Audio Clip 48v Hiss / MIC input CLEAN

[Mike Prevette]

The 416 likes to be close to it's subjects. I have the older "t" power version. It would be interested to see if you powered it via an external mixer for the phantom power, and then passed a line in into the cam. Just trying to narrow down if it's indeed the phantom power circiut causeing the hiss.

 

[jbeale]

fan noise and thermal management

fan noise and thermal management

The technical difference is this - VARIABLE runs the fans at a variable rate, in both record and when not, SILENT runs the fans at full speed when not in record and a fixed speed of about 10% when in record. And it will stay at that same speed throughout a recording.
If its cold, shoot VARIABLE mode. Else consider SILENT mode.

If I'm understanding this right, it sounds like the (only?) way to get "truly inaudible" operation, as I would understand that term, is to set the fan in VARIABLE mode, AND prevent the camera body from getting any warmer than about 72 F by whatever external means may be necessary. So in normal room-temperatures, that might mean a large slow-turning external fan, a large external heatsink clamped to the camera, a tripod plate with chilled water supply, freeze spray, ice packs, frozen peas, whatever.

 

[Greg M]

The 416 likes to be close to it's subjects. I have the older "t" power version. It would be interested to see if you powered it via an external mixer for the phantom power, and then passed a line in into the cam. Just trying to narrow down if it's indeed the phantom power circiut causeing the hiss.

Yes, the bulk of the problem w/ usability of Zacs clip is related to the distance from the subject. But I can confirm w/ Build 13 Phantom Power does introduce hiss. The biggest issue though is the DC offset.

 

[Elizabeth Lowrey]

Yes, the bulk of the problem w/ usability of Zacs clip is related to the distance from the subject. But I can confirm w/ Build 13 Phantom Power does introduce hiss. The biggest issue though is the DC offset.

I magnified a waveform in Vegas to where I could see the offset. I understand that it restricts normalization range, but what are the other audible consequences of DC offset?

 

[zak forrest]

Yes, the bulk of the problem w/ usability of Zacs clip is related to the distance from the subject. But I can confirm w/ Build 13 Phantom Power does introduce hiss. The biggest issue though is the DC offset.

i dunno man, i have gotten some pretty damn nice results with that distance and that mike before..

and yeah, the gain could have been higher, but i didnt bother doing another test with higher gain because i already saw that the problem was that hiss and the hiss would just get louder with the gain change so i stopped..

 

[Steve Sherrick]

DC offset can affect headroom(can reduce in direction of the offset). If excessive enough it could affect gaining up (clipping). Interesting, have to see if this is an issue during my tests.

Zak, If you like the 416 from several feet away, then no one can hold that against you. You are entitled to get the "sound" you want. Personally, for medium and closeup shots I wouldn't want that mic that far away. But f a wide angle, it might be an okay perspective. Also, the 416 is not the ideal indoor dialogue mic but that's yet another subjective area. And besides, Schoeps just raised their prices so....

Steve

 

[Brian Ferguson]

I don't know what the problem is but when i downloaded the 416 audio on my iBook at home with the volume full up I could barely hear the dialog let alone the hiss. It seems to be output at a very low level. I held the computer to my ear and heard the hiss but if your levels are that low to start with you only amplify your signal to noise issues maybe the mic was set at way to low a db setting?

BriFerg

 

[zak forrest]

DC offset can affect headroom(can reduce in direction of the offset). If excessive enough it could affect gaining up (clipping). Interesting, have to see if this is an issue during my tests.

Zak, If you like the 416 from several feet away, then no one can hold that against you. You are entitled to get the "sound" you want. Personally, for medium and closeup shots I wouldn't want that mic that far away. But f a wide angle, it might be an okay perspective. Also, the 416 is not the ideal indoor dialogue mic but that's yet another subjective area. And besides, Schoeps just raised their prices so....

