Re: Zoom H6 line out phase inversion problem
 

I never got the impression that it was about actually using camera audio in the finished video. I just use it as a reference for getting different angles roughly aligned before fine tuning the alignment to some visual event, then muting the camera audio. Well, I'll also use it to rough in the finished audio, but I fine tune that by comparing it to the video. Either way, the camera audio gets muted.

Re: Zoom H6 line out phase inversion problem
 

As is often the case the topic has changed from my original one which was not about using camera audio except in an emergency situation. It was about a probable fault with the Zoom recorder. I posted it in the dedicated audio thread as I thought it would not interest folk elsewhere. A unit that inverts the phase of an output is bad as it will cause problems for anyone who works closely and especially creatively with audio at some point.

Re: Zoom H6 line out phase inversion problem
 

And we still don't know whether the Zoom inverts the polarity of the electrical output, or whether it inverts the polarity of the recorded file. You could ascertain that as follows.

1.) Get a single mic that is known to work with the Zoom and a few other recorders, without needing any adapters that might possibly flip polarity. (An omni would be my first choice, because that would eliminate any phase shifting design to obtain some directional polar pattern.)

2.) Record some asymmetrical sound (perhaps a stick on a slate), preferably in open air so there will be no confusing reflections. Check the waveform and confirm that the asymmetry is clearly visible.

3.) Repeat this test on each of the recorders (always using the same mic in the same acoustic environment).

4.) Now compare all the waveforms. Presumably all of them (ignoring the Zoom) will be the same, so that can be called the "reference" polarity.

If the Zoom waveform is the same polarity as the other recorders then the polarity of the Zoom file is correct. In that case its electrical output must be inverted.

OTOH if the Zoom waveform is flipped from the other recorders then the polarity of the Zoom file is flipped, and the Zoom's electrical output is in phase.

-----------------------

At any rate, this situation might be annoying, and certainly is "wrong" from a theoretical standpoint. But it's trivial to invert the waveform in your editing software, right? If so, then it's not really causing you any problem in this scenario.

Re: Zoom H6 line out phase inversion problem
 

Or use an XLR splitter known to be wired correctly and record the exact same sound to the Zoom and another device.

Re: Zoom H6 line out phase inversion problem
 

I agree with Geoffrey that any recorder that a recorder that doesn’t follow convention is bad, but the ‘problem’ is something far easier to fix than in the past, because the fix is a click and spotting it needs to be done can often be confirmed visually. If you take your microphone collection, I’d guess quite a few have reversed polarity. Hopefully each model is consistent, but it seems rare now to see the statement in the spec saying a positive pressure on the diaphragm produces a positive voltage on pin 2 (or 3). Shure had this reversed on their products for a long time, then moved to the same system as others. We don’t get any problems from using old mics do we? Nowadays we hear a problem and easily fix it. Just because we can shift waveforms tiny increments in time, or invert polarity my feeling is we’re curing things that usually are not even a problem.

I’m amazed the inverted polarity was even noticed.

Re: Zoom H6 line out phase inversion problem
 

That assumes you're 100.000% certain that all the XLR cables, as well as the splitter itself, are all wired in correct polarity.

