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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Questions about sound in Red One

C

craesmeyer

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As a sound guy, i would ask some questions to the Red people.

  1. The 4 mic inputs are mic/level switchable?
  2. There would be 48V Phatom?
  3. The camera will have some kind of cooler or another component tha can produce an louder than aceptable sound (higher than an modern - not effect -35mm camera)?
  4. The Red Hard Disk recording solution will be fan cooled?
  5. And the Red Flash?

Just a sugestion... There will be an mic company who will be endorsed by Red? Suggested microphones?

You know about Core Sound's Tetra Mic? It seens to be an intersting companion to an doc/run & go type of production... I think it only needed to be a little shorter, or have an angled output to fit Red perfectly...

http://www.core-sound.com/TetraMic/2.php
http://www.core-sound.com/TetraMic/1.php

I didn't test it (nor see an review about it), but sit hould be an nice mic.

Thanks for watching

PS: Theres no slight chance that Red will get any digital audio input? AES/EBU yould be great... SPDIF not so, but... Red will be an evoution in picture, why not be an revolution in sound too? :cool:
 
All good questions... (surely the Red team is not still adding new features, new circuits and new connectors at this late date?)

Just one note, it is slightly non-trival to add external digital audio input to a digital video camera, because the input has to be re-clocked. In general the external audio clock will drift relative to the camera master clock so you cannot simply transfer the bits directly. I'm sure there are chips that handle this, but if that chip is not already on the board, I assume this would be something for Red 2, not Red 1.
 
Interesting mic. Michael Gerzon was a sound genius, and this, if based on his work like they say, should be superb. The 4 tetrahedrally placed mics would allow you to record the full 3dimensional soundfield on 4 channels, that you could decode into practically an surround sound format you want, as you have full XYZ information, just waiting to be pulled out of the data you recorded.

Graeme
 
Audio Specs recap

Audio Specs recap

All four audio inputs are mic/level switchable

All inputs support 48V phantom power for mics

The camera can suppress any active cooling (and hence sound) during a take

RED-DRIVE and RED-RAM and RED-Flash are all fan-less designs

Each audio input is sampled at 48KHz at 16 or 24 bit depth

We have considered methods for pre-digitized audio capture, but we have no news to share at this moment.
 
Would 96khz be a huge problem?
Because it does sound better, the sound is noticably clearer and more define and would make the camera much more future proof.
24 bit is great allready, but 96khz is a very nice iceing on the cake, and would fit better in a demanding audio environement.

Yours "at any freq" Emmanuel
 
I've taken good care of my ears, but I'm over 40 now and I have no hearing at all above 15 kHz. I envy you if you can detect 96 vs 48 kHz sample rates, all other things being equal! Of course they usually aren't... when you go to 96 kHz sampling there are normally other differences at various places in the audio chain- at the very least the details in the reconstruction filter- so unless it's a very controlled test, there is more than just a sample rate effect.
 
- How many channels of audio monitoring will there be?

- Is it safe to presume that you can control how all the channels get mixed to the monitoring outputs?
i.e. you can hear all 4 channels at once, or just input 1 in both ears, etc.
 
jbeale said:
I've taken good care of my ears, but I'm over 40 now and I have no hearing at all above 15 kHz. I envy you if you can detect 96 vs 48 kHz sample rates, all other things being equal! Of course they usually aren't... when you go to 96 kHz sampling there are normally other differences at various places in the audio chain- at the very least the details in the reconstruction filter- so unless it's a very controlled test, there is more than just a sample rate effect.
Click to expand...

The difference is there to be heard on good monitors.
But I agree that it only get obvious when you are going to mix several tracks together, you really get a lot of clarity and definition, and things are being mixed a lot easier.

Yours Emmanuel
 
Audio monitoring

Audio monitoring

Because of the approach we have taken we have a fair bit of flexibility regarding what channel(s) can be monitored on the L and R outputs of the headphone and XLR outputs.

It would be interesting to collect inputs to what you guys would like, so we can compare it to what we've come up with as the first priority for product implimentation.
 
1- Throwing out an idea here: It might be better to have 2 independent headphone outputs, as opposed to XLR outputs. Some mixers like the Sound Devices stuff take headphone/mini-jack as the return feed, not XLR.

If you want to record sync sound, a reasonable setup would be:
Two audio persons. Each sound operator holds a boom and a single wireless lav (or handle two wireless lavs). They also handle their own levels and mix their feeds. They can monitor right off the camera (via the return on their mixer).
This works well with the Sound Devices mixers, since they can't output more than 2 channels. They can have 2+ inputs, so you can have a boom and at least one lav. As well, if you make a custom snake/cable for a Sound Devices mixer (Trew Audio / Remote Audio does this), it will have a headphone jack (not XLR).

