Gain staging between Synth FX and Master FX

Polyphonic Analog Synthesizer
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Sugar
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Gain staging between Synth FX and Master FX

Post by Sugar » Wed Jan 15, 2020 2:15 pm

I find that the level of Master Effects is very low unless I turn on a Synth Effect as well. Even if a Synth Effect MIX is at 0.
With Synth Effects off, Master effects are barely audible. Is it normal?

soundsubs
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Re: Gain staging between Synth FX and Master FX

Post by soundsubs » Thu Jan 23, 2020 3:35 pm

Make sure you've upgraded to the latest version of firmware, as this has been addressed in code fixes along the way.

Aside from that, see if it changes when set to 100% fully wet.

Sugar
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Re: Gain staging between Synth FX and Master FX

Post by Sugar » Thu Jan 30, 2020 2:30 am

yes, I'm on 1.2.

after more testing here's what I found:

Example A:
- SYNTH FX OFF
- MASTER FX at 10
- VCA at 0
result: fully wet sound through MASTER FX, no dry signal

Example B:
- SYNTH FX ON
- MASTER FX at 10
- VCA at 0
result: no sound

is there a diagram of how this routing is supposed to work?
It looks like MASTER FX @10 works as 100% wet with SYNTH FX and 50% wet without.

vwizz
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Joined: Sat Mar 23, 2013 11:38 pm

Re: Gain staging between Synth FX and Master FX

Post by vwizz » Fri Jan 31, 2020 3:40 pm

After my short tests I found I had no more level issues between Synth FX and Master FX since I updated to 1.2.1 :)

Sugar
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Re: Gain staging between Synth FX and Master FX

Post by Sugar » Fri Jan 31, 2020 11:33 pm

1.2.1 solved the issues! Thanks, guys.

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TabbyCatte
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Re: Gain staging between Synth FX and Master FX

Post by TabbyCatte » Sat Jun 04, 2022 9:37 pm

I've always had this problem, and it has never gone away. I'm currently on v1.5. Any suggestions? Is this something that one of the new calibration routines might help with?

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TabbyCatte
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Re: Gain staging between Synth FX and Master FX

Post by TabbyCatte » Wed Jun 08, 2022 4:00 pm

OK so I spent some more time with this, and I even tried a complete wipe + re-initialization of the user space, with no luck. Here's what I'm seeing - can anyone be so kind as to confirm / deny they are having the same experience? This experiment should only take about 30 seconds and I would be so grateful :wink:
  • Init a patch
  • In mod matrix, assign any source to VCA pan (e.g. random keybed, whatever). Confirm the voice panning is now stereo.
  • Instantiate a mod effect on the Synth (not Master) bus, e.g. Stereo Chorus.
  • Turn the MIX level of this Synth effect to 0% (important).
  • Enable the Synth effect with its ON button.
On my system, two things then happen:

1) The stereo voice routing completely disappears, even though the MIX is at 0%;
2) The gain increases substantially (~4dB), even though the MIX is at 0%.

It's my understanding that neither of those should happen, because according to the docs and various forum posts,, the dry signal -- which is 100% dry in this case -- should always pass untouched to the (stereo) VCA. It is clearly going completely to the Synth effect because the stereo image disappears and the gain gets wacky. Like the OP, this also causes the Master effect to become much more prominent - and in fact is the only way to even get the Master effect audible in some cases.

The Synth MIX level does control the amount of effect that you hear (for example the chorus effect increases when you turn the knob), but the signal path has been completely grabbed by the effect.

To make it crazier (lol): this doesn't happen with Synth delay FX! Only mod FX like chorus, flange, etc. So if you try this, make sure you are using one of those.

Can anyone confirm? If doesn't happen to you, then I can open a ticket.

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TabbyCatte
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Re: Gain staging between Synth FX and Master FX

Post by TabbyCatte » Tue Jun 21, 2022 2:41 pm

I might politely bump this - is anyone getting stereo / gain problems detailed above when using mod FX?

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noisebit
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Re: Gain staging between Synth FX and Master FX

Post by noisebit » Tue Jun 21, 2022 3:57 pm

If you mean the spread function, I can agree. Effect button off and the voices are spreading, with effect button set to on than the spread function fails.

It seems, that the synth drives a mono channel in fx mode going a digital routing 🧐 Is it caused by leaving the analog path?

MO is on 1.5 fw

Hope, this helps, regards Tom
Moog One 16 - NL C15 - Waldorf Iridium - Prophet XL - Access Virus TI2 - 2600 - Prophet 10 D - OB 6 D - Behringer VC 340/Deepmind 6 - Kurzweil PC3K7/2500 - Reason - NI Ultimate - Logic X

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TabbyCatte
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Re: Gain staging between Synth FX and Master FX

Post by TabbyCatte » Tue Jun 21, 2022 9:01 pm

Thanks for having a look Tom - I appreciate it!

The signal entering the FX is mono, the docs discuss this - but what should happen is that when the Synth FX are 100% dry, that drysignal should still pass in stereo to the VCA. I.e. it doesn't make sense to "grab" the dry signal and mono-ize that as well, since by definition it shouldn't even be entering the FX chain.

The weird thing is that it doesn't happen with FX like delays (!) Makes no sense lol. I also still have the other problem the OP mentioned, with the Master FX gain changing with Synth FX on/off.

I have to conclude this is a bug. Somehow it looks like it was fixed for some people in v1.2.1...but not for others.

Thanks again for trying it :)

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