I guess you could try a 3.5mm splitter with one unbalanced microphone, but you'd need to be cognizant of "plug-in-power" issues.

~~~~~~~~~~~~~~~~~~

ALSO, is there any chance that M/S mode is activated somewhere in the Zoom? If M/S is activated in the *monitoring* chain, then the right channel input (and right recorded channel) will be inverted at the right channel output. I'm not familiar with the H6 so I don't know whether this is even possible, but it would be one legitimate reason for a polarity reversal in that situation.

Re: Zoom H6 line out phase inversion problem
 

I own the H6 never had an issue. For what's being described, recording a poetry reading, it should be a simple as one mono condenser mic. Even if there was a phase inversion, there shouldn't be anything to conflict. I get the feeling OP has too much time on his hands, creating a "problem" where none exists.

The H6 does have MS setting but if one doesn't know how to properly set it up they shouldn't be using it.

Re: Zoom H6 line out phase inversion problem
 

Perhaps the OP would like to have a thorough understanding of his gear, so he can anticipate potential problems before they occur. Is "curiosity" equivalent to "too much time on his hands"? (Admittedly, flipping polarity is trivial in audio software, but still it can't hurt to be aware that this situation might occur.)

IIRC the OP has stated that polarity is *not* an actual problem in this [spoken word] case; but it can affect timbre of musical instruments in some other situations, so he's curious about what's causing it.

Re: Zoom H6 line out phase inversion problem
 

He explained in his first post that he's sending the H6 audio to the camera for syncing. So it doesn't matter if it was inverted, because it's being used as a scratch track. There is also no need to send audio to the camera for syncing since the camera's internal mic would work as well. Even he wants to use that audio whether it's inverted doesn't matter since there is only one sound source. Since I don't see where a problem exists, then all that is left to search for a situation where you can create a problem. You might be curious why a device works the way it does, but since you can't change how it was designed and there is no apparent problem...

Re: Zoom H6 line out phase inversion problem
 

I wouldn't assume, I would use a DMM to verify the polarity.

Re: Zoom H6 line out phase inversion problem
 

You show your ignorance.

I am not just recording the poetry but the ambience as well at the same time using a stereo spaced pair. It is an outside setting, often quite windy and with visible trees blowing in said wind. Therefore it needs to be in sync so cannot be primarily a separate ambience track recorded 'clean' (though I do some of this as well in between takes for remedial needs). Inevitably the voice is also picked up by the spaced pair as well as the mono mic. I work alone also, so this all needs to be manageable by me in the field and I have to be primarily concerned with filming the poets dynamically and creatively handheld and on the tripod. Good quality sound recording of both elements is crucial to the project.

The reason for looping the audio from the Zoom back into the camera is for a genuine backup as well as scratch synch track. Using the inbuilt camera mics would be useless in the first instance and if very windy, quite possibly useless for the second as well, as the mic distortion could be considerable.

The 'problem' was never couched as such, merely an observation that the Zoom seemed to be inverting the signal.

I have no need to use the M/S setting as I am using a spaced pair.

Got it?

Re: Zoom H6 line out phase inversion problem
 

Geoffrey,

That sounds like an interesting project. I have occasionally tried recording ambience for the sake of capturing "nature sounds" (sometimes overnight) but nothing as ambitious as recording poetry at the same time.

Just to clarify my earlier comments ... I am aware that you don't have any *need* to use any M/S setting. I was simply suggesting that if some M/S function is *accidentally* activated, probably in the analog output chain, it *might* cause some polarity problems. I wasn't thinking that you had knowingly turned it on, just wondering if something was lurking in one of the menus somewhere. Obviously if you've already looked through the menus and found nothing, then my comments are moot.

Good luck with the project!

Re: Zoom H6 line out phase inversion problem
 

Thanks Greg and no worries about the M/S I understood the point.

In all am recording 10 poets who are writing commissioned poems based on the place. Also going to write and record / film some musicians performing music in the woodland to break up the poetry. Also going to do some other creative sound design in response to the texts. So kind of audiovisual poetry / music. Whole film will be about 30 minutes. Recorded three poets so far and am learning best methods as I go.

Re: Zoom H6 line out phase inversion problem
 

Lets please stay civil and polite.

Re: Zoom H6 line out phase inversion problem
 

Pete Cofrancesco accusing me of having too much time on my hands and essentially not knowing what I am doing is not at all civli or polite. Why not pick him up first? His comments were ignorant.and rude.

Re: Zoom H6 line out phase inversion problem
 

Perhaps because he did not lead his post with a flame.

Too much poet in the ambience track? Can's that bet mitigated that with different ambient sound mic placement?

Re: Zoom H6 line out phase inversion problem
 

I thought it was rude, but I didn't respond because I wasn't going to get dragged down into a fight.

Right in the title is says "phase inversion problem" and there is none that I could discern. I know the type of person who asks a question and gives limited info. When you make a suggestion they get defensive and add new info, tell you know what you're talking about.

