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Pocket 4K - weak preamps?

PostPosted: Tue Nov 06, 2018 10:46 pm
by Johan Cramer
I've discussed this issue with fellow Pocket 4K owners, and all cameras seem to be affected, not just my copy: When recording sound internally via the stereo mini jack or the mini XLR connector, audio levels are much lower than they should be (and than they were with previous BM cameras such as the BMCC and first-generation Pocket).

These were my observations:

- The Rode Stereomic X connected to the stereo mini jack needs its output level set to +20db and camera audio levels set to 100% to reach normal peaks when recording acoustic music or conversations.

- Same is true for the binaural Ohrwurm mic whose output is 16db stronger than average mics. It needs 100% audio levels on the Pocket 4K in situations where 20-40% sufficed (to avoid clipping) on the old Pocket and the BMCC.

- Finally, the Rode NTG2 connected to the mono mini-XLR port with +48V phantom power and being ca. 10cm away from the mouth of a speaker talking in a normal voice needs 100% amplification on the Pocket as well. (Which means that levels will be too low when booming the mic.)

I wonder whether this is a production error of the cameras that have been sold to date, or an issue that could be fixed in firmware.

Re: Pocket 4K - weak preamps?

PostPosted: Tue Nov 06, 2018 10:52 pm
by jimyiapanis
After 2 cameras and numerous back and forth with BMD support I returned my camera for a refund.

Re: Pocket 4K - weak preamps?

PostPosted: Tue Nov 06, 2018 10:55 pm
by John Paines
jimyiapanis wrote:After 2 cameras and numerous back and forth with BMD support I returned my camera for a refund.


What did BMD tell you? I didn't test the xlr port, but the 3.5mm is as described above -- much lower levels than the same mic on the BMPCC or what you'd normally expect.

However, the onboard mics of the P4K seem to get more or less normal levels, at 50%.

Re: Pocket 4K - weak preamps?

PostPosted: Tue Nov 06, 2018 11:14 pm
by jimyiapanis
I experienced exactly the same thing as you. They’re cagey about whether it’s a widespread hardware issue or addressable through firmware.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 12:13 am
by DavidNJ
I have this problem also...had to turn it all the way up on a Sennheiser MKE440 and on the camera.

Annoying.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 1:14 am
by Robert Niessner
You might have a read through this discussion:

viewtopic.php?f=2&t=81236

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 6:11 am
by Justin Jackson
You returned the camera because the audio was weak? I mean.. I guess some people require the audio portion of the camera with good audio.. thats fair. I am biased because I bought external audio records.. and mainly want audio on camera to sync audio from external. Though, I also read elsewhere that the audio capabilities of this camera are really good. Hopefully it is solvable via firmware update for those that already have cameras.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 2:03 pm
by Jcorbz
I actually had a very positive experience with audio on the p4k.

For a shoot last week I used an AKG ck93 on a boom approx 1.5 feet away from the subjects, had the gain on the p4k at approx 60%, though I was aiming for lower levels than I normally would to allow for shouting/laughing. I found the audio to be exceptionally clean in post; at one point I was able to boost gain by 45db on some whispered dialogue with barely any noise floor coming through at all.

I also had a G3 wireless lav going into the 3.5mm input. While the level was initially much lower than on my gh4 - all it took was to change the output on the receiver to 0db instead of -18db, which gave me a clean signal at 60% gain with enough headroom. I actually find this much more intuitive/logical - I never understood why I had to set receiver levels to -18db and camera levels to -12db to get clean audio on the gh4.

All in all, while the pre-amps may be weaker than a dedicated recorder, being able to leave the zoom at home and record an XLR mic with phantom48v and a wireless lav simultaneously, onto separate channels, plugged straight into camera is pretty amazing.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 2:40 pm
by John Paines
I believe the G3 receiver outputs a much hotter -- line level? -- signal. Most of the reports here concern direct mic hookups to the 3.5mm jack, where the input levels are necessarily much lower.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 3:29 pm
by joe12south
Yesterday I tried running a few different mics through a Juicedlink Riggy Micro and then into the P4K. I had to crank the levels on the Micro to their max (where on a GH5 I have them well below 50%) to get a decent signal level. Sadly, at that point, I couldn't really find a noise advantage to using this very clean pre-amp vs just cranking the levels on the P4K.

