Audio, ML, and T3i

Started by Rick M, December 26, 2012, 04:54:29 AM

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Rick M

Okay, I've spent the last hour or two exploring my options for capturing good audio with my t3i. I have a few questions and am hoping the more experienced users can answer.

One of the routes I'm considering is buying a Rode VideoMic Pro, and plugging directly into my camera. If I'm reading right, all I need to do then is turn off the AGC using Magic Lantern, and then turn down my in-camera preamp as well to eliminate more noise, which would be offset by the +20 dB provided for on the VideoMic Pro.

But then I also read that version 2.3 of Magic Lantern doesn't include Audio Controls for the t3i and that instead I would have to download a nightly build. Was looking for confirmation on this, and if so, where I can get the correct download of the nightly build. Also, if there is a separate way that these builds need to be installed, a link to that particular guide would also be useful.

One additional feature I was hoping to take advantage of was headphone monitoring, but it seems the t3i is lacking in this department. I found this video (http://www.youtube.com/watch?feature=player_embedded&v=BnEtj5l3acs#!) where he uses a mini-usb to rca adapter included with the camera. The problem with this is that you then lose the on-camera monitor, which I do not want to happen. So I was wondering if anyone else had thought up a scheme where you could monitor audio through headphones on the t3i, while still keeping the on-camera lcd functioning.

I think that's about it for now. I'm looking to make the camera do run & gun fairly well, and I think the the Rode VideoMic Pro is the best way to get there because it eliminates the additional burden of external recorders. From what I've seen, it also works fairly well for small interviews, in place of lavaliers (still on a small budget at this stage), which is why I'm more interested in the internal monitoring. I've done some noise removal using Adobe Audition before and think I could do the same to eliminate any residual noise; I just want to make sure I've got the method of going about the settings on ML correct, as well as that it's possible for the t3i, and where I can get the correct ML build. In addition to that, I'd really like to know if anyone has a way to monitor audio levels via headphones.

Thank you all for the responses in advance! I apologize if this has been answered in-depth already elsewhere on the forum, I did a search which is how I found some of the stuff above, but it left me with a few questions. If there's a really good topic on it, feel free to point me there too. Just trying to make sure I get this all right before I go about implementing ML and getting various audio equipment.

scrax

For t3i ML is not needed to switch off AGC canon has it already, ML 2.3will add bar meters (when recording). With the rode AGC off and a correct in vol you should be ok.

For headphone monitoring all camera have the problem you mentioned but ML permits you to send audio to the usb cable without losing video preview onscreen (you will need some adapters for plugging headphones to it)

Nightly have this for t3i, you just need to overwrite on card the autoexec.bin from the 2.3 package with the one in the nightly

With the nightly only on t3i you can keep audio off in canon menu but you have to switch on Audio Override in ML's audio menu (turn it off to preserve battery when not in use) for ML audio function to work.
I'm using ML2.3 for photography with:
EOS 600DML | EOS 400Dplus | EOS 5D MLbeta5- EF 100mm f/2.8 USM Macro  - EF-S 17-85mm f4-5.6 IS USM - EF 70-200mm f/4 L USM - 580EXII - OsX, PS, LR, RawTherapee, LightZone -no video experience-

Rick M

Ah, so just so I'm sure I have this straight, I can monitor audio via headphones, while keeping video preview on camera, using the chain of adapters from the video I linked above, or a cable like the one here: http://www.amazon.com/DSLR-550D-HOCF-Out-Headphone-Monitoring-Cable/dp/B008BMK3HE/ref=sr_1_1?ie=UTF8&qid=1356540721&sr=8-1&keywords=Sescom+DSLR-550D-HOCF+AV+Out+Headphone

The trick to doing this is that I have to use the Nightly Build of ML instead of 2.3, correct? I've seen this solution not work for others (they lose video preview) but I'm assuming that's because they were not using the nightly build?

If so, it seems like the nightly build would solve the issues I'm looking for. I see a list of archives here:
http://nanomad.magiclantern.fm/nightly/archive/

I know these builds have large disclaimers of being "less stable" than the official releases like 2.3; what I'm curious about is, are the older ones more likely to be stable, is there a date that's been found by other people looking for this feature to be an optimal for stability, etc? Does anyone else have experience with this feature?

scrax

Quote from: Rick M on December 26, 2012, 06:21:53 PM
Ah, so just so I'm sure I have this straight, I can monitor audio via headphones, while keeping video preview on camera, using the chain of adapters from the video I linked above, or a cable like the one here: http://www.amazon.com/DSLR-550D-HOCF-Out-Headphone-Monitoring-Cable/dp/B008BMK3HE/ref=sr_1_1?ie=UTF8&qid=1356540721&sr=8-1&keywords=Sescom+DSLR-550D-HOCF+AV+Out+Headphone

The trick to doing this is that I have to use the Nightly Build of ML instead of 2.3, correct? I've seen this solution not work for others (they lose video preview) but I'm assuming that's because they were not using the nightly build?

If so, it seems like the nightly build would solve the issues I'm looking for. I see a list of archives here:
http://nanomad.magiclantern.fm/nightly/archive/

I know these builds have large disclaimers of being "less stable" than the official releases like 2.3; what I'm curious about is, are the older ones more likely to be stable, is there a date that's been found by other people looking for this feature to be an optimal for stability, etc? Does anyone else have experience with this feature?
About audio monitoring you got it right. For 600D it was added after 2.3 release so it will be officially in the 2.4 and for now it's only in nightly. You can have more info on how it works and how to use reading this topic and this also about it's development, if interested.

