D-Verb: Hi Cut vs. Low Pass

[nathanjb]

I've always been perplexed by the inclusion of both a high cut and a low pass filter on the Digidesign D-Verb plug-in. I know there must be a subtle difference, but it seems to me that they both do essentially the same thing. Does anyone know why they would include both?

Thank you for your help,

Nathan

[DAS]

They work differently. I haven't confirmed this, but believe it to be true.

The Low Pass filter acts on the signal before it enters the reverb. The Hi Cut filter acts on the reverb signal as it regenerates. This causes the hi frequencies to decay faster than the low ones, which helps simulate how a reverberant signal actually decays in most acoustic spaces.

[dpd]

^^^ thanks! Although I despise D-Verb (that little sucker is one unstable plugin - on LE, at least) I have always wondered what the difference was.

Let's see, a Low Pass filter passes low frequencies and rolls off high frequencies past the 'cutoff' frequency.

A High Cut filter is just another name for a Low Pass filter. Why couldn't they just say Low Pass (pre) and Low Pass (post)?

[DAS]

It's not as simple as just being "post." It's in the regeneration path of the reverb signal. It doesn't just filter the final output. This is why it is just called "Hi Cut," that's (supposedly) a clue that there's something more to it.

In old Lexicon products this property is called "rolloff." Yes, that is much more helpful. ;-)

[dpd]

It's not as simple as just being "post." It's in the regeneration path of the reverb signal. It doesn't just filter the final output. This is why it is just called "Hi Cut," that's (supposedly) a clue that there's something more to it.

In old Lexicon products this property is called "rolloff." Yes, that is much more helpful. ;-)

Oh - gotcha on the signal flow. thanks! Still, so why not call a LPF a LPF and simply state where it is located in the flow?

[DAS]

Oh - gotcha on the signal flow. thanks! Still, so why not call a LPF a LPF and simply state where it is located in the flow?

Yeah, I'm not sure how to do it in the six to ten characters available in the user interface. I think this is explained in the manual somewhere (though I could be wrong about that -- I don't think I ever read it. I sort of figured this out based on use and past experience.)