Noisy Canon C70?
 

I know C70 has a noisy preamp but I don't know if my C70 has faulty preamp or this is a normal noise level. Can someone verify for me? I'm attaching a file.

Some info:
1. Firmware 1.1.3.1
2. No mic attached
3. vol level set to 5, Manual
4. audio input selection set to INPUT TERMINALS Input1 MIC+48 for both channels.
5. No fan running while recording

https://www.dropbox.com/scl/fi/rqhdt...11rkb9sj1&dl=0

Re: Noisy Canon C70?
 

Hi Kathy, I don’t have a Canon C70 but I set an average music level playback level on my latest iPad and listened to your noise sample. It sounded Ok to me, another example might be to have someone speak at normal level and record her/him at ‘normal’ level on your C70 and listen for the background noise on that example so you’ve got a reference. Is your firmware the latest version?

This might help you with your audio settings and check the comments …
And you should look around the web, there’s C70 groups. Don’t forget to let us what results you get, to help others here in future. Good luck.

Re: Noisy Canon C70?
 

Thanks Allan. I watched the video and I understand all the settings. I also reset camera to factory settings for testing purpose, but I get the same noise with factory settings. I'm on the latest firmware. The thing is I just feel like it's more noisy than it used to be. I just checked my files from 2 years ago and it's the same noise level, so maybe I'm imagining it. But I have no way of verifying my settings from 2 years ago and what my volume level was etc. The puzzling thing is that when I have no mics attached I wouldn't expect to have an audio recorded but when I drop my files to Final Cut, I do have a audio track and it's just noise. I can obviously delete it but I don't remember ever needing to do that. Maybe I need to find C70 forums and post there.

Re: Noisy Canon C70?
 

Hi Kathy niggles with gear you can’t seem to solve can drive you crazy after a while, and yes with audio noise you might be imagining it unless you’ve got the gear that can actually measure it.

You might have seen these, to avoid audio channel noise have you ensured your phantom power is turned off if your microphone does not need it. Dynamic mics and many modern units do not use it. And be aware that the camera's fan can introduce noise. Set the fan mode to automatic to minimize this during recording.

There’s the C70 community forum …
https://community.usa.canon.com/t5/P...p-2/m-p/513546

Re: Noisy Canon C70?
 

Yes, I tested the noise with phantom power and without. I have the camera set to turn off the fan while recording.
Thanks for the forum link, I posted my query there.

Re: Noisy Canon C70?
 

Dedicated audio recorders and mixers will always outperform cameras. So you are free to upgrade to the many audio devices offered today.

Outside of that I’ve found people on message boards tend to obsess over things the client isn’t complaining about. While you might hear noise in silence sections there are audio noise software filters to clean this up. In a normal interview preamp noise will not be heard if you’re getting proper levels from a well placed mic. Usual the audio issues of the acoustics and noise of the location will far outweigh noise of the camera’s amps.

I also can’t stress enough how important mic placement is. If it’s too far away from the subject when you turn up the gain it will raise the noise floor and bring out any defects in your audio chain.

Re: Noisy Canon C70?
 

We can’t tell the noise level without a reference. The noise could be loud or quiet, but where is the maximum? Even plugging a mic in and going one two at your usual level, then pull the plug out. I may have been listening too loud? It sounds noisy, but what actual level is the noise? Has it been squished or compressed? I suspect you just set the input to 5 and pressed record? What is 10 like or 2? We don’t have a reference

Re: Noisy Canon C70?
 

Hi Paul,

Yes I just set the input to 5 and pressed record.

Here are the reference files:

Level 2: https://www.dropbox.com/scl/fi/a7qa4...m6d3l9net&dl=0

Level 5: https://www.dropbox.com/scl/fi/5lelj...z7f9ylo6e&dl=0

Level 10: https://www.dropbox.com/scl/fi/a3te4...bvu2xm8rt&dl=0

Re: Noisy Canon C70?
 

I had a look and listen, Kathy.

In iZotope RX that audio is modulating between -57 and -54 and the wafeform is looking like it is active and possibly has an auto gain function going on. -60 is generally considered a good noise floor.

I am not saying that what I am outlining below is your answer but do some checking on the following.

I think you may find if you kill channels #3 and #4 to ∞. In other words set them to MANUAL and then set their Gain Levels to 0dB, which is Infinity, then you may solve the problem. I know this works for some Sony cameras. I have never tried it on a C70.

