Pocket 4K - weak preamps?

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John Paines

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Re: Pocket 4K - weak preamps?

PostThu Nov 08, 2018 6:18 pm

Denny, for gawd sake -- nobody said he/she intended to use the 3.5mm jack as a sole or primary recording device. Some of us tested the input, as one would with any new camera, and came up with the results here.

That's all. A feature advertised to work doesn't. That's not decisive for me personally, but whether it is or not is beside the point. I'd like to see the audio at mic levels working, as would others.
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostThu Nov 08, 2018 6:25 pm

OK, it kind of sounded like that was, what the fuss was all about. :roll:
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Last edited by Denny Smith on Fri Nov 23, 2018 7:34 am, edited 2 times in total.
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Justin Jackson

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Re: Pocket 4K - weak preamps?

PostThu Nov 08, 2018 7:03 pm

Hmm.. maybe its good my camera wont be in my hands for 2 more months.. hopefully they figure this out and fix it, possibly with recall for those already owning.

One post said that BM indicated a possible fix with a firmware update down the road, attenuating input by 6db. I am no expert.. but if they attenuate the input, could that cause distortion in the audio vs if there is a real problem with the input circuit replacing/fixing it? I would be a bit disappointed if the firmware simply increases input gain that results in crappier recorded sound.

To Denny's point though, I would typically assume anyone using this camera (or at least most people) would either record externally and use audio as a sync track in post, or use the XLR input only. When I first read of the 3.5mm being a two way in/out, I was curious why they even bothered. Heck, would have been better to just put two mini XLRs for stereo input.

Before anyone slams me for those wanting to use the audio in because it is advertised as high quality audio.. I suspect (or at least read it as) the XLR is high quality, didnt really assume the 3.5mm was high quality. Again I question why not 2 XLR minis for audio in this case..but its done now. I would always feel like the 3.5mm is purely for an audio sync track. But I can see how the lure of this cameras size and video quality would have some wanting an easy 3.5mm mic input to work well, so I would agree that if it is indeed either a software issue (firmware fix) or hardware issue (recall/fix) BM should (and they are apparently) resolve it.

As for those saying BM is not responding is deafening.. I actually have seldom see anyone from BM reply in these forums. I have seen more regarding Resolve/Fusion respond, but the couple dozen threads around hardware I have been part of or read, I havent really noticed any response. Does irk me sometimes.. like why there is apparently no way to tell us how long the wait is to get our camera, etc.
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joe12south

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Re: Pocket 4K - weak preamps?

PostThu Nov 08, 2018 7:43 pm

I appreciate the spirit of looking for solutions, but I think it is wrong-headed to proliferate the idea that XLR = quality/professional and 3.5mm = inferior. There is no technical reason one connector must perform better than the other, outside of the obvious benefits of a balanced connector for long runs, etc.

It's also wrong to suggest that the XLR input on the P4K doesn't suffer from the same weak pre-amp as the 3.5mm jack, because it does.

The problem is real. The workaround is to use an external amp or particularly "hot" microphone. Which jack is utilized is something of a red herring.
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Robert Niessner

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Re: Pocket 4K - weak preamps?

PostThu Nov 08, 2018 10:36 pm

Yesterday I was filming with the Sennheiser G3 receiver plugged into the mini-XLR. That is a real pita, because you have the 50 cm 3.5 mini to XLR cable from the receiver, then the 50 cm XLR to Mini-XLR adapter cable dangling around your camera. And I don't see the quality benefit in up-converting the 3.5mm output into XLR, XLR and mini-XLR instead of just going 3.5 to 3.5 mm with small footprint.
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Chris Frechette

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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 2:22 am

This is really unfortunate. I haven’t had time to do much with my camera yet, but had to test out the 3.5mm after seeing this thread. Tried a Rode VideoMicro, Rode Videomic Pro and an Audio Technica 2.4ghz wireless lav. Pretty much unusable as a mic input at the moment. Hopefully it can be improved in a firmware update.
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John Butler

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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 3:59 am

HMMMMM. I can deal with intermittent touch screen functionality, poor battery life, buggy media recognition, clipping red channel, quick to arrive dead pixels & faulty battery doors, but this preamp issue is a deal breaker. Looks to be the reason I'm opting out of purchasing a BMPCC4K. I hope it gets sorted/fixed for everyone that owns a BMPCC4K. :(
Last edited by John Butler on Sat Dec 15, 2018 11:36 pm, edited 1 time in total.
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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 4:31 am

I’ve just never understood manufacturers putting poor quality audio stages in cameras.

