Quirk of synthesis that needs explaining

Basically i'm playing around with a bassline at the moment, the sound of which relies on a 2 voice unison. The problem is the sub bass drops out at seemingly random intervals (and i mean random, sometimes it won't do it for absolutely ages). Took me ages to figure out what was causing it, at first i thought it was some kind of pulsewidth issue as both oscs are square wave, but it turns out its the unison.

Can someone explain why its affecting the sub bass in this way? It's annoying as it's the EXACT sound i want, it's perfect apart from the sporadic bass loss.

Broken subwoofer? LOL

Haha, i hadn't actually considered that.

It's almost definitely not that though.

something to do with the phase cancelling somewhere? if you can mix each voice to a seperate channel then try that so you can have a look in a wave editor to see whats up - gives you the means to see each seperately but you can mix them together to find the point where it's going wrong. what are you using for it? (i don't expect you actually can send one to each channel since most vstis cannae do that but if it's modular or something it's an option.)

Yeah phase cancelling is what i thought, but i know so little about it - anyone know of a good site i can learn up on?

yeah it's phase cancellation. it will happen any time you have two things making slightly different sounds. you just notice it more when the bass content of those two things is important. you could get a physics degree, or you could just not use a unison thing to generate your sub bass. Try scooping the subs out of your unison bass sound, and adding a 3rd sub only voice (with its tops equally scooped)

add these two waves together you add the positive parts (the half circle above the line) together and the negative parts (the half circle below the line) together

invert just one of the waves then add them together and they will cancel each other out

have you got adobe audition or cooledit?

make a 50Hz sine wave, then make an other one at the same frequency then click invert which will

change the phase.

you'll be adding the sine wave and the inverted sine wave together, which should give you nothing because they cancel each other out.

ill try explain more later if you dont get it

http://www.kettering.edu/~drussell/Demos/s...erposition.html

  Quote

The animation shows two sinusoidal waves travelling in the same direction. The phase difference between the two waves varies increases with time so that the effects of both constructive and destructive interference may be seen. First of all, notice that the sum wave (in blue) is a travelling wave which moves from left to right. When the two gray waves are in phase the result is large amplitude. When the two gray waves become out of phase the sum wave is zero.

Thanks for the help chunky

I think what im going to do is just record it several times and patch it together, turning off the chorus ruins the sound.

  analogue wings said:

Try scooping the subs out of your unison bass sound, and adding a 3rd sub only voice (with its tops equally scooped)

Good advice, but i've already tried it and i can't seem to get it to sound the same.

FUcking bloody physics, someone should invent some new fundamental laws of science so shit like this doesn't happen.

you don't really want to have chorus or anything similar on low frequencies

some synths have a sub-osc that bypasses effects / unison, i guess for that reason

what 'boo said^

chorus works in a very similar way to phase.

are the oscs all going at the same frequency?

try detuning them

try filtering one slightly

i think the important thing is getting the waves of each one to be different from each other so the top cycle of one wave is not cancelling out the bottom cycle of the other

what synth is it?

it might be fun to make a song based on the weirdness of the bassline cutting out randomly haha :-D

give us a listen when youre done m8