5.1 recording of environment

[WmAx]

I really doubt I could go and record a symphony orchestra or a large choral work with that Behringer.

Actually, yes you can, and people have.

It has a significant dynamic range, btw. While a waste of it's potential IMO, it's actually become rather popular for drum overhead micing - where it has no problem capturing the 130+ db peaks from a live drummer.

The Nueman you linked has a poor response graph (talk about colored recording) - and in reality it's response is probably much worse. Manufacturers like to use pressure response measurement + very heavy smoothing of the response chart = non-realistic response. I have measured many microphones and it's rare they come close to the manufacturer's pretty and smooth graphs. Now, you could use that Nueman to make accurate recordings; one just needs to measure it's actual acoustic response and then apply a compensation filter to negate the coloration - which is what I would do if I used that unit.

I measured a very low noise large diaphgram mic of similar style of that Neuman made by Studo Projects (Model C1), which has a very similar response as compared to that Nueman, but it's far lower in price.

As for the Earthworks - that has nothing to do with the B5. The B5 has a larger diaphragm capsule (and thus lower noise) than the Earthworks mic you linked, which has a very tiny capsule.

I'm afraid the days of high priced mics needed to make very high fidelity recordings is over....

-Chris

 

[Paul_Apollonio]

Hey guys,


I have a small query and didn't know where else to post so... what sort of setup would I need to record the environment in 5.1

I mean I know that 5.1 is just panned channels and that the .1 is the LFE channel but if I were to place 5 mics in the appropriate positions like a star, what other equipment would I need to record as well as how can I get the LFE recorded? I want to record the rainstorms here in Calgary but want it in 5.1 (I find the sound of rain soothing including the thunder)...

Thanks

Grinder,

A few weeks ago I went to downtown LA and visited with Tom Holman (THX, 5.1 etc). If you look on the Audyssey website, you will see the results of the research done at Audyssey, based on the results out of the Immersive Audio laboratory at USC. Do not worry about the 0.1 channel, you can derive that from the other channels, so no seperate recording for low end is needed. Based on what Tom Holman has said, I would think you would want left, right, (each at 30 degrees) wide left, wide right,(55 to 60 degrees) surround rear (180 degrees). Zero degrees in on center front. Center can be derived from L+R. Lots of good info on Audysseys website. - Paul A.

 

[slisgrinder]

Thankx...I have been on their website but for other reasons, the Behringer B-5 looks tempting but first I need to get the theoretical fundamentals burned into my head...

Oh and please continue any discussions openly here as I am slowly learning from it so please don't be discouraged...

 

[WmAx]

It would probably be ideal to build an isolation jig to reduce cross channel information to each microphone. You could build this by starting with a star shaped ply wood or MDF structure. Perhaps each wall should be at least 2', and 2' high, and the walls should be covered with 3"-4" of high density fiberglass or rockwool (4-8lb/ft^3 density) to remove all reflective ability of the walls, thus have them act only as cross channel isolators.

-Chris

 

[ingvar]

slisgrinder,

From what your project seems to be, I would suggest you buy a camcoder which can record 5.1 surround sound. Check out the newer full HD camcoders which often support 5.1. I just used one to record a play here locally and watch it with just regular Logitec 5.1 speakers on my computer (100 CAD at futureshop (I'm in Canada too)) and feel like I'm sitting right in the audience.

I don't see your robots running around with 20k recording equipment...

I would imagine this would be sufficient for your study, plus you get the side benefit of a video
You'd be looking at something like this:
1. Take your 5.1 camera out for a trip.
2. Transcode the MTS file to get just the audio. (Check if ffdshow can do it. Winamp can stream to wave file, but haven't tested 5.1 with it yet)
3. Download the beta version on Audacity (ver 1.3.8 beta as of Aug 12, 2009)
4. Go to edit -> preferences and under sound output choose to allow 5.1 export (default is to mix everything to 2 channels)

If you are running Windows Vista, you may need to install a driver as Microsoft quit implementing DirectSound on Vista.

Open DirectSound on Wikipedia and look under Windows_Vista

I have a realtek soundcard and installed Realtek's "3D SoundBack" and added VLC and Winamp as applications and get full surround sound.

You might get a full setup for 500 CAD with this approach (just the Camera).
Audacity is free.

If you want a more professional setup, consider getting a few of those "Behringer B-5. $80-$90 each" microphones mentioned earlier and buy a little home mixer with a SD card or hardrive. If you get one using 12V, you can easily plug it into your car. With the ignition off, the car battery should supply a pretty decent and noiseless power too. These are fairly inexpensive and can record WAV files with one track for each channel. These can then be opened with Audacity. Read a few documents out there about positioning the microphones and connect them all to this little mixing board.

Example of a mixer: samsontech.com/products/productpage.cfm?prodID=60
Samson MDR6
Disclaimer )) I don't know anything about the mixer above. I just googled "small audio mixer".
The sub channel can be added by mixing all other channels and running it through a proper low pass filter in Audacity.
Download a 5.1 demo wave file somewhere to open with Audacity to see what they look like if you feel like. Simply just 6 channels....

How's the robot comming along?

Check out this: www dot holophone.com/products_h4.html

The pro-s on this forum might get after me for setting you up with something which will create a non-concert-quality-result, but that seems sufficient for you, though.
Bear in mind that it is important that you have the right kind of microphone as they need to have the correct pickup pattern for sound. No use having a front pickup microphone if it listens just as much to the back as to the front anyway... See en.wikipedia.org/wiki/Microphones

Have fun!

 

[alexsabree]

Wait... You have a camcorder that can record 5.1 surround sound?

You mean not only does it record HD Video, but it also has 5 microphones mounted on all of its sides? .. for $450 USD?

 

[slisgrinder]

no, its processed surround sound. i don't know the specifics but its not "real" surround sound. i have an hdr-sr1 from sony...and no i would not have $20000 worth of equipment on a robot, but if i could figure out how to get 5 signals from 5 differeny mics and transform that to surround sound signals, that would pretty much solve my problem...