Schoeps CMC641 --- PRE-AMP?

[Tommy Owen]

Hi....

Just purchased the Schoeps CMC641 and I'm curious as to whether or not I need to get a pre-amp to go along with it, and if so, any suggestions?

Any info appreciated!

Tommy

[Seth Bloombaum]

What are you connecting it to?

[Tommy Owen]

Thanks, I'm going into a Canon D50....

T

[Steve House]

The Schoeps requires phantom power and the naked camera doesn't provide it so you'll need something between the mic and the camera. At the minimum a phantom supply similar to this one from Denecke Denecke PS-1A - Mic Power Accessories - Mic Accessories - Trew Audio. You'd be far better served by going for a mixer, at the least something like the Sound Devices MixPre-D or the SD302, to both provide the phantom the mic needs and to give you proper control over the audio. The Schoeps is an outstanding mic, don't cheap out on the rest of the system.

[Stephen Hall]

Originally Posted by Tommy Owen

Thanks, I'm going into a Canon D50....

T

For a single channel into the D50, consider a Sound Devices MM1 preamp. You get phantom power, headphone monitoring, SD-quality preamp and limiter.

http://www.bhphotovideo.com/c/product/292989-REG/Sound_Devices_MM_1_MM_1_Single_Channel_Portable.html
Runs on a couple of AAs and is very configurable.

Cheers,

Stephen H

[Steve House]

Originally Posted by Tommy Owen

Thanks, I'm going into a Canon D50....

T

Hang on - my previous reply was based on the assumption that you're going to a DSLR that records video, But as far as I can tell, there is no such animal as a "Canon D50" and the Canon EOS 50D is a still SLR that does not record video, hence dosn't record audio either. So what are you shooting with and what are you using the mic for?

[Tommy Owen]

Okay... So based on all of your suggestions/comments just a few followup questions:

Question 1..... This seems like a good pre-amp/mixer?: http://www.google.com/products/catal...ed=0CEwQ8wIwAw

Question 2..... Should I also consider compression while shooting or should this be done in post?

Just a reminder, the exact camera I'm using is the: Canon EOS 5D Mark II..... Microphone: Schoeps CMC641

Any additional direction appreciated..

Tommy

[Steve House]

Originally Posted by Tommy Owen

Okay... So based on all of your suggestions/comments just a few followup questions:

Question 1..... This seems like a good pre-amp/mixer?: Sound Devices MixPre-D Compact Field Mixer

Question 2..... Should I also consider compression while shooting or should this be done in post?

Just a reminder, the exact camera I'm using is the: Canon EOS 5D Mark II..... Microphone: Schoeps CMC641

Any additional direction appreciated..

Tommy

Mix Pre-d is an excellent choice. Save any manipulation such as compression for post

[Jon Fairhurst]

When feeding audio to the 5D2, I recommend one of the juicedLink preamps. It bolts right to the camera and has the correct format output for DSLRs. The DT454 has a bit more gain for slightly (very slightly) higher quality, but costs more than the CX231 in that the DT454 has a headphone output and an AGC killer for DSLRs without manual audio control.

The MixPre-D is a great product with better meters, but it's really meant as a field mixer to be worn over the shoulder. I'm not sure of the levels, but I assume the Tape Out could be sent to the DSLR. That's an unbalanced signal, so you want that link as short as possible; hence, the importance of bolting the preamp to the camera. A 1/8" jack isn't captive, so you want the preamp to be mechanically secure to avoid static from a moving connection.

The juicedLink electrical quality is excellent. Recording into the 5D2, swapping between the JL and SD preamps wouldn't have any significant effect on the overall quality. The 5D2 is the weakest link in the audio chain.

You'll get the best results when using Magic Lantern. The 5D2 has a high pass filter, so it's fine for dialog, but not for full range music. With a JL/ML/5D2 setup, the signal to noise is as good as you can get from a 16-bit system. Aside from the high-pass filter, my only other criticism is that the 5D2 sounds slightly harsh, compared to the creamy sounds of a high-end recorder.

One solution is to bolt a juicedLink to the camera/rig and to have a MixPre-D over the shoulder of the boom operator. That allows the boom op to monitor and control levels and to run an XLR cable to the camera.

They're really two different products. The JL gives you an XLR front end for the camera. The SD is a field mixer for the boom op.

[Steve House]

Originally Posted by Jon Fairhurst

...

The MixPre-D is a great product with better meters, but it's really meant as a field mixer to be worn over the shoulder. I'm not sure of the levels, but I assume the Tape Out could be sent to the DSLR. That's an unbalanced signal, so you want that link as short as possible; hence, the importance of bolting the preamp to the camera. A 1/8" jack isn't captive, so you want the preamp to be mechanically secure to avoid static from a moving connection.
...

The MixPre-D incudes a consumer mic level output on a TA3 connector specifically designed to mate to DSLR extrernal mic inputs, as well as having the usual line level outputs A TA3->1//8 cable (available from SD) and you're in business. They also have an accessory mount, called the XL-CAM, made for mounting the mixer to the bottom of a DSLR camera via the tripod screw. http://www.sounddevices.com/download...re-d-facts.pdf Note the pic in the lower right corner of that page. And the Mark II model Canon has a manually defeatable AGC so the Juiced AGC killer is moot with that camera. And the SD has tone for camera alignment and high-pass filtering, something very important with the Schoeps mic. Not knocking the Juiced, I have one, but if one has the budget I think the SD is the better choice.

[Jon Fairhurst]

Very cool about the mount and the DSLR output levels. And having tone is nice. The high-pass filter is moot as the 5D2 had a HPF that can't be defeated. Still, I'd think that the sound quality difference would be negligible with the 5D2 as the recorder. It really comes down to price, features, personal preference, and possible future uses. For instance, if one planned on adding a 7D to the stable, the DT454 might make the most sense. If one planned on adding a pro recorder, the SD would make sense as a future field mixer.

Regardless of the preamp, I strongly recommend using Magic Lantern when audio quality matters. From memory, it improves the S/N ratio by 9dB, compared to the Canon manual audio feature. This is significant when you need a low noise floor.

[Jon Fairhurst]

On another forum, I read that the MixPre-D gain was set to match Canon's manual audio firmware in the 5D2. Unfortunately, that poster is finding that it doesn't provide enough gain with Magic Lantern.

ML allows you to adjust both the analog and digital gains in the camera. Canon only adjusts the digital gain, leaving the analog gain at roughly +30dB. That's why I can get better S/N with ML than with the Canon firmware. I can reduce the (poor) analog gain in the camera and boost the (clean) analog gain in the juicedLink.

That said, I don't know how the gain in the MixPre-D compares with the JL. And I don't know what mic, distance, source and settings the poster was using.

I'd say that this needs some exploration. If the MixPre-D can match the gain of the JL, the sound quality with either preamp into the 5D2 with ML should be equivalent. If the gain is lower, the S/N may suffer somewhat when recording low level sounds. The key is to crank the gain in the preamp and reduce it in the camera.

FWIW, my tests showed that +10dB or +17dB analog gain (m_gain) and 0dB digital gain (l_gain & r_gain) is the ideal setting range for ML. Go lower and you have to drive it with too hot a signal. Go higher and you compromise S/N.