audio to Mini?

[filmmaker1977]

okay i thought you already read my PM but now i was checking your unconfirmed PM receipt and i'm seeing that you didn't.

check your PM box please!

[ESTEBEVERDE]

Personally, I think the SI is an Earth shaking development.

This is the for real deal.

Red sounds great and in all probability it will be.

With that said, Silicon Imaging is quickly proving it is as the wave of the future today!

I personally prefer off camera recording for many reasons so the fact that SI is even considering having any on board sound capture is just icing on the cake to me!!!

[Emanuel]

filmmaker1977, though I'm not Jason and you must wait for his answer not mine, of course, here is an interesting post from Markus (the previous post of the Yuval's post) around the subject:

I'm not an expert either, but I have some synthesizers and other audio gear and I searched for the best way to record the audio. I looked for A/D converters and found out there are alot of cards/racks which are 24 bit/96 kHz between 50$ and 5000$.
I wanted to know what the difference is and its not about features, but about dynamic range and signal-to-noise-ratio (SNR). This is what the quality of audio depends on.

My Soundblaster Live card (16 bit) has about 80 dB. Sounds good, but that means that about 20% of the 16 bit audio is just noise. So you can call it a 13 bit card, or "not a real 16 bit" card. For 16 bits, noisefree audio you need about 100 dB.

The audio file is just a container (like .avi, .mov, .mxf) for signal + noise. To get the best quality, you have to minimize the noise and maximize the signal.

Some newer cards and chips have 110 dB, up to 120 dB. So 16 bits is not sufficient to record every information. But it would be silly to produce "17 bit, 18 bit, 21 bit, ..." converters. The next step would be 20, or 24 bits.
Most manufacturers use 24 bit resolution when the dynamic range is above 100 dB. But that does not mean they have a 24 bit signal. They actually waste about 6 bits with noise.
The higher the dynamic range, the more expensive the A/D converters are. To reduce the thermal noise, you have to install some serious active cooling devices.

About DV: DV is 12 or 16 bits. It's just the container. To find out how good your camera records the audio, you have to ask the manufacturer about dynamic range and SNR. Sometimes they print this in the manual. I just looked at my DVX100AE manual, but it just says "12/16 bit".

But the big question is: who needs anything above 16 bit / 100 dB?

- Music producers need that as a headroom for mixing or alternating/pitching/bending/transformating the signal.
- People recording extremly loud stuff (way louder than a rock concert).
- Scientists

For just recording and playback real-world stuff, you won't need that. Listen to a good CD, that's "oldschool 16 bit".

http://www.dvxuser.com/V6/showpost.p...15&postcount=9

[filmmaker1977]

Emanuel

but..

"Most manufacturers use 24 bit resolution when the dynamic range is above 100 dB. But that does not mean they have a 24 bit signal. They actually waste about 6 bits with noise.

The higher the dynamic range, the more expensive the A/D converters are. To reduce the thermal noise, you have to install some serious active cooling devices."

and that's why I asked what I asked.. 24/48?.. besides the pre-amps provided from these kind of external USB/Firewire devices, will it be necessary any other source with good pre-amps or anything else to go to theatrical release?.. specially if we know that any laptop can be a hassle considering the potential electronic interference level of a computer basis recording?.. or isn't it so?

..and please don't talk me about 16/48 is CD quality blabla.. i know.. but if all the people will record at highest 24/48 or even 24/96, will i be recording with an inferior set-up?.. only if anyone like Jason may clarify that > 100 db issue..

[Jason Rodriguez]

Okay . . .

The problem you have with trying to record 24/96 on a computer motherboard (or near a computer motherboard like internal to a laptop), is that while the specs on the audio recording codec are great (i.e., the Sigmatel chipsets are around 100db right now), you're placing them right next to very noisy electronics inside the motherboard or the laptop. That means the theoretical 100db you'd get from the chip in isolation is out the door . . . motherboard manufacturers are not manufacturing their devices for audiophile recording, they're mostly doing it for playback, and they're expecting the super-high quality playback to be piped out as a digital signal (SPIDF), so the isolation needed for great analog performance simply isn't there. Additionally, since there's no isolation, you can't have great analog pre-amps . . . you can have pre-amps with great specs on paper, but again, their real-world performance is going to be compromised by noisy electronic gear sitting right next to them on the motherboard or somewhere else inside the computer. For instance, I remember doing audio recording with the on-board on a laptop one time as back-up to a Nagra and I could hear electronically an odd clicking sound (that wasn't on the Nagra) when the hard-drive would start spinning up! So that's not what you want . . .

By using an external device (which has isolated analog pre-amps, and isolated A/D converters optimized for their theoretical dynamic ranges) you get much better audio recording. You can actually take advantage of 24/96 (or at least hope to have the possibility). On a computer motherboard, you simply can't, and 16/48 will be perfectly fine, as there's so much possible noise on the line, if you tried to record with the potential dynamic range of the 24-bit depth, you'd end up hearing the noise of the electronics inside your computer when you normalized the signal in post rather than what you were actually trying to record. And 16/48 is *perfectly* fine for the dynamic range of dialog and production sound.

