Muff's Modules & More

[Norbert_Noob]

hello all!

im relatively new to modular synths, and am trying to figure out how to patch my system (dark energy+envelope follower) to act as an envelope filter like the mxr m 82 for instance. the objective is to come as close as possible, not to copy the functionality perfectly in detail of course.
maybe somebody can tell me how these envelope filter boxes(m82, EH q-tron, etc) work.

my understanding is that its an envelope follower controlling a filter. i want to get more punch on my bass-guitar and so far i havent gotten the results i wanted, a lot of other interesting stuff though ;].

any kind of help or inspiring words are very welcome!

wiggle on, folks!

[Cat-A-Tonic]

You definitely have the right idea.

I posted sound and patch notes of a modular auto-wah (on guitar) over here:
http://www.muffwiggler.com/forum/viewtopic.php?t=53945

It doesn't use the Dark Energy Low Pass filter,
but a Wien Bridge Bandpass instead.

[Norbert_Noob]

thanks Cat-A-Tonic!

more valued reading is found here:
http://www.geofex.com/article_folders/ecftech/ecftech.htm

...and i already got better results fiddling with the input-signal(env/gate-out)(twas a bit tricky)- its an auto-wah already, but needs more attack/boost. my suspicion is that the definition of my low-cost bass sucks- and that can and should be changed with money ; plus i might have to boost the signal in some way ...

im still curious about other thoughts/inspiration and
will send some audioproof when i get around to it... g'dday y'all!

[felix le chat]

You are right: when it comes to envelope filters (and other things that are controlled by an envelope follower), getting the right levels is highly important.

On the one hand, the electric bass guitar usually has an instrument-level output [unless you have a high-technology active bass with a built-in preamplifier that outputs line level; let's assume you have a standard, passive bass].

On the other hand, modular synths use high-voltage line level signals.

So the first thing you have to do is to convert the instrument level from the bass into high-voltage line level. Search for "guitar into modular" threads on this forum. You can do this with modules, dedicated boxes, mixing desks, whatever. In particular, it is possible to 'break' the conversion into 2 devices, like a preamplifier or computer audio interface that has an instrument input for instrument/line level conversion + a module that boosts the signal (like the the Circuit Abbey Gozinta, or even the Expert Sleepers ES-3 if you use a computer).


Then the envelope follower is of course very important. A good analogue envelope follower can be patched with a rectifier (half or full wave, but it sounds different) and a slew limiter. I prefer slew limiters with separate attack and decay controls. For example, Malekko 8nu8r + Livewire Dual Bissel Generator, or a (single) Makenoise Maths. I personally use the Maths, or a software envelope generator that I developed when trying to reduce the typical "growl" artifact associated to fast analogue envelope generators.
Of course, there are also dedicated envelope follower modules.

The bass, like many other instruments, is quite dynamic, so maybe "most of the time" it will not trigger the envelope follower so much. Because of this, some people use a compressor or a limiter (which has a built-in envelope follower btw). This device should be connected to the follower input only, not to the filter input.


Finally, the filter itself is less a problem because most modular filters have a CV input for cutoff. For the bass, I would recommend a 12dB/oct resonant lowpass filter (try many different resonance settings). You can also check 24dB/oct lowpass filters but from my experience 12/oct was better with bass instruments. Optical filters are usually better because you don't "hear" the envelope sound in the output. That said, some non-optical filters don't suffer from this problem, and this is a lot more bothering when using LFOs instead of envelopes anyway.

Offset and attenuator between the follower output and the cutoff CV input are advisable for controlling the filter sweep range.


You can read more on envelope filters here:
http://elliott-randall.com/2011/06/envelope-controlled-filters/
http://www.beigelsoundlab.com/02.html


Cheers
Flc

[EMwhite]

12db indeed.

I used to have the MXR Bass env filter pedal but parted with it. I've had the Moogerfooger MF101 for ages and have settled into that, sacrificing pedal board space for it.

For me, the 2-pole mode and 'fast' envelope is what the doctor ordered.

The advice above, proper levels such that the envelope amount rise enough is key. Look at it this way. At it's 'base' level, the envelope cuts off a certain amount of highs. The trick is to give enough signal such that the envelope follower pushes the cutoff high enough such that resonance kicks in for that desired effect.

Not sure if my somewhat poor description helps at all but once you get that formula down you'll be golden. On the Moog, there is a light that is green, amber, or red depending on how hot the incoming signal is and that is very handy.

Another thing that might help ALOT is a compressor between your bass and the pedal. I have a Jazzbass with Passive pickups and it doesn't put out much. My Musicaman on the other hand is a monster. So I put a Carl Martin compressor pedal in front of the Fender and bingo.