I mean - SURELY an extra $100 spent on preamps and DACs would have dramatic impact on component quality and minuscule impact on purchase price. Maybe my needs are special but I’d happily pay several times that for it.

I would give my back teeth for top quality audio on my UMP for use in a doc setting and this news about the Pocket 4K is pretty disappointing for those of us still waiting for one and wanting to use it as a lightweight, small second camera (with audio) in that context.
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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 11:30 am

Robert Niessner wrote:Yesterday I was filming with the Sennheiser G3 receiver plugged into the mini-XLR. That is a real pita, because you have the 50 cm 3.5 mini to XLR cable from the receiver, then the 50 cm XLR to Mini-XLR adapter cable dangling around your camera. And I don't see the quality benefit in up-converting the 3.5mm output into XLR, XLR and mini-XLR instead of just going 3.5 to 3.5 mm with small footprint.


I soldered a new cable for this - locking 3.5mm to mini xlr. No real difference in size between the 3.5mm cable and so much better than having adapters dangling around.
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Robert Niessner

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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 12:09 pm

Jcorbz wrote:I soldered a new cable for this - locking 3.5mm to mini xlr. No real difference in size between the 3.5mm cable and so much better than having adapters dangling around.


Yeah, I am planning to do that too.
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Justin Jackson

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Re: Pocket 4K - weak preamps?

PostFri Nov 09, 2018 6:01 pm

Can you put a picture of that here.. would like to see what you mean and what it looks like.. the cable ends connected, apart, etc. I think I get what you are saying but not 100% sure.

I agree that the camera should not have such severe attenuation issues on the 3.5 and especially not the mini-XLR.

Me personally I plan to use external audio.. which is why I bought the Mixpre 10T, and feed the XLR mini out from that to the XLR mini in on the camera to provide a sync track (though I think timecode will be better.. never used it so not sure yet).

Would definitely be nice if a firmware update can fix this issue though. I can see the lure of just run-n-gun with the camera, lens and a small shotgun mic on top.
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Re: Pocket 4K - weak preamps?

PostSat Nov 10, 2018 11:44 pm

Sorry to hear about the crappy audio. I guess I'll be hanging on to my Bolex D16
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Re: Pocket 4K - weak preamps?

PostFri Nov 23, 2018 3:02 am

Also disappointed in the 3.5mm input. When I get a mini xlr adapter, maybe I'll be disappointed in that too :) Many of us need basic ambient/fx sound from a camera-mounted mic. We're not going to use it for speech in any critical way (except in an emergency :)) but it's a vital part of shooting b-roll. And maybe I'll come round, but I'm not happy using the camera mics under any circumstance.
Hoping this can be fixed. But from what I've seen, a 6db boost won't come close to cutting it. Needs at least 18db boost to get in the ballpark.
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Robert Niessner

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Re: Pocket 4K - weak preamps?

PostFri Nov 23, 2018 7:58 am

I have used the 3.5mm input now with the Sennheiser G3 wireless and the receiver set to +12dB output. That came out surprisingly well. For interviews very usable.
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Re: Pocket 4K - weak preamps?

PostFri Nov 23, 2018 3:01 pm

The other night I opted for a direct audio connection to my P4K using a Sennheiser MHK 416 shotgun. It was a simple short scene in a short film. I had the mic attached to the mini XLR adapter, set the gain values to 100% (which were good levels, barely peaking at full voice) and started to roll. (Yes, it was a little scary that I had to crank it all the way to get decent levels.) I normally record dual audio, but I wanted to see if I could get away with plug and play, run and gun. Nice surprise. It came out great. I am unapologetically thrilled with this camera. The images are on par with the UM4.6K and with the Samsung 1TB USB-C drive, I can shoot forever. I love it.
Having said that, like all of you, I always want more! Perhaps they can address the low audio issues in a firmware release. Maybe we have to wait for the next camera. However, if you are an indie film producer, this camera rocks. I will certainly mount up my UM4.6K on sticks for scenes where I am in a studio, or on a set where the camera stays put, but for exterior, quick scenes, or any scenes requiring camera motion, the P4K is a no brainer. The footage rivals the UM4.6K and the post process is identical. I should also mention, I am a Prores, sometimes Raw shooter. Soon we get to try BMRaw. For me, being able to edit in these formats is the frosting on the cake, especially using Davinci Resolve. The whole package at this price point blows my mind. It's like Christmas every day of the week!
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rick.lang

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Re: Pocket 4K - weak preamps?