I know that there is a great deal of variance in levels between different recorders, but the mic level amplification on the P4K is ridiculously low. Detrimentally so. Anything but known "hot" mics are cut to a whisper. Forget about "quiet" mics like the NTG-2.

While the main reason I bought this camera was for the image, I did believe BMD statements about good in-camera pre-amps. Good isn't just low noise, good has to mean low noise at reasonable levels.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 4:14 pm
by jimyiapanis
Justin Jackson wrote:You returned the camera because the audio was weak?


Not only for the audio. Between average sound, immovable screen, crappy battery, no support for DNxHR, sketchy MFT lens support this camera is rendered unusable as a standalone unit without a rig.

I know it’s sacrilege to say in this forum but I returned mine and bought a Ninja V and Mixpre-3 to compliment my weather sealed GH4 instead.

Happy days!

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 4:18 pm
by joe12south
jimyiapanis wrote:
Justin Jackson wrote:You returned the camera because the audio was weak?


Not only for the audio. Between average sound, immovable screen, crappy battery, no support for DNxHR, sketchy MFT lens support this camera is rendered unusable as a standalone unit without a rig.

I know it’s sacrilege to say in this forum but I returned mine and bought a Ninja V and Mixpre-3 to compliment my weather sealed GH4 instead.

Happy days!

Your GH4 supports DNxHR? ;-)

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 4:21 pm
by jimyiapanis
Yes, GH4 plus Ninja V ;-)

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 4:26 pm
by Thomas Schumacher
jimyiapanis wrote:[ this camera is rendered unusable as a standalone unit without a rig.

..... I returned mine and bought a Ninja V and Mixpre-3 to compliment my weather sealed GH4 instead.

Happy days!


:lol:

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 4:53 pm
by Robert Niessner
jimyiapanis wrote:I know it’s sacrilege to say in this forum but I returned mine.


Why should that be a sacrilege to say in this forum? If you are not happy with the camera or it can't fulfill your working needs better return it and use another tool. This is not a cult here.

Anyway, today I've shot lots of coverage and interviews of an event all day long. My new Olympus 12-100 was well spent money and turned out to be great - even tough the whole event was quite low light and I had to shoot up to ISO 6400 and sometimes ISO12800. The OIS is really great and you can get stable shots at 100mm, but it seems to suck even more on the battery's life than the Panasonic 12-35 P-OIS.

Interviews were done with a Rode Reporter mic and a Sennheiser EW300 G3 transmitter, on the camera the Sennheiser EW100 G2 went into the camera's XLR port. That recordings sound great, nothing to complain here.

But I also tried to catch the ambient sound with a Rode VideoMicro (which works great on my DJI OSMO) into the 3.5mm input. Wow, what a noisy mess and low signal.

I mean, c'mon Blackmagic - it was ok to have bad sound with your very first camera and maybe the second because of the learning curve, but with the latest camera this should not be an issue anymore.
Did nobody a test of the 3.5mm audio input with standard video mics during development? This is not rocket science anymore today. Even the crappiest camcorder in 2018 can do that ok.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 5:53 pm
by Denny Smith
Comment withdrawn.
Cheers

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 6:43 pm
by joe12south
Denny Smith wrote:Since the ca era was equipped with a XLR Balanced inout for mics, the good mic preamp went on hat input, and the 3.5mm is more of a line inout feed from a small mixer like the MixPre or a wireless setup thst has a good line out. The 3.5 does work with a good line level signal from other reports I have read.

My question is why are you guys trying to use small, inefficient, consumer mics designed for DSLR type cameras that do not have a balanced mic/line input, when you can plug in a professional xlr balanced mic thst will have yiu the result you want. The Rohde VideoMic and the MKE400, and other similar small inexpensive mics, are not the right tool for recording good audio in the first place. Putting them on the camera 10-feet from the subject is worse yet!

