7D's Audio Capabilities [Archive] - DVXuser.com -- The online community for filmmaking

Rick Rock

09-09-2009, 12:54 PM

Some more audio info:

"Higher audio sample rate: The 7D's audio sample rate is 48khz, up from 44.1khz in the 5D Mark II." - From Rob Galbraith's review. This is great! Just need to find the bitrate now. Should be either 16-bit or 12-bit based on standard videocamera audio. Hoping for the former.

Link: http://www.robgalbraith.com/bins/multi_page.asp?cid=7-10042-10239-10240

And from the Magic Lantern website:

"Will it work on a 7D?

Short answer: Not yet. Until there is a firmware update for the 7D, it will be difficult to get a firmware dump. It might be possible to generate one with the 5D dumping toolkit, which would allow a very quick port to the 7D. Send me a camera and I'll get right on it."

So who here wants to donate their pre-order? Anyone? Bueller?
.

Rick Rock

09-09-2009, 01:00 PM

http://www.robgalbraith.com/data/1/rec_imgs/3293_7d_rode.jpg
Source: http://www.robgalbraith.com/

Nice setup for run & gun. Will have to get me one of these mics.
.

Luis Caffesse

09-09-2009, 01:12 PM

From what I've seen it seems the 7D will have the same AGC issues of the 5D, correct?
As far as I know it can't be disabled without something like the beachtek adapter.
Hopefully someone will correct me if I'm wrong on that.

On a sidenote - I used that Rode mic recently with a GH1, and I have to say, I was pretty impressed with the results (granted, my expectations were pretty low at the time)... but it's actually a pretty solid solution.

Lucian

09-09-2009, 01:15 PM

What the 5 owners swear by: http://www.juicedlink.com/index_files/CX_camcorder_XLR_microphone_adapter_audio_mixers_C X231.htm

Luis Caffesse

09-09-2009, 01:23 PM

I don't understand why anyone would use an adapter like that without something like the Zoom -
seems that dual system is the only way to go with these cams right now, until one of these manufacturers decides to throw 10 more cents at their camera costs and actually grace us with a headphone jack.

I could see using a Zoom and jacking the output into the camera just in case the camera audio was actually good enough to use....but at least that way you can monitor the zoom that you're recording onto. Using an adapter like that (or the beachtek by itself) you're only able to monitor the signal before it gets recorded...

Audio recording without the ability to monitor the actual recorded signal seems kind of like shooting with your eyes closed.

Rick Rock

09-09-2009, 01:23 PM

AGC is confirmed. From the Canon 7D user manual, page 151:

"Stereo sound recording is possible by connecting an external microphone equipped with a stereo mini plug (3.5mm dia.) to the camera's external microphone IN terminal.

The sound recording level will be adjusted automatically."

So yeah, we'll be stuck with AGC till Canon releases a firmware update and the Magic Lantern guys make improvements to it.

One work around is to use a mixer with a limiter built-in. This will ensure that that audio won't clip, which in my experience is more of a pain than just remixing wild audio levels.
.

Eddy Robinson

09-09-2009, 01:29 PM

There are those of us who got the Edirol HR9 and edit on Windows...what is the PluralEyes equivalent for us?

Use a slate, o make sure time-of-day is set accurately on both camera and recorder. Won't be frame-accurate, but lining it up isn't really that much work. Take notes. Split the headphone output from the HR9 or whatever and run it into the camera. Tehre's about 20 different ways to solve this problem, and while it may take longer than the PluralEyes you'll get to know your footage better.

J Davis

09-09-2009, 01:34 PM

It's 2-system sound for me. AGC is horrendous.

Even if magic lantern disables AGC you have no way to monitor
how can you tell your peaks?

livelikeriley

09-09-2009, 01:36 PM

Rick Rock

09-09-2009, 01:42 PM

"Even if magic lantern disables AGC you have no way to monitor. how can you tell your peaks?"

According to the info for the most recent build of Magic Lantern, it disables AGC, adds some gain controls, routes audio out of the A/V jack, and gives you a level meter.

I'd say that's some pretty darn good monitoring right there. Hope they can port it to the 7D sooner than just waiting for the first firmware update from Canon.

