Strange A6500 audio problem?

[jungleexplorer]

So this is not a new problem, it has been happening since day one, but I thought I would give it another shot at finding a solution to it. Fingers crossed.

Here's the setup. I use my A6500 for in-studio video recording while connected to my laptop running the Sony Imaging Edge for Desktop. I also use it with the Smartphone Imaging Edge APP if in my outdoor studio setting. I use an external Rode Shotgun mic that is connected to the camera for audio capture in some cases.

While using this setup, with either the desktop or the Android app, if my microphone sensitivity is set to anything higher than 5 in the camera, I get an AGC boost that virtually ruins the audio of the recording. Now, let me explain that last sentence a little, What I mean by AGC boost is, the camera automatically increases the sensitivity of the microphone to the maximum level during times of silence. For example. Say I read a line from my script and then pause for five seconds to read the next line before speaking again. During that five-second pause, the sensitivity of the microphone will boost all the way from level 6 to level 30. So when I start talking again, the to will be at max loudness. Now as I keep talking the mic will adjust back down to level 6 (or whatever I have the mic set to) and stay there as long as I keep talking. But as soon as I stop talking, even for one second, it starts going back up again.

A couple of things about this problem.

1. It only happens when using the app to control the camera. I use this same mic on this camera all the time in the field while using the on-camera buttons and I do not have this issue.

2. It does not happen if the mic sensitivity is set to 5 or below.

The current theory as to what causes this issue is that the Sony A6500 has an AGC function in the firewire that is activated only when the camera is controlled remotely. If you don't know what AGC is, it stands for Automatic Gain Control. It is a function that is supposed to be reserved for the Stage mic so that as the singer moves around the microphone the mic will try to keep the volume equal by boosting or reducing the mic sensitivity. Technically there is nothing in the spec sheet that declares that the a6500 is even supposed to have AGC, but as clearly the case, it does and I have had Sony techs admit this. This a problem that many users that use Imaging Edge software face, but as of yet, there has never been an attempt at a real solution (that I know of).

Of course, there are two workarounds (workarounds are not solutions). One is to set the mic sensitive to level 5, but this means that you will need to boost the audio in Post to make it loud enough, and then you risk distortion. The other is to record on a separate microphone. This of course doubles the post-production editing workload if you have to do a lot of cutting and splicing in order to keep the audio in sync with the video.

I am just wondering if anyone else has a better workaround or solution?

 

[DirkPeh]

You should use manual gain control instead of automatic gain control. The AGC works like a compressor/limiter, but a very bad one. You can only switch to manual gain, if you are not in full auto mode on Sony A6…

Never ever set recording levels too high in a digital recording device, never!!!

Set them low and then a bit lower. This is even more true for cheap preamps like the ones in most cameras. You only boost their inherent noise and activate their cheap limiters.

You don’t risk distortion, when you change the wave -file audio in post, not a bit! What you are doing first is to normalise the track. All video editors offer this. Normalizing just raises the existing level to 0 db or based on the settings to -10 db for example. It doesn’t change the dynamics of the signal. It just takes the loudest part you recorded and pushes it to the loudest level PRIOR to distortion and raises the volume of the other parts accordingly. If you like it, you can then add other effects like a GOOD limiter or compressor etc. Whatever you like.

 

[jungleexplorer]

The A6500 does not have to switch to Manual Gain Control, because it is not supposed to even have AGC to begin with. It only has MGC. That is the issue. It is automatically MGC, unless you try to control it with the Imaging Edge program. Then, it overrides Manual and goes wacky, and does what I described. Believe me, if there was a way to force it to go manual, I would.

You have an A6. The A6 does have AGC, and that is why you can choose to go manual. Due to the problems with the AGC in the A6, they were supposed to have scrapped AGC in the A6500, but someone somewhere screwed up.

 

[DirkPeh]

The A6500 does not have to switch to Manual Gain Control, because it is not supposed to even have AGC to begin with. It only has MGC. That is the issue. It is automatically MGC, unless you try to control it with the Imaging Edge program. Then, it overrides Manual and goes wacky, and does what I described. Believe me, if there was a way to force it to go manual, I would.

You have an A6. The A6 does have AGC, and that is why you can choose to go manual. Due to the problems with the AGC in the A6, they were supposed to have scrapped AGC in the A6500, but someone somewhere screwed up.

I own the A6400. In your case I would estimate that if you set the levels as high as you do, there is no other chance to save the audio somehow. If you set the recording level too high in digital audio, the signal doesn’t get a bit distorted, it gets completely unusable.

The manual of the A6500 says

“Regardless of the [Audio Rec Level] settings, the limiter always operates.“

By setting the level too high, you trigger the limiter. Simply don’t do it!

 

[jungleexplorer]

If you consider level 6 too high, then I guess you have a different definition of what too high is. But I think you failed completely at understanding the OP. If you understood what was said, then you would know that your accusing me of setting the gain too high is a ridiculous assertion with no basis in reality.