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Dan Wake

Ambisonic or custom setup? Which microphones to buy?

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Hi, I’m looking for an advice about which mics to buy for field recording and which technique is best for my purposes please.

 

I’m looking for those goals:

 

1) taking field recording audio for 5.1 mix (the mics needs to be enough silent for room tones). Needs it for documentaries and short movies

2) build sound libraries to sell online

3) make field recordings for VR audio (for videogames development). 

My budget is limited. I can buy a sound device mixpre II 6 or 10 

 

For mics I have those options for now:

 

1) DIY second order ambisonic mic up to 9 Primo EM272 to buy from LOM or Micbooster. 14dBA of self noise, data sheet: https://www.primo.com.sg/sites/default/files/EM272.pdf


2) DIY first order ambisonic with 4 matched Primo E272

 

3) five Primo EM272 for a non-ambisonic config, something like this https://ibb.co/g6vwtXX

 

4) four matched Rode NT1-A 

non-ambisonic for taking audio in this configuration: https://ibb.co/QmwS5SW
data sheet (only 5dBA): https://it.rode.com/microphones/nt1-a

 

5) NT-SF1, first order ambisonic mic. Data sheet: https://it.rode.com/ntsf1#specifications

 

Talking about which technique is best for my purposes I really needs to ask you to your expertise because I always used stereo recording and this is my first time with multichannel recordings. 

 

Thx for help,

 

Dan

 

 

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7 hours ago, Dan Wake said:

make field recordings for VR audio (for videogames development). 

100% go for the NT-SF1 ambisonics mic, if 360VR is a major focus for you and you're on a tight budget. 
That mic has been on my radar ever since it got announced, but I just don't do enough work to justify owning one. (thus it remains on my want list, rather than on my need list)
I'd only go for anything else if by chance you happened to see a really good deal on some other secondhand ambisonics mic. (such as a SoundField SPS200)

 

7 hours ago, Dan Wake said:

My budget is limited. I can buy a sound device mixpre II 6 or 10 

 


I'd go for a Zoom F8n instead (or F6, or a secondhand F8 which can be found for a steal these days). For numerous reasons why, a couple of them: if you want to be able to record a couple of point sources at once as well then the Zoom F Series can do that by the MixPre series can't in ambisonics mode, and the F Series has a better app too (for instance allowing you to remotely change gain, which is a crucial feature while doing 360VR recordings as you can't be right next to the recorder itself).

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"as you can't be right next to the recorder itself"

 

Trying understand why this is. 360 VR puts everything in the environment on camera including the recorder and/or cables used so requiring practical or digital techniques to hide them – is an extendable cable (from mic to recorder) not easier to hide than the recorder and easier to extend than BT range? I suppose 1 could use a combination of all the above techniques to get 1self over the horizon or into the next door building

 etc.

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9 hours ago, IronFilm said:

100% go for the NT-SF1 ambisonics mic, if 360VR is a major focus for you and you're on a tight budget. 
That mic has been on my radar ever since it got announced, but I just don't do enough work to justify owning one. (thus it remains on my want list, rather than on my need list)
I'd only go for anything else if by chance you happened to see a really good deal on some other secondhand ambisonics mic. (such as a SoundField SPS200)

 


I'd go for a Zoom F8n instead (or F6, or a secondhand F8 which can be found for a steal these days). For numerous reasons why, a couple of them: if you want to be able to record a couple of point sources at once as well then the Zoom F Series can do that by the MixPre series can't in ambisonics mode, and the F Series has a better app too (for instance allowing you to remotely change gain, which is a crucial feature while doing 360VR recordings as you can't be right next to the recorder itself).

Thx a lot for suggestions I’m very grateful. I’m sorry I didn’t understood the text in bold can you gives me an example please? What do you mean a couples of point sources at once in ambisonic mode?

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3 hours ago, daniel said:

"as you can't be right next to the recorder itself"

 

Trying understand why this is. 360 VR puts everything in the environment on camera including the recorder and/or cables used so requiring practical or digital techniques to hide them – is an extendable cable (from mic to recorder) not easier to hide than the recorder and easier to extend than BT range? I suppose 1 could use a combination of all the above techniques to get 1self over the horizon or into the next door building

 etc.