Audio feature for 600D on the nightly was tested before submitting it and should be well tested since it's a lot of time it was introduced.
The older builds are the one with less differences from 2.3, so they could be more stable than the last one, but also they can miss bug fixes introduced later.
Audio for t3i is there in all of them so if you are interested only on that use the older one you can find (11/10/2012).
To reduce risk of instability don't trust the functions that are not in 2.3 (except for audio of course)
I'm using ML2.3 for photography with:
EOS 600DML | EOS 400Dplus | EOS 5D MLbeta5- EF 100mm f/2.8 USM Macro  - EF-S 17-85mm f4-5.6 IS USM - EF 70-200mm f/4 L USM - 580EXII - OsX, PS, LR, RawTherapee, LightZone -no video experience-

1%

Nightly is not that buggy. Haven't had much instability. Sometimes stuff is forgotten about and breaks but I haven't come across any yet besides full screen MZ in crop mode. Try the feature you want to use at home first for like 15 minutes and post up anything that's not working right to be sure.

deleted.account.01

u peoples must realize some true here about extra cables + extra adapters and patetic adiing gain up after tis..

more cables  + more special super nonesense audio boxes on way to outside rec device + adapters (for monitoring ? ahahaha..u guys are realy realy ...) = losse in sound quality+ more nozie ..

all these patetic extras jsut lowering your signal on end but u connect more preamps xDDDDDDDDDDDDDDD.. end on end u all set gains up..none sense..but what i can knwo im jsut suporter

maybe some of u need to learn what is compressor

1%

the adapter for monitoring is just the usb cable, what do you want, there is no headphone jack. It shouldn't affect quality.

the preamps in the camera aren't so good but if you set them low and feed a decent signal from something (i.e a mixer) its not the worst you could do. Its just slightly better than feeding a signal into your PC and recording a sound file with the onboard sound card. the only other solution is an external recorder and then you can have fun matching up the audio.

jordancolburn

The solution I've found is to use a zoom h4 (the old model, not the h4n) as the main mic mounted  onto the camera.  I monitor audio using the headphone out of the h4 and run the line out of the h4 into the t3i with the mic input gain set a notch or two above 0.  The h4 is a decent stereo mic as is and I'm able to use the xlr ins for 2 channels of lav in a sitdown interview.  Because of the line-in, no sync is needed, but if you hit record on the zoom for important interviews, then you always have a backup in case something clips or drops out.  You can also do this with the h4n or any audio recorder that doesn't have a line out by using that sescom monitoring cable or by making your own similar cable.

C.films

I've downloaded the latest version of the Magic Lantern Raw for my 600D T3i. One thing it's giving me now is audio options. Wondering if anyone has any suggestions on what's the best run and gun settings I should setup, since I'm noticing filters and gain options. I have yet to find a tutorial that's based on this current version. Turning off AGC is pretty much all I know.  And does Override Audio Settings just turns off whatever manual settings you have on the T3i main menu? And if I leave it off, then whatever levels I have set in the main T3i Menu are used?

Rick M

I have the Rode VideoMic Pro, which has a +20 dB boost. I've also used the following settings with Sennheiser Lav mics directly into the camera; the key is that you need either a microphone with a very boosted signal (thus the +20 dB boost on my Rode, the Sennheisers went to +18 dB) or an audio mixer like 1% mentioned above. Otherwise, you just won't be able to get decent levels without any noise.

Settings:
Audio Override: On
Analog Gain: 0 dB
Mic Boost: Between 20 and 30 dB
AGC (Under the Digital Gain Section): Off
Left/Right Digital Gain: -8 (Not sure if this makes a difference, I think it might be the default, but it's what I have it set on)
Output Monitoring at 5 dB, Audio Meters ON, Headphone Monitoring ON, etc

The Mic Boost is the only one I have to change, based on my subject, how loud they're talking, etc.

If you monitor through the USB cable with adapters like I do, you will hear noise while monitoring. However, I've found that there will NOT be noise when you review the final footage. I highly recommend testing for yourself before using this set-up for real work.

Also, just as another random bit, this new shotgun mic came out a month or two ago, and didn't get much fanfare:

http://www.bhphotovideo.com/c/product/966010-REG/shure_vp83f_condenser_shotgun_mic.html

I haven't used it personally, so can't vouch for how well it would work, but it looks like it has a pretty big boost for going into the camera, and also records a separate file to miniSD cards. Could be an interesting option, depending on your needs and how well it works.

And thank you to 1% for taking the time to answer my questions originally. Glad it's still providing some guidance for people.

field1post

I too have found that monitored audio is much noisier than recorded audio.  It seems to me that the recording versus the monitoring circuitry could be modified so these levels match better.

I have also discovered that on my t3i with 2.3 installed i lose headphone monitoring after playing a video clip.  The camera speaker becomes activated for any subsequent playbacks....until i power cycle the camera.

Has anybody found a way around the monitoring circuit problem or the loss of monitoring after playing a video clip?

1%

I think the noise in the monitor is from digital gain being applied... on AK4646 cameras the monitoring is very low until you apply a digital gain to one channel and then its noisy and loud like on T3i. Seems like the nature of the beast but maybe there is a reset missing for after you play something back. Similar setup is working on 7D/6D and monitoring comes back after.