PostFri Nov 23, 2018 5:15 pm

Thanks for the comments especially regarding the Sennheiser MKH416 since that’s my camera-mounted option. I usually record with low levels as long as I can see some visual feedback on the audio scope. Then I boost in Resolve as needed. Have you tried both approaches and found it’s better to boost before recording?

The AVX MKE2 system I ordered looks like it’s going nowhere during the postal strike in Canada. Maybe it will come mid-December.


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Norman Lang

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Re: Pocket 4K - weak preamps?

PostFri Nov 23, 2018 5:45 pm

Honestly Rick, my levels (set to 100%) seemed fine right out of the box in Resolve. I just added compressor. However, this was my maiden voyage with that set up. I am going to experiment with a couple of other mics as well.

I did a studio shoot where I loved the images from the P4K, but the audio was just a scratch track using the camera mics. Main audio was done with Zoom F8 and shotguns.

I love reading the posts and opinions on this board. I learn a lot. I always keep in mind that these are tools in a tool box. We mix and match and try to use them with their best utility in mind. It is true that in many cases a C200 would be a better tool for an application where sound and video are captured in the same box. In other cases where cost, size, or format may be a consideration, you would choose another tool. One size doesn't fit all. For the moment, the P4K ticks a lot of boxes as a great tool for many uses. In-camera sound may be usable in some cases, but realistically not for all!
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 12:40 am

I was looking at my Sound Devices MixPre D mixer, and I was reminded that it has a special Camera audio output that is a unbalanced mic level stereo feed. You need a special cable to go from the port in the mixer to a 1/8 (3.5mm) TRS connector to plug into the camera.

Can somebody who has the the new Pocket 4K Camera and a SD MixPre D test this connection? You,should be able to boost the unbalanced mic output to get a good signal into the camera. This worked for me in the original Pocket Cinema Camera to get a good signal to the camera that recorded audio thst was useable. The BMPCC also had a weak mic preamp, and the MixPre D unbalanced mic output solved the issue for this camera. I would be interesting to see if this works with the new Pocket 4K.
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Justin Jackson

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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 4:08 am

Ray.. is that a joke.. or did I miss something in that 3.5mm jacks actually provide phantom power to 3.5mm mics? I have only ever used my first small shotgun mic, Azden, on my old T2i. It had a battery to turn it on.. so I dont know to be honest.
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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 6:53 am

Yes, the phantom power for XLR. It’s is much higher, up to 48 volts, than the power required for unbalanced mics like the Rohde VideoMic. Some DSLR and mirrorless cameras provide unbalanced mic power, (not phantom power, but a lower voltage) but not the BM cameras.
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Last edited by Denny Smith on Tue Nov 27, 2018 7:45 pm, edited 2 times in total.
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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 1:37 pm

I could be wrong, but I don't think you can do phantom power on an unbalanced connection.
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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 2:42 pm

I believe the phrase you’re looking for is “plug in power” (3-5v) - which is what the Rode Videomicro needs.
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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 5:02 pm

That makes sense.. as I had never heard of phantom power on 3.5 plug.
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Re: Pocket 4K - weak preamps?

PostSat Nov 24, 2018 10:20 pm

Ray, that is a 3-4VDC power feed, not really phantom power per se. The Nikon Z cameras have this feature also.
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Justin Jackson

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Re: Pocket 4K - weak preamps?

PostSun Nov 25, 2018 10:34 pm

i dont know ray... battery life is already dismal. I would suspect they knew that and adding more power drain may not have made sense.. but if the xlr supports it maybe so.
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John Paines

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Re: Pocket 4K - weak preamps?

