Ladder Filter Drive Only Working in Duo-Split Mode?

[SentientMachine]

I think I may have just stumbled upon an issue, and I'd love if someone else can verify this for me.

Basically what I'm noticing is that the Ladder Filter's Drive knob is WAY more apparent in Duo-Split mode.

To test it out like I did set all the ADSRs to the same setting with Sustain at 100% and no attack, and only use VCO 1 set to a Sawtooth wave and assign it to the Ladder Filter. Turn VCO1's mixer up to like 3 o'clock. For VCF2 you can just open the Cutoff completely and keep the Resonance at 0. Make sure the Brute Factor is also at 0. Put the filter in LP 24db mode.

Now switch between Monophonic and Duo-Split modes while playing and sweeping the Drive knob. Even with the Drive set to 0, I'm hearing a slight volume boost and timbre change between Monophonic and Duo-Modes.

[sahmb]

I just did this and it's the same for me. In monophonic mode with the same settings, I get slightly lower volume and the drive knob pretty much doesn't do anything, in duo-split however, the drive knob clearly makes the sound brighter when turned up and a bit louder.

Hmm, strange behavior, especially about the drive knob. I always wondered why in a a lot of situations drive didn't do much to change the sound. Now I know, it's because I rarely ever use duo-split mode... Surely this is not by design?

[DrJustice]

It's like that on mine too. There's no such effect on the Steiner Parker.

The Drive knob doesn't really make the sound brighter though (louder can be perceived as brighter). The lower harmonics get a greater increase than the higher ones, depending on the waveform - a 6dB increase for the fundamental, and somewhat less for the upper harmonics. I checked with saw, square and triangle using a spectrum analyzer.

The difference in loudness between mono and Duo Split, with Drive at minimum, appears to be ca. 3dB, with an increase in level of less than 0.5dB when using the Drive knob in Mono mode.

[SentientMachine]

Thanks for confirming with some more concrete data DrJustice. Are Arturia aware of this issue already or do we need to create a support ticket?

[DrJustice]

I've submitted a ticket, suggesting giving the same range of Ladder Drive in Mono/Paraphonic modes as in the Duo mode - if possible via firmware (I suspect it is...). The overall level difference of 3dB doesn't bother me too much, but more Drive range would be welcome. If you guys want this too, submit tickets to support it.

[SentientMachine]

Will do. After experimenting with the Drive in Duo-Split mode it made me really wish it was available in Monophonic mode lol. I didn't realize there was a whole range of warmth and grit I was missing out on with that filter!