BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

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Alex Delfont

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BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostThu Nov 25, 2021 7:15 pm

Hi

I've recently got the Rode Wireless Go II, 2 TX and 1 RX. I plug the RX into the mic input with the stereo 3.5mm jack provided. I get each TX coming on L and R line inputs.

In the BMPCC4k settings I choose 3.5mm line input, and you cannot adjust the gain. But the signal looks and sounds very weak. I've read about this in other threads. I didnt find anyone saying anything could be done about it?

But even recording at such a seemingly low level, if I put it in Resolve and up the gain about 25db to a usable level, it sounds ok to me. I would say the signal to noise ratio is quite similar to if I plug the Rode Wireless go II into my Zoom H1 in which I can get a very good signal. (Doing this seems to work better with the Rode at max output, and the zoom turned right down).

How can this be? I was expecting to bring the gain up on the BMPCC4k audio and hear unbearable hiss. How can it be similar to using the zoom H1 with a decent signal

Am I missing something? Do people recommend against this? It sounds ok and surely thats what matters. Of course I want the best S/N ratio possible but really want the convenience of recording straight to camera

Any help would be great before I have a shoot in two days
thanks
Last edited by Alex Delfont on Fri Nov 26, 2021 5:11 pm, edited 1 time in total.
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostFri Nov 26, 2021 8:04 am

Strange I got an email saying someone has replied, and now its gone?
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Nick Heydon

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostFri Nov 26, 2021 8:11 am

I can adjust the gain on the P4k with this same setup. Are you sure you're not set to Line In?
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostFri Nov 26, 2021 5:10 pm

Nick Heydon wrote:I can adjust the gain on the P4k with this same setup. Are you sure you're not set to Line In?


Sorry yes I meant 3.5mm Line in! I cannot adjust the gain in camera
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Nick Heydon

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostFri Nov 26, 2021 6:04 pm

Ah, then change it to Mic input, and then you can control the input levels.
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostFri Nov 26, 2021 11:02 pm

Nick Heydon wrote:Ah, then change it to Mic input, and then you can control the input levels.


Thats interesting, Mic input was greyed out, couldn't select it or change the gain. So I plugged in a lav mic, turned the camera off and on and it was then available. Then I plugged in the Rode Wireless Go II instead and the gain was much higher even at the standard 50% as it was intended for a mic signal, not Line signal.

But the Rode Wireless GO RX is Line Level. Is it ok to plug it in and use the mic level? Would that create any issues
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dondidnod

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 12:39 am

Alex Delfont wrote:Mic input was greyed out, couldn't select it or change the gain.

Are you using a fully charged genuine Canon LP-E6 battery?
I've noticed problems getting phantom power to work on 3rd party batteries.
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Robert Niessner

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 5:54 am

Alex Delfont wrote:
Nick Heydon wrote:Ah, then change it to Mic input, and then you can control the input levels.


Thats interesting, Mic input was greyed out, couldn't select it or change the gain. So I plugged in a lav mic, turned the camera off and on and it was then available. Then I plugged in the Rode Wireless Go II instead and the gain was much higher even at the standard 50% as it was intended for a mic signal, not Line signal.

But the Rode Wireless GO RX is Line Level. Is it ok to plug it in and use the mic level? Would that create any issues


No, the RX is not line level. And yes you can and should use mic level.
Saying "Thx for help!" is not a crime.
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Robert Niessner
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 9:06 am

dondidnod wrote:
Alex Delfont wrote:Mic input was greyed out, couldn't select it or change the gain.

Are you using a fully charged genuine Canon LP-E6 battery?
I've noticed problems getting phantom power to work on 3rd party batteries.


Yes I am using a genuine LPE6
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 9:08 am

Robert Niessner wrote:
Alex Delfont wrote:
Nick Heydon wrote:Ah, then change it to Mic input, and then you can control the input levels.


Thats interesting, Mic input was greyed out, couldn't select it or change the gain. So I plugged in a lav mic, turned the camera off and on and it was then available. Then I plugged in the Rode Wireless Go II instead and the gain was much higher even at the standard 50% as it was intended for a mic signal, not Line signal.

But the Rode Wireless GO RX is Line Level. Is it ok to plug it in and use the mic level? Would that create any issues


No, the RX is not line level. And yes you can and should use mic level.


I was under the impression these receivers were always line level, as they amplify the signal from the microphone right?

Also do you know why 3.5mm Mic input was greyed out when I had the Wireless go plugged in before I plugged a lav in and turned off and on?
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Robert Niessner

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 6:32 pm

Alex Delfont wrote:I was under the impression these receivers were always line level, as they amplify the signal from the microphone right?


No, that's a wrong assumption.

I am quoting John Blankenship from the Sounddevices forum here:

A large reason for this is miniaturization and portability. The maximum output level of an audio circuit is determined in large part by power rail voltages. In a device with constrained size and heat limitations, it becomes more difficult, and more inefficient, to have higher supply rail voltages. Add to that the fact that such powering would diminish battery life, and you can better understand why such compromises are made.


That was about the MixPre 10 recorders from Sounddevices - so you can figure what that means for the tiny Wireless Go RX.

Alex Delfont wrote:Also do you know why 3.5mm Mic input was greyed out when I had the Wireless go plugged in before I plugged a lav in and turned off and on?


My guess would be that you had set left input to 3.5mm line and tried to set right input to 3.5 mm mic - which is then grayed out because you can't have line and mic on the same input the same time.
Then maybe the camera recognized the input signal and changed to mic level.
Or you did tap the left input and changed it to something else - then it also activates the mic level of the right input.
Saying "Thx for help!" is not a crime.
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Robert Niessner
LAUFBILDkommission
Graz / Austria
--------------------------------
Blackmagic Camera Blog (German):
http://laufbildkommission.wordpress.com

Read the blog in English via Google Translate:
http://tinyurl.com/pjf6a3m
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostSat Nov 27, 2021 7:57 pm

Ok thanks so I guess I'll just use it on Mic Input then. Thank you :)
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smunaut

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostMon Nov 29, 2021 9:30 am

FYI some time ago, I characterized the 3.5mm and XLR inputs on my bmpcc4k :

viewtopic.php?f=2&t=136953#p739231
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Alex Delfont

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Re: BMPCC4k 3.5mm line in quiet, but sounds ok normalised?

PostMon Nov 29, 2021 10:22 am

smunaut wrote:FYI some time ago, I characterized the 3.5mm and XLR inputs on my bmpcc4k :

viewtopic.php?f=2&t=136953#p739231


Thanks thats really useful and makes sense now why it was so quiet

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