Luis Caffesse

09-09-2009, 01:43 PM

According to the info for the most recent build of Magic Lantern, it disables AGC, adds some gain controls, routes audio out of the A/V jack, and gives you a level meter.

Wow.
Well... that's something.

J Davis

09-09-2009, 01:47 PM

I got nothing against 2 system audio except it ads post time. Zoom H4 you need to timestretch everything to 99.99% unless its a 20 sec clip. its out 1 frame every 6 minutes at 24p. You'll need to know how to do sub frame audio editing in FCP as well in order to get it perfect.

Slating is a pain but it can be done in audio only. I usually just call out the time.

"Even if magic lantern disables AGC you have no way to monitor. how can you tell your peaks?"

According to the info for the most recent build of Magic Lantern, it disables AGC, adds some gain controls, routes audio out of the A/V jack, and gives you a level meter.

I'd say that's some pretty darn good monitoring right there. Hope they can port it to the 7D sooner than just waiting for the first firmware update from Canon.

can't wait bro, this will be salvation

Luis Caffesse

09-09-2009, 01:54 PM

Something just occurred to me:

...adds some gain controls, routes audio out of the A/V jack

On the 7D engaging the A/V jack will supposedly disable the LCD screen -
I wonder Magin Lantern will somehow be able to work around that?

Would be a shame to get the ability to monitor audio, at the cost of monitoring video.
:)

J Davis

09-09-2009, 02:08 PM

Something just occurred to me:

On the 7D engaging the A/V jack will supposedly disable the LCD screen -

Now that's a deliberate cripple. Shame on you canon.

ydgmdlu

09-09-2009, 02:12 PM

I've only heard of PluralEyes since reading this post...what's the point if you're shooting with only 1 camera? What's so hard about using a slate? Does it do something I'm missing - also, thanks for letting me know about the zoom, much cooler than the solution I was going to buy.
It automatically syncs the double-system sound with the video for you, and it works with single-cam set-ups. No more manual syncing!

Rick Rock

09-09-2009, 02:37 PM

Awwww, man. The Canon 7D manual confirms that when doing video out during Live View, either by the HDMI or the A/V adapter, the LCD is turned off.

So lame! I'm guessing they thought it would save battery life, but for crap's sake, give us the option to turn it back on!

Let's hope Magic Latern is working on this as well, if only on the 5Dmkii for the time being.
.

mico

09-09-2009, 02:42 PM

livelikeriley

09-09-2009, 02:44 PM

Sorry to highjack the thread...but so plural eyes will sync the audio from the onboard cam. mic with the audio I'm recording independently to a compact flash recorder? Cool!

J Davis

09-09-2009, 02:46 PM

It automatically syncs the double-system sound with the video for you, and it works with single-cam set-ups. No more manual syncing!

The lining up/syncing is easy. Does it time stretch without affecting pitch?
Because using a 7D and an external recorder the audio is gonna slip

mhood

09-09-2009, 02:47 PM

Mac only it seems. Nothing out there AFAIK for we Windows folks.

ydgmdlu

09-09-2009, 02:51 PM

Sorry to highjack the thread...but so plural eyes will sync the audio from the onboard cam. mic with the audio I'm recording independently to a compact flash recorder? Cool!
Now you get it. :)

Lucian

09-09-2009, 03:39 PM

The Juicedlink provides XLR's and a dandy preamp to clean up your audio. 5d guys are liking it. A better option for one man bands.

Luis Caffesse

09-09-2009, 03:41 PM

The Juicedlink provides XLR's and a dandy preamp to clean up your audio. 5d guys are liking it. A better option for one man bands.

But again - you would really want to go into an external recorder, unless you're okay with recording audio without being able to monitor it
(unless I misunderstood the product you linked to, seems to be an adapter ala beachtek...not a recorder).

J Davis

09-09-2009, 03:48 PM

I'm sure the juicedlink is a great preamp, sh*t you could even use a sound devices
but its still going to sound like garbage unless the Auto Gain Control (AGC) in the camera is disabled.
Luis is right, external recorder! Onboard sound is only good for sync unless magic lantern pulls thru with a hack

Luis Caffesse

09-09-2009, 03:55 PM

Onboard sound is only good for sync unless magic lantern pulls thru with a hack

Keeping my fingers crossed on that one - I really dread the idea of dual system sound...
but the images from these things is getting too good for me to ignore any longer.

