Pocket 4K - weak preamps?

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Leon Benzakein

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Re: Pocket 4K - weak preamps?

PostSat Dec 01, 2018 10:33 pm

Australian Image wrote:
Leon Benzakein wrote:
Australian Image wrote:My audio is now excellent, through just a Rode VideoMicro. Some morning tests today picked up even faint bird songs in the distance.


What did you do different?


I detailed this in a previous post, but received no interest.


Huh :?: :?: :?: :?: :?:

I thought that asking questions was showing interest.
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Wayne Steven

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Re: Pocket 4K - weak preamps?

PostSun Dec 02, 2018 9:44 am

I quoted it before for you Leon.
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Leon Benzakein

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Re: Pocket 4K - weak preamps?

PostSun Dec 02, 2018 4:03 pm

Wayne Steven wrote:I quoted it before for you Leon.


Thanks Wayne. I appreciate that.

I must have been on Mars with my buddy Matt Damon when Ray informed us that he had received the part he was waiting for.

My bad.

Are all Australians bad tempered or just the ones that purchase BMD products?
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostSun Dec 02, 2018 6:47 pm

[quote="Leon Benzakein”

Are all Australians bad tempered or just the ones that purchase BMD products?[/quote]

That is a good one Leon :lol:
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Wayne Steven

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Re: Pocket 4K - weak preamps?

PostMon Dec 03, 2018 9:20 am

Leon Benzakein wrote:
Wayne Steven wrote:I quoted it before for you Leon.


Thanks Wayne. I appreciate that.

I must have been on Mars with my buddy Matt Damon when Ray informed us that he had received the part he was waiting for.

My bad.

Are all Australians bad tempered or just the ones that purchase BMD products?


Don't know, but find a lot of bad tempered non Australians on cinema forums.

I tend to find low end people a bit moodier around here and higher end people more wonderful on forums, but then again, non left wing Australians tend to not suffer foolishness gladly (except themselves). So, repeatedly asking about something posted and pointed out might fall in that category with them It doesn't really affect me that much, just a misunderstanding unless it refuses to resolve. Certain Europeans are the worst as far as attitude, worse then certain Americans. Australians tend to let things fly more than I do (because I SEE), but rough necks are rough necks, which gets me into Australian builders.

But still, I did require a logical leap to ascertain the reason why the video mic started working by itself, was because he inserted the part he had received previously to do it, between the camera and it. Still, good news. But BM should publish a microphone sticky with which mokrs work with it.


Hmm, just a thought I want to do my own processor array, and BM does enough products to run an volume asic wafer program with a mixture of parts on the wafer, allowing them to custom asic all their cameras reducing cost, size and heat. I could hitch a ride. They can do this where it is maybe more expensive for Red (though they may have arrangements with their sensor provider) because BM produces a range of products making their volumes much higher). Maybe I should talk with them in the future my designs would outdo most anything they are using. Got to dig up that asic chip making software out they used for industry leading low energy solutions.
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Benjamin de Menil

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Re: Pocket 4K - weak preamps?

PostTue Dec 04, 2018 6:52 pm

I just tried out the stereo videomic X with the pocket 4K's 3.5mm jack. With the mic seto to +20db mode, levels barely showed when I clapped right in front of the mic.

Also, the pocket 4k's mic gain is grayed out when I have inputs set to 3.5mm. Is this normal?
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Benjamin de Menil

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Re: Pocket 4K - weak preamps?

PostTue Dec 04, 2018 7:30 pm

Benjamin de Menil wrote:I just tried out the stereo videomic X with the pocket 4K's 3.5mm jack. With the mic seto to +20db mode, levels barely showed when I clapped right in front of the mic.

Also, the pocket 4k's mic gain is grayed out when I have inputs set to 3.5mm. Is this normal?


I just got of the phone with BM support and discovered something that may be helpful to people using 3.5mm inputs:
The 3.5mm inputs can be set to line level or mic level. But the mic level option is not available in the menu if one of the channels is set to 3.5mm line. So before setting the first side to 3.5mm mic, make sure the other side isn't set to one of the 3.5mm line options. The reverse is true for discovering line level options if you have a side set to mic level.