360VR productions already have/expect a nadir, perfect for you to drop you mixing bag there and it will be hidden away. 

You could always ask them to paint out part of the scene for you to run cabling out from the mic to where you're situated, but I strongly suspect most productions wouldn't like the suggestion of this extra work for them. 
 

 

2 hours ago, Dan Wake said:

Thx a lot for suggestions I’m very grateful. I’m sorry I didn’t understood the text in bold can you gives me an example please? What do you mean a couples of point sources at once in ambisonic mode?


Point sources, that you'd mix in during post to make them more prominent, such as lav on someone speaking or an item of interest in the scene that you've placed a close mic next to. 

With the MixPre series, once you're in ambisonics mode then you can't record extra channels on top, but you have no such restrictions with the Zoom F Series. 

Another minor point to keep in mind, is that Sound Devices charges for the Ambisonics firmware update, while it comes free with the Zoom F Series. 

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On 7/23/2020 at 10:16 AM, IronFilm said:


360VR productions already have/expect a nadir, perfect for you to drop you mixing bag there and it will be hidden away. 


 

what is a “nadir”?

What are the high end choices for Ambisonics mics. Also is “ambisonics“ intellectual property of a certain company or a generic term?

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2 hours ago, Derek H said:


 

what is a “nadir”?

What are the high end choices for Ambisonics mics. Also is “ambisonics“ intellectual property of a certain company or a generic term?

Nadir is the lowest point from the observer, the camera. If you look straight down in 360 videos you'll most likely see a logo, bug or other graphic to cover up the area where the tripod and sound bag would be.

 

High end choice for Ambisonic mics would be the Soundfield mic.I believe that  Rode bought the company a few years ago but I doubt that their current offering ( NT-SF1) can compete with the Original Soundfield product line.

I use a Calrec Soundfield MK-IV and a Sennheiser Ambeo. The Calrec is absolutely amazing sounding while the Ambeo sounds like a cheap condenser that happens to be ambisonic.

To my knowledge "Ambisonics" is a generic term. It's important to remember that Ambisonics wasn't created to accommodate VR, 360  videos, or anything like that. It just happens to be the perfect format for distributing 360 / VR audio. Here's a nice article from 1979 to fill you in on it's history.

 

https://www.ambisonic.net/sfexp.html

 

 

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3 hours ago, Werner Althaus said:

Nadir is the lowest point from the observer, the camera. If you look straight down in 360 videos you'll most likely see a logo, bug or other graphic to cover up the area where the tripod and sound bag would be.

 

High end choice for Ambisonic mics would be the Soundfield mic.I believe that  Rode bought the company a few years ago but I doubt that their current offering ( NT-SF1) can compete with the Original Soundfield product line.

I use a Calrec Soundfield MK-IV and a Sennheiser Ambeo. The Calrec is absolutely amazing sounding while the Ambeo sounds like a cheap condenser that happens to be ambisonic.

To my knowledge "Ambisonics" is a generic term. It's important to remember that Ambisonics wasn't created to accommodate VR, 360  videos, or anything like that. It just happens to be the perfect format for distributing 360 / VR audio. Here's a nice article from 1979 to fill you in on it's history.

 

https://www.ambisonic.net/sfexp.html

 

 

 

Rode still selling Soundfield, as as you suggest, the NT-SF1 is far from the real Soundfield SPS200, but is cheap and IMMO better than Ambeo

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9 hours ago, Derek H said:

what is a “nadir”?

What are the high end choices for Ambisonics mics. Also is “ambisonics“ intellectual property of a certain company or a generic term?

@Werner Althaus already answered your question so well!

https://en.wikipedia.org/wiki/Nadir

The only other comment I'd add to that... is what @ramallo already addressed. (that SoundField mics are still being sold, and the NT-SF1 comes pretty close and is great value for money)

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20 hours ago, IronFilm said:

@Werner Althaus already answered your question so well!

https://en.wikipedia.org/wiki/Nadir

The only other comment I'd add to that... is what @ramallo already addressed. (that SoundField mics are still being sold, and the NT-SF1 comes pretty close and is great value for money)

 

I said far, not close (I have both), but the NT-SF1 is nice for the price (the SPS200 cost three times more)

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21 hours ago, ramallo said:

 

I said far, not close (I have both), but the NT-SF1 is nice for the price (the SPS200 cost three times more)


Hi, do find the NT-SF1 to be good enough for room tones recordings? Thx

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Hi Dan, I wasn't planning on commenting on your original post simply because I have no experience (nor knowledge of for many) the mics you mention, nor really the understanding of what you really plan to do with ambisonic mic technique - but

 

5 hours ago, Dan Wake said:


Hi, do find the NT-SF1 to be good enough for room tones recordings? Thx

 

As a dialogue editor, if confronted with room tone recorded on an ambisonic mic, I would:

 

1. swear

2. listen to decide if it was any good ...

