Wavelength

The wavelength "^" of a wave is the actual distance in the medium between the begining and the end of a cycle.

^=V/f

^ is the wavelength in the medium, V is the velocitity in the meduim, f is the frequency in herz.

that is the formal that gives you the wave lenght

and this formal is for the time of one cycle of the wave lenght

T=1/f

exsample- 30hz travels 37.66 feet in one sec and 300 hz travels 3.76 feet in one sec so you can tell that diffrint frequnceys travel at diffrent speeds and get to your ear at diffrent times.

Reflection of sound is another factor you have to deal with when recording or performing. also known as acustiics of a room or area. when recording you have to think about what dirrection the sound is going and what is it going to bounce off of and how it will come back to the mic. these can add unwanted ecko's and reverbs to your recordings. One fix for this is to record into a conner start directly facing a 90 degree conner and move to your right a foot or 2 but dont turn your body to sing or rap into the conner directly. rap into the wall at the same angle you were before this will thou the sound away from you more than right back to you mimimizing the reflection of sound back into the mic.

Diffraction of sound is simmular but diffrent to reflection of sound.
Sound has the inherent capablity around or thought a physical barrier. In other words sound can bend around an object in a manner that reconstructs the orginal waveform in bolth frequencys and amplitude " relative to the size of the obstacle "
So keep barrers away from the mic and if you do have things like a muisc stand look at how the sound will bounce off the stand and adjust acordingly. this also can help you for instance if you want a partular band with then you can set the mic thou a door way and angle the sourse of the sound on the other side of the door way to fit your band with. this acts like at band with filter and minumizes unwanted frequencys.

Phase

A Cycle can begin at any point on a waveform, so its possible to have 2 wave gererators. IN which they reach there peeks at diffrent times and this is said to be out of phase. A Cycle can be divided into 360 Degrees. same as above when i mentioned Frequencys. If you invert one of the two wave singnals at the same points you can cancell eachother out knows as 180 degrees out of phase.

Phase shift is a term that discribes the amout of lead or lag in one wave with respect to another. it results from a time dealy in the one of the waves. For exsample a 500hz wave completes one cycle every 0.002 seconds, If you start with two in phase 500hz waves and dleay one of them by 0.001 seconds (half the period of the wave), the delayed wave will lag the other by one half of a cycle or 180 degrees. The number of degrees of phase shit introduced by a time delay can be figured out by the following formala.

@=At X f X 360

@ is the phase shit in degrees
At is the time delay in seconds
f is the frequnecy in hz
360 is 360 degrees


From the formalua you can see that the amout of phase shit resulting from a fixed time delay varies in direct proporion to the frequency involved. Fluggin in the values of a few diffrent freuences show that for 1 millisecond (0.001) time delay the following phase shits at diffret freuences will occur-
250hz=90 degrees, 500hz=180 degrees, 1000hz=360 degrees, 1500 hz=540 degrees-360 degrees=180 degrees, 2000hz=720 degrees - (2 X 360 degrees) = 0 degrees...... ect


Harmoic Content...
Ok ill try to make this simple as I can....

Up to this point ive talked about single frequnceys of a wave form composed from one sourse such as a intrument or any other source. this invloves mulipule frequnecys and how they relate. ok for exsample Concert A is 440 hz and 880 is a harmonic with 440 hz because it is 2 times the 440 hz frequnecy. So 1320 hz is also a harmonic of 440 hz because it is 3 times 440 hz. so this is also called harmizing. singings do it with notes but it also relates to Frequencys sincy you can use this to get the most out of your relations in notes and cords. Cords are a lil more complex but releate the same way.

and with in this there are 2 diffrent types of wave forms simple and complex simple would be for exsample a square wave or a tiragle or a saw and they all look like they sound. thous are simple cauz they repeat them selfs over and over and never change. Complex wave forms are completly diffrent, there always changing and no pattern is the same like your voice, Your vocal cords are your most dynamic intriment in the world. It can do more than any other man made intrument. SO it geterates only complex wave forms.

You can filter peaks with simple wave form filters kinda like a limiter only it does this in a pattern that stays the same such as a square form.. If you want more info on this ask me.

If you want to know more about Harmoic stuctures and Frequncey Postioning when you record ask me and ill try to help with that too.

Acustic Envelope

the envelope of an acustic signal is composed of 3 sections, Attack, Internal Dyanmics, and decay. The Attack is the manner the sound begins or increases in intensity. Interanal dyammics descrees volume increases, degreases and sustenations after the attack period. and decayis the manner in which the sound ceases or ends.

Like a someone yelling might have i very High amplitude at the Attack and then die down in the Internal Dyanmics and then get a very low amplitude at the decay. Looks simular to a sideways long triangle.

there is also volume and paning envelopes that can be changed in the course of a track or channel in your recording work. thous are pritty self exsplanitory.



Next Ill talk about ...

Sound Pressure Level
Auditoy perception
Cominaton tones
Masking
Perception of direction
Perception of Space

Then we might go inot Studio Acoustics and Design...

aght this is enough for today ... Peace