With 3.5mm inputs set to mic level I got plenty of gain with rode videomic X. I'm not experiencing the level issues others on this forum have reported. Maybe my unit is from a later batch. But I haven't had a chance to check the quality of the audio - I'm just going by what I see on the levels, which is plenty of gain to spare.
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John Paines

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Re: Pocket 4K - weak preamps?

PostTue Dec 04, 2018 9:51 pm

Benjamin de Menil wrote:
Benjamin de Menil wrote:I just tried out the stereo videomic X with the pocket 4K's 3.5mm jack. With the mic seto to +20db mode ... I'm not experiencing the level issues others on this forum have reported.


From your description, you're experiencing exactly the same levels reported here. The difference is, the mic's amplifier is adding 20db to the signal. Set it to zero added gain, and see what happens.
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Benjamin de Menil

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Re: Pocket 4K - weak preamps?

PostTue Dec 04, 2018 11:32 pm

John Paines wrote:
Benjamin de Menil wrote:
Benjamin de Menil wrote:I just tried out the stereo videomic X with the pocket 4K's 3.5mm jack. With the mic seto to +20db mode ... I'm not experiencing the level issues others on this forum have reported.


From your description, you're experiencing exactly the same levels reported here. The difference is, the mic's amplifier is adding 20db to the signal. Set it to zero added gain, and see what happens.


I just had to lower it to zero because I had too much gain, even with the pocket's gain at 50%. It looked like with gain set to 50% I was clipping the Pocket 4K's pres or AD at about -6dB. That would mean that at 50% gain it's not possible to get to 0dB. Could also be the Rode mic was saturating. Anyway, was fine once I set the mic to flat gain. I was recording a concert, drums and amplified instruments. I'll see how it fairs tomorrow with conversational level volumes.

Generally speaking, I'd always get as much gain out of the mic as possible, because I figure the mic's gain is better than the camera's. With Rode video mics, it doesn't seem to me that my version of the Pocket has a problem.
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Joe Giambrone

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 12:05 am

This is new, and potentially important:

Does it mean the issue is solved, and it was just a matter of the correct setting?


I just got of the phone with BM support and discovered something that may be helpful to people using 3.5mm inputs:

The 3.5mm inputs can be set to line level or mic level. But the mic level option is not available in the menu if one of the channels is set to 3.5mm line. So before setting the first side to 3.5mm mic, make sure the other side isn't set to one of the 3.5mm line options. The reverse is true for discovering line level options if you have a side set to mic level.

With 3.5mm inputs set to mic level I got plenty of gain with rode videomic X. I'm not experiencing the level issues others on this forum have reported. Maybe my unit is from a later batch. But I haven't had a chance to check the quality of the audio - I'm just going by what I see on the levels, which is plenty of gain to spare.
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John Paines

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 12:23 am

Joe Giambrone wrote:This is new, and potentially important:

Does it mean the issue is solved, and it was just a matter of the correct setting?


No. He had some user error to contend with. It sounds like his mic is "hot" to begin with (and may have additional amplification even at zero), and he was recording loud electric instruments and drums. Too many unknowns here to conclude much of anything.
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Gene Kochanowsky

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 2:39 am

Benjamin de Menil wrote:The 3.5mm inputs can be set to line level or mic level. But the mic level option is not available in the menu if one of the channels is set to 3.5mm line. So before setting the first side to 3.5mm mic, make sure the other side isn't set to one of the 3.5mm line options. The reverse is true for discovering line level options if you have a side set to mic level.


That's weird and unexpected. I hope BM considers this a bug. I would expect 3.5mm Line and Mic should be selectable no matter what the other channel is set to.
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John Paines

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 2:42 am

Gene Kochanowsky wrote:That's weird and unexpected. I hope BM considers this a bug. I would expect 3.5mm Line and Mic should be selectable no matter what the other channel is set to.


There's only one 3.5mm jack (with right/left channels), so how could you have line and mic levels at the same time? It's one or the other, for both channels.
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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 2:52 am

John Paines wrote:
Gene Kochanowsky wrote:That's weird and unexpected. I hope BM considers this a bug. I would expect 3.5mm Line and Mic should be selectable no matter what the other channel is set to.


There's only one 3.5mm jack (with right/left channels), so how could you have line and mic levels at the same time? It's one or the other, for both channels.


