Where do get a good deal on a cheaper Wireless mic and how do they work? - Page 2 at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > All Things Audio

All Things Audio
Everything Audio, from acquisition to postproduction.


Reply
 
Thread Tools Search this Thread
Old April 11th, 2008, 02:05 AM   #16
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
Bill's got a point, and Minidisc recorders do have their advantages (and disadvantages of course).

Tony, I'm not saying the Samson is bad, just that for a few dollars more you get a lot more by going Sennheiser or Sony.
Tom Hardwick is offline   Reply With Quote
Old April 11th, 2008, 10:45 PM   #17
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Bill, can you elaborate more on "the problems associated with audio via Rf" with the Sennheier wireless mic systems ? I was planning on finally getting the sennheiser wireless mic system and would appreciate any info, or potential problems in advance. I really don't know much about these systems and have read about the iriver units and have gotten one along with the giant squid mic. I have yet to try to use the audio from the iriver in edit and have heard that syncing the audio from the irivers and your cameras audio/footage, requires some "tricks" with stretching the audio in post to get it synced. Any info would be much appreciated.
Robert Acosta is offline   Reply With Quote
Old April 12th, 2008, 04:44 AM   #18
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Robert Acosta View Post
Bill, can you elaborate more on "the problems associated with audio via Rf" with the Sennheier wireless mic systems ? I was planning on finally getting the sennheiser wireless mic system and would appreciate any info, or potential problems in advance. I really don't know much about these systems and have read about the iriver units and have gotten one along with the giant squid mic. I have yet to try to use the audio from the iriver in edit and have heard that syncing the audio from the irivers and your cameras audio/footage, requires some "tricks" with stretching the audio in post to get it synced. Any info would be much appreciated.
There's an old sound mixer's adage "Always use a cable whenever you are able." Radio links are always potentially subject to interference, dropouts, multipath distortion, etc, problems that hard-wired mic are not. The Sennheiser G2's are good enough to be considered entry-level professional quality but many of the differences between a G2 setup at ~$600 and a Lectro or Zaxcom setup at $3000 to $4500 is the relative immunity from such problems with the higher priced units. But a $50 XLR cable is even more immune to such problems than even the top of the line wireless rig would be. That's not to say you shouldn't get the Sennheiser setup, just be realistic about your expectations for ANY wireless.

The problem with sync using consumer recorders like the iRiver lies in the stability of the sample clocks. If the clock in the camera and the clock in the recorder are running at slightly different rates, when you line up a 'frame' of audio to its matching picture in post at the start of the shot you'll find that over time as the shot progresses the two will drift apart. Audio that was initially recorded over exactly 5 minutes will play back in 5 minutes plus or minus some fraction when transferred into your editing workstation. Alas, rock-solid stable and accurate clocks require careful engineering, high quality components, careful assembly, and vigilant quality control and all that costs money. It's just not something the manufacturer of a product designed for consumer entertainment and selling for ~$100 can afford to do.

There aren't really any tricks to get things synced in post. Use editing software that lets you stretch the audio track to make it longer or shorter without shifting its pitch. When shooting use a slate or something like a handclap to mark a point near the start of the scene and another near the end. In post, after importing both the audio and video files, place them on the editing timeline. Slide the audio back and forth until the sound of the slate or clap in the audio at the start of the shot matches the frame showing the clap in the video. Scroll to the end of the shot and see if the 'tail slate' frames match. If they do, fine. If not, figure out by what percentage the audio running time needs to be expanded or compressed to bring them into alignment.
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old April 12th, 2008, 06:55 AM   #19
Regular Crew
 
Join Date: Apr 2007
Location: UK
Posts: 112
As Steve says, clock accuracy is not cheap -- and of course it may not be the external audio recorder's clock that's at fault.
It could be spot on, but if the camera clock is slightly adrift, you've still got a problem. And as the camera track is the one already synced to the video, it's still the external recording that has to be changed, even though it's recorded at the right speed!

I reckon you can do quite well for external audio recording quite reasonably.