If you want ambient localtion sounds, use a short shotgun outdoors or the csmera’s own built in mics indoors, and you should be good. The camera’s mics are good enough now for scratch audio to sync to external recordings also.
Cheers

No, the weak pre-amp also impacts the XLR input. The Rode NTG-2 is virtually unusable either with its own power or via phantom power. (Admittedly, this is a quiet mic, but it is not a "small, inefficient, consumer mics designed for DSLR type cameras that do not have a balanced mic/line input".)

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 7:07 pm
by Johan Cramer
joe12south wrote:My question is why are you guys trying to use small, inefficient, consumer mics designed for DSLR type cameras that do not have a balanced mic/line input, when you can plug in a professional xlr balanced mic thst will have yiu the result you want.

Because the XLR input is mono, but often you need stereo ambient sound. Mics like the Videomic Stereo X and the Ohrwurm are not weak mics at all.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 7:12 pm
by Denny Smith
OK, good points. The Rode NTG-2 is notorious for its low output. Try a better mic, like a Sennheiser ME66, or other mic with a good output. A high gain mic preamp the camera has not, but a useable one with a good mic, from other user reports I have read.
Cheers

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 7:28 pm
by joe12south
Denny Smith wrote:OK, good points. The Rode NTG-2 is notorious for its low output. Try a better mic, like a Sennheiser ME66, or other mic with a good output. A high gain mic preamp the camera has not, but a useable one with a good mic. ;)
Cheers

The severity of the level discrepancy compared to ANY other camera, mixer or recorder I've ever touched is extreme. It's not a mic thing, and it's not a XLR vs 3.5mm thing. It's a "this is ridiculously little pre-amplification" thing.

0% - 50% is basically unusable for average mic levels. 70%+ is where most mics seem to start approaching usable.

This isn't something we should have to work around - there's no trade-off for doing so - this is simply bad. I'm digging this camera overall, I love the RAW image, but this is just plain bad.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 7:54 pm
by John Paines
Denny Smith wrote:A high gain mic preamp the camera has not, but a useable one with a good mic. ;)


But it's not usable. As you'd know -- if you had tried. The only acceptable reports with this jack are with lav receivers and external equipment with gain controls.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 8:51 pm
by Nick Lavigne
I have not received mine yet, but it looked good audio wise here

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 8:57 pm
by John Paines
Why folks who have no experience of the camera feel obliged to muddy this question with speculation and third-party youtubes I'll never understand.

You might be less patient with apparent attempts to confuse the issue or pretend it's not a problem, if you actually owned the camera. The idea is to get BMD's attention, for a serious defect, reported by numerous people, here and in other threads, and on non-BMD forums. If that's not convincing enough, it might be better to wait for your camera for before reporting success.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:06 pm
by Nick Lavigne
You do realize no one on this thread has posted a single thing showing the results they speak of, right? I posed that to show an example of the inputs. It doesn't prove anything either way, but is more evidence than people merely talking.
John Paines wrote:Why folks who have no experience of the camera feel obliged to muddy this question with speculation and third-party youtubes I'll never understand.

You might be less patient with apparent attempts to confuse the issue or pretend it's not a problem, if you actually owned the camera.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:10 pm
by John Paines
So we're all making it up.... Maliciously, I suppose. Here, and elsewhere.

BTW, did you notice that in the video you cited -- yes, I had already seen it, days ago -- they used lavs with receivers and in one instance added 12db gain to the mic input?

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:14 pm
by Nick Lavigne
John Paines wrote:So we're all making it up.... Maliciously, I suppose. Here, and elsewhere.

BTW, did you notice that in the video you cited -- yes, I had already seen it -- they used lavs with receivers and in one instance added 12db gain?