PostSun Nov 25, 2018 10:44 pm

Ray (that's what it is) wrote:It seems kind of inconsistent. Anyone using the camera to power a mic would also be prepared to take a hit on the power requirements. I just feel that it could have been done like with the E-M1 where you have the option of providing power or not.


Even forgetting that the vast majority of unbalanced mics with the 3.5mm jack are powered by batteries, this issue won't be a high priority when the 3.5mm jack is currently useless, without added amplification. Perspective....?
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 3:23 am

Ran a micro on the bmpcc4k in the weekend, at a gig some friends were playing. Seemed to be powered ok. So I'm assuming the 3.5mm jack does put out the required low voltage. (I haven't seen a camera where that's selectable. Seems to just be there or not.)
The 3.5mm input gain is still terribly low though. Because it was a loud band, getting a level wasn't a problem. The micro had a decent level at 70% and the internal mic matched it (a tiny bit lower) at 6% on the other channel.
So it's possible the videomicro was working, but you just weren't seeing anything on the monitor because the signal was too low?
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 7:15 am

It's interesting seeing all these comments about the lack of "Phantom Power" through the 3.5mm jack on this camera. To put this in perspective, the original Pocked worked extremely well in this regard and this set up has served me well for the last few years after someone on here suggested it. Quite why the new camera doesn't do this is a bit of a puzzle. Also why the 3.5mm audio is so bad after all of the flack BM got on the original Pocket escapes me.

At the moment I am so glad that I decided not to buy this camera. I hope that my position will change as it gets improved, but I am not holding my breath!

All the best

Steve
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 9:20 am

If you put it that way “serious” users of cine / video cameras aren’t using the BMPCC4K.

Why build a camera in a DSLR form factor? Why price it accessible to the masses?
Why include a 3.5mm jack in the first place?
Why include onboard XLR? (serious users are using dual audio)
Why include a fixed screen? (serious users are using viewfinder and / or external monitors).

Let’s get real for a second, BMD can’t have their cake and eat it, they want everyone (pros and amateurs alike) to get their hands on this camera and they want them to be using Resolve. It is targeted to everyone and everyone has and uses on camera mics with a 3.5mm audio jack.

I’ve said this before, I love what BMD is trying to do but in my book this is a pioneering beta product, an iPhone 2G if you will. I’m sure the next versions will be great.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 1:16 pm

jimyiapanis wrote:Let’s get real for a second, BMD can’t have their cake and eat it,


But they do! It's a successful business model, despite all the contradictions you accurately point out. The vast majority of people who buy this camera aren't shooting cinema. Most probably aren't shooting anything.

That aside, I assume that the current 3.5mm performance reflects a malfunction somewhere; that they couldn't have designed and shipped the camera with its current performance as "spec". The preamps do work, as evidenced by the performance of the onboard mics, which sound reasonably good, as these cameras go. Haven't tested the XLR port myself, and reports there are fewer and inconsistent. Some suggest good performance at mic level, others not.

So we'll see what happens, if they address the matter or not.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 2:17 pm

Seems like the list of early adopter issues keeps growing. I'm hoping for a micro with more worked out version of the hardware. Seen the spec of the 60Mp Sony sensor for up coming digital stills next year too, looking good, 8k p60 10 bit support. Maybe the next pocket will have better audio and use something like this in 16:9 (33mp+). Yum! :)
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Wayne Steven

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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 2:38 pm

Jim. Yes. It has fault because it is based on limited hardware. For instance, whatever they are using is likely limiting the HDMI spec. While I would prefer a HDMI 2.1 interfaces, it can't even do a HDMI 2 interface. It's called cobbling together. Audio issues are also a big no no to me too. The external disk handeling issues are also a no no. The 13 stops (is there a HDR mode coming?). But then again, watching some recent new footage of camera men rushing a car bringing a suspect in, with their mobile phones, and other interviews with mobile phones stuck out, and maybe even a bush fire brigade interview by a mobile phone, and local news report, that really spells the future. BM needs to have this stuff worked out to make it really convenient to use to compete. I mean, soon they could make a 4kp60 pocket a centimetre or so thick, with regular format liquid multifocal lens (go to Samsung to license that). Actually, Samsung has no more skin in the game, but has brilliant still camera hardware going to waste, they were developing as next generation to their previous top rating cameras, and you don't have to be dependent on a competitor for sensors.

