why won't my synth pulsate damn it

[ross22]

im a new synth user and a new home recording forum user too
anyway i have got a lot of the lfo envelop filter changing stuff down but i don't know how to make my synth pulsate
ie hold down a chord and it pulsates
im pretty sure when i hear it in songs i 1: love it 2: am pretty sure its not delay effects becasue that would require to let go of the keys

so any help would be muchly appreciated

and if this is a dumb question everyone has permission to slap me haha

[altitude909]

Try modulation the VCA with the LFO

[SuperJX]

What synth are you using? Got a song in mind that you're referring to?

There are various "pulsating" sounds. A lot you hear on the radio now are based on arpeggiators, which are basically like re-keying notes repeatedly. Back in the day, you could hold down a chord and the notes would arpeggiate up, down, up and down, or at random. Now there's all sorts of "phrase" stuff that mixes sequencing with old-school arpeggiating.

You could also be hearing 909's mention of VCA modulation with an LFO. Using a sine, tri, or square wave LFO to mod the VCA will vary or chop up the tone, from a tremelo effect all the way to an arpeggiator-like effect.

You can also use LFOs to modulate the pulse width of an oscillator, for another variance on the pulsating theme.

Good luck!

[ross22]

yeh i own a roland rs-70 not bottom of the bottom but not incredibly flash
basically its not a nord lol or an analogue juno or something rad like that

but yeh i don't have a VCA filter
and when i change my LFO Filter and alter the rate and depth it starts to modulate past teh original note?

maybe if i set the arpeggiator to play the same note or just one note a third or fifth higher it could work

all very interesting but very confusing
playing guitar was so much easier lol

[stray411]

A VCA is a voltage controlled amp…so you definitely won’t have that, but you do have an amp…I believe Roland calls it a TVA (time variant amp).

And the LFO is not a filter…it’s a modulation source. It can modulate the filter, amp, pitch and other stuff. If it’s changing the note, you have it modulating pitch. Like 909 suggested, try using it to modulate the amp (TVA).

[altitude909]

To expand on this since you are probably a little lost on the terminalogy:

VCA = Voltage controlled amplifier, this does not necessarily need to be voltage controlled but subtractive syths almost always have an amplifier stage where you can set the level, envelope usually ADSR (ADSR = attack, decay, sustain, release btw), and other amp related things for each note played. A short attack will result in the sound being played as soon as you press the key, a long attack will gradually fade in the note. The reverse is true for release, so a short release will turn off the note immediately when the key is released and a long release will gradually fade the note out

LFO = Low frequency oscillator. Low meaning sub audible range to (sometimes depending on the synth) the audible range. You can usually select the shape of the LFO from square, sine, saw, triangle, or random; again this depends on the synth

Modulation = Using one thing to change or modulate another. In this case you will be using the LFO to modulate the VCA level so it pulsates (use a Sine if available). Set the LFO to a fairly low setting, make sure the the modulation level is turned all the way up and off you go

[TexRoadkill]

Originally Posted by ross22

and when i change my LFO Filter and alter the rate and depth it starts to modulate past teh original note?

You are modulating pitch. I think what you are looking for is to modulate the Amplitude or volume. That will give you a pulsing or throbbing type of sound.

[ross22]

yeh i did some reading last night about the diff types of waves etc

i found a patch already in the synth that pulsates but after goin thru settings i don't know how it does it which doesn't make sense because i should be able to start from nothing with my synth and make the same patch myself so im still working on that one

but the patch is named as a sine patch
im gonna keep reading and see if i can work this out

i'll write out what my real time controls are set out as and i know they aren't on par with a real analogue synth but here they are anyway:

ENVELOPE - ATTACK, DECAY, RELEASE
BALANCE - BALANCE
LFO - RATE, DEPTH
which is altered by pressing another LFO button which when engaged changes pitch with LFO and when NOT engaged changes the filter cutoff frequency with the LFO
then the Filter section - CUTOFF RESONANCE


that probably seems really confusing so im sorry for that
and i don't know if that will allow me to modulate the volume or amplitude
but i'll just have to see

thanx heaps for terminology help 909
u guys have been awesome

[SuperJX]

Just did a quick skim of the RS-70 on the Roland site, and I can see what you mean about limited parameter control. I'm not sure that you can dig into the LFO routing from the front panel of the synth itself, but I'll be that there's a compatible patch editor for your computer somewhere. I think the RS-70 is based on the sample player engine from the current/last generation Roland synths. You might be able to hook it up to a computer and edit the patches you have to add/change the LFO settings. I have a Roland Fantom and it's pretty useful to use the PC editor when you need to dig into the deeper patch structures.

It also looks like you have some onboard insert effects you can use in a patch on the synth, with a couple variations on Tremelo. I'd suggest playing around with the effects section on a patch that's close to what you want.

You might also try posing your question on http://www.rolandclan.info as there's a pretty helpful user group there. Odds are that someone there has an RS-70 and can hook you up with a patch editor or further details.

Good luck!

[ross22]

yeh thanx heaps mate

i did some more playing around i can use the tremelo but the whole thing is its preset and as song tempos aren't always exactly the same if i were to use it in a live situation i would want to be able to edit the speed of the pulse in real time

the manual speaks of limits in modulating the volume in real time
i do have the editor so i will have a look

i've just been curious thats all i hear something in a song and i like to be able to recreate it
looks like the real answer is a proper analogue synth or higher end digital like the phantom which im sure has more real time controls

and i also had a listen back to a track that i was originally refering to and the way they did it was slowing down a pulse which also modulated at the same time to the key of the next song
im pretty sure changing speed modulates pitch sometimes yes?
well at least that is what happens when i use a delay pedal with my guitar and slow down the rate haha

thanx again this is all really interesting and im learning a lot