Voxengo

Creator: CinningBao (Old forum username, you may re-own it on the Options page.)

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Date: Apr 17, 2005, 3:36pm

Hi,
I just bought HarmoniEQ, and am extremely happy with it, however I noticed something and I'm not sure whether it's a 'feature' or not:

When changing the Quality from Normal to High I notice the orange line changes slightly, from what appears to be 5Khz up - a slight boost is registered, (try this on the 'Acoustic Guitar' preset for a quick example) and the opposite happens when changing from High to Normal.

I hadn't expected this behaviour - is it working as designed?

Cheers

Creator: Aleksey Vaneev

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Date: Apr 17, 2005, 4:46pm

Yes, this slight curve change is unavoidable and works as it should. It's not easy to avoid this.

Creator: CinningBao (Old forum username, you may re-own it on the Options page.)

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Date: Apr 17, 2005, 5:31pm

Thanks Aleksey,

Can you please explain to me, unless it is a secret, how and why this is the result?

Again, thanks

Creator: Aleksey Vaneev

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Date: Apr 17, 2005, 8:16pm

This is caused by so called 'frequency warping' - it's an effect found in digital filters and caused when the center frequency of the filter is very close to the processing samplerate. This can be resolved by increasing samplerate or by using some non-conventional filter design (that's usually not very practical).

Creator: CinningBao (Old forum username, you may re-own it on the Options page.)

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Date: Apr 17, 2005, 9:28pm

Again,

Thanks. I guess, until I start trying to understand DSP, I'll not be able to come up with a more practical solution which doesn't cause this frequency warping.. ;)

Creator: flashco (Old forum username, you may re-own it on the Options page.)

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Date: May 12, 2005, 12:29pm

Thanks

Creator: Aleksey Vaneev

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Date: May 13, 2005, 12:08am

You are welcome... Just want to clarify a bit more:
It warps (folds) when the center frequency of the filter is close to the half the processing sample rate (for 44.1kHz it is 22kHz). So, around this frequency filter changes its shape considerably.

I also want to add that I'm trying to find a good solution to this problem. Hopefully this can be resolved at some point in the future.

Creator: CinningBao (Old forum username, you may re-own it on the Options page.)

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Date: May 13, 2005, 1:29pm

Thanks for explaining those details, and I wish you luck (if you need it) finding a suitable solution.

Creator: Aleksey Vaneev

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Date: May 13, 2005, 9:14pm

Thanks :)