-2009, 03:20 PM
Like the others said, the mic was too far away to do any good, even if it wasn't crapping out on you. Someone needs to be monitoring the audio from the recording device at all times. There is no way you can determine if everything is working properly merely by looking at the audio levels. But, it sounds like everyone else bailed on you so it can't be all your fault. These things do happen to all of us, live and learn I guess. You'll probably have to re-shoot unfortunately.

Noiz2
01-28-2009, 05:56 PM
If you go to the products page they have this slide show. They make mics for conference rooms and such, but look at the places! They are mostly chinese military and security. So just for the record I'm not saying anything bad about that mic ;~)

Stacey
01-28-2009, 07:08 PM
Jordan, thanks for your input. So far, the sound quality is BAD, but passable. I'm bummed to hear that the mic is no good... I'm well aware that $65 is a cheap mic, but I'm in a cheap position right now and I really thought it would be okay. I've used Sennheisers as rentals, so I don't have a whole lot of experience in buying mics.

Time to Ebay that mic to another sucker, I guess. I'm just mortified that this happened on my watch.

Stacey
01-28-2009, 07:11 PM
Phoric,
What's strange to me is that it sounded okay when I checked it. It had fresh out-of-the-box batteries and was close enough to pick up the subject (6'), but ideally not the Midwestern cold-season hacking going on outside the room. A reshoot isn't really an option, but, god, I wish it was. Gross!

Stacey
01-28-2009, 07:17 PM
Steve,
So I'm Ebay-ing this mic on account of bad behavior. I bought the cables from my local rental house, so I know they're good; I've bought XLR from them before. The batteries were fresh from the pack.
Out of curiousity, what about the specs stand out to you as weird? I'm way more versed on visual and writing, so I'm not so schooled on mic shopping. I'd rather opt to have someone else handle that, but it's not in the cards for me right now.

Stacey
01-28-2009, 07:19 PM
Noiz,
Whatever, I'll proudly go on record swearing like a sailer about this mic. ;)

(If the mic caused it and not something I've done... I don't know which is better.)

-Stacey

JordanBlock
01-28-2009, 07:21 PM
Stacey, from listening to your clip on vimeo with the level cranked up, the sound from the camera further away really isn't that bad, perhaps with some noise reduction it would be good enough to save the shoot.

I think the problem with the other cam may have just been the perfect storm of a cheap mic, bad cable, poor power and some kind of RF interference.

Then you tack on the bailing of the Director & AD and the hurried talent and you get a really crappy day.

JordanBlock
01-28-2009, 11:32 PM
Stacey,
I downloaded the clip from vimeo to play with it a little. In the file, the noise is only in one channel, is that the case in the source audio, or just the result of how you put the clips together for the demo? The way it looks to me is that the first 3 seconds is the far camera, and then the final 2 seconds is the near camera.

I took a quick stab at the file, and I've posted my results here (http://www.jordanblock.com/files/audio/stacey_noise.mp3). (77KB mp3)

After discarding the right channel altogether, I converted the left channel to a mono file, brought the gain up 30dB, and then ran just a basic noise reduction on the two chunks of the file separately. The result isn't perfect by any stretch of the imagination, but with a little work you might be able to get something you can use.

Steve House
01-29-2009, 02:27 AM
Steve,
So I'm Ebay-ing this mic on account of bad behavior. I bought the cables from my local rental house, so I know they're good; I've bought XLR from them before. The batteries were fresh from the pack.
Out of curiousity, what about the specs stand out to you as weird? I'm way more versed on visual and writing, so I'm not so schooled on mic shopping. I'd rather opt to have someone else handle that, but it's not in the cards for me right now.

What jumps out is the listing of two values for the output impedance and sensitivity labeled "near" and "far" and although the mic is listed as being a shotgun, the pickup pattern diagram posted is a wide cadioid, not even close to the highly directional pattern of a shotgun. It may be that the mic is switcahble between a wide and shotgun mode but there's nothing on the web page that says that's so.

Just because you've bought cables from that source before and they were okay doesn't mean this one was - things break in service all the time, that's why you carry backups.

What kind of camera do you have and how was this mic connected to it?

John Willett
01-29-2009, 04:14 AM
Did you have the mic. in a proper basket windshield? or Softie?

Or was it naked?

If naked, that is likely to be a lot of your problem.