Surrounded! Recording 5.1 Surround Sound to your Camcorder with Holophone

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There was a time when shooting HD video meant big equipment and even bigger budgets. Nowadays, you can shoot amazing HD footage with something that costs under $200 and fits in your pocket. But how about great sound, or even surround sound, to match that awesome video? Like HD video, surround sound used to be bulky, expensive, and reserved for use by the pros. Nowadays, thanks to a company called Holophone (not to be confused with the instrument from Futurama) just about anyone can add 5.1 surround sound to their home movies or independent films without having a duffel bag full of equipment or a Hollywood budget.

The PortaMic 5.1 is an egg-shaped microphone with a standard shoe mount that allows you to capture 5.1 surround sound from a single unit mounted on top of your camera. It has 6 built-in microphones that capture left, center, and right channels in the front, left and right channels in the rear, and a subwoofer channel. The positioning of the mics in the elliptical body emulates human hearing to create a natural surround sound experience. The mic runs on a standard 9V battery with a life of about 3 hours, so no mixers or power supplies are needed. A control knob on the back of the unit makes it easy to adjust the mic’s gain. A -12dB pad is also built in for when you run into unexpectedly loud situations and need to lower the mic’s sensitivity.

An integrated Dolby ProLogic II encoder takes the signals from the mic and sends them out via a stereo 3.5mm connection, the same type of connector found on most camcorders and video-capable DSLR cameras. This means you can hook up the PortaMic to a camera such as the Canon 5D MkII in under a minute, and capture surround sound directly to the camera’s existing stereo mic input. Of course, the PortaMic will also work with standard definition video cameras and stand-alone audio recorders, as long as they have a 3.5mm stereo mic input.
 

So how about playback? Surely some sort of complex decoder or degree in audio engineering will be required to enjoy these new, enhanced movies once you get them home, right? Not at all. Any computer or home theater system that supports Dolby ProLogic II will automatically decode the audio, sending the audio to the appropriate channels. If you have a 5.1 sound system as part of your home theater that was made in the last few years, odds are it’s likely to already have Dolby PLII capability. If you’re the kind of person who likes to slice and dice your movies and needs to edit and re-encode the audio, the PortaMic comes with software that will allow you to change the audio format to other types of Dolby, DTS, and more.

 


Side View of the PortaMic 5.1
 

Being able to capture surround sound in a package that weighs less than half a pound, attaches to any standard camera shoe mount, and comes with a price tag that’s in the hundreds rather than the thousands is a terrific breakthrough in allowing folks to capture natural, immersive surround sound in an easy-to-use package.

For those who need more of a pro-level unit while sticking to a budget, there’s the PortaMic Pro. The Pro is very similar to the standard PortaMic, but adds a balanced stereo TA6 output in addition to the 3.5mm output. The TA6 connector allows you to connect the mic directly to certain models of wireless beltpack transmitters for use in a wireless system. The Pro version also adds an audio zoom feature. The audio zoom works like a camera’s telephoto: when you zoom in, the balance of the microphone elements shifts to put more weight on the front mic channels, reducing the pickup of the rear channels in order to put more emphasis on the sounds in front of you. It should be noted that while this is a cool feature, it isn’t designed to be a substitute for a good shotgun mic when it comes to focusing on a particular sound source.

Whether you’re a soccer mom who wants to capture the complete impact of being in the stadium with a roaring crowd, or a nature photographer who needs to capture the full soundscape of the forest, there’s now a wonderful solution that lets you bring your audio quality in line wth your HD video.

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Wait a minute.  If you take 6 channels and run them through a Dolby Prologic system and record them in stereo (left and right channels).  How can you get true 5.1 sound?  It's merely Dolby Prologic which is an audio "trick" which combines the left and right sounds to make the center channel audio, and subtracts the left and right to create a set of mono surround sounds.  

AC-3 Dolby Digital 5.1 has five discrete channels of sound plus an LFE sub-woofer channel (.1).  There's a huge difference in listening to a movie in "old fashion" Dolby Digital versus 5.1.   This is a nice gadget, but unless you record 6 discrete channels, it's not 5.1 sound.

I guess this is slightly different, in that it starts with 6 discreet sources. Perhaps that means it is easier for their software to split out into separete channels, which can be mixed however you want to.

After  all, ProLogic ii 'simply' analyses a stereo signal with some phase, delay and reverb, wthout 'knowing' what the original source sounded like in surround.

This compromise is worth trying. Especially if you add this to a good stereo capture for the front sound stage.

At least you will have some more directional atmosphere to add to your productions that won't require 6 microphones and a multitrack recorder at many ***** the costs and inconvenience.

Must be better than Stereo only.

 The audio "trick" is that the audio is encoded. While it's true that the sound is actually recorded on two (l&r) tracks additional encoding allows dolby systems to extract the additional tracks and route them to the appropriate channels. Playing an off the shelf hollywood movie on a stereo only system results in stereo sound. On a surround sound system those two tracks are expanded further into the respective channels. 

In Apple's Final Cut Suite for example you can take additional tracks (audio) and produce your own surround image. This can be either real time audio or simulated audio which hollywood probably does more of than real time. Think about it. The only thing actually behind the lens is camera crew etc.

The way I understand it, the ProLogic II can certainly be used to create that bit of technological magic/****ry that Fred describes above when turning a stereo signal into a 5.1 signal.

