Build 14 Audio

[Greg M]

It appears improvements have been made to the audio in Build 14.
From my initial tests the DC Offset has been eliminated and the hiss is gone.

I am shooting a commercial in the morning and will have better results, but it appears major improvement have been made. Well done!!

[Elizabeth Lowrey]

Good news! Would love it if you could post a short, uncompressed sample with details on the setup when you get the chance.

[JFirestone]

The audio is definitely a lot better in this build. The hiss is gone. RED may just be able to pull this off with software after all. Let's hope they can re-enable phantom power with these results.

[Jeff Kilgroe]

Why was the +48V phantom power removed? I asked in one of the Build 14 threads, but the question went unanswered.

[Adrian T.]

Why was the +48V phantom power removed? I asked in one of the Build 14 threads, but the question went unanswered.

I wonder the same thing. I could record perfectly clean audio with phantom power enabled under build 13. No hiss whatsoever. :huh:

[Steve Sherrick]

Phantom Power has been removed? That probably explains why the hiss is gone. They must have found an issue with it. But is this a firmware issue or a hardware issue? Keep us posted guys on what you find out.

Steve

[BASSAM MSSALATIE]

now if we need to record audio we must use our phantom power mics
with it her own power supply (voltag must be provided from mic itself)
or from audio mixer :huh: .. is that right ?:innocent:

[Steve Sherrick]

If phantom power has been disabled, yes you will need to power microphones with their own power supply which can come from battery (for mics that have them like the ME66), a mixer that has phantom power, or a phantom power device.

This will get fixed if it's not working right now, I'm sure of it. Otherwise the audio capabilities will be severely flawed. They're not going to let that happen. I'm giving them the benefit of the doubt on this one.

Greg, can you confirm this is not working on your end too? Anyone else?

Steve

[Paul Hazlett]

I really don't care if they bring it back, If you are using a audio guy, he is going to give you a line level feed that does not need power and if you need
an on board mic you can use a battery or outboard power.

If it helps make clean audio, so much the better.

[Mark Linthicum]

I wonder the same thing. I could record perfectly clean audio with phantom power enabled under build 13. No hiss whatsoever. :huh:

Are you sure you heard no hiss? I you are recording noisy stuff it would cover the noise from the phantom power, you need to check it in a semi quiet environment.

Mark

[Emery Wells]

Why does everyone jump to conclusions?

The beta release notes says that phantom power was *temporarily* removed which indicates it will be back in a future build.

[Adrian T.]

Are you sure you had not hiss? I you are recording noisy stuff it would cover the noise from the phantom power, you need to check it in a semi quiet environment.

Mark

I'm absolutely sure. I'm also from a sound engineering background and I know what I'm talking about. When the mic was close to the camera all I could hear was its fan. But far away the sound was crystal clear.

Will make more tests soon with various mics. Maybe it depends on how much power the mic needs.

[Adrian T.]

Why does everyone jump to conclusions?

The beta release notes says that phantom power was *temporarily* removed which indicates it will be back in a future build.

No conclusions. Just wondering why it was removed because it was working perfectly well for me. :wink:

[Steve Sherrick]

Why does everyone jump to conclusions?

The beta release notes says that phantom power was *temporarily* removed which indicates it will be back in a future build.

It's a legitimate concern for people. I have nice sound gear and will almost always have a sound person or myself available for shoots so I'd have a way around this issue, but others who are spending a few bucks for the camera and may be wanting to use onboard audio may have some concerns if phantom power were to continue to be a problem. Not saying it will, in fact I think they will have this problem fixed maybe as soon as the next release if the camera is coming out of beta.

Steve

[Elizabeth Lowrey]

I'm absolutely sure. I'm also from a sound engineering background and I know what I'm talking about. When the mic was close to the camera all I could hear was its fan. But far away the sound was crystal clear.

Will make more tests soon with various mics. Maybe it depends on how much power the mic needs.

Will you be able to post some test results?

[philper]

I would love to see some actual audio specs, like s/n, distortion etc.. Are they posted somewhere else already?

