Audio feature request

[Shawn Nelson]

Everyone always talks about the optical side of Red, but I for one am extremely happy about 4 channels of uncompressed audio via 4 mini xlr connections. My request is that you allow for a 2 channel only setup, where in channel 1 is recorded as channel 1 and 3, with individual volume controls and channel 2 as channel 2 and 4, ditto. The purpose being that if you are only interested in piping in 2 channels, then you can get two copies of each at different line settings, say one copy at -12db tone and the other at -20db tone.

Any chance of this?

[Stuart English]

Almost as you request Shawn.

To do that you'll need to split the analog audio input signal outside of RED ONE and feed it to mini-XLR inputs 1 & 3 and 2 & 4.

[Shawn Nelson]

Well I know I could have done that, any blind 4 channel recorder can do that. Why can't Red duplicate the channels internally like a lot of cameras are doing now?

[tj williams]

The two level thing maybe should go to the ENG thread where the opportunity to save yourself in the camera, when the talent Screams into the microphone will make single shooters day!

[Mark B.]

I think it's a little late to be asking for any more improvements. They've probably started locking down to get ready for production.

[Shawn Nelson]

Lowkus, I'm fairly certain what I have asked for is a software feature.

[Anders Holck]

But the input pre-amp (volume control) is an analog device that sits in front of the AD converter.
A Software feature would only be able to duplicate the digitized signal post AD, and thus the already clipped signal, in case of overload.

To have a feature like you want, an analog channel patch feature is needed routing the signal into two different pre-amp's and ADC's

Suppose the built in pre-amp is good noise less quality, you could choose to record in 24-bit, and just lower the gain for more headroom with the same quantize resolution as a hotter 16-bit signal.

[Jochen Schmidt-Hambrock]

Recording a 24bit signal with 30db headroom is quite ok if the preamp does not mask anything that low with its noise.

We have not heard anything about limiters or compressors on the audio AD, haven´t´we?

Because that would make it even easier. Current auto-settings sound often awfull because they try to stay in the peak 15 db. In a decent 24 bit chain that would not be necessary.

Still, for that last bit of audio quality in a 2-channel recording I will surly split the channels and record with AND without limiters at a maybe 20 db difference.

Jochen

[Martin Drew]

Something to bear in mind is that top notch 24 bit AD converters, well implimented, are only actually going to give you about 20 bits of information. The least significant bits will be lost to noise.

M

[Stokestack]

Lowkus, I'm fairly certain what I have asked for is a software feature.

Given that there don't seem to be any physical input-level controls on the camera, that seems a good guess. Hm, now that I think about it, the lack of physical controls portends a cumbersome and fiddly level-adjustment process.

Anyway, I think this is input-mirroring/multi-level idea is an excellent suggestion.

[Adrian T.]

Something to bear in mind is that top notch 24 bit AD converters, well implimented, are only actually going to give you about 20 bits of information. The least significant bits will be lost to noise.

M

20 bit are still 120 dB dynamic range. That's more than enough for production sound.

[jbeale]

Even if the input preamp gain is software-settable, mixing together two inputs before the A/D requires an internal analog bus that can do that, and if it isn't in the design now I can't imagine they're going to respin the boards to add it :-). There are good reasons not to include such circuits- any circuit in the audio path may be a limitation to your ultimate noise level, crosstalk, distortion and dynamic range figures so designers like to simplify these architectures as much as they can.

[Craig Ryan]

I'll be the first to admit I know nothing about audio; sorry for being off topic (Red), but can this 2 channel with one mic setup be done with my DVX100A? Would I need some kind of XLR router that converts both XLRs into one? Or is this only a professional grade feature? I am clueless here...

[jbeale]

You can do this with any recorder if it has an unused input channel. You would just use a Y-splitter with a 20 dB pad going into one channel and straight through on the other channel. Maybe there is a box already made that does this, but really it's just a few cables and connectors.

[Mark Allen]

This is an interesting suggestion - what it makes me wonder is if there might be some plan for offering an API for users to input their own software upgrades which could either be given to RED for incorporation or sold as a third party upgrade or put out to boards like this as user software.