 

3. if, as expected, it was no good, swear again, then laugh, then find something in my library

4. if it actually seemed useful, say "oh ok" (possibly swear again whilst laughing) and either choose (if possible) or randomly select a single channel of the 4 (to NINE?!?) available and delete the rest.

 

Although I would expect '3' to be the final stage and if pressed for time just '1'.

 

Different recording techniques for different purposes. Different media even. Buy the mic that suits what you REALLY want to do ...

1 x hyper, or

2 x cardioid, or

1 x ambisonic

... none of these options (for instance) can be a desirable replacement for any of the others.

 

Jez Adamson

 

 

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24 minutes ago, The Immoral Mr Teas said:

Hi Dan, I wasn't planning on commenting on your original post simply because I have no experience (nor knowledge of for many) the mics you mention, nor really the understanding of what you really plan to do with ambisonic mic technique - but

 

 

As a dialogue editor, if confronted with room tone recorded on an ambisonic mic, I would:

 

1. swear

2. listen to decide if it was any good ...

 

3. if, as expected, it was no good, swear again, then laugh, then find something in my library

4. if it actually seemed useful, say "oh ok" (possibly swear again whilst laughing) and either choose (if possible) or randomly select a single channel of the 4 (to NINE?!?) available and delete the rest.

 

Although I would expect '3' to be the final stage and if pressed for time just '1'.

 

Different recording techniques for different purposes. Different media even. Buy the mic that suits what you REALLY want to do ...

1 x hyper, or

2 x cardioid, or

1 x ambisonic

... none of these options (for instance) can be a desirable replacement for any of the others.

 

Jez Adamson

 

 

Jez thx for the funny post it made me laugh that's very funny. Here in Italy we swear a lot too lol

If you would need to peek the option 3 after option 1 would you look for a stereo roomtone or mono, or multichannel (> 4 channels), do you have a preference? and how would you mix it in a 5.1 film (on which speakers would the sound of the room tone come out)?

I'm asking cause I'm trying to learn 5.1 in both field recording and post production. I always did everything in stereo, I started learning 7 years ago, I don't have a school education I leared with trial and errors and with few private lessons about post production to learn the DAWs & rudiments. Now it's happening that directors are liking my works, and people at film festivals are appreciating my mixes and recording quality, I earned a little budget and I wish to invest buying something that may help me to learn more and experiment.

I expect the things to learn will be a lot expecially being alone this will be a hard journey. I would like to just start doing small experiments to discover my taste for it.

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Mr. Teas can correct me, but you're confusing the concept of room tone and ambience

Room tone is 20-30 seconds of silence recorded from the mics, in the same position, that were used to record dialog. This means that you need your actors (or interview subject) to sit on their mark silently for a bit to get the track. Room tone is used in the dialog edit to smooth over edits and added spaces. This track is played with the dialog on the dialog bus (typically through the center channel)


Ambiences are multitrack (stereo, quad, surround, ambisonic... etc.) used in the sound edit to create the environment for which the scene takes place, this is placed in the Sound Effects bus and doesn't have any dialog elements in it. Can room tone be ambience... sure, but mono mixes are boring.

 

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13 hours ago, The Immoral Mr Teas said:

...As a dialogue editor, if confronted with room tone recorded on an ambisonic mic, I would:

 

1. swear

2. listen to decide if it was any good ...

 

3. if, as expected, it was no good, swear again, then laugh, then find something in my library

4. if it actually seemed useful, say "oh ok" (possibly swear again whilst laughing) and either choose (if possible) or randomly select a single channel of the 4 (to NINE?!?) available and delete the rest.

 

Although I would expect '3' to be the final stage and if pressed for time just '1'.

