Filter sounding brighter with Envelope all the way up

[Portico]

Hello everyone,

Before writing to support, I wanted to ask here as it's very likely that some of you might have an answer for some strange behaviours I found with my Prophet 10.

1. With an initialized sound, the filter (when all the way open)  gets brighter when the filter envelope amount is at 10. When the filter envelope is at 0 then the filter sounds considerably duller. This is especially true when both Half and Full Tracking modes are off. But even when Full tracking is on, the filter sounds brighter when all the way open when I turn the envelope all the way up.
Is this normal behaviour? Sounds very strange here, I can't remember if the old Prophets did that.


2. When you start from an initialized preset, with tracking modes off, the filter is dull until you either open the filter envelope all the way up or if you go for Full tracking- when you go FULL, the sound is bright as it should but still not as bright as when you turn up the filter envelope. Of course, this is very tightly connected to issue no.1

So my question is, do you also get this behaviour?
Shouldn't the filter open all the way up regardless of the tracking (for high notes of course) and regardless of the Envelope amount?

I have tried searching for a YouTube video but none that I've found does a simple test of the filters from an initialized preset.

Thanks a lot in advance!

[Analog Prophet]

I don’t have the P5 rev 4 where I am at the moment but as I can recall I’m pretty much sure it’s normal.

[Quatschmacher]

Totally normal and as expected on both counts.

[LPF83]

I wasn't 100% sure if the questions were asking about behavior relative to the original Revs 1-3 (in which case I can't provide first hand experience, but I'm pretty sure the filter behavior was referenced against vintage models and calibrated to behave identically).

If you were just asking if the sound is brightest when envelope amount is at max, yes that's standard on any subtractive synth.  One way to think of it is the cutoff value is like minimum brightness level, while envelope amount is maximum possible brightness value, and the ADSR represents modulation stages within the range of that min and max.

Probably the part that seems unusual is that by default an init patch is not wide open, where on a lot of synths an init will give you a saw with a fully open filter.  I've always assumed it was that way because the vintage units did same.

[Portico]

Hi guys,

Thank you so much for confirming! I just wanted to make sure that everything is normal.
I actually have quite a few analogue synths (including an OB-6) and none of them exhibit this behaviour. Then the filter is all the way open, the envelope doesn't make it any brighter if you turn it up.
That's why I wanted to make sure this is the norm with the Prophet 10.