Vicki:
Which method of producing realistic stereo soundscapes is superior? It all
depends on how you intend to play back your recorded material. Coincident
stereo recordings sound fine when played using a conventional speaker setup.
Binaural recordings, on the other hand, contain the interaural time and
level difference information. This makes for very good headphone listening
and allows for excellent results when speakers are placed more widely, even
straight out to the sides. Also, binaural recordings lend themselves well to
processing with crosstalk cancellers, which I've described in detail in
earlier posts.
I'm clearly a binaural enthusiast, but admittedly there are good arguments
for other types of stereo recording as well, including M/S and
near-coincident techiques. Bernie is an advocate of M/S and has done great
work with this approach. And don't forget the stereo parabolic option, which
addresses the need to home-in on a small portion of the total soundstage.
Remember that one very positive aspect of binaural setups using omni mikes
is that omni mikes are much less sensitive to wind in comparison to
directional mikes. For this reason alone you should seriously consider the
SASS and similar setups based on omni mikes.
It all boils down to what you're after. If you're primarily recording for
the movie industry, you maybe should use M/S because it's pretty standard in
that industry. However, if you're recording for yourself or the production
of CDs, then the SASS or other binaural techiques are very attractive
options, especially if you desire a wide and spacious playback soundstage.
On the other hand, if you want to produce DVDs for people with surround
sound systems, then you face an entirely different set of choices.
So which is "superior"? Well, it depends.
Lang
> Lang, Rich and All,
>
> Your very clear comments on 360 degree sound are much appreciated, Lang.
> And after reading the PDF file mentioned by Walt on boundary mics and SASS,
> I am further enlightened.
>
>> Walt wrote:
>> The SASS and PZM in general is discussed fairly well in the Crown
>> Boundary Microphone Application Guide, which I recommend all who are
>> thinking of making a SASS read. Available in pdf here:
>> http://www.crownaudio.com/mic_htm/mic_pubs.htm
>
> My next question is, how much difference would there be for realistic stereo
> effects, using binaural and omni mics, compared with my present set up of a
> co-incident pair of cardoid mics? Is binaural worth the hassle, is it
> noticeably superior? And could you make a sphere using upholstery foam or
> should the material be more dense?
>
> Vicki Powys
> Australia
>
>
>
>> on 5/2/02 1:09 AM, Lang Elliott at wrote:
>
>> Rich:
>>
>> I think your setup will produce a very nice binaural-like effect, and it is
>> similar in many respects to what you'd get using a sphere setup like the one
>> designed by Schoeps. Really, yours is a simple setup using a barrier to
>> isolate and directionalize the two microphones.
>>
>> While I can't know for certain, the primary weakness will probably be poor
>> imaging (= localization) of sounds off to the sides. The reason is pretty
>> simple. Because of the large size of the barrier and its shape, I doubt that
>> movement of sounds sources straight out to the sides (for example, a sound
>> source moving in a thirty degree arc off to one side) would result in
>> significant changes in the signals arriving at the two mikes. If there are
>> no differences at the mikes, then such subtle movements would not be audible
>> over headphones or speakers.
>>
>> On the other hand, frontal or rear sound sources moving from left to right
>> or vice versa will be imaged much better due to the barrier design of your
>> setup. At least that's my guess.
>>
>> One good way to test all binaural mike setups is to do a "walk around"
>> recording where you begin out front and center, then walk all the way
>> around, talking to the mike all the while. Return to the center, then walk
>> the other way. As you're talking, describe where you are in relation to the
>> mike so that you know this upon playback. In other words, say "front center"
>> when you're at that location. Other positions where you should stop and
>> identify them should be "right 45 degrees", "right 90 degrees", "right rear
>> 135 degrees", "rear center", and so forth. But remember to talk all the
>> time, even when you're moving between positions.
>>
>> Then, depending on your playback techique (via speakers or headphones), you
>> will see how sound sources from all these directions translate into the
>> final listening soundfield, and how well you can image your voice moving
>> from position to position.
>>
>> This simple test will tell you a lot about how the final listening illusion
>> is created, and it's a very good way to test the effects of different
>> speaker arrangements.
>>
>> Lang
>
>>
>> For the best 360 degree binaural, I think that some of you should experiment
>> with sphere setups, using spheres with a diameter of around 19-20 cm (=
>> 7.5"). The Schoeps KFM 6 has a diameter of 20 cm.
>>
>> Of course, the ease with which one can do this depends on the mikes used,
>> and how they could be inserted or mounted inside the sphere so that their
>> elements are flush with the surface.
>>
>> That said, I do want to say that the SASS setup will probably serve most of
>> you better than a sphere under most circumstances. The SASS produces
>> excellent imaging of sounds in the 180 degree frontal soundscape, and also
>> has fair rejection of sounds to rear (which is usually desired). Sphere
>> mikes are just as sensitive to the rear, which will often be a considerable
>> annoyance as such a setup will hear you breathing and swallowing, unless
>> you're at a distance from the mike.
>>
>> With my SASS setup, I usually use a ten foot cable and stand back while
>> recording. This works pretty well unless my stomach grumbles. I actually
>> prefer to use a longer cable, placing myself twenty or thirty feet behind
>> the mike so that I can relax and make my normal creature-noises without
>> worry.
>>
>> Lang
>>
>>> Rich and All,
>>>
>>> Your 360 degree mic set up looks wonderful, Rich. I can't see that the
>>> sound would be all that different to the Schoeps stereo sphere that Lang
>>> mentioned. What sort of mics are you using? I'd love to hear some sample
>>> recordings. Does this set up work best with headphone listening or with
>>> speaker listening? How thick is the foam?
>>>
>>> Vicki Powys
>>> Australia
>>>
>>>
>>>
>>>
>>>
>>>> on 2/2/02 11:12 AM, richpeet at wrote:
>>>
>>>> ok, honest please, no holds barred. Upfront, slam dunk, is requested.
>>>> Here is an outdoor stereo setup. I am not able to see a hole in the
>>>> middle.
>>>>
>>>> I seem to get a full 360 for dawn forest recording and have another
>>>> chunk of foam for a rear block that I can attach for a T with
>>>> coathangers punching through if I want a block in a given direction.
>>>>
>>>> Granted I have no PZM gain which I wonder if it is freq specific
>>>> anyway.
>>>>
>>>> What is the weakness of this system. I can post sample recordings if
>>>> requested as well.
>>>>
>>>> The foam was $3.00. The mics over $600.00. The stand $15.00.
>>>>
>>>> http://people.mn.mediaone.net/richpeet/sounds/foam1.jpg
>>>>
>>>> http://people.mn.mediaone.net/richpeet/sounds/foam2.jpg
>>>>
>>>> I agree I need some polishing but tell me where.
>>>>
>>>> Rich Peet
>>>>
>>>>
>
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