I agree, however on my camera I do not see selections for both 3.5mm line and mic unless the other channel is set to an input other than 3.5mm. Looks like a bug. Otherwise if both channels are set to 3.5mm line then mic is not selectable on either channel and visa versa.
Last edited by Gene Kochanowsky on Wed Dec 05, 2018 2:55 am, edited 1 time in total.
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 2:53 am

The Ursa Mini Pro OS, which the Pocket 4K is using, has two audio channels that are independent of each other and each channel can be individually selected (think stereo left/right) between the two audio input sources, XLR and XLR AES. Where the Original Pocket and Micro only has one audio source connection the 3.5 stereo inlut, so both channels were selected together from mic to line.

My guess, looking at the manual, the new Pocket 4K has a XLR inlut and two channel 3.5mm input. So the OS is Since the two are locked to gather on the 3.5 connection, both sides/channels need to be switched from mic to line, so you need to switch channel 1 and channel 2.

In theory, you could select one channel from the 3.5 and the other channel from the XLR. This would make sense, if using a lav wireless set to mono for one channel on the 3.5 Mic inlut and the other channel set to XLR Mic. for a shotgun or hand held mic. like in an interview situation.
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Gene Kochanowsky

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 3:52 am

When this issue is described in text there seems to be some problems in understanding the issue, so for that instance I've made this little video.
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 6:45 am

A Pix is word, and Yes, I see now what yiu are talking about, thanks for the video. This is not how the UM Pro/Broadcast audio menu works. Each audio channel is independent of the other, and one side can be mic, while the other side is line or AES.
So this indeed does seem to be either a design error or a bug in the OS.
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Kristian Lam

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 8:19 am

Unlike URSA Mini Pro, the stereo 3.5mm inputs can either only be line or mic, hence when mic level is selected for one side, the other has to be the same which is why line is not available.

I can see why this could be confusing and the interface wi be tweaked to better communicate that the other option is not available.
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Wayne Steven

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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 9:10 am

Thanks Kristan. I think people probably would like a 3 to 5 line 3.5mm jack in the future, where each line could he independently set to anything, if BM is listening? Can hook up some surround that way. BTW, when's the next camera announcement? (Have to try, CES, new micro?). :)
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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 3:47 pm

Kristian Lam wrote:Unlike URSA Mini Pro, the stereo 3.5mm inputs can either only be line or mic, hence when mic level is selected for one side, the other has to be the same which is why line is not available.

I can see why this could be confusing and the interface wi be tweaked to better communicate that the other option is not available.


A possible way to restrict selection for the PC4K is not to restrict line/mic selection for 3.5mm inputs but when a given channel is changed from line or mic to the opposite value, if the other channel is set to a 3.5mm input it is automatically changed to the corresponding line or mic value. That might be surprising to the user but I think they will quickly understand how it works and not jump to the conclusion that their camera is broken because it appears to be always stuck in line or mic mode and when they plug in a mic or line source their audio levels are way too low or high.
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Re: Pocket 4K - weak preamps?

PostWed Dec 05, 2018 9:20 pm

Good idea Gene, having both sides of the 3.5mm input set together, would reduce the confusion.
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 6:10 am

Leon Benzakein wrote:
Are all Australians bad tempered or just the ones that purchase BMD products?


Bad tempered? I'm trying to be informative and pass on what I've discovered, but the posts that actually describe the details appear to elicit little interest. So what gets post in this long thread will become buried in short order.

However, my solution appears to be working quite well, but I'm yet to go through my video taken during a week in the bush. I might have to do a complete writeup on this issue, as I do appear to be making some headway which might give others ideas.
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 4:22 pm

That would be very interesting. Looking forward to it.


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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 4:29 pm

Australian Image wrote:However, my solution appears to be working quite well


As best I understand it, you're amplifying the signal and using another device in the middle to power the mic. That's fine, but it's not a "solution". It won't help anyone who wants to to plug directly into the camera and record audio, but can't because the levels are much too low.

The idea is to get the mic input working without additional equipment, at least for occasional use or convenience.
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 7:38 pm

John Paines wrote:
Australian Image wrote:However, my solution appears to be working quite well


As best I understand it, you're amplifying the signal and using another device in the middle to power the mic. That's fine, but it's not a "solution". It won't help anyone who wants to to plug directly into the camera and record audio, but can't because the levels are much too low.

