Topic: RØDE NT-SF1

[BlindGuyEars]

In time for the @NABshow, #RØDE Mics announces its first broadcast-grade, 360-degree capture mic.

The @SoundFieldMic By RØDE NT-SF1 is the first true condenser #ambisonic mic available under USD $1000.

http://www.rode.com/nt-sf1

Now, can someone tell me how Ambisonics differs from say, binaural?

[heathen]

I'm no expert, but the main difference is that ambisonic mics basically capture sound at a single point, whereas binaural mics are positioned at the ears (so there's not only space but also a baffle).  There is software that can create binaural sound from an ambisonic recording.

Another big difference is that an ambisonic mic gives you flexibility in manipulating the recording in post (for example, you can take a single ambisonic recording and, with software, convert it to Blumlein, XY cards, XY hypers, omni, etc), whereas that is not the case for binaural.

[Gutbucket]

To expound on that a bit-

Think of Ambisonics as Mid/Side -  except 3-dimensional, and with an unconstrained relationship between pickup pattern and microphone angle.  So no need to choose a Mid pattern, or even point the mic in any specific direction beforehand (you do need to know its orientation, it just doesn't matter which way it points).  You can choose any pattern and point the virtual mics in any direction afterwards.  That flexibility is its advantage.   The drawbacks are that it is limited to coincident patterns only, requires 4 recorded channels, and requires post-recording decisions and processing.

Binaural is not a coincident arrangement and is not as flexible, using a dummy head or a real head with microphones placed in the ears.  It records Head Related Transfer Function HTRF cues including those derived from ear-shape which can make for very realistic playback over headphones as long as the HTRF and ears used for recording match those of the listener closely enough. It requires only two recorded channels and no post-processing.  Drawbacks are that it is pointed in a specific direction and that orientation cannot be adjusted after the recording has been made, the post production manipulation options are more limited, and speaker playback may somewhat compromised compared to headphone listening.

[Hypnocracy]

RØDE Capsule sound has never been my favorite...that they have a remote capsule setup NT6 that is not frequently used by TS members IMO speaks volumes...I'd love to hear one of these... 

[2manyrocks]

There's a youtube video from NAB where the Rode rep shows the windshield and shock mount that comes with this mic.  The windshield looks pretty large to me.  https://www.youtube.com/watch?v=gtTs7fk1mmI

[heathen]

There's a youtube video from NAB where the Rode rep shows the windshield and shock mount that comes with this mic.  The windshield looks pretty large to me.  https://www.youtube.com/watch?v=gtTs7fk1mmI

That looks like a Rycote Baby Ball Gag, which I use for my TetraMic.

I like what Sennheiser did with their Ambeo.  There's a rigid mesh around the capsules that looks like a vocal mic.  While that's certainly not enough wind protection on its own, I like that it's small enough that even when used indoors with no wind you don't need to take it off, so the capsules stay protected all the time.  That said, I just keep the BBG on my TetraMic all the time and I'm fine with that.

[Nick's Picks]

Ambisonics use a Z axis for height information as well.   

[Gutbucket]

Yes.  One of the cooler things when recording on-stage relatively close to the sources, you can tune the sound by adjusting how much the virtual microphone patterns point up or down (in addition to polar pattern shape and left right angling).  Very cool to tweak the sound of the drum kit afterwards balancing kick against cymbals, dial in the timbre of the guitar amp depending on how much floor reflection is being picked up, I've even used a Z-axis adjustment to focus on the delicate fingering sound of an upright bass (pointing more up) rather than all the bass coming from the amp.

You are constrained somewhat in how far you can go with this by needing to keep everything else balanced at the same time.   And such options can be a burden as much as a benefit if you have a hard time juggling all the combinations and making a decision of what's most appropriate.

But all this is why I feel one of the more appropriate applications of an ambisonic mic is on-stage taping, where the sources are both in close proximity and yet distinct from each other.

[Nick's Picks]

I was all horny to get one of these....., but then I scored an ebay auction on an ST-250 last week....at a most excellent price

[Gutbucket]

Cool Nick, let us know how you like it.  ST-250 uses larger diaphragm capsules and an analog hardware matrix box, no?

Has the mic/hardware box been recalibrated recently? Correct calibration is critical for any ambisonic microphone - far more important than close matching of a stereo microphone pair if it is to operate correctly.  Else the virtual patterns derived through matrixing of the assumed closely-calibrated capsules be all wonky and weird.