This list of issues is worrying, as the product that wins is the reliable one that is most convenient to work with and performs well enough, like Arri.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 4:55 pm

Wayne.. while I too would love a perfect camera day one, that does everything and then some.. I think you are a bit unrealistic with the cost of this thing and what you are asking. I am not saying or trying to make excuse for BM to deliver faulty cameras. But, I do think that given the cost of this, they are putting well beyond what we had just a few years ago for 5x+ the price, not including the features (e.g. 5+ years ago most cameras were recoding pro-res at best, if not h.264.. certainly not 12-bit RAW)... so it is really really hard to slap them for possibly not nailing every feature.

I do understand wanting good audio out of the box, and they did say it is the best audio out of the box of any camera they have released (except maybe UMP)... but still.. I gotta believe for $1K (when you discount the studio license), being able to record audio if for any other reason as a sync track is already damn good. That it has XLR input (even if mono) is fantastic. The 3.5mm jack.. honestly to me is something I would not have ever considered. I would go out of my way to use a 3.5 to XLR adapter or something over using 3.5mm jack. Not saying everyone will, but I would suspect overwhelmingly that the design of this camera was mostly with the thought of indie developers with external audio, or b-roll camera where audio doesnt matter. Does that mean they should ignore it.. not at all. But I would much rather see good quality video, easy to use OS and options like recording to SSD via USB-C (a first if I am not mistaken) over high end audio quality. Slap on a cheap audio recorder or hell, even the Pre-3 or F4 is not too bad in price to get really high end audio capabilities.

I am sure my .02 is not very relative, but I for one am dying to have a camera like this vs my current 8 year old DSLR with 12 minute limits of HD low DR quality h.264 video!!
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Denny Smith

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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 8:20 pm

Well said, the new Pocket is Not a mirrorless DSLR style,csmera like the Alana GH5/S, is is a video camera that can be used for a variety of situations. As for the mics:

The 1/8 (3.5mm) inout works well with an external preamp, like the SD MicPreD, which has a 1/8th mic level output that should be able to feed a high enough gain for a useable signal level, al,owing for a stereo audio recording from the mixer

The Mini XLR is the main mic input, works equally well with both line and mic level inputs. Mics also have to have a a good level output, some of,p the Rhode mics do not.

The built in mics are good for location sounds or for a speaker (blogger) close in to the camera.

To get decent audio, you need to start out with good mic and a good audio workflow. Separate and/or Dual recording has been the Cine standard.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 8:33 pm

Denny, do you think then that the very low 3.5 as well as lower XLR was intended due to pre-amps and/or external audio and the typical cine use case with audio? While I can see a valid argument to an extent.. I agree that a camera in this form factor, similar to DSLR is primarily going to be run-n-gun use, where many will have small mounted mics on it and expect to record audio to the camera and not external audio. If that is the case, which from all the comments here sounds more so than not, then perhaps the intended use of the audio inputs was mis-communicated by BM in regards to how it should be used. I would think that if they had intended for a pre-amp or high gain mic only... they would indicate that they are for those purposes yah?
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 8:37 pm

Denny Smith wrote:The 1/8 (3.5mm) inout works well with an external preamp, like the SD MicPreD, which has a 1/8th mic level output that should be able to feed a high enough gain for a useable signal level, al,owing for a stereo audio recording from the mixer

The Mini XLR is the main mic input, works equally well with both line and mic level inputs. Mics also have to have a a good level output, some of,p the Rhode mics do not.


Again, Denny? These are not established facts and as far as I know, you haven't done any independent testing. Even if you had, there appears to be variations between units. And some units which start out well, and then stop doing well.

Is there any sense in repeating a report here and a report there -- sometimes contradicted by other reports -- and presenting that information as definitive, as if you have direct of knowledge of it? These posts are misleading at best, and one could be less charitable than that in describing them.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 9:18 pm

Australian Image wrote:That's really the point, the BMPCC4K should have been designed so that you could select phantom power for a 3.5mm jack as well as XLR. I don't think it would have been that difficult.


Since there's really no such thing as phantom power on 3.5mm, it would be pretty pointless. The 3.5mm jack is a consumer standard, not professional... and that comes with compromises.

