MF 101 LPF question

The Moog Forum Moogerfooger Forum
1

Hello, this is my first post and I hope someone out there in Moogville can help. I just got my MF 101 Low Pass Filter and I can’t seem to get any wah sounds like the manual describes. I noticed that the bypass and level lights work fine and the cutoff section of the pedal works fine, but the envelope light doesn’t go on. I was wondering if you really need to purchase the expression pedal in order for this feature to work ( I haven’t).
I own the Boss wah pedal and I’ve gotten envelope and wah sounds without using any expression pedal and am wondering why my LPF doesn’t do the same. I’ve checked all of my cable connections and they are fine.

Any response or thoughts would be greatly appreciated.
Best Regards

2

Hello,

Although you didn’t state which instrument you are using the Moog filter with, I am assuming its a guitar (please correct me if I’m off the mark).
Based on your description, the enveloped wah (also called auto-wah) effect you refer to from the Boss pedal is possible because the Boss may have an envelope follower circuit in addition to the filter. The envelope follower creates a transient peak, based on your playing dynamics, and this peak
opens and closes the filter cutoff frequency accordingly.
Most wah pedals utilize a bandpass filter circuit.
To my knowledge, the Moogerfooger lowpass filter pedal doesn’t have an internal envelope follower which is what it would require for auto-wah effects, but does have a cv input so that it IS possible to manually control the filter cutoff frequency manually from the Mooger expression pedal or from an external envelope module.
Hope that helps.

regards,


LWG

3

Hello again,

My apologies for the previous post, as I use the Voyager synth and do not have the filter pedal, I had a chance to eye MF-101 page for the pedal and it does have an envelope follower. This is good.
You may first want to check the settings on the pedal. Even if you have the
envelope amount set sufficiently high, you won’t hear that much of a difference if the initial filter cutoff os set high also.
Given this, you may want to first set the initial filter cutoff frequency to a low value and the envelope amount to a fairly high one. Try adding resonance to about halfway. Based on these settings, if everything else is cool hardware-wise, you should be able to hear the auto wah effect.

regards,


LWG

4

Hello -

The envelope follower in the MF-101 produces a voltage that corresponds to the loudness of the signal at the input.
The envelope light indicates the strength of the envelope follower - it is your best indicator of how much “auto-wah” effect you will be able to acheive.
There are two things to consider that will affect the strength of the effect:

  1. The setting of the Drive level. This should be set so if you play hard, the Level LED should go a little into the red. Experiment with setting the drive control while you play and watch the Envelope LED - it should light up more and more as the Level LED goes from green to yellow to red. Your average level should cause the Level LED to light up yellow.
  2. The tone of the signal going in - because you are running your sound through a lowpass filter, and a lowpass filter removes high frequencies, you will hear more effect if the sound going into the filter has lots of high frequencies to begin with. For guitars, this means tone control up, and a little overdrive or distortion in front can make the effect stronger.
5

Thank you all so much for your quick responses, they really helped.

I didn’t realize what I was doing wrong until after I posted, now see it’s kind of a dumb question.

MoogMusic you hit it right on the head. My input signal wasn’t strong enough, I was playing too quietly. You have to turn the Drive and Amount knobs full and up the volume on the amp a bit to hear that effect. Although I was only following the directions in the manual for Screaming Dynamic Wah where it says Amount 6. You need much more than that (or maybe it’s just my gear).

My one quibble. Why is it required that you play loud to hear the effect ? Shouldn’t you be able to hear and play it at, let’s say, the volume of your TV set ? Is this the way it’s supposed to work ?

All in all a great piece of equipment !! Fantastic sound. Also bought the Ring Modulator and I can’t say enough good things about it !! If any of you guitarists don’t own it, forget the cost, just buy it, you only live once. You can get sounds like Keith Emerson on Brain Salad Surgery. Amazing. And the TRACKING IS EXCELLENT. Which is an issue that’s important to most guitar synthisists and which oddly enough, I haven’t seen discussed on this forum.

Thanks again for everyone’s advice !
Best Regards
Tony
NYC

6

I don’t know that any of the Moogers require tracking. The ring mod maybe? Let’s discuss.

How does the ring mod work exactly? There is a carrier signal and the frequency of that signal and the frequency of your guitar are added and subtracted from each other so those frequencies are also itroduced?? I’ve never fully understood how it works. So is the ring mod “tracking” the frequency of the guitar? Does the mooger do this better then other ring mods?

