48 KHz audio at DVinfo.net

Go Back   DV Info Net > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon EOS Crop Sensor for HD

Canon EOS Crop Sensor for HD
APS-C sensor cameras including the 80D, 70D, 7D Mk. II, 7D, EOS M and Rebel models for HD video recording.


Reply
 
Thread Tools Search this Thread
Old September 2nd, 2009, 01:24 PM   #1
Wizard Status
 
Join Date: Jun 2005
Location: New York, NY
Posts: 239
48 KHz audio

Another feature to try to tease out of the 7D firmware when it is available -- 48 KHz audio:
Quote:
Higher audio sample rate: The 7D's audio sample rate is 48khz, up from 44.1khz in the 5D Mark II
The ak4646 in the 5Dm2 supports it. Hopefully it is just a matter of selecting the right bits in the sample rate register.
Tramm Hudson is offline   Reply With Quote
Old September 2nd, 2009, 01:32 PM   #2
Obstreperous Rex
 
Join Date: Jan 2001
Location: San Marcos, TX
Posts: 26,900
Images: 513
Hmm, this gets more interesting by the day. Thanks Tramm,
__________________
CH

Search DV Info Net | DV Info Net Sponsors | A Decade (+5) of DVi | ...Tuesday is Soylent Green Day!
Chris Hurd is offline   Reply With Quote
Old September 2nd, 2009, 02:16 PM   #3
Inner Circle
 
Join Date: May 2006
Location: Camas, WA, USA
Posts: 5,513
I'll say this, Canon's photo people have definitely spent time with their video people. Not only is the 7D getting 29.97, 25, and 23.976 fps, but 48 kHz too. Canon is taking this video stuff seriously - at $1,700 and up. I can't wait to see what they announce at NAB.

48 kHz would be very nice in the 5D2. Currently, the JL/ML is really quiet, but is a smidge crunchy to my ears. My guess is that I'm hearing some aliasing. (This is due to the camera, not the juicedLink. It could probably be solved with an external anti-aliasing filter, though I haven't tried it.) 48 kHz would make the camera that much less susceptible to aliasing. In fact, the filter rejection band might be set for 24 kHz, rather than 20.5.

I'm confident that Tramm can change the bits to deliver 48kHz from the audio chip. I'm not confident that the DIVIC will receive it and interleave it into the video files properly though. My hunch is that the encoder will need some bit twiddling as well.

Fingers crossed...
__________________
Jon Fairhurst
Jon Fairhurst is offline   Reply With Quote
Old September 4th, 2009, 06:31 AM   #4
Major Player
 
Join Date: May 2007
Location: Fayetteville, GA
Posts: 772
So, what audio quality do we expect from the 7D if we run a good mic to it's 3.5mm plug? I know it has AGC, but is the sound otherwise clean and accurate. I hope someone (Canon?) will eventually crack the AGC.

If I can run my NTG-2 and Sennheiser wireless thru 1/8" jack and get good sound, I'd be very happy. I really want to avoid having to sync audio on an external Zoom.
Roger Shealy is offline   Reply With Quote
Old September 4th, 2009, 07:22 AM   #5
Major Player
 
Join Date: Mar 2006
Location: Chicago
Posts: 706
Quote:
Originally Posted by Roger Shealy View Post
So, what audio quality do we expect from the 7D if we run a good mic to it's 3.5mm plug? I know it has AGC, but is the sound otherwise clean and accurate. I hope someone (Canon?) will eventually crack the AGC.

If I can run my NTG-2 and Sennheiser wireless thru 1/8" jack and get good sound, I'd be very happy. I really want to avoid having to sync audio on an external Zoom.
Likely the same electronics as the 5DII. Cheap. You can certainly get much better sound than the internal mike. Does Canon make anything with great audio?
Don Miller is offline   Reply With Quote
Old September 4th, 2009, 07:43 AM   #6
Major Player
 
Join Date: May 2007
Location: Fayetteville, GA
Posts: 772
But if you supply a good externall mic to the 3.5mm jack, will the electronics in the 7D (probably similar to 5D) capture it audio accurately?
Roger Shealy is offline   Reply With Quote
Old September 4th, 2009, 07:53 AM   #7
Wizard Status
 
Join Date: Jun 2005
Location: New York, NY
Posts: 239
Quote:
Originally Posted by Roger Shealy View Post
But if you supply a good externall mic to the 3.5mm jack, will the electronics in the 7D (probably similar to 5D) capture it audio accurately?
Jon Fairhurst did a series entitled http://www.dvinfo.net/conf/canon-eos...k-cx231-3.html

His results were that if the (cheap) preamp in the 5D is disabled or set to very low gain and a high quality preamp like the juicedLink CX231 is used instead, then the results are as good as a standalone audio recorder. Even better, if you consider the time saved in post trying to sync the audio and video without timecode.

It remains to be seen what audio chip the 7D is using. My guess is that it is the same AK4646, but until we've looked in the firmware we won't know.
Tramm Hudson is offline   Reply With Quote
Old September 4th, 2009, 10:42 AM   #8
Contributor
 
Join Date: Jan 2003
Location: Kansas City, MO
Posts: 4,449
Can you turn off the auto gain?
Bill Pryor is offline   Reply With Quote
Old September 4th, 2009, 10:52 AM   #9
Inner Circle
 
Join Date: May 2006
Location: Camas, WA, USA
Posts: 5,513
Magic Lantern can set a fixed gain in the 5D2. Not sure about the stock 7D. All indications are that Magic Lantern will be on the 7D before too long, and should also be able to set a fixed gain.

The standard disclaimer about predicting the future applies...
__________________
Jon Fairhurst
Jon Fairhurst is offline   Reply With Quote
Old September 4th, 2009, 10:53 AM   #10
Inner Circle
 
Join Date: Nov 2005
Location: Elk Grove CA
Posts: 6,838
Quote:
Originally Posted by Roger Shealy View Post
So, what audio quality do we expect from the 7D if we run a good mic to it's 3.5mm plug? I know it has AGC, but is the sound otherwise clean and accurate. I hope someone (Canon?) will eventually crack the AGC.

If I can run my NTG-2 and Sennheiser wireless thru 1/8" jack and get good sound, I'd be very happy. I really want to avoid having to sync audio on an external Zoom.
Roger:

I just got the NTG-2, as well as a free Rode M3 as part of their free mic offer. I tested on the 5D, which I would expect to comparable to the 7D. The NTG-2 kit I got from BH came with an XLR to mini adapter. Using Magic Lantern to disable automatic gain, and directly plugging into the camera with the mini adapter, I have shot decent levels running the camera setting at +23 gain analog, and +12 gain digital without using the Juiced Link. With Mic right up on the talent, these can go down to 17, 12 levels.
__________________
Chris J. Barcellos
Chris Barcellos is offline   Reply With Quote
Old September 4th, 2009, 11:45 AM   #11
Contributor
 
Join Date: Jan 2003
Location: Kansas City, MO
Posts: 4,449
Thanks, Jon. Yeah, we really don't know all that much about the yet-to-be-on-the-market 7D at this time. I'm still torn between shooting double system sound with something like the Tascam DR-100 or Zoom H4N or going with a Beachtek or Juicedlink (in the somewhat likely event I buy the 7D in a few months).
Bill Pryor 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 > Canon EOS / MXF / AVCHD / HDV / DV Camera Systems > Canon EOS Crop Sensor for HD

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 05:44 AM.


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