Often by default these channels #3 and #4 are set to internal mic and are set to AUTO. Even though there may be no ambient sound across these circuits they remain active and are searching automatically, looking for input sound levels. If they are doing that, they are auto gaining and this can lift sound floor noise levels.

Have a look at page #101 of the C70 owners manual.

Good luck!

Chris Young

Re: Noisy Canon C70?
 

FWIW, the unloaded noise floor numbers of Kathy's files are . (to the nearest whole number) which do not look too bad.
Level 2: -90 dBFS
Level 5: -60 dBFS
Level 10: -40 dBFS
A high sensitivity mic is a good idea which requires less gain. Proper mic placement usually requires less gain as well. The Audio Technica 40 series mics has very high sensitivity.
The AT 4071a long shotgun sensitivity spec is a whopping (89 mV) re 1V at 1 Pa
The AT 4073a short shotgun is (71 mV)
However, the Max SPL dB for both are in the mid 120s

Re: Noisy Canon C70?
 

Hi Christopher,

Thanks for looking into this for me. My channels 3 and 4 are not active at all.

Re: Noisy Canon C70?
 

Thanks, Rick. I'm using Sanken COS-11D mics.

Re: Noisy Canon C70?
 

"I'm using Sanken COS-11D mics"
- Wireless or with a XLR adaptor/power supply (Battery or Phantom Pwr?

Re: Noisy Canon C70?
 

XLR, phantom powered.

Re: Noisy Canon C70?
 

What confuses me is that if I don't have mics plugged in, why turning the gain up and down make a difference?

Re: Noisy Canon C70?
 

Right, Kathy. Understood.

The levels I'm seeing on the clips you have uploaded sit between -57 and -54. These levels aren't too bad.

All I can suggest is that when you are running mics is to keep your levels between -10 to -6dB to obtain better saturation. Thereby better SNR levels all round. I consistently stick to these figures to achieve good signal-to-noise ratios. Some tips at the link below may help you. Good luck!

Chris Young

https://ohda.matrix.msu.edu/2012/06/...ng-good-audio/

Re: Noisy Canon C70?
 

If there is nothing plugged in, the track will not be used anyway. Or just turn the record level down to 0.and make sure there is no autogain enabled. It is not uncommon for preamps to generate a little noise when there is no load, especially with Phantom Pwr.

Re: Noisy Canon C70?
 

I think I have also seen instances where phantom power going into a non-phantom mic will also cause self-noise / hiss to be generated.

Andrew

Re: Noisy Canon C70?
 

Phantom power was first used for microphones in 1964 with the introduction of the Schoeps model CMT 20, which was designed to operate with 9–12 volt DC phantom power. The standard 48-volt phantom power was later established in 1966.

So this is not about phantom power problems, but close.

In 1962 the brand new NBN Channel 3 in Newcastle Australia was a complete RCA package, everything from the 2 RCA black and white transmitters, all the cameras, control rooms, to the RCA mics in the studios. In the U.S. because colour tv was now in vogue, RCA had to find RCA engineers who were proficient in B&W installations and still available.

But they did and we met some great older engineers, who enjoyed their time in Newcastle.

But the strange thing was, for the microphone package, it seems RCA never knew what our mics. earth pin was 1-2 or 3, and not wanting to cause trouble and with no advance notice to us, they sent all our mic. cables with the 3 output leads unterminated, no Cannon or Neutrik mic. connectors to plug our mics into the wall input connectors in our studios, which were correct and must have come from another RCA dept., it was a big company.

We needed about 60 and because they were expensive and we’d already paid for them, we sent our RCA contact a cable requesting an urgent delivery, but for some reason that got lost in the system. After about a week with no answer we sent another one, time was running out.

So as the first audio engineer the only thing I could do was to poke the 3 mic leads into pins 1-2 and earth 3 into the wall input connectors , then jam match sticks in to stop the leads from pulling out. And warn no threaten the floor crews not to trip over any of the mics extension cables laid on the studio floors.

And on 4th March 1962, that’s how we did Channel 3s opening show and the first 3 weeks rehearsals and daily live programs. Thankfully I had no trouble, and bliss! The day the RCA carton arrived, 3 of us spent all one Saturday morning with soldering irons, to get ready for the teen rock show, TEENBEAT live at 6pm.

I had a great time in Newcastle, we were just kids 64 years ago, still in touch with a couple of the crew.