 

Different recording techniques for different purposes. Different media even. Buy the mic that suits what you REALLY want to do ...

1 x hyper, or

2 x cardioid, or

1 x ambisonic

... none of these options (for instance) can be a desirable replacement for any of the others.

 

Jez Adamson

 

 

Just out of curiosity, are you saying if someone delivered B-Format room tone to you, you'd swear....OR...anything captured with an Ambisonics mic and decoded as , mono, coincidental stereo, 5.1 or whatever would make you swear?

I'm only asking because, while  I've never used an Ambisonic mic for roomtone, I have used Ambisonics mics extensively to decode in post as needed, mostly for music recording. I find the decoding options of a Soundfield mic to be very useful, kind of like MS, only times three ( which is exactly what it is.)

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Hi Dan,

 

to answer your question to me first, as dialogue editor I would be looking for mono fill for the dialogue track(s) - being the 'fill' track which may have been recorded by the PSM specifically to help me with the edit. Of course there is nothing to stop me just using one leg  of a stereo track if room tone has been recorded in stereo.

 

If I'm handling the ATMOS tracks (which I might well do as a dialogue or effects editor on a job with a few editors) as well as the fill I would most usually put a couple of tracks of stereo room tone, although if I had a good track which fit the scene of a 4.0 or 5.0 I might use that (those). Although this really does depend on the film how we decide to prepare the tracks. Note that I am talking here about "bland" room tone, NOT a detailed ambient recording. Two stereo tracks is often sufficient to be blended and panned multichannel and fill out the mix (remember that the dialogue tracks and more characterful Atmos tracks are also present). In fact an added difficulty of recording a 'plain air' track in 4 or 5 channels rather than 2 is that attention-grabbing little sounds or areas become far more noticeable. Of course this 'difficulty' becomes an asset when recording an ambience (like a country or city scape) where you want to breath life into the sound and to some extent draw the audience attention toward it. I have recorded room tones (as opposed to atmos) in multichannel but it is only when conditions are very good (location acoustic) that you will get tracks suitable for this purpose. Again, if the conditions, and thus sound, was more characteristic, bingo, you are recording not a room tone but an interior and there is nothing to stop an editor using two legs of a blandish multichannel interior to reduce the stereo perception. You probably weren't asking me for a differentiation between room tone and atmos but you did use the term so got my answer thus.

 

Back to the issue of ambisonics. I avoid it in film generally (search elsewhere why). For recording multichannel ambiences I actually favour a 4.0 approach but often go 5.0 (or am asked to) amusingly for its 'resale' value perception (people [think they] know what 5.1 is and it is surely superior to four point ... whatever it is you just did)! I often go for spaced omnis for all types of film effects but would push people to consider IRT recording.

 

So a brief look back to your original post (which I'm afraid I can't be much help with either).

 

On 22 July 2020 at 8:05 PM, Dan Wake said:

I’m looking for those goals:

1) taking field recording audio for 5.1 mix (the mics needs to be enough silent for room tones). Needs it for documentaries and short movies

2) build sound libraries to sell online

3) make field recordings for VR audio (for videogames development). 
 

 

For 1 and 2, I would say the first mics to buy for film making are a hyper and a shotgun. Perhaps you already have these, perhaps you have no intention to record dialogue but ONLY find jobs where you record effects and atmospheres. I'm not sure what your position is so couldn't think to give advice. For recording effects and field recording in general I would suggest a pair of cardioids or a pair of omnis, or both pairs. For multichannel that's 4 of either or of both.

 

For 3, I have no experience so wouldn't have commented, but I notice that many are using ambisonics so that's very probably the route to go down. Again (2 again) if you want to sell ambisonic recordings then get an ambisonic mic: I am not in the marketplace for such recordings however.

 

Personally I had several other mics before I bought my Soundfield or put together my first MS rigs. I use neither generally for film fx recording generally though but they both have other uses. My principal mics for fx are cardioids and omnis although others get a lot of use. My inkling, especially if '3' is really a plan, is to buy, hire or indeed build(?) an ambisonic mic and start experimenting with it.

 

I must say I hadn't realised but am much impressed by your proposed intention to build an ambisonic mic, and a second order one at that! Me, I'm scared to solder a hirose ....