It's possible that BMD could have implemented plug-in power on the 3.5mm jack, but it's also possible that the additional power regulation required to support for 48V phantom power on the XLR port and (I don't remember the voltage specs for plug-in power) on the 3.5mm port required significantly higher complexity than BMD's price target allowed.

The XLR port is there for people who want to use these cameras as A cameras for interviews, v-logs, and similar situations where the on-board audio recording is useful. While priced like toys, these really are intended for professional use, which means with professional audio solutions.
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Re: Pocket 4K - weak preamps?

PostMon Nov 26, 2018 9:52 pm

Ray, like someone else pointed out, seems some cameras have that option. I have only dabbled with a few DSLRs/handy cams and none have had that option. I also only have one 3.5mm boom mic that uses batteries, and the cheap mics for computers, only thing I see on computers is input gain option, but have never seen option on any device to provide power to 3.5mm. Could be feature only a select few cameras provide. I am curious if the mic you have and if there are others that specifically draw power from 3.5mm (obviously) as.. and to my response before, I have never seen/heard of a phantom or power option for 3.5mm mics. Just assumed you plugged it in and it worked. E.g. movement on the diaphragm generated tiny electric pulses that was picked up by the circuitry in the mic input plug/components. It never occurred to me that that same plug might send power to the mic?
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 12:16 am

John, my assumptions (and these are just what hey are, not facts, nor presented as such) are based on previous BM cameramexperience with the Original Pocket Camera, and both Micro Cameras, all of which only had the 3.5mm unbalanced input. The input on all three was also weak, but it seems from other reported tests her, it is also weak. My info on the new Pocket performance is based on Robert Niessner (who also has extensive pro audio experience) and others, who’s opinion I trust. And yes, there is alway variation on different camera samples, due to the quality control issues BM seems to have in their Camera production. I also have the original Ursa and Ursa Broadcast Cameras.

Audio has always been a weak point on the BM Cameras. The Ursa Mini Pro to date has the best audio so far. I had high hopes for the new Pocket 4K, based on reports from preproduction Camera tests, but it appears this has not planned out, as the new Pocket suffered from weak audio inouts on its 3.5mm input, the jury is still out on the XLR inkut, which seems a little better, but how is it compared to the UM Pro?

Cheers
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 12:45 am

Denny, there's evidently no stopping you from offering advice and instruction on every conceivable subject, whether you know anything or not.

If your own errors haven't shamed you by now, I guess it's pointless to say more.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 3:21 am

John.. that is a bit harsh. Denny knows a ton and has offered plenty of fantastic advice in many posts. He, like many of us is just sharing thoughts, sometimes formulated from others possibly from several other forums to help would be readers. There is nothing wrong with communicating thoughts, ideas, and expertise, in any combo in an open forum. If he is wrong, he has come forward saying so. Whats the big deal? Lets all enjoy the sharing of info and be cool to one another.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 3:42 am

Justin. We have been ripped off for many years. Most of the things we talk about are things worth dollars to add, probably in total. This $59 prepaid, fillin, phone is likely more complex. The only reason the pocket is good value in reality, is they have done what they could with FPGA. The camera if done differently, is sub $500 value. You can pickup $299 m43rds 4kp30 camera (but with 1080p HDMI) which just uses it's design differently, but illustrates reality. I have great hope for a new micro, mini and next pocket. After they figure out what is wrong here they can sort out and even upgrade (HDMI). I'm not saying they should reduce the price to $500, unless they get something cheaper to replace FPGA, which could halve the size, with a new sensor. I wonder if that $299 (with lens maybe) m43rd special, could he programmed to do cdng or raw output. I've been waiting firbthe next version for a couple of years maybe.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 7:26 am

Justin Jackson wrote:John.. that is a bit harsh. Denny knows a ton and has offered plenty of fantastic advice in many posts. He, like many of us is just sharing thoughts, sometimes formulated from others possibly from several other forums to help would be readers. There is nothing wrong with communicating thoughts, ideas, and expertise, in any combo in an open forum. If he is wrong, he has come forward saying so. Whats the big deal? Lets all enjoy the sharing of info and be cool to one another.


