How much do filters/eqs adjust phase??

[martian]

its something ive never really listened for. i understand vaguely what linear phase filters/eqs do, but just wondering about all other 'standard' filter/eqs.

1. is the adjustment in phase proportional to the size of boost/cut?

2. which type of eqing/filtering affects the phase the most?

3. is the phase always altered in the same way, ie. highs slow down/speed up relative to lows, or not like that at all?

thanks

[Christian Budde]

its something ive never really listened for. i understand vaguely what linear phase filters/eqs do, but just wondering about all other 'standard' filter/eqs.

Download a) VST Plugin Analyser and maybe b) posihfopit (any other >simple< EQ will also work).
Load the according dll in the VST Analyser. Select the FFT Analysis tab and check phase (the units are -180° to +180° on the right axis). Now hit 'analyses'
With a simple EQ, you will get 2 flat lines (magnitude and phase).
Now open the GUI ([CTRL]+G) and modify the EQ. Hit 'Analyse' and see what happens. Now modify the Bandwidth\Q\Slope. Notice how the phase change gets more narrow and notice, that the max amount of phase change depends on the order of the filter (e.g. 90° for a biquad).

Regards,

Christian

[Christian Budde]

Oh, i forgot:

1. is the adjustment in phase proportional to the size of boost/cut?

To the 'size' in the sense of bandwidth/Q/slope, not in the sense of gain.

2. which type of eqing/filtering affects the phase the most?

The order of the filter controls the ammount of affects. A 48dB/Okt-filter affects it 8 times more than a simple (biquad) EQ Boost cut filter (usually found in your DAW).

3. is the phase always altered in the same way, ie. highs slow down/speed up relative to lows, or not like that at all?

The phase change is independent of the frequency, if it is that, what you mean.

[martian]

thanks!

i got your vst analyser prog, and doing some tests.

i see how the phase is affected mainly by the bandwidth and less but still altered by the size of boost/cut, also how it occours around the area being adjusted instead of at the extremes of the spectum.

so how do analog eqs adjust phase then? more or less in general? and what kind of phase changes are considered nice?

your analyser prog is quite unstable here though. if i import sx's Q then the behaviour of the gui's graph when moving parameters is quite unpredictable, doest really work at all if you try to engage 'cut'. but this behaviour doesn seem to affect the analysis results which seem correct for the chosen values. also loading up hydratone makes the app disappear completely, maybe doesnt like convolution based stuff?

then often when trying to load another plugin i get an error message, so doesnt work unless i restart.

also the gui parameters opperate in a rotary mode, which is quite anoying, linear would be much better.

finally, is there a way to add more verticle lines to the log graph, so i can see the freqs between 10(1), 10(2), etc, clearer?

thanks, will fiddle further.

[Christian Budde]

thanks!

i got your vst analyser prog, and doing some tests.

i see how the phase is affected mainly by the bandwidth and less but still altered by the size of boost/cut, also how it occours around the area being adjusted instead of at the extremes of the spectum.

so how do analog eqs adjust phase then? more or less in general? and what kind of phase changes are considered nice?

your analyser prog is quite unstable here though. if i import sx's Q then the behaviour of the gui's graph when moving parameters is quite unpredictable, doest really work at all if you try to engage 'cut'. but this behaviour doesn seem to affect the analysis results which seem correct for the chosen values. also loading up hydratone makes the app disappear completely, maybe doesnt like convolution based stuff?

then often when trying to load another plugin i get an error message, so doesnt work unless i restart.

also the gui parameters opperate in a rotary mode, which is quite anoying, linear would be much better.

finally, is there a way to add more verticle lines to the log graph, so i can see the freqs between 10(1), 10(2), etc, clearer?

thanks, will fiddle further.

I've just uploaded a newer version. Should be more stable. Especially i have fixed the graphical issues. Hydratone for example loads fine here.

Regards,

Christian

[duncanparsons]

I can never get the analyser to work Christian. I have asio4all installed, load up a VST and the dynamics and FFT always show a blank line..

Do you have any usage tips?

DSP

[Christian Budde]

I can never get the analyser to work Christian. I have asio4all installed, load up a VST and the dynamics and FFT always show a blank line..

Do you have any usage tips?

1. Download the latest version
2. Use posihfopit just to make sure it isn't the plugin which may cause the problem
3. Check VST Settings (VST->Settings)
4. Load Plugin (with the latest version you can drag&drop the xyz.dll directly on the form)
6. show GUI ([CTRL]+G) and change something.
5. go to FFT (best in case of posihfopit)
7. leave everything unchecked except 'magnitude'
8. hit 'analyse' (maybe twice if needed)
9. explore the results

Hope this is useful. Regards,

Christian