Parametric EQ - HISE_USE_SVF_FOR_CURVE_EQ

[DanH]

As per video below changing the Q doesn't seem to affect the sound or the curve. The High Pass Q changes the curve, but also appears to have no impact on the sound... I just checked a commit from April 2022 and its the same there. Is this expected behaviour? @Christoph-Hart

EDIT - I just checked the source and it states the high and low Passes are one pole filters where gain and Q are not available. So might be best to remove the change in curve for the Low Cut. HOWEVER - This is actually the behaviour that I want for a specific project :face_with_tears_of_joy: (as in the curve responding to Q changes). Could it be possible to get the Low Pass Q to change the curve?

EDIT 2! - I've also just seen (and remembered from awhile back) the option to add HISE_USE_SVF_FOR_CURVE_EQ preprocessor - I assume this changes the one pole filters into the SVF filters... I'll try and rebuild Hise with this flag and see if the curve changes - unless anyone can confirm either way?

[DanH]

@DanH ok using that flag does indeed change the curve of the Low Pass mode. So I guess the curve of the High Pass should ned to be changed for consistency when not using that flag...

Also, and this was a quick test, but now the Parametric EQ sounds very noisy, a load of glitchy noise in there! Is anyone using the HISE_USE_SVF_FOR_CURVE_EQ flag?

[Fortune]

@DanH I haven't used this flag before. But for the standard Parametric EQ, Q doesn't function for High-Pass and Low Pass filters, and this is normal.

I think since this uses Biquad filters, it is normal.

[DanH]

@Fortune yes that's what I figured out, but the curve changes for the High Pass, so it looks like it does something. I guess that it shouldn't...

[ustk]

@DanH what are your ears telling you?

[DanH]

@ustk that using HISE_USE_SVF_FOR_CURVE_EQ makes the Parametric EQ sound horrible!

[Christoph Hart]

@DanH HISE_USE_SVF_FOR_CURVE_EQ just swaps the filter types between the standard biquad ones to the svf ones (so basically the same filters that you have available in scriptnode).

The SVF variants actually sound a little bit different when static, but they don't produce any zipper noises like the biquads do so if you want prefer a smooth sound while dragging around the handles you can enable this.

I need to check again, it's always this problem with compile time flags that are off by default, but last time I used it (for PercX) the sound was perfectly fine.

[ustk]

@Christoph-Hart said in Parametric EQ - HISE_USE_SVF_FOR_CURVE_EQ:

... it's always this problem with compile time flags that are off by default...

Yeah I noticed this strange behaviour too regarding to the default flag state. Like for instance a enabled by default one that has to be forced enabled otherwise it won't work. I reckon it was the FORCE_AUDIO_INPUTS and maybe others...

[Christoph Hart]

Alright, I've tested it and there was in fact a typo in the code that caused the buffer glitch sound. I've fixed it so now it should sound at least as good as the default one :)