I'm confident in my abilities so I don't feel the need to defend myself. I'm happy to let you believe whatever you want.

Re: Zoom H6 line out phase inversion problem
 

'Make a suggestion' like I have too much time on my hands and only need to use one mic anyway even though I explained exactly why I need more and in fact have given plenty of info though this thread yet you shoe in another untrue slight here about me being the 'type of person who gives limited info'. I am reduced simply to a 'type of person' yet you know absolutely nothing about me.

And then you finally say 'there is no problem'. Who are you to say exactly? Nothing you have said has been at all helpful, only the opposite.

Maybe it isn't the done thing to get annoyed when people treat others with open disdain on here but I see no reason I should have to put up with it. And I have posted on and off for years and never once had this problem before.

Re: Zoom H6 line out phase inversion problem
 

I work alone so having a pair of mics somehow in a different place is practically unworkable - they have to be mounted on the camera. Also the close synch between ambient sound and image matters quite a lot at times. Imagine a poet standing in front of some trees reacting their work and the wind gets up blowing the branches and leaves, rustling them vigorously as they talk - capturing the synchronised audiovisual dynamism of trees and poet really matters.

Re: Zoom H6 line out phase inversion problem
 

This is getting rather strange.

If you buy two mics that have pins 2 and 3 reversed, I just cannot imagine ANY scenario when you'd notice the inversion. In fact, I'm not even sure any of our usual tricks of flipping channel polarity would reveal it on any digital equipment clearly because of latency. We cannot use a Y split and test in to out against direct because of the A/D and D/A conversion time. With analogue, we can test and check the polarity. With digital - time domain changes take place that sort of spoil the thing.

All I know is that I have never checked the polarity of any of my current digital audio products - and I also feed audio to cameras and no issues whatsoever have ever appeared to cause me any issues. Even worse - when you do spaced mic recordings for stereo you have even more time delays.

The Zooms may or may not have polarity reversed, but I personally won't lose any sleep not knowing if one or the other of mine have this issue?

Geoffrey's original post said:
Is it possible that the real issue here is not phase inversion at all, but just the in to out latency of the zoom? It goes mic-zoom SD card (the A to D) then the output is that digital stream back to analogue - so a few mS is to be expected? Is it inverted or is it delayed?

Re: Zoom H6 line out phase inversion problem
 

If it were delayed then I would have noticed that what I needed to do is shift one signal along a few ms but no, that isn't what is happening and I can clearly see the corresponding waveform shapes, albeit with one upside down. The proof is that when I align them as exactly as the software allows (down to sample level) then the phase cancellation is massive. Note I double-checked this using a single mono mic only.

I'll say again this isn't a major problem. And fixing it is easy by flipping one signal in the software. Serious audio folk would however note that this should not be necessary as there should be no inversion in the first place and it is worth knowing what the root cause is if it effects all signals coming form the Zoom line out for future reference.

Re: Zoom H6 line out phase inversion problem
 

For a one-man-band shoot: Some would suggest only the mic gain controls need to be on/at the camcorder, the mics can be anywhere. And many would argue the poet should have a lav mic, not a camcorder-mounted mic. Using a camcorder mounted mics might introduce handing noise if one is not careful. (Perhaps a wireless lav to give the poet and camera more freedom to move.) It becomes a matter of the art of mic selection and placement.

But then you already knew that and chose to go the way you did. Please just don't expect others to understand your reasons without clear explanation.

Re: Zoom H6 line out phase inversion problem
 

The poet does have a radio lav mic. There are three mics going into the Zoom. I mentioned this when I said a few posts back: 'Inevitably the voice is also picked up by the spaced pair as well as the mono mic.' This was the plan from the very beginning because clearly the voice is the most important element.

I am sorry if this was not 100% clear but the whole point is that this thread was not about my project but a specific issue with the zoom line out and my mic set-up is not relevant so I never went into that detail so as not clog up the main point. The topic has since morphed into a different discussion which is fine but I cannot be blamed for not giving full info on a topic I never posted about in the first place and then even attacked for being the sort who deliberately withholds information!

Re: Zoom H6 line out phase inversion problem
 

You strike me as someone who is thin skinned, perceiving attacks where there are none.You're fixating on unimportant technical details while ignoring the big picture of using the proper setup. This is why we are asking these questions because they matter more than the phase of the output. The two logical approaches to spoken word outdoors are lavalier with under/over covers or a boomed shotgun inside a blimp.

Re: Zoom H6 line out phase inversion problem
 