So, while we're going to support on-board audio recording, we suggest that's mostly a "scratch-sound" interface, or just a simple audio interface like a normal camcorder . . . the actual audio quality will be about the same as your typical broadcast camera . . . since they too aren't that worried about the isolation of audio components. This of course tends to work for around 80-90% of the situations you'll encounter, so we see it as useful. But, If you must have the highest level of audio recording, you will need to have an external device via USB/Firewire that enables you to get away from the noise-sources inside the computer/camera.

[filmmaker1977]

Jason for your nice input!..

actually, I'm thinking to shoot with this set-up:

Mini + USB/Firewire external device for help the audio -> laptop

..that's why i'm worried..

can you help here:

http://www.dvxuser.com/V6/showpost.p...0&postcount=15

as hemophilia helped with his non-technical post i'd like your answer because:

1st
the english is not my mother language;

2nd
i do art for living and unfortunately i must learn about these boring hassles.. i can assure you it's worst than to have money to buy it..

when i'm asking if these usb/firewire external devices have or not pre-amps inside, it's just because maybe you wanted to say that they will need good pre-amps.. so considering my technical ignorance, i don't know if you are saying that they already have good pre-amps included (?) or if they need for another pre-amps source (?) and if it is the case where can i solve the problem?

Hi Filmmaker . . . yes, the USB devices have VERY good pre-amps . . . and they are noise-free, meaning that they are very well isolated, unlike audio on a motherboard which is close to a lot of other electronics that can create noise in the signal . . . so although the specs on a device might be 100db, if they sit it next to a noisy gigabit ethernet chip on a motherboard, that S/N is lost. The external device allow for that to be avoided.

aside any no private content i'm posting it because our exchange PM can be interesting to this debate and to other future SI users and i hope sincerely the best success for your project.. it will be mine also as customer.. and a warranty to the future.. your luck is our welfare too..

aside my bad english, my last concern is:

i) with an external USB/Firewire like those referred similar to DIGIGRAM UAX220-MIC, i can have something around > 100 db avoiding the natural electronic interferences of any laptop?

ii) or i must have an external recording device like Tascam or Edirol just for to assure quality enough to theatrical release.. because if so, i must count with more 4 - 5 lbs. right on my shoulders + a pain ass just to handle with more one device around my run and gun work..

iii) last but not least.. since a long time ago, i've been dreaming with a laptop solution for the filmmaking..

but also for the audio embedded with the image?..

can it be possible to guarantee high quality audio recording with a laptop if working via a USB/Firewire device like that DIGIGRAM UAX220-MIC?..

you're saying:

By using an external device (which has isolated analog pre-amps, and isolated A/D converters optimized for their theoretical dynamic ranges) you get much better audio recording.

and if so, 24/48 will it not be the best option?

You can actually take advantage of 24/96 (or at least hope to have the possibility). On a computer motherboard, you simply can't, and 16/48 will be perfectly fine, as there's so much possible noise on the line, if you tried to record with the potential dynamic range of the 24-bit depth, you'd end up hearing the noise of the electronics inside your computer when you normalized the signal in post rather than what you were actually trying to record. And 16/48 is *perfectly* fine for the dynamic range of dialog and production sound.

(but) when you're saying:

So, while we're going to support on-board audio recording, we suggest that's mostly a "scratch-sound" interface, or just a simple audio interface like a normal camcorder . . . the actual audio quality will be about the same as your typical broadcast camera . . . since they too aren't that worried about the isolation of audio components. This of course tends to work for around 80-90% of the situations you'll encounter, so we see it as useful. But, If you must have the highest level of audio recording, you will need to have an external device via USB/Firewire that enables you to get away from the noise-sources inside the computer/camera.

can i trust in a cheap device like that?.. when you're saying: "so although the specs on a device might be 100db, if they sit it next to a noisy gigabit ethernet chip on a motherboard, that S/N is lost. The external device allow for that to be avoided." how much will it be?.. in an efficient manner?..

and if so, would it be possible to increase up to 24/48 or even 24/96 recording if the USB/Firewire will have good pre-amps?.. or is there ONLY great specs on paper?.. in this DIGIGRAM UAX220-MIC case, the S/N ratio on paper does it mean good pre-amps? did you test any external device similar?.. or did you know who had been working or testing a set-up like this one?.. because if theoretically speaking it can be work, nothing better than the practice to confirm, or not, any hassles.. or may i be confident with my set-up?..

and if so, just at 16/48?.. or can i dream with the 24/48 or 24/96 with the basic quality requirements (to theatrical release) IF via an external USB/Firewire external device like UAX220-MIC + laptop audio/video recording?


Jason!

i will shoot with SI.. the first digital cinema camera of the History!

and i'm sure that there are a lot of people with me too..

[Jason Rodriguez]

Hi Filmmaker,

The problem is analog isolation . . . the external devices move the analog front-end away from the computer, and are straight digital into the computer as bits . . . so the external USB/Firewire adapters avoid the noise issues, and you don't need to have an actual external recorder, i.e., a Sound Devices or HBB, etc.