soundfield mics

Anyone got any schems relating to soundfield type mics i.e. tetrahedrall
quartet array.
Steve

You could use 4 amplifiers and record 4 channels. Then decode later. The hard part would be the decode circuit. I know some people are working on decoder plugins.

I saw that somewhere but have lost the ling. I'll keep looking.

Well, the way I want to go is a "All-in-one" hardware solution. Plug ins will come for sure but I want a portable and compact set-up with a mic using electrets, could be a nice DIY project.
Steve

In the raw format, I think it would take six channels of recording:



http://www.soundfield.com/soundfield/soundfield.php

Jakob E.

(edit: No - there's only four capsules there...! I thought it had six..)

:shock: That is Awesome! :shock:

Yeah, I've been fiddling with four Oktava MK219 capsules like that. I've recorded them discretely onto a four track, but I haven't got a clue what to do with those four tracks...

What is going on in the decoder ?

you can find encoder/decoder plugins at

http://www.dmalham.freeserve.co.uk/vst_ambisonics.html

also check

http://www.ambisonic.net/

for lots of info.

Michael

No plugs for me, thanx :twisted:

I've read up on a lot of ambiosonic biz, but I still have no idea how to make an analog decoding of the four tracks.

Encoder schematic:

http://homepage.ntlworld.com/henry0...eap_soundfield_scems/mini_soundfield02-01.pdf

:grin:

Way koool man, thanx! :green: :grin: :thumb:

Doesn't the mic contain electronics as well? Or just preamps?

Anyone else up for this project?

I would be up for it... a project like this has been on my mind for awhile.

I dont think there's any special electronics in the mic, but the capsule array has to be really precise (angles & spacing). That could be the hardest part.

I have alot of ambisonics info piled up at home somewhere, time to start digging through it :grin:

[quote author="mfilter"]Encoder schematic:

http://homepage.ntlworld.com/henry0...eap_soundfield_scems/mini_soundfield02-01.pdf[/quote]

I don't understand that circuit at all.

What are all the input filters for?

Jakob E.

Yeah, I looked at it again, don't get it either :? :?:

Thanx "mfilter". Also found this site this morning. Now we need a pcb genius to produce a layout, anyone up for it?
The mic preamps cold be any four channel mixer with the right hand chunk
of the "B" format matrix or even better pcb's for both.
I have heard a recording of a jam-session (all acoustic+vocals) made with a soundfield mic placed in the middle. The soundstage through headphones was amazing, it had me turning round to look at the player who sounded as though he was behind me.
Ambiosoncs got a bad name when it was confused was Quadrophonic, which WAS crap, but I liked what I heard.
Steve

There's more about the circuit on the page I took that from

http://homepage.ntlworld.com/henry01/cheap_soundfield/cheap_soundfield.htm

That circuit is a UHJ encoder to convert B-format to stereo. I think the filters are to shift the phase of the B format signals before they're combined. Maybe I can find more about that....

Well, when I heard the Trinity Session with the Cowboy Junkies I pissed my pants. Just a mic and a DAT. No fancy audiophile bull.. Oh and that 16 bit record got WAY more dynamics than any 24 bit record I've heard.

I've pondered 'bout buying the SoundField many times. It's really not that expensive. I think it's THE mic for me. I'd rather have one than ten U47s/M49s/C-12s/251s.. really I would.

P.S.
The placing of the capsules is much less critical if you use electrets, as they are small you can avoide phase errors (non coincidence) the bigger capsules need compensation in the phase shifting filters in the encoder.
Fascinating stuff I think.

Steve

I've pondered 'bout buying the SoundField many times. It's really not that expensive. I think it's THE mic for me.

Click to expand...

Same here! It could be my next big non-diy purchase. Luckly diy has been keeping me nice and broke, so I dont have to worry about it too much :green:

I would like to keep this one going if possible. I have no expertise in drawing up PCB layouts but this is an interesting DIY project to build a complete ambiosonic mic and controller to give a Stereo output for recording. Anyone up for it?
Steve