Mid-side and Open-Source Bass Trap
0. For starter.

http://en.wikipedia.org/wiki/RCA_Type_77-A_microphone

http://www.diyaudiocomponents.com/ribboninfo.php?sub=index

(transinets contain more high frequency energy than continuous sound)

((ribbon microphones are inductive sources (they have output transformers) and such sources tend to be affected by their loads (signal recipients) more evidently then active output circuitry.))


http://en.wikipedia.org/wiki/Harry_F._Olson

1956 Unidirectional Microphone
(Low Cost Ribbon Design) 2,751,441

1958 Directional Microphone
(Using Two Microphones To Increase Directivity) 2,854,511

1. So. For the must.

M/S technique: mid/side stereophony
This coincident technique employs a bidirectional microphone facing sideways and another microphone at an angle of 90°, facing the sound source.

The second microphone is generally a variety of cardioid, although Alan Blumlein described the usage of an omnidirectional transducer in his original patent.

This configuration produces a completely mono-compatible signal and, if the Mid and Side signals are recorded (rather than the matrixed Left and Right), the stereo width can be manipulated after the recording has taken place.


Tying it all together, like , guesswork:
http://web.archive.org/web/20120306035045/http://www.tfpro.com/masterclass.html

Stereo-shuffling:
http://www.audiosignal.co.uk/Resources/Stereo_shuffling_A4.pdf

..in production:
http://www.phaedrus-audio.com/shuphler.htm#crossedfourexplanation

MS-Decoder DIY:
http://www.recordingmag.com/resources/resourceDetail/326.html

(Also)
http://en.wikipedia.org/wiki/Alan_Blumlein#Stereophonic_sound
http://en.wikipedia.org/wiki/Blumlein_Pair


Patents:
Improvements in and relating to Sound-transmission, Sound-recording and Sound-reproducing Systems:
http://www.doramusic.com/patents/394325.htm

THE 'STEREOSONIC' RECORDING AND REPRODUCING SYSTEM:
http://www.phaedrus-audio.com/stereosonic.pdf

2. For a sweet.

Real bass trap:
http://www.ethanwiner.com/basstrap.html

3. Offtop.

ftp://ftp.orban.com/245/245F_Manual.pdf

http://en.wikipedia.org/wiki/Perspecta

4. Next time: eq.