If I knew for a fact that Magic Lantern could come through with a stable firmware hack to allow for the onboard audio to be used and monitored - I'd preorder a 7D this second.

J Davis

09-09-2009, 04:01 PM

I really dread the idea of dual system sound...

It's actually not that bad. I've done 5 or 6 shoots using dual system sound and the GH1 in the last two months. You have to be diligent with slating because when you have a lot of audio files on your H4 and a camera full of clips it can be tricky when it comes to logging them. I have never used plural eyes, I just sync using the FCP sub frame editing and make sure I time stretch to account for slippage. The results from combining a vDSLR and zoom H4 can be sweet though LINK (http://www.youtube.com/watch?v=FVstdQNDsxs&fmt=22)

xbourque

09-09-2009, 04:02 PM

For anyone still confused about PluralEyes:

Philip Bloom PluralEyes tutorial w/ Zoom H4N and 5D2
http://www.vimeo.com/5774898

J Davis

09-09-2009, 04:05 PM

For anyone still confused about PluralEyes:

Philip Bloom PluralEyes tutorial w/ Zoom H4N and 5D2
http://www.vimeo.com/5774898

I know about how it works but I am almost certain that it doesn't compensate for slippage.
For example the audio from a zoom h4 is 1 frame longer than the audio in the camera every 6 minutes when recording 24p. So your plural eyes edit may line up at the start but by the end of a 6 minute shot you are a frame out. Even after 2 minutes the slippage becomes noticable

Barry_Green

09-09-2009, 04:06 PM

So who here wants to donate their pre-order? Anyone? Bueller?
I'd consider it... I mean, loan, not donate, but -- yeah, you knew that anyway...

xbourque

09-09-2009, 04:12 PM

I know about how it works but I am almost certain that it doesn't compensate for slippage.

Anybody who has actually used the software care to confirm or deny?

-X

Luis Caffesse

09-09-2009, 04:18 PM

The results from combining a vDSLR and zoom H4 can be sweet though LINK (http://www.youtube.com/watch?v=FVstdQNDsxs&fmt=22)

As a quick aside - Nice work.
:thumbsup:

Eddy Robinson

09-09-2009, 04:24 PM

Keeping my fingers crossed on that one - I really dread the idea of dual system sound...
but the images from these things is getting too good for me to ignore any longer.

Why? It's pretty easy. There's some more work involved on the post side but it's not that bad. I can never understand video shooters' paranoia about double system sound, all that workflow was perfected years ago for film and it still works just fine.

Only bad part is you need a sound person, but frankly if you're trying to be a one-man band you're not likely to do a good job of both shooting and getting a tasty audio recording. You're in Austin, there should be a bunch o sound people aound there.

Eddy Robinson

09-09-2009, 04:31 PM

One man bands can't slate.

Don't be silly, of course they can. Mic yourself, turn on camera audio, say 'this is shot 1-2-3' or whatever at the start of the take. Bang, instant take ID and sync on both media. Alternatively, start the audio recorder, start the camera, point camera at recorder - instant clip ID and time offset. There's lots of ways you can do it.

mico

09-09-2009, 04:36 PM

Don't be silly, of course they can. Mic yourself, turn on camera audio, say 'this is shot 1-2-3' or whatever at the start of the take. Bang, instant take ID and sync on both media. Alternatively, start the audio recorder, start the camera, point camera at recorder - instant clip ID and time offset. There's lots of ways you can do it.

Have fun.

Luis Caffesse

09-09-2009, 04:36 PM

Why? It's pretty easy. There's some more work involved on the post side but it's not that bad. I can never understand video shooters' paranoia about double system sound, all that workflow was perfected years ago for film and it still works just fine.

Only bad part is you need a sound person, but frankly if you're trying to be a one-man band you're not likely to do a good job of both shooting and getting a tasty audio recording. You're in Austin, there should be a bunch o sound people aound there.

