Week 3

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DATA

Comb Filtering:

Is caused by a wave combining with a slightly delayed version of itself resulting in a constructive and destructive interference.

Common causes of comb filtering are having two microphones at different distances recording the same source, reflections from nearby surfaces and two identical sounds in a DAW up to 10ms apart.

from 0-10ms is comb filtering and 10-30+ ms is a delay.

Odd harmonics cancel and even harmonics reinforce.

Using the formula f=v/λ were f is the frequency v is the velocity of sound (344m/s) and λ wave length (2x meters) you can find the fundamental frequency of cancellation between two microphones.

TASK:

60cm difference between two microphones. f=v/λ | f=344/λ | f=344/(60/100)*2 | f=286.66

Dynamic Range:

The difference between the highest and lowest amplitude of sound: ie throughout a song, humans hearing, sound device can handle different, formats (tape, cd, vinyl).

The dynamic range of human hearing is accepted to be 120dBSPL. Sound amplitude is referred as Pascal (Pa, the unit for pressure). 0dBSPL = 0.00002 Pascals (20 uPa)

120dBSPL = 20 Pascals

Dynamic range of different formats: cassette 50dB, Vinyl 60dB, 16bit 96dB, 24 bit 144dB.

This screen shot talks about how natural reverbrations from the room can make the release tail of instruments longer depending on the recording location in the room.

This image is the result of adding two sine waves 180 degrees out of phase.

This in example of how a sound reflecting off a surface causes comb filtering.

This image is the result of adding to sine waves in phase.

Reflection

What?

What activities have I completed this week?

I watched 3 videos one on the envelope of sound, one on comb filtering's constructive and destructive effect and one on what can cause comb filtering to occur.

So What?

So, what have I learned this week?

I learnt what comb filtering is and what causes it and a way to calculate it. And that dynamic range is the difference in the highest and lowest point in sound.

Am I on the right track with this unit?

I think so.

Now What?

Now what will I do to move forward?

Keep doing my pre and post class work.

Reference

https://youtu.be/Q-ot9AaJx-Y

https://www.linkedin.com/learning/audio-foundations-delay-and-modulation/constructive-and-destructive-interference?autoAdvance=true&autoSkip=false&autoplay=true&resume=false&u=76178842

https://www.youtube.com/watch?v=dQ5DEdO9ELg&ab_channel=MidwestAudioClub

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