How do I use a boomed shotgun if I am working alone, something I stated quite clearly? It is a pointless suggestion. I am using a lavalier (COS-11D with Sennheiser G4 system). I have thought long and hard about the best setup and tested various possibilities. This involved comparing various signal levels which is where I came across the phase inversion and wondered if anyone else had any thoughts on that specific matter. I never asked for advice about the general setup as I had already spent a lot of time testing possibilities and arrived at my current configuration. I am not ignoring the big picture of a proper setup at all so you are wrong to say that (again).

Frankly wish I had never posted anything at all.

I'm out.

Re: Zoom H6 line out phase inversion problem
 

I agree the thread has morphed from "does the Zoom have a phase issue" to more of what is a good way to acquire audio for the shoot whether or not the Zoom has an issue. Probably in part because most folks posing questions here are seeking solutions or work-arounds rather than confirmation of an observation.

I read the boom pole suggestion as being a generic approach for outdoor work, not as a suggestion for an one-man-band.

All this points out why Hollywood-class production add ambient and other sound effects in post where it can be controlled and synced to the image and not rely on mother nature and passing traffic to behave. After all, the background/ambient should complement the image. Except for things like legal proceedings and select documentation efforts (and perhaps some artistic demands not related to viewer perception) it need not be time and/or spatially coincident with the shoot.

But video is an art form, so to each their own.

Re: Zoom H6 line out phase inversion problem
 

I work almost exclusively solo and I often use a portable boom stand such as this https://www.bhphotovideo.com/c/product/546705-REG/Manfrotto_420B_420B_Combi_Boom_Stand.html/BI/2855/KBID/3801
If its really windy I bring a c-stand that has a boom holder https://www.bhphotovideo.com/c/product/885688-REG/Auray_BPH_BOOM_POLE.html/BI/2855/KBID/3801
I'm surprised that I even have to suggest this. I thought it would be common knowledge. For interviews and even for this a poetry recital the subject isn't moving so you don't need a boom operator.

I don't understand why listening suggestions from like minded people makes you mad. The day when you say I know everything is the day you stop learning and growing. I always keep an open mind. But that's just me...

Re: Zoom H6 line out phase inversion problem
 

I have confirmed that the Zoom H6 does indeed have reversed polarity on the line out. The SD card recording is normal.

I also checked the sources direct to the tascam interface.

Microphone direct into the Tascam 1604 interface. a tap on the windshield produced a negative going peak in Cubase.
Microphone recorded on the H6 SD card, read into the computer, inserted into Cubase also has a negative going peak to the tap.
Microphone connected to H6 input, and the 3.5mm line output connected to the Tascam produces a positive going peak.

Interestingly, swapping the H6 for an H4 produces a negative going peak, as with the other connections.

Conclusion
The H6 does indeed have an inverted output, but this is not a standard in the Zoom recorders, as the H4 does not do this.

My H4 gets little use, but the H6 does, and I would never have found this out. I tried all the handheld microphones I have in the video studio - quite a few from all eras. Only one microphone produced a positive going waveform on the tap test - an old Shure SM61. So this mic - an omni - has, with it's brother, been used by me for years and I have never noticed that difference.

Geoffrey is quite right, the Zoom H6 output, not recording internally, is reversed - but as to why? We will never know.

Re: Zoom H6 line out phase inversion problem
 

Paul good detective work. Zoom is a bit of an odd duck maybe because they initially built it for musicians. For example, the xlr input permanently set to mic level. If you get xlr line out from a sound board you must use a 1/4 jack

Re: Zoom H6 line out phase inversion problem
 

That's true on the H4s that I've used, but it's not true on my H5, which has a a software selectable 20 dB pad making it compatible with +4 line level via XLR. I have not yet seen a clipped waveform since I started using that setting.

Re: Zoom H6 line out phase inversion problem
 

Good tip. I'm not sure if I knew this at one time but forgot. So is taking mic level and padding it to line is that proper or good enough for field work? I'm not crazy about software setting like this because if you don't use a recorder on a regular basis you could easily forget pad is on and the time you plug in a mic...

Re: Zoom H6 line out phase inversion problem
 

I think it would be fairly obvious that you're running the preamp gain a lot higher than normal to get proper levels.

Re: Zoom H6 line out phase inversion problem
 

It's fine just an annoyance because I use the H5 for a very specific thing, unattended recording of the board feed. Most of the time you have student or amateur board operator who is struggling to figure out how to send an out, neither I nor they know if it's mic or line.

I've heard Zoom will be releasing a new recorder that will be better suited for this type of work because it has 32bit float.
https://www.bhphotovideo.com/explora/pro-audio/news/zoom-f3-a-pro-level-palm-size-32-bit-float-recorder-for-xlr-mics/BI/2855/KBID/3801

Re: Zoom H6 line out phase inversion problem
 

Perhaps print a small check lists and attach it as a reminder?

Re: Zoom H6 line out phase inversion problem
 

Thank you Paul. I'm not going mad then!

Re: Zoom H6 line out phase inversion problem
 

I already considered this. I work in music and audio so a boom mic stand is very familiar to me indeed. It isn't suitable for the freedom and ease of movement that I desire, by either me or the subject. But I can solve any time delay artefact issues in the field by delaying the radio mic input by a few milliseconds, or doing that in post, or in worst case scenarios replacing the ambience altogether.