The idea is to get the mic input working without additional equipment, at least for occasional use or convenience.


Not so. The solution that I've come up with is working very well, with recording levels in the camera now quite decent. But I'm still looking for a better way to power the mic. The latest option that I tried didn't work, so I'm searching once again.

I could have found an easier solution, but I want something that's not overly bulky and fiddly to set up. I'm sure that everyone would be interested in a solution that's portable and usable even when the camera is not on a rig.
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John Paines

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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 8:01 pm

It's always been understood that by raising the level of the signal, using a mixer or similar device, you could record. That's never been in doubt. I'm glad that it's working for you, but what you're reporting doesn't answer the question being asked: what's going on with the camera's preamps?
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 8:27 pm

In my own nonscientific testing the same mic plugged into the 3.5mm and the xlr is exactly 12db louder on the xlr and it sounds fuller and better on the xlr.

That being said, the xlr is still more quiet than I would like. I recently did an interview and had to set the gain to 100% using a professional sony clip on lapel using phantom power. A co-woker used the same setup with the same interviewee and his gain was set much lower on his sony ENG camera to achieve the same level.

It works as is, but for sure it's lower level than other cameras.
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 8:45 pm

It was a crude comparison, but I couldn't equal the levels of the onboard mics even after adding 30db to the 3.5mm Sony mic recording in Resolve, with both at 50% gain in camera.
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Re: Pocket 4K - weak preamps?

PostFri Dec 07, 2018 9:30 pm

I think the issue of what the camera is doing is a Blackmagic problem awaiting a solution, if that can be achieved. The user issue is how to make do in the interim, especially with small and simple solutions. There are plenty of bulky and expensive solutions available, but they are kind of crazy given the size and price of the camera.
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Leon Benzakein

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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 4:52 pm

Ray, at the risk of the Aussie thunder raining down on me you keep mentioning how your solution works but I do not remember if you have ever described your solution aside from saying that you are waiting for a part to arrive.
If I have missed that post please forgive me, but what is your solution?

I am interested in knowing how you have gotten power to the Rode VideoMicro.

Thanks
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Benjamin de Menil

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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 6:21 pm

John Paines wrote:
Joe Giambrone wrote:This is new, and potentially important:

Does it mean the issue is solved, and it was just a matter of the correct setting?


No. He had some user error to contend with. It sounds like his mic is "hot" to begin with (and may have additional amplification even at zero), and he was recording loud electric instruments and drums. Too many unknowns here to conclude much of anything.


I've now tested at regular conversation and there seems to be plenty of level using the rode stereo video mic x set to zero gain. It's true that it's a hot mic. Not sure what the situation might be for a passive dynamic mic for instance.
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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 6:28 pm

at various different gain settings, I've noticed clipping on the VU well below 0dB. I haven't listened to what it sounds like yet, but it looks to me like digital clipping - it very abrupt. If so, there are some issues with the pocket 4K's firmware. Digital clipping should not occur at less than 0 dB.
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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 8:11 pm

Leon Benzakein wrote:Ray, at the risk of the Aussie thunder raining down on me you keep mentioning how your solution works but I do not remember if you have ever described your solution aside from saying that you are waiting for a part to arrive.
If I have missed that post please forgive me, but what is your solution?

I am interested in knowing how you have gotten power to the Rode VideoMicro.

Thanks


I have previously stated that I use an Olympus LS-14 to provide power to my Rode VideoMicro, that's the first hurdle. I'm looking for a simpler solution to the LS-14. If you use a powered mic, then you don't have that issue.

To boost the signal I use a Cayin C5 headphones amplifier from the LS-14 to the camera. This provides all the needed boost to allow the camera to record even the lowest level sounds. There are many alternatives to the Cayin C5.

Alternatively, you can get any number of devices that perform all of this in one unit, but none are small or inexpensive.

I've posted much of what I've done here: https://australianimage.com.au/blackmag ... a-4k-pt-4/ and will post another story specifically on the audio issue at a later date, as I search for an alternative to the LS-14.
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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 10:00 pm

I'm assuming that anyone doing any kind of professional work has a few preamp/dedicated recorder options as well as mic options.

None of that addresses the question of the thread - "weak preamps?"