99% of my work is documentary style shooting and/or interviews where I"m working alone. Adding another component to the production chain means adding another set of batteries that need to be charged, another set of menus that need to be checked and set, another set of cables, another piece of gear to start/stop after each take, and another set of files that need to be offloaded, organized and backed up .... essentially it doubles the odds of something going wrong.

It's not about the work on the post end for me - that I dont' mind so much because sitting in an edit bay there is very little pressure and little that can go wrong that can't be undone - it's being in the midst of production where I really need things to be as efficient and streamlined as possible.

Like I said - the images from these cameras are becoming too good for me to ignore - but first and foremost my responsibility is to make absolutely certain that my clients get what they want. I have no problem jumping through certain hoops for my own personal projects, short films, online series, or what have you - but when it comes to paying work - the less links in the production chain that can go wrong... the better.

So - while I might be tempted to move into dual system for now... I wouldn't want it to be a long term setup for me.
But like anything else, obviously, everyone's point of view on it will depend on what they need and what kind of work they're doing - so I'm not claiming that it's a problem for everyone... just happens that it's a problem with the type of work I do.

Eddy Robinson

09-09-2009, 04:41 PM

I got nothing against 2 system audio except it ads post time. Zoom H4 you need to timestretch everything to 99.99% unless its a 20 sec clip.

I don't think this will necessarily be the case for the 7d. 5Dii wasn't fully compliant with SMPTE drop-frame timecode, looks to me like the 7d is because it records at 59.94, 29.97 or 23.976. If you plan to stay on video then this will be OK, if you expect to go to true 24 fps (ie you are going to do a film out to actual honest-to-god film) then you will need to pull up your audio.

This audio pull-up/down thing is hideously annoying, so much so that even Walter Murch complains about it. Euros in PAL-land can cheerfully ignore this entirely and just assume everything happens at a frame rate of 25 fps, forever...at least until they want to send stuff to NTSC land.

Mind you, there'll always be a little bit of drift with cheaper gear, due to inaccuracies in their clock - errors of an audio sample or two over 10 minutes, say. This is most unlikely to affect anyone seriously, though if you were using two recorders it could result in phase cancellation effects when all the tracks were played back together.

Eddy Robinson

09-09-2009, 04:51 PM

Have fun.

You'll thank me later.

Like I said - the images from these cameras are becoming too good for me to ignore - but first and foremost my responsibility is to make absolutely certain that my clients get what they want. I have no problem jumping through certain hoops for my own personal projects, short films, online series, or what have you - but when it comes to paying work - the less links in the production chain that can go wrong... the better.

I really don't get it. If work is at least partly about the beauty of the image (vs more functional stuff like depositions or so), then just bring an assistant and pad your bill a bit rather than feel overwhelmed.

To be frank, I would feel a lot more confident and relaxed with a dedicated piece of gear taking care of the audio than some half-assed solution involving multiple preamps (the input to the 7d doesn't look to be switchable to line voltages, and that means you're going to be taking a pre-amplified mic signal from a beacktek or whatever and dropping the volume way down so it can be amplified again nside the camera...this is not a recipe for good audio).

I mean a camera with its own preamps and XLRs and level controls OK, but now you're back to functional rather than aesthetic considerations or you could just go with one of the standard workhorse camcorders.

Sttratos

09-09-2009, 05:42 PM

I have never heard of the Zoom H4n before. It seems to be made more to record music etc. But a recorder is a recorder. How people use it to record dialog or interviews? Do they use the built in mic and just have the recorder off frame or do they plug in a shotgun mic and boom and use the Zoom as a recorder only?

Eddy Robinson

09-09-2009, 05:50 PM

J Davis

09-09-2009, 05:51 PM

The results from combining a vDSLR and zoom H4 can be sweet though LINK (http://www.youtube.com/watch?v=FVstdQNDsxs&fmt=22)

As a quick aside - Nice work.
:thumbsup:

Thanks!
This was a one man band scenario BTW. Just me, her, the morning sun, no screens or bounceboards, just cam, tripod, NTG2, MM1, zoomH4

I don't think this will necessarily be the case for the 7d. 5Dii wasn't fully compliant with SMPTE drop-frame timecode, looks to me like the 7d is because it records at 59.94, 29.97 or 23.976. If you plan to stay on video then this will be OK, if you expect to go to true 24 fps (ie you are going to do a film out to actual honest-to-god film) then you will need to pull up your audio.