Steve

well when the camera isnt hissing etc, it really sounds pretty good for me if i'm doing run and gun type stuff. not feature stuff. does that make my decision seem more sane to you?

what do you recommend over the 416 for an on camera documentary mike, where you are alone and have only the camera mounted mike? and you are filming things that arent staged (no lavaliers allowed)

 

[zak forrest]

I don't know what the problem is but when i downloaded the 416 audio on my iBook at home with the volume full up I could barely hear the dialog let alone the hiss. It seems to be output at a very low level. I held the computer to my ear and heard the hiss but if your levels are that low to start with you only amplify your signal to noise issues maybe the mic was set at way to low a db setting?

BriFerg

ill try and do another test with it at several gain levels. it just seemed obvious to me that it wasnt a low level trick, that hiss would only get louder as i boosted the gain so i cancelled the test and decided to wait for red to fix this. ill try another test though but i think its just bogus right now to begin with..

ive recorded stuff from the same distance, in fact kept the mike on the camera and kept talent in the same place, and just plugged the mike into my MBOX and recorded some dialogue onto the computer and the results were really amazing. my first reaction was "oh my god are the preamps on the red complete garbage????" but now i'm hoping they are just fine and the problem can be fixed with software. and if it can't, i would say they should do a recall...

 

[Fergus Meiklejohn]

ill try and do another test with it at several gain levels. it just seemed obvious to me that it wasnt a low level trick, that hiss would only get louder as i boosted the gain so i cancelled the test and decided to wait for red to fix this. ill try another test though but i think its just bogus right now to begin with..

ive recorded stuff from the same distance, in fact kept the mike on the camera and kept talent in the same place, and just plugged the mike into my MBOX and recorded some dialogue onto the computer and the results were really amazing. my first reaction was "oh my god are the preamps on the red complete garbage????" but now i'm hoping they are just fine and the problem can be fixed with software. and if it can't, i would say they should do a recall...

I don't doubt it Zak. I've also recorded plenty of stuff with an on-camera shotgun at that distance and it didn't sound anything like your test. There is clearly something wrong with RED audio, and I don't think RED should get distracted by the nuances of your test. But thanks for doing it again anyway.. just to ram the point home

Incidentally some users seemed to suggest that by reinstalling the Firmware they were able to make the hiss go away (for a while). Has that been your experience?

 

[Stuart English]

Hiss on +48V

Hiss on +48V

I've also recorded plenty of stuff with an on-camera shotgun at that distance and it didn't sound anything like your test.

Incidentally some users seemed to suggest that by reinstalling the Firmware they were able to make the hiss go away. Has that been your experience?

There is obviously a MAJOR difference in quality between these two clips, and the hiss evident in the +48V case should not be taken as de-facto evidence of a poor A/D conversion - the Mic input passes through the same section and it is clean. I don't know why only the +48V input is exhibiting this behavior, but I do know we are on it.

For the majority of cameras that I am aware of, on Build 13 the Mic and Line inputs are hiss free. Please PM me or Brent if you have a camera that isn't.

 

[Fergus Meiklejohn]

the hiss evident in the +48V case should not be taken as de-facto evidence of a poor A/D conversion - the Mic input passes through the same section and it is clean.

I agree with you Stuart. Good luck solving the problem.

 

[donatello b]

"on Build 13 the Mic and Line inputs are hiss free"

on monday when Red 103 was returned - i shot a few clips .. i had a low volume tone/noise in all clips ( not a hiss ) when played in FCP . i didn't have a mic connected ... looking into it more ( as in hrs).... the camera was returned with all audio channels enabled. the tone was coming from 3 & 4 in Mic mode changing it to LINE or un-checking 3 & 4 ( un-enable) got rid of the low volume tone ( which you can hear thru headphones ) ...

if i plug a mic into 3 and disable 4 the tone goes away ... and if i plug mic into 4 and disable 3 tone goes away ...
there is no tone in 1 & 2 when they are enabled with no mic connected ..
so why the tone in 3 & 4 ?

2:00pm ... correction - i am finding the low tone in channel 1 if 2 is enabled ...
also one of my mic's is very low - so i have to set RED channel 1 volume to 41 - which now i hear the low tone .. if i reset the volume to 26 i do not hear it but then i can't get any volume out of my mic ...