I never said you are making it up, you just have no proof. If you want a company to listen, you have to show evidence or they cant tell if you are competent or incompetent. Companies deal with this stuff all the time and have to decipher what is and isn't a problem. Do a favor and record some samples with production notes.
That +12 was the internal mic.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:20 pm
by John Paines
How would you know what evidence has been presented to BMD? Or what BMD has asked for? You'll also find actual sound pressure graphs in other threads, and at least one user reported the substance of discussions with BMD tech support on this issue, where they apparently acknowledged it. And that's only the public record.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:44 pm
by joe12south
Image
Top: GH5; Level: 0 (-12/12)
Bottom: P4K; Level: 79% (0/100)

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:50 pm
by Nick Lavigne
joe12south wrote:Image
Top: GH5; Level: 0 (-12/12)
Bottom: P4K; Level: 79% (0/100)

wow... what do you have plugged in? are you using one of those xlr to 3.5mm cables?

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 9:56 pm
by joe12south
Nick Lavigne wrote:
joe12south wrote:Image
Top: GH5; Level: 0 (-12/12)
Bottom: P4K; Level: 79% (0/100)

wow... what do you have plugged in? are you using one of those xlr to 3.5mm cables?


Giant Squid Omnidirectional Mono Lav (v2) straight into 3.5mm jack on both cameras.
I can't show a true 1-1 comparison with XLR mics as the GH5 requires a Juicedlink Riggy Micro pre-amp, but the results are equally dramatic.

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 10:02 pm
by Nick Lavigne
Do you by chance have the spectral display of that file?

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 10:18 pm
by joe12south
Image
The difference (other than overall energy) you see is from the handling of the mics. (Two identical mics, and yes, I did swap them between cameras to ensure that one mic was not defective.)

Re: Pocket 4K - weak preamps?

PostPosted: Wed Nov 07, 2018 10:23 pm
by Nick Lavigne
joe12south wrote:Image
The difference (other than overall energy) you see is from the handling of the mics. (Two identical mics, and yes, I did swap them between cameras to ensure that one mic was not defective.)

15k has something going on there. not good. what's the noise like if you equalize these?

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 12:47 am
by Wes Greene
I've had issues and very tempted to return the camera - however I've already dropped the equivalent in lens mount (too late to return now) and accessories!!

I've been back and forth with BM and did get this as part of a response.
"That said, there is an issue with the 3.5mm input where the audio level is around 6dB below what should be the maximum which we hope to address in the next software update."

Not a solution but hopefully an improvement coming. Obviously important to make sure you're getting the strongest signal to the camera possible through mic settings or mic selection.
I have the NTG-2, which is a great mic, but maybe isn't going to work with this camera.

cheers

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 12:50 am
by Wes Greene
Any other shotgun suggestions alongside the Sennheiser ME66??

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 3:27 am
by rick.lang
Joe, that comparison looks like a lot more missing than simply the level. There are wavelengths that don’t seem to appear at all in the bottom image which have spikes in the top image.


Sent from my iPhone using Tapatalk

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 3:34 am
by joe12south
rick.lang wrote:Joe, that comparison looks like a lot more missing than simply the level. There are wavelengths that don’t seem to appear at all in the bottom image which have spikes in the top image.

As I explained, they are from two individual (but identical) lavs. The differences you see are handling noise.

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 9:07 am
by Robert Niessner
Nick Lavigne wrote:You do realize no one on this thread has posted a single thing showing the results they speak of, right? I posed that to show an example of the inputs. It doesn't prove anything either way, but is more evidence than people merely talking.



You do realize that we have already posted samples and I have linked to that thread already in this thread:
viewtopic.php?f=2&t=81624#p452282

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 9:29 am
by Robert Niessner
Denny Smith wrote:My question is why are you guys trying to use small, inefficient, consumer mics designed for DSLR type cameras that do not have a balanced mic/line input, when you can plug in a professional xlr balanced mic thst will have yiu the result you want. The Rohde VideoMic and the MKE400, and other similar small inexpensive mics, are not the right tool for recording good audio in the first place. Putting them on the camera 10-feet from the subject is worse yet!

If you want ambient localtion sounds, use a short shotgun outdoors or the csmera’s own built in mics indoors, and you should be good. The camera’s mics are good enough now for scratch audio to sync to external recordings also.
Cheers


Denny, no need in trying to teach me about sound - I have decades of experience myself ;-)

There has never been the need for balanced input with very short cable runs like the 30 cm you have from the Rode VideoMic. The PCC4k is all about having a small footprint camera and I won't mount up a Rode NTG-3 or Sennheiser MKH416 just for ambient sound which will get attenuated down by >12dB in the editing room and just has to be there for coloration of the mix, never to stand on its own.