This audio pull-up/down thing is hideously annoying, so much so that even Walter Murch complains about it. Euros in PAL-land can cheerfully ignore this entirely and just assume everything happens at a frame rate of 25 fps, forever...at least until they want to send stuff to NTSC land.

Mind you, there'll always be a little bit of drift with cheaper gear, due to inaccuracies in their clock - errors of an audio sample or two over 10 minutes, say. This is most unlikely to affect anyone seriously, though if you were using two recorders it could result in phase cancellation effects when all the tracks were played back together.

I did tests of 1 hour duration with the GH1 and the zoom H4 for audio sync. Pulldown has nothing to do with audio. The audio on 24p = audio on 30p. I feel the error is in the H4 and if you have someone talking it becomes noticeably out of sync after about 1 minute. First thing I will be doing when I have a 7D is an audio sync test.

Sttratos

09-09-2009, 05:56 PM

Both. You can mount it on a stand, for example, and plug a boom and a lavalier into it - it'll record up to 4 channels simultaneously. I think it's the best all-round recorder in its price range. Of course, you can spend considerably more for pro gear, up to about $10k for the top of the line pro stuff. The Zoom is geared at music but is solid and flexible enough to be useful for film work.

I think for dialog in drama recording directly with it may not be the best option. The mics in it are not shotguns. Hanging it from a boom would be pretty awkward. In that case, using it as a recorder only is the best I think.

Luis Caffesse

09-09-2009, 05:56 PM

I really don't get it. If work is at least partly about the beauty of the image (vs more functional stuff like depositions or so), then just bring an assistant and pad your bill a bit rather than feel overwhelmed.

Not to derail the thread - but it's a bit more complicated than that for me - as the bulk of my work is out of town, on the road, etc... so adding a member to the crew increases costs significantly for the clients before we even talk about dayrates for the added sound person (airfare, hotel, food, expenses) - unless we try to pick someone up in each city, which has its own logistical issues for me.

To be frank, I would feel a lot more confident and relaxed with a dedicated piece of gear taking care of the audio than some half-assed solution involving multiple preamps (the input to the 7d doesn't look to be switchable to line voltages, and that means you're going to be taking a pre-amplified mic signal from a beacktek or whatever and dropping the volume way down so it can be amplified again nside the camera...this is not a recipe for good audio).

And I totally agree - which is why I would record on the Zoom, and only jack the zoom into the camera for reference to make syncing easier. I was only saying that I hope that at some point the manufacturers of these cameras will give us something that is useable in terms of audio.

I mean a camera with its own preamps and XLRs and level controls OK, but now you're back to functional rather than aesthetic considerations or you could just go with one of the standard workhorse camcorders.

Which is exactly what I've been using (HPX170 right now) - but like I said...the images I'm starting to see now are becoming too good to ignore - so I'm weighing the pros and cons.

J Davis

09-09-2009, 06:06 PM

Sttratos

09-09-2009, 06:49 PM

So the 7D has a built in mic? Is it loud or clear enough to use as reference for sync with Plural Eyes? Or do you need to plug in an external mic just for the sync reference on top of having the H4N?

J Davis

09-09-2009, 07:12 PM

So the 7D has a built in mic? Is it loud or clear enough to use as reference for sync with Plural Eyes? Or do you need to plug in an external mic just for the sync reference on top of having the H4N?

That would depend on how far the talent is from the lens. At least the on camera mic in the 7D is pointed forwards.

The on cam mic for the GH1 is pointed vertically upwards, in the direction of the camerman's nostrils. But it does move because it is part of the flash pop up after which the mic points backwards to the cameraman's throat. Great if you happen to want heavy breathing during a porn scene. Other than that it is one dumb ass design. Almost as bad as having an internal mirror.
Sorry I'm so sarcastic right now ... crappy day at the ad agency.