 

Best, Jez

 

 

Addendum for Werner - are you talking about post for broadcast or for feature film? It is the latter I do not like ambisonics (nor indeed MS) for. I also worked (over the decades) in TV, radio, music where I consider such phase related techniques an asset rather than an issue to manage.

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I am not a software programmer so take my advice with a grain of salt, but I believe one of the caveats with using an ambisonic mic is that for the best results, the software you use to process the files after recording and turn them into something listenable should be calibrated for the exact microphone you’re using - sensitivity, distance between the capsules, etc. 

 

just something else to think about if you’re thinking about going the DIY route - even with a great mic you may get less than ideal results unless you invest in a custom software solution as well. 
 

-Mike

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19 minutes ago, Mobilemike said:

I am not a software programmer so take my advise with a grain of salt, but I believe one of the caveats with using an ambisonic mic is that for the best results, the software you use to process the files after recording and turn them into something listenable should be calibrated for the exact microphone you’re using - sensitivity, distance between the capsules, etc. 

 

just something else to think about if you’re thinking about going the DIY route - even with a great mic you may get less than idea results unless you invest in a custom software solution as well. 
 

-Mike

 

Core Sound (who makes some inexpensive, but high quality ambisonics mics) does provide a calibration service where they will analyze your off the shelf mic and give you a custom calibration file to use with their ambisonic decoder, no personal experience but I've heard it steps up the quality in commercial mics

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13 hours ago, The Immoral Mr Teas said:

Personally I had several other mics before I bought my Soundfield or put together my first MS rigs. I use neither generally for film fx recording generally though but they both have other uses. My principal mics for fx are cardioids and omnis although others get a lot of use. My inkling, especially if '3' is really a plan, is to buy, hire or indeed build(?) an ambisonic mic and start experimenting with it.

 

I must say I hadn't realised but am much impressed by your proposed intention to build an ambisonic mic, and a second order one at that! Me, I'm scared to solder a hirose ....


Maybe Dan hasn't realized yet the sheer scope of that task, especially the tricky aspect of getting perfectly matching capsules. (and remedying any imperfections)

 

12 hours ago, Shastapete said:

 

Core Sound (who makes some inexpensive, but high quality ambisonics mics) does provide a calibration service where they will analyze your off the shelf mic and give you a custom calibration file to use with their ambisonic decoder, no personal experience but I've heard it steps up the quality in commercial mics


Although having them do it would make life a bit easier, didn't know they offered that service. 
But can't find the info about calibrations for DIY ambisonic mics? They mention this service for a few specific mass produced ones on the market, for $250/each:

https://www.core-sound.com/coresound_services.php
I'd imagine doing it for your DIY mic would cost at least the same amount, or more. 

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On 7/27/2020 at 4:16 PM, The Immoral Mr Teas said:

Hi Dan,

 

CUT to reduce text legibility

 

Back to the issue of ambisonics. I avoid it in film generally (search elsewhere why). For recording multichannel ambiences I actually favour a 4.0 approach but often go 5.0 (or am asked to) amusingly for its 'resale' value perception (people [think they] know what 5.1 is and it is surely superior to four point ... whatever it is you just did)! I often go for spaced omnis for all types of film effects but would push people to consider IRT recording.

 

 

 

Hi Jez, I'm super grateful for your message, I really absorbed the infos like a dry sponge seeing some water and I'm thirsty eheh, I love to edit dialogues I'll makes treasure of your suggestions.


I searched on the forum to understand the issue of ambisonic for films you mentionend in your post. I have found this message here where you say Ambisonic technique doesn't works for theatrical films. I wish to ask you if I understood your message please. Is the problem related to Phase issues (as an unwanted lowering of the amplitude/volumes) when reproduced inside the speaker system of the theater? does this happens only for atmos or also for 5.1 mix?

I'm sorry for my problems with english. when you say theatrical films do you mean films shown in theaters?  

I mostly makes audio for films (documentaries) that goes to film festivals and I wish to be sure that if I use Ambisonic as my primary microphone for ambience recording there will be no phase problems in the theaters after 5.1 mix.

Thank you very much,

Dan

 

https://jwsoundgroup.net/index.php?/topic/32077-new-zoom-h3-vr-recorder-mic-combo/&page=3&tab=comments#comment-352413

 

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