32-bit float

[redscreen]

The final render device is a computer with a good soundcard.
(and sometime CD).
And I want all my files stay 44khz/16-bits uncompressed wav format.

I was just surprised to have to apply a "noise shaping MBIT+ dithering" while the original imported file is already 16-bit.

[pandy]

The final render device is a computer with a good soundcard.
(and sometime CD).
And I want all my files stay 44khz/16-bits uncompressed wav format.

I was just surprised to have to apply a "noise shaping MBIT+ dithering" while the original imported file is already 16-bit.

Any processing on 16 bit is automatically preceded by up conversion (probably can be turned OFF) to higher bit depth then at the output there is no longer 16 bit thus question about reducing bitdepth seem to be justified.
If results will be converted directly to analog signal without any additional processing then go for noise shaping.

[redscreen]

another thing regarding resampling: what exactly does filter steepness mean? I read this: "Higher steepness will reject unwanted frequencies but cause more ringing in the time-domain and a higher CPU load".


So what would be the best filter steepness value when downsampling from 96khz to 44.1khz ?
I use iZotopeRX2 and the default value is "32".

[pandy]

So what would be the best filter steepness value when downsampling from 96khz to 44.1khz ?
I use iZotopeRX2 and the default value is "32".


http://sox.sourceforge.net/SoX/Resampling

[redscreen]

http://sox.sourceforge.net/SoX/Resampling

This is a link for "SoX" software, but not for "iZotope RX 2".
And I use iZotope RX 2.

[pandy]

This is a link for "SoX" software, but not for "iZotope RX 2".
And I use iZotope RX 2.

Check provided link carefully - there is explanation and additional link with comparison also with iZotope.

But overall difference is related to difference between IIR and FIR filters.

[redscreen]

Thank you for your link if it answer my question.
But I really don't understand the graph.
I just want to know "the" good value for filter steepness in iZotope SRC.
Better 32, 200, 2000 ?...

[pandy]

Thank you for your link if it answer my question.
But I really don't understand the graph.
I just want to know "the" good value for filter steepness in iZotope SRC.
Better 32, 200, 2000 ?...


Better for what? - everything is variable and depends - there is always tradeoff between pass band and stop band - as i don't have iZotope (it is to expensive for amateur like me) i can only do educated guess based on what i've seen on http://src.infinitewave.ca/

Seem that higher steepness extend pass band probably at a cost for longer FIR filter (more taps).
It depends only from You but personally i don't see a point to go over 20kHz and i've rather prefer mild settings and i sometimes even distorting signal by some IIR Bessel to imitate "analog" sound.

Make some test - use samples whit different music then judge sound yourself - as always good quality piano and good quality harpsichord or triangle recordings shows real face of used algorithm.

[redscreen]

Better for sound quality in general !
I want the better sound quality, no matter the timeprocess.
Thank you for all your precision.
But I don't know what is FIR and a IIR...
Yes pass band over 20khz is useless, but is "filter steepness" value affect this ?
Apparently higher value is a good thing, nearer the "ideal" filter.
But apparently also a bad thing with "ringing".
I am really not a professional and I just wonder what valule is ideal.

[pandy]

Better for sound quality in general !
I want the better sound quality, no matter the timeprocess.


If you dont hear difference between settings then you achieve some point where going for higher quality is meaningless

But I don't know what is FIR and a IIR...


Finite Impulse Response - family of filters where usually some window function or windowed (by windowing function) Sinc (sinx/x) funcion is used - those filters are predictable and stable as they not use feedback (opposite to IIR) - they usually can't be recreated with "normal" components i.e. resistors, inductors, capacitors in analog domain (however they can be recreated in analog domain with different processing)

Infinite Impulse Response - family of filters where feedback is used thus they impulse response is infinite - those filters are very similar to "normal" filters created with resistors, capacitors, inductors. Sometimes this filters can be unstable and usually they require very high precision of the calculations to avoid problem with quantization errors.

From your perspective IIR sound more "analog", FIR is quite transparent or neutral (as DSP neutral can be).

https://en.wikipedia.org/wiki/Infinite_impulse_response
https://en.wikipedia.org/wiki/Finite_impulse_response



Yes pass band over 20khz is useless, but is "filter steepness" value affect this ?

Apparently to iZotope yes - with fixed sampling frequency to filter frequencies closer to half of sampling frequency a much sharper - with higher steepness - filter is required - this filter is longer thus more ringing and longer time.


Apparently higher value is a good thing, nearer the "ideal" filter.
But apparently also a bad thing with "ringing".
I am really not a professional and I just wonder what valule is ideal.

Value that satisfy your ears not ears of unicorn...

[redscreen]

I don't hear difference with my current system.
But maybe with another big sound system I will...

Thank you for all this explanation.

And I still don't know what value enter for "filter steepness".

Never mind...

[pandy]

I don't hear difference with my current system.
But maybe with another big sound system I will...

Thank you for all this explanation.

And I still don't know what value enter for "filter steepness".

Never mind...

leave default one or made few experiments to choose one your eye like (probably difference between max and minimum can't be heard anyway by anyone except those that live in Amazon rainforest and they never hear cars and street noise - believe or not but nowadays modern people have seriously damaged hearing abilities).