The built-in mics pick up any handling noise, which is distracting in the mix, because it is so loud compared to the rest.

So please do not assume the needs of others.

And again (like when we were discussing audio issues with the BMCC back then in 2014) I just quote straight from the BMD website's description of the PCC4k:

True Professional Audio
Incredibly high quality built in microphones, plus mini XLR!
Designed from the ground up to capture amazing high fidelity audio with incredible clarity, the Blackmagic Pocket Cinema Camera 4K features 4 built in microphones with extremely low noise for capturing the subtle detail in live sound. All this means professional audio is a major design goal for this camera. There’s also a mini XLR input with 48 volts of phantom power for connecting professional boom and lapel microphones. You can also use the 3.5mm input to connect standard video camera microphones. With the Blackmagic Pocket Cinema Camera 4K, you get professional quality audio with flexible options for microphones!

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 2:26 pm
by jimyiapanis
This thread has become the unofficial BMPCC4K Audio testing team. I mean quite ridiculous when you think about it. You've got people who paid money for the camera acting as unpaid beta testers. BMD silence on this is deafening.

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 2:41 pm
by joe12south
Giant Squid Omnidirectional Mono Lav (v2)

TOP: GH5...3.5mm...level: 0
BOTTOM: Pocket 4K...3.5mm...level: 50

Image

Both signals normalized to same volume
Image

Link to both WAV files: http://www.humcrush.com/p4klevels/p4k-gh5-squid.zip

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 2:50 pm
by joe12south
And lest anyone dismiss this as just a 3.5mm jack issue, here is the Audio Technica Pro 7a via XLR, with the P4K level set to 83!!! to match the GH5/Juicedlinked combo set to minimum levels.

Image

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 2:59 pm
by joe12south
And finally, the Rode NTG-2 just inches from my mouth with levels at 100 on the P4K:
Image

I think this is sufficient "proof". Or you can believe YouTube videos from people that sell cameras.

Again, I am generally happy with this camera, but I won't pretend that the audio levels don't suck. I shouldn't have to buy new microphones or add a pre-amp in order to get acceptable levels.

And don't tell me I should record externally. I don't always have that choice, and that's not how Blackmagic marketed this camera.

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 4:14 pm
by rick.lang
Joe, those pictures are worth a thousand words. We have had a statement from BMD Support that they are investigating.


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Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 4:18 pm
by John Paines
rick.lang wrote:Joe, those pictures are worth a thousand words. We have had a statement from BMD Support that they are investigating.


I know there are cameras in the service loop for this issue, but it's unclear whether it's well understood at Headquarters. Doesn't look it, based on what I know of it. Where's the statement?

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 4:21 pm
by rick.lang
Post #34 in this thread has that comment, John.


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Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 4:23 pm
by John Paines
Oh, that. I've had more recent discussions. Could be a different office, but the issue doesn't seem to be well understood at this point. That, or information isn't shared in tech support/repair.

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 5:17 pm
by Denny Smith
Denny, no need in trying to teach me about sound - I have decades of experience myself ;-)
Robert Niessner

Robert, sorry, My comment was not directed towards you or other Audio savy users.

No worries, Ich werde meine Kommentare und Gedanken dazu für mich behalten. :roll:
Cheers

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 5:22 pm
by John Paines
Denny Smith wrote:
I am not trying to suggest to others how they should work, just offering alternative suggestions to working around the camera’s issues. John P, kept pushing the camera had worse audio than the original Pocket Camera, and I was trying to point out his error, not yours.
Cheers


With all due respect, Denny, I'm not sure where I "kept pushing", but you don't have to point out my errors either. I'll manage fine without it.

Re: Pocket 4K - weak preamps?

PostPosted: Thu Nov 08, 2018 6:05 pm
by Denny Smith
Sorry John, nothing personal, I was not trying to single you out, just an example. Deleted my comment, :oops: OK?

Cheers