EX1/r Distorted Audio - Why no trim in auto?

F

Frankieplus

New member
Hi everyone -

I bought an EX1R recently and the audio in auto is distorted.

Am using an external NTG1 Mic and I just noticed that I can only set the TRIM if the audio is on manual. The trim in the audio menu is greyed out as soon as I flick the switch on the back to 'auto'.

As a result, I got distorted audio duign a shoot I did in a nightclub (Dancing). -41db is too hot.

Does anyone know why / how I can turn down the -41db and also use auto audio?

Or should I use an attenuator in line with the mic?

I can't understand why sony would dismiss the TRIM in auto mode.

Also, there is AGC = High and AGC = Low in the audio menu. Would setting it to 'low' do the trick and does anyone know what value 'low' and 'high' actually is?

Oh and Happy new year everyone!


-Frankie
 
When doing loud live gigs I always use in-line attenuators. The ones I use have 3 settings (-10, -20,-30db) and will save your audio. You should not be using auto anyway. The auto AGC will ruin the sound of music, and suck out the dynamics. Go to manual and turn down your trim and keep your audio levels at 5. It's better to have a quiet audio file that you can turn back up, than clipping that you can't fix. I suggest you read the post about EX1 audio. It starts off based on the original EX1 firmware, but then the info changes based on the way the current firmware works.

http://www.dvxuser.com/V6/showthread.php?t=132249

Here are the attenuators I use, even when using my Sound Devices mixer with double stage limiting: http://www.bhphotovideo.com/c/product/68085-REG/Audio_Technica_AT8202_AT8202_In_Line_Attenuator.html

You need to physically attenuate the signal before it gets to the camera.
 
Chadfish said:
When doing loud live gigs I always use in-line attenuators. The ones I use have 3 settings (-10, -20,-30db) and will save your audio. You should not be using auto anyway. The auto AGC will ruin the sound of music, and suck out the dynamics. Go to manual and turn down your trim and keep your audio levels at 5. It's better to have a quiet audio file that you can turn back up, than clipping that you can't fix. I suggest you read the post about EX1 audio. It starts off based on the original EX1 firmware, but then the info changes based on the way the current firmware works.

http://www.dvxuser.com/V6/showthread.php?t=132249

Here are the attenuators I use, even when using my Sound Devices mixer with double stage limiting: http://www.bhphotovideo.com/c/product/68085-REG/Audio_Technica_AT8202_AT8202_In_Line_Attenuator.html

You need to physically attenuate the signal before it gets to the camera.
Click to expand...

Hi Chadfish - Thanks for the helpful response. Just got a few questions for you.

Are you suggesting to attenuate with an external attenuater in line with the microphone -as well as- set the record level at the back of the camera to the midpoint (5) and also set the trim in the audio menu to an acceptable level?

I figured that setting trim and record levels should be sufficient for recording in a nightclub?

Also - Thanks for the link above, I read it and it suggests that to adjust the audio it's best to leave the levels at the back of the camera at 5 and to adjust trim and to keep the levels on the meters 3 points below the red marks. Is all this still the case?

And - The EX1/R has a limiter in the menu which is off by default, should I turn it on maybe?

Lastly - Again in the EX1/r there is a 'Mic - AGC = High/Low' (Set the sensetivity of the mic inputs)

Should I bother with the AGC? I assume not, but if i did would you have any idea what values 'high/low' that is in the menu actually represent?

Thanks heaps for your help and have a great new year!


-Frankie
 
1. "Are you suggesting to attenuate with an external attenuater in line with the microphone -as well as- set the record level at the back of the camera to the midpoint (5) and also set the trim in the audio menu to an acceptable level?"

Yes. Leave the audio levels at 5-6. More will introduce noise. You will have to do some tests, but try -10db on the in-line attenuators, then adjust the trim to taste.

2. I figured that setting trim and record levels should be sufficient for recording in a nightclub?

If it's a rock band I think the attenuators will save you from clipping the input of the camera. TEST ON ANOTHER BAND BEFORE THE REAL GIG.

3. "leave the levels at the back of the camera at 5 and to adjust trim and to keep the levels on the meters 3 points below the red marks. Is all this still the case?"

Pretty much. I think it's 6 now with the new firmware. Remember when setting levels to set it by the loudest sound that will happen.

