Moog Music Forum

so how exactly does an analog sequencer get it's pitch? I've got a copy of Arturia's Moog Modular software and have been trying to figure out how all this crazy patching works. when i open up some of the preset sequences i don't see any patching on the sequencer. i had always assumed that each step on a sequencer had a gate output that went and triggered something else like a vco or something. and although this option is there in the software i don't see any patching on the sequencer. i know that the keyboard is activating the sequencer but how is it getting a pitch?

Arturia is good for learning how patches work i am tired- i hope i don't botch my terminology...

in the same way that the drivers and the keyboard send pitch information in the form of voltage to the oscillator, the sequencer takes incoming CV, modifies it and sends it to a location such as a driver. [in many cases to change pitch by the 1 volt per octave rule...., but can be used in any CV situation for filter cutoffs, etc.]

the drivers and other modules receive this information, in Arturia's program- completely internally. The driver has a digital readout [S1, S2, S3, S4, No] to tell what row from the sequencer to read pitch voltage information from. You can have several drivers reading different rows and groups on the sequencer at once

The second important function of the sequ is sending trigger signal, that is usually wired to an envelope filter. If you look at most of the presets in arturia, MMv2- most of them have an active envelope with the input [lit red] that is paired to seq trigger, or possibly a specific step in the sequencer. This is how you get the attack and the pitch change at the same time.

I like to set patches up where one driver powers pitch on row 1 of the sequencer, and the highpass filter is controlled by the 2nd row [it has sequencer row selection as well] you can create almost endless note manipulation with that... [it is fun having the different rows controlling different functions have different levels of smoothing, the far right control on each row]

any module that reads voltage levels can be controlled

I recently saw posted an idea to get the sequencer effect with out one.....]use the 101 and the control processor], by patching a LFO saw wave a sample and hold.. with saw wave at say 3hz and the sample and hold at 8hz, run into the 101's freq. control - with the resonance turned all the way up.... it takes some tuning, but with the slight misalignment on the sampling and the saw wave- gets you a pattern- but ever changing

the murf triggers envelopes on 8 band pass filters in different patterns, so it is entirely different than the standard sequencer.


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here is a 20 second fun patch with pitch only modulation- that may help you see what in a more controlled environment what the sequencer does...

-saw wave [octave 4'] to VCA 1 [or any combination of bright -high pitched oscillator signals on a driver]

-LFO #1 @3.29 hz- "saw tooth -out" to "sample and hold -in"
-sample and hold at 8.49hz out to FM on driver [with oscil attached] crank the effect amount to .5
take factory bass #1

if you want more fun, with the sound of coming in and out of the phasing...
patch and other LFO [#2] sine wave .1306 hz to the "FM in" on LFO #1 put the effect amount hex nut ] at .0701 or .0681

To put it as simple as possible, an analog sequencer outputs a voltage based on the knob (or slider) position. If you plug the output into a VCO, the VCO changes pitch based on the voltages the sequncer outputs. The clock advances the sequencer from one step to the next.

You can, of course, plug the sequncer output into anything. It could be used to change filter frequency, PWM, volume, etc. that's what makes modular synths so flexible.

I was asking this because i'm also interested in getting a small modular synth from either Modcan or synth.com. I'm just trying to think what other modules would be best to go along with a sequencer. i've already got the 101, 102, 104 and 105 and the cp251.

are the drivers on the arturia basically vca's? i don't think i've ever seen driver modules on modcan or synth.com sites

also, will a sequencer produce pitch and sequence itself? i read that they have an internal osc which controls the speed of the rhythmic steping but does this osc also produce pitch?

oh sorry one more thing. does a gate signal have pitch info? or is it strictly just note on and off?

The internal oscillator is for clocking the seq only. Even if it goes into audio range, you don't have an output signal. The gate is just a signalling device: For instance: it can tell your envelope generator when to fire. If you gate a VCA without an envelope, signal will pass when the gate is on. A gate has no pitch information. It's usally a 5 or 10 volt signal. Kinda like binary, I guess. Off or On.

I have a gate sequencer from Analogue Solutions: 2 rows of on/off gates that are cloked externally. It makes for a great drum sequencer. Sequencers that are clocked at an audio rate can be useful complex waveform oscillators. Lots o' fun!

Try not to think of an analog seq as "just" a pitch sequencer, and you'll come up with a lot of fun and creative uses!

Hope this helps

-andrew bunny

thanks man. it's starting to get clearer. so each step of a sequencer has to send a signal to an envelope generator or filter or something. so lets say there is an empty step. would the sequencer provide a rest in the music or would it skip that step in rhythm?

also still a bit confused on that driver stuff

"I'm just trying to think what other modules would be best to go along with a sequencer."

A frequency/clock divider and a module with logic functions (AND, OR, etc.) make great additions. You can set up more complex rhythms using these.

"The internal oscillator is for clocking the seq only. Even if it goes into audio range, you don't have an output signal."

If you have a clock out on your sequencer, and if the clock goes into the audio range, the clock output is a square or pulse wave. The output of the sequencer is an audible waveform, the shape of which is determined by the levels of each step.

"so each step of a sequencer has to send a signal to an envelope generator or filter or something."

Or you can also send the clock to the EG so it will trigger at every step.

"so lets say there is an empty step. would the sequencer provide a rest in the music or would it skip that step in rhythm?"

If you weren't sending the clock to the EG, but instead the gate out for each step of the sequencer, it would be like a rest (or the previous note will be longer, depends on the EG). In other words, instead of the EG triggering at every step, it would only trigger at the steps that are sending a gate out.