The answer to that, for anyone recording direct to the P4K is - Yes, relatively speaking.

Using the basic audio principle of feeding a strong signal to any gain stage (to minimize the inherent self noise that virtually any gain stage will add) is predicated on the idea that you can then use low gain at the recorder. Even on the mini XLR we have to run the input gain high.

That said, the pres on the XLR stage are clean enough and so far cranking up the input to around 70% still results in a solid sound.

I haven't tried anything into the 3.5 but I'd like the option in challenging situations.

Mainly, because of it's design, small form factor - it's pretty important that it doesn't need to be rigged with anything in order to capture good audio.

We do most work with sparate audio but I really like the opportunity to record direct for a lot of other work and, at least with the XLR/phantom power setup with a simple ME-64, it does sound good - if a bit underpowered.
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Re: Pocket 4K - weak preamps?

PostSat Dec 08, 2018 11:23 pm

It does seem odd that the camera can't effectively use external mics without any sort of assistance. But that's the way it appears to be, so workarounds are the only option. I'm sure that Blackmagic is well aware of the complaints and there's not a jot that any user can do to change what's built into the camera. Flogging a dead horse isn't going to achieve anything.
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Leon Benzakein

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Re: Pocket 4K - weak preamps?

PostSun Dec 09, 2018 1:44 am

Thanks Ray.
Got it.
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Re: Pocket 4K - weak preamps?

PostMon Dec 10, 2018 3:19 am

Although it's a workaround and not a solution, a Tascam DR-60d Mkii or DR-70D recorder can output a 3.5mm line level stereo signal from it's preamps to the mic input of the BMPCC 4K. For the DR-60D Mkii this is a 200 ohm signal with an output level of -10dBV to +10dBV. The DR-60D Mkii also has a 3.5mm camera low mic output at 200 ohms that has a separate volume control for a level of -50 dBV to -30 dBV. These units have 1/4-20 screws that bolt to the bottom of the camera and fit between it and a tripod. They have mixers and can be set to monitor the audio coming out of the camera and mixing it into a stereo mix on it's SD card or as a separate stereo file plus the stereo file of mics connected to the Tascam. A manually operated or automatically operated slate tone is provided to sync the SD card's files with the scratch tracks of the camera's video files in post. The class A discrete circuit preamps provide a generous 65 dB of gain and use up alkaline batteries in 2.5 - 4.5 hours, but they can be powered externally through the USB port (something you can't do with a Zoom H4N). There is also a Tascam DR-701D with more features including a time clock input.
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Re: Pocket 4K - weak preamps?

PostMon Dec 10, 2018 3:31 am

I've looked at the Tascams and similar, but all of them are excessively large.

I've asked Curtis Judd whether he could shed some light on whether there are any 'small' units available that could power a non-powered mic (such as the Aputure A.lav module). I believe that he has, or has access to, a BMPCC4K and might have some suggestions down the track.

I could easily solve the mic power issue if I bought a powered mic, but I kind of like my Rode VideoMicro. It's not only small, but a very good mic for what I need.
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Re: Pocket 4K - weak preamps?

PostMon Dec 10, 2018 7:54 am

While I agree that Blackmagic Design is aware of this, between the posts from BMD reps here, I still don't think we've seen anything that resembles a "yes, we've been able to replicate the issue and we are seeing the same thing—we're looking into it".

Maybe in another thread?
I use the following (might help me and/or others with trouble shooting)

DaVinci Resolve MacOS | FCPX | Motion | Cinema 4D | Adobe PS, LR, AE | Affinity Ps+De
1Dx mkII | XC10 | BMD Pocket 4K | 12c MacPro5.1, 48GB, Vega Frontier Edition 16GB | MBPtb
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Re: Pocket 4K - weak preamps?

PostMon Dec 10, 2018 8:31 am

Companies often don't publicly admit to issues because it could cause a rush of complaints of false advertising, returns etc. If the issue is fixable via a firmware update, then it'll simply come in a future firmware update.

I'm just wondering whether Blackmagic focussed on the in-board audio, which works quite well, and assumed that users would be using audio boosters etc when using external speakers and using these on a rig. The BMPCC4K was, after all, supposed to be a cine camera usable without any additional accessories, which it is.
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