4. "And - The EX1/R has a limiter in the menu which is off by default, should I turn it on maybe?"

I was not aware of that. The limiter is on all the time on the EX1. It's a nice sounding limiter, and it will save you from some clipping. It would be wise to use that in a loud situation. Limiting squashes the peaks so they do not clip. AGC pushes up the levels AND limits the top, so everything sounds the same level. This causes noise on quiet sources, and generally takes the life out of music. Keep it off at all times, unless you are grabbing your camera to catch something and have no time to set levels. I believe it's on whenever you are in Auto mode with the audio.

I would think the "Low" mode would mean it's not squishing the signal as much, and that's good. Go with low on the AGC setting. BUT YOU MUST TEST THESE THINGS OUT! Don't just go by me.

Create a situation and test out these settings. Say out loud what the settings are while you are taping so you have a reference. Import the files into FCP or whatever, and look at the wave forms. Do they look maxed out and flat on top? That's what AGC looks like in a loud situation. The goal is to have smooth blobs of sound (except for spikes when something like a drum hit, or clap happens). You can always normalize the audio later to bring up the volume if it's too low when you record it. But you can't fix distorted audio. Well, I have some tools that can help some digital clipping and crackling, but distorted audio is not going to be massaged back into a stellar sound no matter what you do.


Cheers mate, and Happy New Year to you!



Frankieplus said:
Hi Chadfish - Thanks for the helpful response. Just got a few questions for you.

Are you suggesting to attenuate with an external attenuater in line with the microphone -as well as- set the record level at the back of the camera to the midpoint (5) and also set the trim in the audio menu to an acceptable level?

I figured that setting trim and record levels should be sufficient for recording in a nightclub?

Also - Thanks for the link above, I read it and it suggests that to adjust the audio it's best to leave the levels at the back of the camera at 5 and to adjust trim and to keep the levels on the meters 3 points below the red marks. Is all this still the case?

And - The EX1/R has a limiter in the menu which is off by default, should I turn it on maybe?

Lastly - Again in the EX1/r there is a 'Mic - AGC = High/Low' (Set the sensetivity of the mic inputs)

Should I bother with the AGC? I assume not, but if i did would you have any idea what values 'high/low' that is in the menu actually represent?

Thanks heaps for your help and have a great new year!


-Frankie
Click to expand...
 
Chadfish said:
3. "leave the levels at the back of the camera at 5 and to adjust trim and to keep the levels on the meters 3 points below the red marks. Is all this still the case?"

Pretty much. I think it's 6 now with the new firmware. Remember when setting levels to set it by the loudest sound that will happen.
Click to expand...


Chadfish, you said 'i think it's 6 now with the firmware'.

Did you mean the dial at the back to '6' instead of 5 or did you mean the VU meter's 3 points below the red dots now is 6 points below the red dots??

Sorry for my confusion :)


-Frankie
 
Frankieplus said:
Chadfish, you said 'i think it's 6 now with the firmware'.

Did you mean the dial at the back to '6' instead of 5 or did you mean the VU meter's 3 points below the red dots now is 6 points below the red dots??

Sorry for my confusion :)


-Frankie
Click to expand...

Hi Frankie

I mean the audio level dials on the back of the camera. According to basspig's measurements we can turn up to about 6 before we start to hear noise in the signal chain. You should read the later posts in the "The Skinny on EX1 Audio" thread, because that's where we started talking based on the new firmware. The first post in that thread was based on the original EX1 firmware. The audio has improved a lot since the original firmware.

Happy New Year!

Chad
 
Using auto level control is like using auto focus. The results are far from optimal. The EX series' ALC is primative and you lose the ability to use the attenuators, as you discovered.

There is still a pervasive desire on the part of videographers to 'fill all the white space' with sound. This is not necessary anymore, as we're not fighting the 30dB s/n ratio of optical film tracks, or the 42dB s/n ratio of magnetic tape. The EX series offers close to 90dB of actual s/n ratio. Best approach is to use MANUAL audio, set the REC level on 5-1/2 and set the attenuators so the loudest expected sound barely comes close to the red dots on the meters.

ALC is great for military communications radios, not for cameras where the goal is to get realistic audio.
 
You must log in or register to reply here.
Back
Top