A literature review of psychoacoustics and a review (both historical and current) of surround sound systems is carried out. 3-4 with clean microphones may be useful if a more flat and omni directional frequency response is needed.This thesis describes a system that can be used for the decoding of a three dimensional audio recording over headphones or two, or more, speakers. 2 has a more front-back symmetric pattern with a high midtone boost for sound coming at 90 degrees. 6 shows the most promising behavior for nature recordings due to the good front side presence and the gradual coloration when rotating towards the back. To avoid this, a sound absorbing material must be used. When the sound comes right from the side, the first negative interference occurs when the distance is equal to 1/4 of the wave length, the following at 3/4, 5/4, 7/4 etc. If the material opposite the microphones is reflecting the sound waves, negative and positive interference occurs (comb filter). The surface material of the dummy head is very important and can potentially have a high influence on the received directional response. I believe this should give a good directional sensation. This setup has good reception from font angles and gives a fine coloration as the sound is turned around. Clean microphone placed at the side with a distance of 2.2 cm to the side walls. Here the dummy head has blank textile top layer. Clean microphones, blank textile 2.2 cm from surface The varying parameters are the distance between the microphone and head, different horn addons, and different materials on the dummy head.ġ. The charts below show the results for different dummy setups.
#Binaural sound recording techniques pro#
Again, the post processing was done using CoolEdit Pro to generate a spectral view, which following was converted into polar coordinates in GIMP. Noise was sent out by a speaker 78 cm away, and the setup was rotated 360 degrees in 60seconds. The images above show a typical test setup which can rotate keeping the microphone tip at the rotation axis. The microphone is placed outside the center o the head when seen from the side. On the pictures above an additional collar of fibers is added to further reduce reflections. Different types of top layers can be applied to get a desired acoustic effect.
The dummy is constructed using a yarn bobbin of the same size of a human head, covered with a textile top layer. Top view of the dummy head with one microphone to the left So my approach is to use a combination of a horn addon and a dummy head. Music – will need quite linear lower frequencies, maybe with a bit of warmth.High frequency, ultrasonic recordings – will need linear pickup from +15kHz and up.Long distance recordings – will need HF lift.The frequency response may be optimized depending of recording situation being Directional coloration to emulate back, front, up and down sensation.Delay effect between each channel corresponding to effect with human ears.The overall objectives can be broken down into a set of stereo imaging and frequency response issues: A lot can be read, and a good place to start is wikipedia: We are in the field of binaural recording techniques. Adaptable for various recording situations.Good stereo imaging in headphones, but also usable with speakers.Good and clear pickup of sounds from the surroundings.Getting closer to the final aim of my investigations, this post will present some investigations on combining the microphone horn addons with a dummy head to form a quasi binaural recording setup.
0 kommentar(er)