The Olympus WS200S, and it's successor the WS210S, can give quite good results for less than $100. Not 'top draw',but better than you might imagine for a cheap dictation recorder. And tiny, so easy to hide.

I did a mic comparison here:
http://www.simplydv.co.uk/simplyBB/v...&sd=a&start=15
a while back (second post from bottom of page) which included a WS200S recording. Sorry about the voice, but it is a genuine un-modified simultaneous recording, just to give an idea of the quality you might expect for $100.

Incidentally, the external lav mic used with the WS200S was a $5 Panasonic WM 61A capsule.
Roger Shore is offline   Reply With Quote
Old April 12th, 2008, 07:04 AM   #20
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
Funnily enough my Sony and Sharp Minidisc recorders hold absolute sync with my Z1 over the hour a tape runs, so I assumed (wrongly, it turns out) that digital audio recorders simply ran in sync because they almost 'had to'.

So I was very disappointed to find how far my Zoom H2 (nice recorder that it is) drifts in the hour. Recording MP3 it's a good 12 frames out.

http://www.samsontech.com/products/p...fm?prodID=1916

tom.
Tom Hardwick is offline   Reply With Quote
Old April 12th, 2008, 08:10 AM   #21
Inner Circle
 
Join Date: Nov 2004
Location: Baltimore, MD USA
Posts: 2,323
Tom,

At least now you know what works! (and what doesn't).

Regards,

Ty Ford
Ty Ford is offline   Reply With Quote
Old April 13th, 2008, 01:49 PM   #22
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Thanks to all for the info, much appreciated.
Robert Acosta is offline   Reply With Quote
Old April 13th, 2008, 02:36 PM   #23
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Tom, are you saying that the Sony minidisc recorder, obtains audio over the cousre of an hour, that synced flawlessly with you Sony video recorders audio? But, that the H2's audio was out of sync? Sorry for the dumb question, but, I wanted to make sure that there are recording devices that will record synced audio without the need for editing in post. I have a pd170 and was hoping to find a portable recording device to work in outdoor situations that will work with lav mics to get the audio I need and avoid the "wireless" mic pitfalls and expense.
Robert Acosta is offline   Reply With Quote
Old April 13th, 2008, 02:54 PM   #24
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
That's exactly what I'm saying Robert. My VX2000, FX1 and Z1 all sync beautifully with the Sharp and two Sony Minidisc recorders that I have. I've often run all of them for an hour at a time for stage shows etc, where Minidisc recorders can be dotted about the stage and plugged into the sound board.

The Zoom H2 is lovely because it's absolutely silent and it will easily run 35 hours onto a 2 gig card, but the loss of sync is a real disappointment. Of course many NLE setups will simply stretch or compress the audio to fit the pictures, though my Premiere 6.5 wouldn't do this. Just gone Edius 4.5 and don't know about this new NLE.

tom.
Tom Hardwick is offline   Reply With Quote
Old April 13th, 2008, 08:44 PM   #25
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Tom... are any of these units portable for outdoor use on battery power?
Robert Acosta is offline   Reply With Quote
Old April 13th, 2008, 08:50 PM   #26
Regular Crew
 
Join Date: Apr 2007
Location: UK
Posts: 112
I can't help thinking you've been very lucky Tom -- for the reason that Steve outlines above, there is no guarantee that any device, minidisc or otherwise, is going to stay in sync.
From my post above, my cheapo Olympus WS200S was hopelessly out of sync after only ten minutes - my Panasonic minidisc is much better. But it depends if I use my Canon or Panasonic camera. They're both slightly different in clock frequency, and so even my trusty old minidisc will not keep sync on a really long take - especially with my Canon camera.

The problem is that every combination is going to be different. Some folk are going to be lucky, like you have been, other perhaps not so lucky.
I think it would be useful to have the option to re-sync in post as a technique 'in the toolbox', as it were, if your particular combination of camera and recorder just happens to be one of the 'unlucky' ones.