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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 7:44 am

Rakesh Malik wrote:Since there's really no such thing as phantom power on 3.5mm, it would be pretty pointless. The 3.5mm jack is a consumer standard, not professional... and that comes with compromises.

It's possible that BMD could have implemented plug-in power on the 3.5mm jack,


The Pocket 4k has plug-in power on the 3.5mm jack. My lavs need it and they work.

Plug-in power and phantom power are two different beasts. Different voltage, different wiring, different plugs, different construction of connected microphones.

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Last edited by Johannes Hoffmann on Tue Nov 27, 2018 3:29 pm, edited 1 time in total.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 10:05 am

Have there been any tests on the camera that give a definitive mic gain specification in mV or dbm, most of the comments so far are of the subjective 'this is quieter than that' kind, would be nice to have an accurate figure. All of my Sony cameras come with the audio specification printed in the manual, BM do not seem to do this.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 4:15 pm

Richard Knight wrote:Have there been any tests on the camera that give a definitive mic gain specification in mV or dbm, most of the comments so far are of the subjective 'this is quieter than that' kind, would be nice to have an accurate figure. All of my Sony cameras come with the audio specification printed in the manual, BM do not seem to do this.


I have been testing my 4K inputs using a 1kHz tone and a meter to look at volts RMS vs recorded db.
In short, the 4K is 12db less sensitive than the old BMPCC on its 3.5mm input when the 4K is set to stereo and 6db less when set to mono in both line and mic modes.
A 0db signal (about 1.7V RMS) gives about -12db on the BMPCC4K in stereo and 0db on the old BMPCC.
I can't see any sense in why it should make a difference to sensitivity whether the input is set to mono or stereo on the 4K.
Another observation I made is that the metering on the old BMPCC is inaccurate. There is a non-linear relation between db input and display, with it being about right at higher signal levels but reading too high at lower signal levels. 0db was correct on the camera but a -20db signal displayed as -15db. I verified that by doing recordings at various levels and checking them in Audacity. I also used a BitScope Micro to check signal levels agreed with my multimeter.

My XLR input tests have a bit more work to do.
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 4:35 pm

John Morris wrote:I have been testing my 4K inputs using a 1kHz tone and a meter to look at volts RMS vs recorded db.
In short, the 4K is 12db less sensitive than the old BMPCC on its 3.5mm input when the 4K is set to stereo and 6db less when set to mono in both line and mic modes.
A 0db signal (about 1.7V RMS) gives about -12db on the BMPCC4K in stereo and 0db on the old BMPCC.
I can't see any sense in why it should make a difference to sensitivity whether the input is set to mono or stereo on the 4K.
Another observation I made is that the metering on the old BMPCC is inaccurate. There is a non-linear relation between db input and display, with it being about right at higher signal levels but reading too high at lower signal levels. 0db was correct on the camera but a -20db signal displayed as -15db. I verified that by doing recordings at various levels and checking them in Audacity. I also used a BitScope Micro to check signal levels agreed with my multimeter.

My XLR input tests have a bit more work to do.


Thank you, for objective measurements. I thought the mic level gap between the P4K and BMPCC was greater than you report (more like 18db), but didn't have the means to measure with any precision. Just to clarify, was it your finding that 3.5mm line level stereo is also 12db less sensitive than line level on the BMPCC?

There are two camps on xlr performance (some reports of fine and dandy, others complaining of the same issue as with 3.5mm), so it will be interesting to see what your findings are, at least for your own unit.
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Pocket 4K - weak preamps?

PostTue Nov 27, 2018 6:07 pm

Much appreciate the measurements, John Morris. No wonder BMD has commented on better control of noise... they just forgot to mention they crushed the levels to do it. (I may be guilty of overstating it.) looking forward to the XLR levels as only use XLR.

As John Paines points out, there’s still a suspicion that audio is not consistent across all copies.


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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 6:46 pm

Thanks John Morris for the tests. Looking forward to reading your report on how the 3.5mm line level actually is, and the XLR input both mic and line level.
Cheers
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Re: Pocket 4K - weak preamps?

PostTue Nov 27, 2018 6:48 pm

John Paines, I will not bother you anymore with my thoughts or ideas. It is comments like yours that have forced the most of the original contributors off this forum. Good bye.
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