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-   -   T2i audio mod: $114 (https://www.dvinfo.net/forum/canon-eos-crop-sensor-hd/477936-t2i-audio-mod-114-a.html)

David A. Ludwig May 1st, 2010 12:53 AM

T2i audio mod: $114
 
here's an audio idea. it can't defeat agc, but it makes for a better quality audio recording than the onboard mic delivers.

i was rummaging around in my audio bag and came across two items that i immediately repurposed: hot-shoe shock mount that came with my rode shotgun. ($50 new at b&h)

http://www.bhphotovideo.com/c/product/398316-REG/Rode_SM3_SM3_On_Camera_Shockmount.html

then i came across my sony stereo mic. (down to $64 now)

http://www.bhphotovideo.com/c/product/150434-REG/Sony_ECMMS907_ECM_MS907_Stereo_Mic.html

screwed the mount to the t2i, slipped the 907 through, plugged in and enjoyed. lightweight, simple. i did several tests in the park. the 907 delivered a smooth, non-distorted waveform that somehow didn't sound quashed by the agc. in contrast, the onboard was wild, the agc kicking in & out maybe.

i did it with stuff i already had in my bag. cost to you: the $114 mod.

John Mastrogiacomo May 1st, 2010 02:19 AM

Here is how I fixed the audio problem with the 550D correctly.

I bought a Tascam DR-100 portable audio recorder and a portable XLR pink noise generator.

Gold Line Goldline GLPN Compact Pink Noise Generator with Phantom Power Indicator Phantom Power Supplies at Markertek.com

The pink noise generator goes into one of the Tascam inputs and a microphone goes into the other input.
Then I used a 3.5mm to 3.5 mm cable with a 50db pad to go from the Tascam to the Canon 550D.

Works perfectly although you only have one good channel of audio. I did an A/B comparison and you can't tell the difference. Any low level background noise can be eliminated with SoundSoap.

If you really trust this setup, you can just put the Tascam in record preview mode and then you don't have to worry about hitting start and stop on the Tascam along with the Canon or you can record on both and sync up in post.

Joel Peregrine May 1st, 2010 02:55 AM

Hi John,

Thanks for the ideas.

Quote:

Originally Posted by John Mastrogiacomo (Post 1521843)
Here is how I fixed the audio problem with the 550D correctly.

I don't think there is any one 'correct' workaround for this situation, only effective ways of lowering the noise floor for a better signal to noise ratio. Lots of ways to skin a cat.

Quote:

Originally Posted by John Mastrogiacomo (Post 1521843)
I bought a Tascam DR-100 portable audio recorder and a portable XLR pink noise generator.
Gold Line Goldline GLPN Compact Pink Noise Generator with Phantom Power Indicator Phantom Power Supplies at Markertek.com

How are you mounting that on the camera - the mic and the tascam?

Quote:

Originally Posted by John Mastrogiacomo (Post 1521843)
The pink noise generator goes into one of the Tascam inputs and a microphone goes into the other input.

What mic?

Quote:

Originally Posted by John Mastrogiacomo (Post 1521843)
Then I used a 3.5mm to 3.5 mm cable with a 50db pad to go from the Tascam to the Canon 550D.

This one?

DVcreators Line to Mic Cable at DVcreators.net

If so I wish it were cheaper. Maybe theres another outlet for that...

Quote:

Originally Posted by John Mastrogiacomo (Post 1521843)
Works perfectly although you only have one good channel of audio. I did an A/B comparison and you can't tell the difference.

Do you mean between the Tascam recording and the T2i recording?

James Donnelly May 1st, 2010 04:15 AM

There is a super-cheap way to get pro quality sound, but it involves a soldering iron.

There is an electret mic capsule called the wm-61a, which can be had for a couple of £/$ each. They have a pretty flat frequency response across the usual 20-20k range.

Being electrets, they need phantom power, which I don't think the 550d provides, and even if it did, it would yield vastly improved sensitivity if you provided your own via a battery box.

The design of the battery box is simple, and requires only a few components.

Out of the box, these mics give you pretty amazing sensitivity and dynamic range, but there is a simple modification you can do, known as the Linkwitz mod, which involves cutting line on the back of the capsules and adding a blob of solder. The result is a capsule with a staggering dynamic range of well over 100db

There are tons and tons of pages detailing how to do all this, but here is one good example. The results you can get are awesome, and you should be able to do the job for less than £20

Monkeyphones - Panasonic WM-61A Stereo Mics

Personally I have a UMPC (Wibrain) which records 24/96 audio, so I don't have to worry about AGC. It's not much bigger than a pro portable audio recorder, and I can do a ton of other stuff with it in the field, like running the EOS utility/DSLR remote wirelessly. It's a great tool.

The next stage for me is to incorporate a pre-amp into the design, to get away from the mic amps in the Wibrain.

Jonathan W. Hickman May 1st, 2010 07:56 AM

I've had very good success with my two T2is and my wireless Sennheiser system I use for my TV show.

The ACG has not hurt me too much for interviews and stuff. I've shot more than 20 interviews the dangerous way -- just plugging the receiver directly into the mini-plug on the camera and cutting the mic sensitivity down to -40bds. When using my lav, I've cut the output from the receiver down about -12 or so. I'm sure that lowering the floor like I'm doing is probably not necessary, because the ACG compensates, but I hate peaking.

Obviously, there is no monitoring. So, I do a sound test and visually monitor the mics on the receiver.

Examples can be seen on my blog: The Film Fix: AFF 2010 – Noah Barrow and Ariel Zucker-Brull on RICKY RIGGS: The Story of a Block Bitch

Frankly, I've owned a Panasonic DVX100 (on which I shot the feature CRASHING THE PARTY), a Sony HD1000U (shot my TV show THE FILM FIX), and a Sony FX1000 (went to two Sundance's with me before going on ebay last week), together with several other smaller cams. And the sound I'm getting is probably just as good as anything I've ever shot for interviews.

Sure I'd want more control, but note that I constantly adjusted audio when I had that option and I got good and bad results. Check out my shows over at CrimsonReplay.com that I shot on the FX1000 with wireless and you experienced folks out there will wince about my audio issues. Although the latest show ain't that bad after a lot of post work. Here's the link: Crimson Replay TV

Note at Sundance this year, all my interviews were shot with the 7D and the wireless directly into the camera. We had no significant problems. The rig was a big custom one a bud of mine built and it made the website rounds. We had some audio issues while covering the Macon Film Festival that were related to the mics not the camera.

Recently, I visited the set of Lifetime's Drop Dead Diva and I ran sync sound with my Zoom (the older H4) and with Plural Eyes syncing wasn't a problem. However, I ended up just using the camera's audio. It was just fine.

Honestly, that Juiced Link option looks like the best way to go. Of course, right now, I just don't have an extra 5 or 6 hundred to drop on it.

On the web, you can watch probably 20 examples of stuff I shot with the T2i plugging the mic directly into the camera and most of it is very acceptable sound wise. Ironically, my little Kodak Zi8 has the ability to control external mic volume, if it had monitoring with headphones, it would be even more awesome.


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