Having said that, it would appear that some combinations are worse than others -- I've seen other posts on the net that suggest the Zoom H2 is perhaps more prone than some other devices to be 'adrift', clock frequency wise.
Roger Shore is offline   Reply With Quote
Old April 13th, 2008, 10:37 PM   #27
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Roger...would it be safe to say that your panasonic mini recorders' clock is synced with your panasonic camera as opposed to your canon, and if so, then, can I draw the conclusion that the brand specific recorders will sync with their respective cameras...(Sony with Sony,Pana with Pana) ?
Robert Acosta is offline   Reply With Quote
Old April 14th, 2008, 02:19 AM   #28
Inner Circle
 
Join Date: Mar 2003
Location: Billericay, England UK
Posts: 4,711
Quote:
Originally Posted by Robert Acosta View Post
Tom... are any of these units portable for outdoor use on battery power?
How small do you want a Minidisc recorder to be Robert? My Sony recorder is the size of three Minidiscs stacked on on top of the other. Far smaller than the H2, which is electric razor size. I'm happy to put the Minidisc into a groom's inside pocket, but he'd blanch at the sight and size of the Zoom H2.

So I've been lucky all these years and didn't know it Roger. I'd assumed that all camcorders ran in perfect sync, from old VHS to modern solid state. After all, they have to put 25 fps up onto a TV connected to our 50Hz mains, and if they didn't run exactly to speed the pictures would wobble.

tom.
Tom Hardwick is offline   Reply With Quote
Old April 14th, 2008, 05:16 AM   #29
Inner Circle
 
Join Date: Mar 2005
Location: Hamilton, Ontario, Canada
Posts: 5,742
Quote:
Originally Posted by Tom Hardwick View Post
...
So I've been lucky all these years and didn't know it Roger. I'd assumed that all camcorders ran in perfect sync, from old VHS to modern solid state. After all, they have to put 25 fps up onto a TV connected to our 50Hz mains, and if they didn't run exactly to speed the pictures would wobble.

tom.

Not a valid assumption at all. Picture would "wobble?" It would take a very practiced eye to see the difference between a picture shot at 25 FPS being played at 25FPS versus played at 24 FPS. The issue with sync in double system sound deals with sample clock accuracy, something that is a much more precise issue than mere frame rate. Audio is sampled for video at 48,000 samples per second. That means that in the time equal to a frame of NTSC video a soundtrack contains 1600 samples, 1 minute of a soundtrack contains 2,880,000 samples and 10 minutes would contain 28,800,000 samples. If the clock in the audio recorder and the clock in the camera differ by only 0.0055% you will have a 1 frame loss of sync in only 10 minutes and that will absolutely be noticable. In single system, where the sound and picture are recorded together in one device with sample clocks based on the same master clock, a slight difference from the nominal standard is of no consequence because the audio and video clocks are still together even if they're not right on what they should be. But in double system, if there's nothing to slave one to the other, even the slightest difference between the camera and audio recorder will eventually cause them to drift apart and loss of sync will jump up to bite you in the backside. Some combinations might drift out in 1 minute, some in 15 minutes, some might even hold it longer than that but eventually, it'll getcha.
__________________
Good news, Cousins! This week's chocolate ration is 15 grams!
Steve House is offline   Reply With Quote
Old April 14th, 2008, 06:55 AM   #30
Regular Crew
 
Join Date: Apr 2007
Location: Bflo, USA
Posts: 64
Tom, The Sony portable minidisc you talked about sounds ideal, and if you could post a model # to refer to, I'd appreciate it. The information I've gotten so far on the sync issue has given me a better understanding of the possible probems I'm going to encounter and this at least will provide me with a good starting point. From some of these posts, it appears as if I can use post editing to make the audio acquired from the different recording sources, work using the stretching technique in edit. Having a sound that will "mark" the beginning of the recording seems to be an important requirement. Can audio between the camera and the secondary audio, simply be matched using the beginning of the dialogue at a low hushed level. For example, filming a nest of hummingbirds from 30 to 40 feet away, with someone mic'ed up a few yards from the hummingbirds, would require a hushed initial dialogue at best. Would this be enough to begin syncing the audio to the footage?
Robert Acosta is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > All Things Audio

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 04:17 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network