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Hi !
I have little experience with time filtering ,ad i'd very much appreciate some
input. So here's the deal:
I'm trying to enhance audio with some non-linear processing
so basically I have an audio extract that i cut into 
50% overlapping frames.
Subsequently, i window each frame by a smoothing window.
then I bandpass each frame F with an IIR filter (order N) using the function
'filter' producing an output P, apply some more processing to P that doesn't add
any delay, and after that i bandpass P (using another IIR order N with the same
order N). producing an output Q.
 Now the thing is i want to add Q to the original frame F, so delay compensation
is involved. The trouble I have with the above processing is: 
-How do I perform delay compensation ?
what i did was something like :
final_output = [Q(delay+1:end);zeros(delay,1)] + F where F is the original 
input...
-My bandpass IIR filters have changing caracteristics, ie the the cutoff
frequencies F1 and F2 changes from one frame to another. Could this be the main
source for artefacts ?
By the way do I really need to multiply by a smoothing window ??
thank you very much, any help is appreciated

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   Hello,

   Is this delay coming from IIR filter?=A0 If so, filter=20=20
your=A0sequence=A0with the same filter but=A0first reverse the sequence.=A0=
In=20=20
this=A0case you=A0will have zero phase IIR filter=A0so no delay will be =
=20
involved.

   BR

   =A0

   =D6=E8=F2=E0=F2 =EE=F2 d...@yahoo.fr:

> Hi !
> I have little experience with time filtering ,ad i'd very much=A0=20=20
> appreciate some input. So here's the deal:
> I'm trying to enhance audio with some non-linear processing
> so basically I have an audio extract that i cut into
> 50% overlapping frames.
> Subsequently, i window each frame by a smoothing window.
> then I bandpass each frame F with an IIR filter (order N) using the=A0 =
=20
> function 'filter' producing an output P, apply some more processing=A0 =
=20
> to P that doesn't add any delay, and after that i bandpass P (using=A0 =
=20
> another IIR order N with the same order N). producing an output Q.
> =A0 Now the thing is i want to add Q to the original frame F, so=20=20
> delay=A0 compensation is involved. The trouble I have with the above=A0 =
=20
> processing is:
> -How do I perform delay compensation ?
> what i did was something like :
> final_output =3D [Q(delay+1:end);zeros(delay,1)] + F where F is the origi=
nal
> input...
> -My bandpass IIR filters have changing caracteristics, ie the the=A0=20=20
> cutoff frequencies F1 and F2 changes from one frame to another.=A0=20=20
> Could this be the main source for artefacts ?
> By the way do I really need to multiply by a smoothing window ??
> thank you very much, any help is appreciated
>

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