1b- If you are going wireless in and out of the camera (from your mixer), 2 X mini-plug will still be ok?

2- Another situation would be using double system, where you might just record 2 tracks of guide audio, plus timecode. In this case 2 independent headphones feeds should still be fine.

3- Menu-wise, you'd need controls for:
*Monitoring/mixing. 4 channels of inputs, and 4 channels of monitoring (L+R on headphone out 1, L+R on headphone out 2) would mean a 4x4 matrix. A joystick-like control like on the DVX100 would be a sensible way of setting this if using a menu system.
*Line/mic on each input.
*Limiters on inputs 1 & 2. (I don't forsee needing limiters on inputs 3&4.)
*Phantom power (Probably ok to omit T power.)

I think with this many settings (24 or more), you'd need a menu system. Ideally, the menu system would be so intuitive that you can look at the camera and figure out how to setup the audio.

4- Stereo linking of the limiters can likely be omitted.

Flexibility about what channels to monitor implies that a 4 -> 2 channel monitor downmix is not possible?
Click to expand...
My interpretation is that it implies that it IS possible.
 
Graeme, I totally agreee about MS.

To be honest, for useful production sound, the Red should either have:
- really great preamps + DAC plus MS matrix monitoring for headphones
OR
- digital input (so that you can use an external mixer / preamp / DAC chain).
OR
- take $500 off the price of the camera, have 2 channels with cheap-ass preamps which we just record a reference track to and then we put that $500 towards a Sound Devices compact-flash timecode recorder with great pre-amps, MS monitoring and 192khz / 24bit recording (costs $2000-$4000 depending on how many channels you want)

...actually why don't you just cut a deal with the Sound Devices people to include their audio system on your camera?

The current system looks suspiciously like it has just low enough quality to not be useful.

All of this stuff about holographic 3D sound recording is likewise not that useful for real jobs. If you want to record stereo, MS is the way to go (especially with youtube, phones, video ipods, etc you always want a good mono-compatible signal).
 
Bruce Allen said:
- digital input (so that you can use an external mixer / preamp / DAC chain).
Click to expand...

This sure seems like a possibly good solution.

Yours Emmanuel
 
Stuart English said:
Because of the approach we have taken we have a fair bit of flexibility regarding what channel(s) can be monitored on the L and R outputs of the headphone and XLR outputs.

It would be interesting to collect inputs to what you guys would like, so we can compare it to what we've come up with as the first priority for product implimentation.
Click to expand...

This is admittedly a fairly minor quibble, but... does the camera always record four channels, even when there's no input? It would be nice if channels could be disabled individually, to save a bit of storage space and make things just a little neater in post.
 
I think well engineered 24bit 48khz is fine, 96khz would be nice but 48khz is good enough given that onboard sound will always be a bit of a compromise. If you are in pursuit of ultimate quality you will probably be using separate audio anyway. I think it is more important that the solution is implemented well and the AD stage is well engineered than pushing for maximum spec, that may lead to compromised performance.

There is an interesting paper here about 192kHz and why it maybe isn't such a great idea.
http://www.lavryengineering.com/documents/Sampling_Theory.pdf


Martin
 
Stuart,
may I say that RED one has the options to go for Surround Sound live recording from all the inputs ?

No Camera on earth can record surround sound from the Camera but THE RED ONE ?

Stewart
 
Surround on RED

Surround on RED

The RED_ONE camera has four discreet channels of audio at 48KHz 16 or 24 bits. What you do with that - 2 channels spilt high / low gain or surround sound matrixed recording is for the user to descide.

These user choices do have some impact on monitoring to headphones etc, which is why we'd like to gather likely use data for our consideration.
 
2 or 4 channel audio record

2 or 4 channel audio record

We can turn off channels 3 / 4 ( i.e not record those) if its required.

To answer the follow up question - does that mean we can use that "unused bandwidth" to record Channel 1 & 2 at 96Khz ?

That issue is not related to the above. The audio spec is 48KHz at 16 or 24 bits per channel.

(Usual rider - that all specifications subject to change)
 
Ok, if you want to monitor the surround mix somehow, the camera would have to do a downmix from 4 channels into the 2 channels of the headphones.

So a simple matrix (which input of the 4 provided do I want to hear on my left output channel, which one on the right) would not enough. You´d have to be able to adjust volume and pan for the 4 inputs.

That would indeed be nice also in a non-surround setup with maybe 2 Lav´s plus a stereo ambience mike

Anything more for the surround field would require the ability to encode the 4 inputs into some sort of Dolby-ish matrix for monitoring - bit of an overkill IMHO.

I´d be perfectly happy with the simple I/O matrix for monitoring.
Onscreen metering for all 4 channels though is necessary (to check for dead mikes, cables, etc.)

Jochen
 
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