Paragraphic Bump

[Marc Hildebrant]

Group,

In a multifilter, I am using two Paragraphic filters with the low frequency shelf turned on. When I run this multifilter, I find that a "bump" of large amplitude is created at the beginning of the destination file that wasn't present with the source.

I'm not sure if this large "bump" is produced under other conditions, i.e. just one Paragraphic filter alone yet.

Maybe others can check it out.

Marc

[Craig Maier]

Hi,

I just checked it out and verified that this produces a transient in LF shelf mode. It does it not only in the multifilter, but as a stand-alone filter too. We will check it out.

Craig

[Marc Hildebrant]

Update...if this filter with the low frequency shelf turned on, is placed after the Dynamic Noise filter (Multifilter arrangement), no "bump" at the beginning occurs.

Marc

[Craig Maier]

Hi,

One thing that I know is that the low frequency shelf in the paragraphic eq goes down to DC. When used, it may need to have a HPF in front of it (maybe set for 15 or 20 Hz). Why is this HPF not included in the paragraphic LF shelf setting? Some folks in the scientific world (vibration analysis, seismic analysis, etc) do not want anything but a pure shelf.

Craig

[Craig Maier]

Maybe we should consider adding a HPF checkbox to the paragraphic EQ which could be set for 10 Hz (1st Order) so that it does not respond down to zero Hertz. Its something we could consider. Thoughts?

Craig

[Marc Hildebrant]

Maybe we should consider adding a HPF checkbox to the paragraphic EQ which could be set for 10 Hz (1st Order) so that it does not respond down to zero Hertz. Its something we could consider. Thoughts?

Craig

That would make sense to me.

Marc

[Dan McDonald]

Good idea. I have seen the bump before. Although I think I'll miss hearing some of that 8 Hz bass notes.. Come to think of it, I miss hearing those now!

[Craig Maier]

Lol - and I will really miss those 5 Hz notes too. Come to think about it, won't we all miss hearing that dc component?



Craig

[Craig Maier]

I have confirmed that the bug (thump) is related to the shelf function alone. It could be either an initialization issue or the transient response of the pole-zero pair, especially since its response extends down to zero Hertz (dc). Will have to look into it deeper. Stay tuned.

Craig