Philip Perkins CAS

[Steve Sherrick]

This is the only thing that appears in the tech specs. I didn't see anything in the manual unless I missed it.

4 channel uncompressed, 24 bit, 48KHz

Also, there may be other threads I missed that went into some of the deeper specs of the audio system.

Steve

[Steve Sherrick]

Ah, I missed this.

Line input analog audio received via the min-XLR inputs is immediately digitized at 24 bit per
sample at a 48KHz sample rate. Microphone level audio inputs are routed via an adjustable
gain pre-amplifier before digitization, no gain adjustment is available for Line level inputs.
Reference Line Input level (0dB) is 0.775v. Microphones with an output sensitivity ranging
between -30dB and -60dB can be accommodated by the pre-amplifier, which provides user
adjustable amplification over the range of +22dB to +54dB with minimal signal degradation.
Due to the significantly higher precision and dynamic range of 24 bit sampling, input stage
limiters or AGC’s are not provided by the RED-ONE camera. The digitized audio data
can be considered as high dynamic range RAW sound information that is com-
plimentary to the high dynamic range RAW video information.
Just as linear response RAW video data is converted to REC 709 for metering, the linear re-
sponse audio data is converted to Log Base 10 data for metering. A color coded 4 channel
audio meter is provided in the lower section of the camera GUI. This information is visible in
the RED-EVF, RED-LCD and HDMI (DVI) monitor outputs.
The goal for optimal quality recording is to place the audio reference level at an appropriate
location in the digital range, providing sufficient headroom above the reference level to pre-
vent clipping, while maintaining the sound quality of lower volume sources such as dialog.
A 0dB reference voltage level of 0.775V provides approximately 8dB of headroom above
reference. Microphone pre-amplifier gains should be adjusted accordingly (i.e. 8dB lower)
e.g. With an Azden SGM X1 microphone rated at -41dB sensitivity, set the mi-
crophone pre-amplifier to (41 – 9) = 32dB for optimal recorded signal qualit

[Adrian T.]

Will you be able to post some test results?

I will try to post them after a complete test series.

[Emanuel A.]

It appears improvements have been made to the audio in Build 14.
From my initial tests the DC Offset has been eliminated and the hiss is gone.

I am shooting a commercial in the morning and will have better results, but it appears major improvement have been made. Well done!!Good news!

BTW, any update by Fev-09 morning Greg?...

[Greg M]

Good news!

BTW, any update by Fev-09 morning Greg?...

Audio looks fine. here are the issues I am dealing with;

1. No EVF- This means I have to use the LCD to monitor Audio levels. The problem this presents in the "real world" is, you need multiple monitors in a professional environment. The client needs to see what you are shooting. The only way to currently do this is to use the button on top of the LCD and toggle between LCD and HD-SDI monitors, which is a pain in the ass. Not to mention I had to explain to the client no less than 10 times that the monitor didnt go out, I am just monitoring audio on this shot. Imagine what a hassle this is.

We had issues with levels because I wasnt able to leave the LCD on during actual shots.

NOTE TO SELF: Call poor old Brent at Red and harass him again about my EVF that I paid in full for 5 months ago.

2. When sending tone to the camera from a mixer to set levels, the actual audio levels do not match...really doesnt make sense does it?

The problem is if I send tone to red and set my levels as I normally do, then turn off the tone and listen to a mic, the levels exceed 0db and are distorted. I have to turn down the output of the mixer at least 25% to get an acceptable recording level. Honestly I need more time testing this to figure out why there is such a discrepancy between tone and real world sounds.

Other than these two BIG issues, the audio sounds great, and most importantly the DC offset is gone.

[Steve Sherrick]

Greg, if you are spitting out a standard +4 to the line inputs of the camera, I can't see why there would be a discrepancy. Hmmm....

Steve

[planet e]

What about the metering, digitalfx? Have there been improvements in the metering? On the RED that I visited, you couldn't see the metering in the audio gain menu...have they fixed that?

[JH Fleming]

Perhaps use a limiter between the board and camera?
choices might be Cranesong STC-8, Pendulum Audio PL-2, or Aphex Dominator