[LAU] Filter arrangement - was- Bitwig: what we can learn from it

[Jörn Nettingsmeier]

On 03/31/2014 03:38 AM, Len Ovens wrote:
> Ardour, nonmixer, jackrack etc. are set up linear, one plugin into the
> next. So if I want to use a lowpass, highpass and bandpass filter, they
> will be one after the other. How will this affect the sound?

not at all.

> Is one way
> better than another?

analog parallel filters can have some benefits wrt signal-to-noise 
ratio, but you need to get the phase alignment right. for digital, it's 
mostly an unnecessary complicaton, unless you are going for effects that 
really require parallel processing (such as upwards compression).

> will they turnout to have the same effect anyway?
> This is hard to visualize in my head and more of my experience has been
> live sound reinforcement than recording.

unless you know very well what you are doing, parallel signal paths are 
full of dangerous pitfalls. a while ago, someone on some mailing list 
brought up the concept of parallel equalising (as in, split the signal, 
filter one half, recombine it with the original). reasoning was, hey, 
parallel compression is what the pros do, so parallel eq'ing must be 
great too, right?
makes no sense, and produces something like this (the blue line is what 
you set your eq to, the red line is what you get when combining it with 
an unprocessed signal):

http://stackingdwarves.net/download/4th-order%20highpass.png
http://stackingdwarves.net/download/4th-order%20lowpass.png
http://stackingdwarves.net/download/Parametric%20Mitra-Regalia.png

morale: anything that introduces group delay shouldn't be used in 
parallel processing unless you know what you are doing.

hth,


jörn


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Jörn Nettingsmeier
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