[muj]

problem now With st-250.... they can't be serviced anymore. One of the main reasons the auction had low price

[Nick's Picks]

Rhode will service them, I've been told.   No idea of the calibration aspect.   This is the 2nd one I've had the pleasure to own.  I bought one new back in 2002.   loved it to peaces...it's always been my holy grail mic.
And yes, its all analog remote control on the processor box.    According to the auction, it's coming from a studio that specializes in location and FX.   I might need to dig up a cable for it...as the listing was a bit light on info, otherwise stating that it came with some custom cables.    That is confusing, as you need the soundfield multi-pin DIN cable to go from mic to control box.   From there, it's only 3pin XLR out for stereo output...but you can make a custom B format cable for it as the pinout of the XLR outputs can carry two channels of unbalanced B format, resulting in the 4.

my goal is to have it all together and ready to roll for Dark side of the Mule in mid July, where I have 20th row FOB/DFC seats and want to pull a smoker blumlein recording.

[dactylus]

^ I hope that you acquire the cables needed in time for The Dark Side of The Mule show!!  Good luck.

 

[Gutbucket]

Yeah that sounds cool.

Guessing the custom cable(s) may be for a 4-channel direct out from the microphone, used to record raw A-format to a 4 channel recorder without the processor box.

You'd then need to playback the channel A-format through the processor box to derive either a stereo out based on the processor box settings, or B-format.  The advantage of doing this is that you'd not need to commit to Blumlein or any other config prior to recording.  Instead choosing whatever coincident setup sounds best to you afterwards, even if it's only a slight tweak away from straight Blumlein, like 105-degree crossed hypers, 120-degree supercards, whatev.

Having owned one you probably know all this, but a lot of folks use these mics like a straight stereo mic, recording just the stereo output, meaning they need to commit to a certain pattern combination prior to recording. To me the great advantage of an ambisonic mic is being able to adjust the virtual pattern to whatever sounds best afterwards, especially for a taper where we don't have any opportunity to carefully monitor and try various settings to find the sweet spot setting before making the recording.

[muj]

Great news! Kudos to Røde

[chk]

I’m looking forward to checking this mic out. I’ve never used an ambisonic before, and am wondering from anyone that has, specifically with respect to decoding from A format to B format via software. How involved is post-production for what we do (generally mixing to stereo)?  I presume it’s sort of like anything else, you get the hang of it and it becomes routine?  Curious as this seems to be a pretty compelling, modern application of the Soundfield expertise in an affordable package.  I’ve done a couple blumlein onstage recordings with the LSD2 and I am really impressed with what that mic can do, and have listened to a ton of Soundfield st-250 recordings and love those, the ability to manipulate the height, etc.

[heathen]

A format to B format is easy.  In fact, some recorders will pretty much record directly to B format, but that may depend on the specific mic.  I know the Zoom F8 (and I believe also the F4) will save to B format with the Sennheiser Ambeo.

I use a Core Sound TetraMic, and the post production is definitely more intensive than with a pair of mics, but it's also not all that daunting.

What makes you interested in the Rode mic in particular?

[chk]

The Rode mic interests me for a couple main reasons: the Soundfield pedigree and price point of $999 w/ all accessories including software (thanks to Rode’s scale and ability to produce quality at reasonable cost, of course TBD how well they’ll execute).  I know there are others out there but this seems pretty attractive and worth checking out.

[EmRR]

Still curious about this one.  Doesn't look like much ambisonics talk around here recently at all.  I keep building horizontal only B format arrays out of 3 mics, but it'd be nice to get up/down if the quality drop is minimal.

[Gutbucket]

In my experience with the Tetramic I found up/down tilt control quite nice to have as a form of fine-tuning, using it to home in on the best angle for clarity or timbre, yet found that the degree of vertical angle adjustment needed for doing that was generally not overly large and remained about the same regardless of polar pattern and horizontal angle between the virtual stereo pair for most taper situations.  Exception is on-stage close to a drum-kit, with the microphone positioned low in front, in which case vertical angle adjustment can change sound radically - point up for focus on cymbal shimmer, down for kick and tom whump.

In contrast, typical adjustment of horizontal angle ranges much more widely, because in addition to horizontal angle controlling general orientation of the virtual pair, it also controls the angle between the virtual mics, which tends to correlate quite strongly with choice of polar pattern.  That is to say, for any particular polar pattern, a rather narrow range of adjustment of inclusive angle between the pair tends to be optimal.. switch to a different pattern and a different narrow range becomes appropriate.  Working the other way, if a significantly wider or narrower inclusive angle is desired, then virtual polar pattern needs to be modified to accommodate.

^ Does this description of the horizontal aspect ring true with regards to your experience building and using native 3-mic ambisonic arrays?

The convenience factor of a single microphone able to achieve a virtual coincident stereo pair that can be optimized later is pretty compelling.

[EmRR]

Yes, that all makes perfect sense.  The one application in which I might go more severely up/down would be in multitrack situations where I'm using it for pure ambience intended to mix with other sources.  There've been a couple of times I had an array in the middle of a group who were rehearsing, and used multiple copies of the WXY to make multiple virtual mics.  The Z would definitely come in handy there.   A few times close on a solo singer/guitarist I've turned it sideways so it was WXZ instead.