7

I’m certainly no expert, and I’m probably wording my description wrong. I simply mean that when you play a rapid succession of notes, the ability of the pedal to issue the proper output instantaneously.
For ex, I have a Digitech synth wah which is a good pedal with interesting sounds but it tracks poorly. If I play a really fast scale which contains 10 notes, I’ll hear maybe 6 or 7 of them. With the Ring Mod no matter how fast I play, each note is heard loud and clear and in time.

8

In this context, tracking can be thought of as a device quantifing an external signal and using it to drive something else.

The MF101’s (Lowpass Filter) envelope folower is tracking the input signal’s level and turning it in to control voltage that has normalized connection to the filter’s cutoff. Really, the 101 is two modules in one box: an envelope follower and a lowpass filter.

The MF102 (Ring Mod), doesn’t have a envelope follower - it isn’t really tracking anything. The frequency of the ring modulation or the amount of ring modulation isn’t controlled by your instrument’s output. If all the knobs are left in the same positions, the character of the ring modulation will be the same regardless of what you feed into it.

If you have both the 101 and the 102, you can try this:

Connect your guitar to the 101’s input

Set the Mix on the 101 (to bypass the filter) to 0 and set the Amount to 0 (for the moment…)

Connect the Audio Out on the 101 to the Audio In on the 102

Connect the Env Out on the 101 to the Frequency input on the 102

On the 102, set the LFO’s Amount to 0, set the Mix to 10, Frequency 2.5K

Adjust the input level on both until you are just barely hitting yellow

NOW THE FUN PART!

Gradually turn up the 101’s Amount until you start hearing the Envelope Follower affecting the 102’s frequency. Cool huh?

If you have a MF103, you can also use a similar patch for envelope controlled phasing.

Here’s another neat thing you can do with a 101 and 102. Remember what I said about the 101 being two modules in one box? So is the 102 - it is an LFO and a ring mod. You can turn the 101’s Amount to 0 and Mix to 10, and patch the 102’s LFO output to the 101’s Frequncy input for untracked filter sweeps. Or combine the envelope follower with 102’s LFO for filter sweeps modulated by your note attacks.

And you can really see where this kind of a set up can benefit from a CP-251! You can do some incredibly far out stuff with just these three modules and applications of the Sample/Hold.

9

Actually the MF-101 doesn’t even have to be on to use the Env. Out feature and neather does the MF-102 to use it’s LFO out.

I’ve always thought of tracking as the pedal is tracking the note that being played. For example, the Boss OC-2 octave pedal, it needs to track what note is being played so it can play the lower octave of that note. The better the tracking is the more consistantly you’ll hear the lower octave.

10

True, the MF101 and 102 need to be on (powered up) but can be in bypass with the envelope follwer and lfo still functioning.

Tracking does usually refer to pitch+amplitude rather than either alone.

But I think that tracking is a good term for what an envelope follower does because it is continuously correlating one range of energy (loudenss) to another (control voltage) to drive a function, rather than either being passive (like an ordinary filter or modulation effect). A more limited version of this is a trigger/gate situation. A more complex would be guitar synth, where trigger, pitch, and volume are tracked.

11

Hello,

In regards to the MF-102 Ring Mod, it is true that the output wave remains the same unless you physically change the controls however, there is a workaround for this.
If you happen to have a pitch shifter pedal, you’ll notice they often have a direct (dry) out and an output for the pitch-shifted signal.
By connecting these to the carrier and audio inputs of the MF-102, you can directly control the harmonic spectra of the MF-102 by altering the frequency ratio between the dry and (pedaled) pitch-shifted output.
It also allows you to alter your sound noticeably, without having to reach down to change the MF-102’s settings.
Many tend to only use it for special effects however, ring modulation generates a form of harmonic distortion thats a bit more flexible than the standard crunch box.

regards,


LWG

12

I’ll definately have to try the patch s16016wb listed when I eventually get the MF-102. I was trying to imagine what the MF-102/101 do for eachother, or how they can control one another, but this sounds like just one answer. I’m guessing the MF-102 would deliver higher frequencies while the MF-101 would brighten the lower. I’m going to have to order a EP-2 as soon as I can to control it from my foot…