Luis Caffesse

09-09-2009, 11:31 PM

I once jacked the out of the zoom H4 into the mic in on the GH1. Figured I would get better audio to sync with instead of the on camera mic.

What I didn't realize is that there was some kind of power being sent out by the camera that totally fried the audio on the Zoom. Never did it again.

Woah.
Hadn't heard that before - doesn't seem to make much sense.... of course you may have just scared me off from testing it for myself.

... crappy day at the ad agency.

Is there another kind?
:)

Peter J. DeCrescenzo

09-10-2009, 12:14 AM

Woah.
Hadn't heard that before - doesn't seem to make much sense.... of course you may have just scared me off from testing it for myself. ...

Ozpeter has posted about the GH1 mic input "plug-in power" undocumented feature and how to use it; see:
http://www.dvxuser.com/V6/showthread.php?t=177740

Eddy Robinson

09-10-2009, 01:36 AM

I did tests of 1 hour duration with the GH1 and the zoom H4 for audio sync. Pulldown has nothing to do with audio. The audio on 24p = audio on 30p.

Actually, this is not true. Pulldown and pullup are major issues for audio-for-film because of the way SMPTE frames are counted in drop frame timecode. This is one reason for the continued popularity of Pro Tools - support for this is built in at the hardware level which is a considerable time saver in many cases. Really, it's quite a big deal and it's easy to screw up.

I feel the error is in the H4 and if you have someone talking it becomes noticeably out of sync after about 1 minute. First thing I will be doing when I have a 7D is an audio sync test.

That's possible, but would indicate disturbing amounts of jitter. A simple test which I encourage you to perform is to record several minutes of a pure tone (sine, saw or square wave) from your computer into the zoom, and then bring the resulting file back into the computer, which will enable you to precisely map frequency drift over time. I can help you with this if you like.

http://dansdata.blogsome.com/category/music/ You may find this of interest, by the way :-)

Eddy Robinson

09-10-2009, 01:38 AM

I think for dialog in drama recording directly with it may not be the best option. The mics in it are not shotguns. Hanging it from a boom would be pretty awkward. In that case, using it as a recorder only is the best I think.

No, you could just put it on a stand for ambient recording of the stereo soundifeld from the side of the set. You would run the boom into one of the XLR inputs and have one left over for lavaliers, slate mic or whatever.

ChipG

09-10-2009, 02:12 AM

So who is thinking about buying a zaxcom deva to use with thier 7D?

J Davis

09-10-2009, 05:48 AM

Actually, this is not true.

I worded my example in reference to the GH1 vs zoom H4 only. The slippage error on the audio file is the same when I matched it to the 1080p prores file before pulldown and after pulldown.

That's possible, but would indicate disturbing amounts of jitter. A simple test which I encourage you to perform is to record several minutes of a pure tone (sine, saw or square wave) from your computer into the zoom, and then bring the resulting file back into the computer, which will enable you to precisely map frequency drift over time. I can help you with this if you like.

THe test I used on the GH1 vs Zoom H4 was with a clap off a slate at the start of the clip and the end of the clip. At the same time I was testing the SDHC card, 1 hour take. I'll prob use the same method when the 7D arrives, its a simple test I know but easy and effective, thanks for the offer tho.

monahawk

03-31-2010, 10:15 PM

I'm new to the forum and only had time to read the first page of responses, because I've spent days and days trying to get any kind of decent sound out of the the 7d and filming of my short film project starts in ten days, on location. My 7d is making a clickity sound, with or without any mic or board plugged into the mic input. I've been using a Shure wireless lav mic, running that into an Akai 12 track digital recorder, out of that into the camera, and using a new Asus high def monitor. So far, nothing but ground loop hum, (bought a Hum X today, not much help), then when I tried dropping everything and just listening to the camera alone, there is a problem. Back to the store with it tomorrow, in case I got a dud. So glad to have found this thread, but I may have to shoot this project on a Sony DV, since one of the actors won't be available again for another six months. Though, I am heartened to read about the Zoom H4N and the Edirol, I'm pretty good at syncing sound to video ;o) 30 plus years as a musician or maybe just a lucky sense of timing. Thanks all...will read more tomorrow.