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im looking to use a vocoder to create a monster/demonic vocal. I have sampled the sound of a roaring fire and im looking to place a vocoder on the track, modulating it with my voice so the vocal articulates the fire sample, much in the same vein as this video : http://www.youtube.com/watch?v=d1Z_Rop_iGk
Now im using Logic and Ableton. I know how to set it up, but im having difficulty minimising the filtered vocoding effect. It sounds like its being played underwater and doesnt sound clean and i was wondering if anyone has any advice?
Remember that vocoders work in the frequency domain. What you are doing is passing one sound through the spectral envelope of another. If you like, think of the carrier spectrum as a sieve which the modulator passes through. If you try to pass a sound which is only low frequency energy through one which is only high frequency energy, then you get nothing. EQ the result can't help because there is nothing there to boost.
Part of the problem is that the sound which you have picked probably does not have many frequencies which match your voice, but also the dominant frequencies in fires are like noise - no strong, continuous partials, and this is adding to the problem.
It's worth playing around with pitch-shifting and equalising both signals so they work together, but probably you need to pick another sound. Have you tried animal type sound like in the video?
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One thing to consider is whether the listener needs to hear fire or needs to THINK that he/she is hearing fire. My suggestion is to build a complexly layered sound that is reminiscent of a roaring blaze (perhaps a sample of a forest fire or a molten steel mill), and add something with a voice-like tone to it as Mark said. Vocode THAT combination. Once that's done, instead of using a vocoder on the crackling flame effect, use a gate and send the voice track into the sidechain of the gate. The end result, with a little TLC, should be a well-vocoded roar with a crackling element that pumps up and down along with the voice.
I second, fire as an impulse in your favourite Convolution Reverb also do this take your voice and run it against zplanes pitch tool and add layers of your voice on different octaves...the logic behind this is you adding more signal to your modulator, thus giving you more control over the carrier sound that provides necessary timbre towards the goal sound...so your carrier sound adds more partials to the over all sound...
Also try using the fire as an impulse in your favourite Convolution Reverb (Space Designer in Logic can do this)... by playing with the Decay, EQ and mix settings you may get closer to what you're looking for.
thanks for the reply. I have tried using animal sounds, now with waves morphoder.Now morphoder appears to be perfect as it offers a mixer section allowing me to bypass the filter and morph the carrier and modifier signal, however the morphoder's sidechain input doesnt seem to act like a traditional sidechain (i.e, the signal for carrier is heard even when modifier isnt playing)
thanks for all the advice, its coming along nicely, i'll post the finished clips when they're done.
One more question. The gating effect is brilliant, but is there a wya of having the flames work as an reverse de esser. I.e they are only audible for sibilant sounds? IS it simply using an eq before the noise gate to cancel out unrelated frequencies?