However, with this mic, I do believe the 5.1 signal is preserved.  The PLII technology is simply used to encode the surround signal into a stereo "capsule".  The signal is later decoded, and unfolded back into its original state.  Since the signal started with 6 elements, the info is not discarded, and is still available later on.

So yes, if your original signal only has stereo (from a stereo mic setup), then a PLII 5.1 representation has to take elements of that stereo signal and "****" the surround.  However, with the PortaMic, the PLII is just being used to transport the audio, and the individual information from the various mic elements is not being lost.

I will see if I can get someone from Holophone and/or Dolby to give me some more information about this process so that we can see exactly how it works.

If you're a purist, Holophone does offer a variety of other mics that have an output for each mic element so you can record to a multi-track system.  The mics are, of course, geared to pro users and carry a higher price tag.  With the abundance of new SLRs that shoot video, the PortaMic is a much more affordable solution that delivers more immersive results than shooting direct mono or stereo, regardless of encoding methods.

I have a Sony XR 520VE camcorder that seems to be overly sensitive to wind noise. Can this PortaMic 5.1 solve or reduce that problem? - Any other suggestions please!

Signal theory tells us that with some processing you can combine several data streams together and then separate them later. That's completely different from taking simple stereo audio and "******" surround.

The concept sounds interesting, but what are the technical specifications (i.e. freqency response, polar patterns, output level, overload level, noise floor, external power capabilities, phantom powering compatibilities, etc.)? And are there any user reviews or evaluations of the real thing in applications, rather than a discussion of the "gee whiz" attributes?

The price point is also not addressed for MSRP, and a search of B&H's website finds nada for "holophone" beyond this article and one other reference to the Neumann pro "maniken" artifical head microphone system (similar to B&K's Kemar system).

Such an article is designed to pique interest in the product, but B&H doesn't have it yet listed in their on-line catalogue!?!??? So what's really the point if you can't figure out where to get one to evaluate! Seems to me if you wish to pitch a product, it should be available to purchase from suppliers, not extolled as what turns out to appear to be "vaporware".

Aha! I stand correctped! 

A Google search for "Holophone Portamic 5.1" finds it on B&H at a price of $898.95. But there's little technical information or specifications provided at B&H.

The article has a link directly to the B&H product page for the PortaMic 5.1.  I'll post it again, just in case.

http://www.bhphotovideo.com/c/product/663096-REG/Holophone_PORTOMIC_5_1_PortaMic_5_1_Camera_Mounted_5_1.html#features

If you click on the "Specifications" tab on that page, you'll find a healthy dose of tech specs.

If you're interested in other Holophone mics that we carry other than the PortaMic 5.1, you can check out the following link:

http://www.bhphotovideo.com/c/search?Ntt=holophone&N=0&InitialSearch=yes

From your search results, it sounds like you ran a search of the Insights blog page, and not of our store page.  Definitely make sure you're browsing the proper area.  If you type a search into the blog, it will only come up with related blog posts, not with our product catalog.  To search for products, you can go to www.bhphotovideo.com by clicking the link at the top of the Insights page.

Can this mic be used for nokia lumia 920?

Hi Peter -

This Holophone mic cannot be used with a smartphone. They will not accept a standard stereo mic input on a 1/8" (3.5mm) TRS connector.

Please contact us via e-mail if you have additional questions:  AskBH@BandH.com

Hi,I have sony HDR-XR 160 camcorder which captures audio dolby but also 5.1.this microphone is suitable for this camcorder for capture  both dolby and 5.1?Thank you

Hi POPI -

This mic will work with your SONY CX-160 camcorder.  It does not need the camera to be enabled for Dolby or 5.1 recording.  Please note that this microphone has been discontinued for some time and is no longer available at B&H.  Here is the new, improved replacement:

The Holophone PortaMic 5.1 Pro Surround Microphone provides prosumer video camera users with a simple, yet professional means of capturing audio in true 5.1 surround sound. The PortaMic 5.1 operates on a 9V battery and features an elliptical shape that mimics the acoustical properties of human hearing.

Up to six individual microphone capsules effectively capture left-front, right-front, center, left-rear, right-rear and sub channels. A built-in Dolby ProLogic II Encoder automatically encodes discrete audio for stereo output using the included unbalanced stereo-mini or balanced stereo-mini XLR output cables.

Audio can be decoded back to discrete 5.1 channels in post-production using Holophone D-Code or any Dolby ProLogic II decoder. A 12dB pad switch maximizes headroom and minimizes noise and peak distortion when capturing transient-rich and excessively loud audio signals.

The microphone is built for quick, plug-and-play operation and its built-in camera shoe and low-profile design provide exactly the right combination of familiarity and ease of use expected by professional and consumer camera operators alike.

5.1 Capturing and Encoding
Up to six individual microphone capsules effectively capture left-front, right-front, center, left-rear, right-rear and sub channels. A built-in Dolby ProLogic II Encoder automatically encodes discrete audio for stereo output using the included unbalanced stereo-mini or balanced stereo-mini XLR output cables.
Decode Audio Back to 5.1
Audio can be decoded back to discrete 5.1 channels in post-production using Holophone D-Code or any Dolby ProLogic II decoder.
Portable Design
The microphone is built for quick, plug-and-play operation and its built-in camera shoe and low-profile design provide exactly the right combination of familiarity and ease of use expected by professional and consumer camera operators alike.
9V Battery Powered
The PortaMic 5.1 is powered with a standard alkaline 9V battery.

Please contact us via e-mail if you have additional questions:  AskBH@BandH.com