Ursa Mini Pro Camera mic noise

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David Cherniack

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Ursa Mini Pro Camera mic noise

PostSun Mar 19, 2017 4:14 pm

In a word it's awful, peaking around -30db. I've attached a file recorded in a quiet room at 50% level both channels.

The XLRs are much better at around -55db. However the headphone amp is also very noisy so it's not ideal for monitoring.
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Blackmagic Camera mic Noise Sample.rar
(204.93 KiB) Downloaded 98 times
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Adam Silver

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Re: Ursa Mini Pro Camera mic noise

PostSun Mar 19, 2017 6:23 pm

I should be getting my camera pretty soon. This is the first post I've seen about the sound from the URSA Mini Pro. It sounds like the XLRs are better, but one of my biggest gripes about the URSA Mini 4.6k is that I can't properly monitor the sound. I need to be able to hear what is being recorded.

Adam
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David Cherniack

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Re: Ursa Mini Pro Camera mic noise

PostSun Mar 19, 2017 6:27 pm

It could be I have one that's worse than what you may get. That's why I posted the sample. So us new owners can compare. I suspect a low impedance headphone may make monitoring the XLRs more palatable. I used Zennheiser phones @ 60ohms.
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MontgomerySutton

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Re: Ursa Mini Pro Camera mic noise

PostSun Mar 19, 2017 10:43 pm

Will do some test on ours and get back to you...
Montgomery Sutton
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montgomery@lupoblu.com

lupo blu, LLC (www.lupoblu.com)
Salt Pillar Productions (www.saltpillarproductions.com)

URSA Mini 4.6K | Red Scarlet Dragon | Canon C100 mkII | BMPCC (x2)
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rick.lang

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Re: Ursa Mini Pro Camera mic noise

PostMon Mar 20, 2017 12:39 am

I use the Bose Quiet Comfort at 25% volume successfully. Or less.


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Rick Lang
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David Cherniack

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Re: Ursa Mini Pro Camera mic noise

PostMon Mar 20, 2017 12:18 pm

Rick, those are active phones, I gather. So you use them in high sensitivity mode?

Has BM published the output impedance of the headphone jack?
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rick.lang

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Ursa Mini Pro Camera mic noise

PostMon Mar 20, 2017 3:17 pm

Yes, they're external noise cancelling headphones. Sorry I don't know if they have a high sensitivity mode. I just plug them in and activate the noise canceling feature via a switch.


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Rick Lang
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Andreas Schwarz

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Re: Ursa Mini Pro Camera mic noise

PostMon Mar 20, 2017 6:01 pm

What about the lag, that occurs when monitoring sound. Is there a chance, it will be fixed in firmware update?
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David Cherniack

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Re: Ursa Mini Pro Camera mic noise

PostTue Mar 21, 2017 10:24 pm

Back to OP:

This new article at Pro Video Coalition https://www.provideocoalition.com/ursa-mini-pro-blackmagic-reveals-new-audio-specs/ quotes Blackmagic as saying

"XLR MIC Preamp has E.I.N. (Equivalent Input Noise) = -128 dBV(A) or better."

When I recorded the XLR inputs with no mic attached (but the phantom power on) the residual noise was peaking somewhere around -55dB. How would that reconcile with -128dBV(A). Is the BM figure RMS?

A question which wasn't asked in the article is about the camera mic residual noise. So, Blackmagic or anyone else:
Does the camera mic use the same preamp as the XLRs? (Probably). But if so, why is it so noisy (peaking at -30dB)? Is mine defective? Or is it a shielding from the electronics issue?
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Denny Smith

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Re: Ursa Mini Pro Camera mic noise

PostWed Mar 22, 2017 4:51 am

Built in Mic's are always worse than using good quality external balanced (XLR) Mic's. End of story, you are comparing apples to oranges here. :mrgreen:
Denny Smith
SHA Productions
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Tim Schumann

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Re: Ursa Mini Pro Camera mic noise

PostWed Mar 22, 2017 6:32 am

David Cherniack wrote:XLR MIC Preamp has E.I.N. (Equivalent Input Noise) = -128 dBV(A) or better.
Correct
David Cherniack wrote:When I recorded the XLR inputs with no mic attached (but the phantom power on) the residual noise was peaking somewhere around -55dB. How would that reconcile with -128dBV(A). Is the BM figure RMS?

This is not how you measure the noise floor and why would you switch phantom power on when nothing is plugged in?
David Cherniack wrote:Does the camera mic use the same preamp as the XLRs? (Probably). But if so, why is it so noisy (peaking at -30dB)? Is mine defective?
No the inbuilt Microphone preamps have 100dB(A) audio ADC’s. Our inbuilt headphone preamps are also 100dB(A).

It looks as though one of your inbuilt camera microphones is noisier than it should be and may need to be looked at by one of our support centres.
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Robert Niessner

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Re: Ursa Mini Pro Camera mic noise

PostWed Mar 22, 2017 10:09 am

David, just for your reference:
This is what my URSA Mini 4.6k sounds on internal mic at 50%:

A002_03221044_C002.zip
(1007.03 KiB) Downloaded 23 times

The room had a measured 32dB (C weighted). Total RMS level -56,54dB

EDIT:
Did also a XLR test without an external mic attached:
Phantom power ON/OFF did not make a difference.

Channel 1 Gain 33% High ... Total RMS level -93,72dB
Channel 2 Gain 50% Low ... Total RMS level -103,24dB
Robert Niessner
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David Cherniack

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Re: Ursa Mini Pro Camera mic noise

PostWed Mar 22, 2017 2:25 pm

Robert: Thanks for the file. It's helpful.

Tim: I'd like to get to the bottom of this and determine whether it should go in to a service centre. So here's what I did this morning:

1) I used a sound pressure meter to measure my environment at 40dB (A) at the camera.

2) I recorded using the camera mics at 50%

3) I recorded using the XLRs (no mic, no phantom) at 50%

4)Using Adobe Audition I measured the Amplitude Statistics of files:

a) Camera mics
camers mics.JPG
camers mics.JPG (30.03 KiB) Viewed 667 times


b) XLR Inputs
XLR Inputs.JPG
XLR Inputs.JPG (31.63 KiB) Viewed 667 times


c) Robert's Camera mics (For Comparison)
Robert's camera mics.JPG
Robert's camera mics.JPG (33.02 KiB) Viewed 667 times


Robert's camera mics appear much quieter than mine (in a similar quiet environment) by about 10dB.

So would the advice be to send it in through my dealer?
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Denny Smith

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Re: Ursa Mini Pro Camera mic noise

PostThu Mar 23, 2017 2:22 am

Yes, or request a RMA directly with your BM support center, they will sort the issue and give you a quick turn-around time. :mrgreen:
Denny Smith
SHA Productions

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