Project
NORMALIZER
Copyright (c) 2006 Syed Azhar
By Syed Azhar (Student of SD College (Panjab University), Chandigarh, India)
e-mail: goodluck_azhar@yahoo.co.in
Right Now I am doing B.Sc.(Computer Applications) that is: Bachelor of Science with Computer Applications.
I have tremendous interest in DSP (Digital Signal Processing). These presets are the result of that.
I am very grateful to the Developers of "Nullsoft SPS" for providing a platform for easy "C Style"
code implementation.
What is a Normalizer?
Normalize is a term used to describe the leveling of amplitude of an input signal. If, in case the input is
audio signal then it is used to describe the leveling of the volume of input audio. Any module or
plug-in performing Normalization can be called a Normalizer.
USE IT IF YOU WANT TO LEVEL THE VOLUME
Explanation of terms used in Presets
Gain
It specifies the amount of amplification that it should perform. Suppose if the input signal is very low in amplitude and
+20 dB of amplification is possible, but if you have specified +10 dB then it will amplify the signal to +10
dB only. However allowed amplification can always be achieved but it will lead to noise amplification (if present
in the input signal). So keeping the amplification low, if not required, is a good deal.
Gain Time
It is a time constant. If Gain Time is low, then amplification will take place at higher rate and vice-versa. If
the Gain is high and Gain time is low then fluctuations will be prominent and probability
of clips will increase, instead use high Gain time.
Stereo Handling
You can specify weather each channel should be prosessed indipendently or jointly. Independent
processing can lead to modification of original stereo-image(3D-field) of audio, but is useful
if the input audio is wrongly balanced (i.e. volume in left and right speakers differs signifactly).
Joint Processing is recomended to preserve original stereo-image.
Advance Scaning
It specifies the amount of signal to read in advance, so as to make the amplification "Clip Free".
However "Nullsoft SPS" does not have any function to get the signal in advance, so delay is implimented and
current signal is considered as future signal. Relativity!
Difference between various Presets
Simple Normalizer 1.0
It is the simplest of all normalizers. No Delay. No complex calculations. The only drawback is: if Gain Time is low and Gain is high, and if there is sudden increase in high frequencies, then clip may occure.
Amplification: Exponential (The natural way)
Attenuation: Instant (Clips may occure)
Why? : Use it if you don't want to delay the signal.
Simple Normalizer 2.0
It is again a simple normalizer. but with the following difference:
Amplification: Sinusoidal
Attenuation: Instant (Clips may occure)
Why? : Use it if you don't want to delay the signal and want to use small Gain Time.
Normalizer ( with Clip Protection ) 1.0
It is an advanced normalizer. Delays(Advance Scanning) the signal with specified amount. Higher Advance Scanning, better protection from Clips.
Amplification: Exponential (The natural way)
Attenuation: Instant (But in advance)
Why? : Use it to cut the Clips with less calculations.
Normalizer ( with Clip Protection ) 2.0
It is also an advanced normalizer. But it attenuates the signal smoothly.
Amplification: Exponential (The natural way)
Attenuation: Linear (In advance and Smooth)
Why? : If you are an audiophile, this is for you.
If you have any question, suggestion, etc just email me.