low sawtooth and speech type oscillator synth notes cause sound and tone change

Question

In my current song I created a bass I really like in NI Massive. The only problem is that in my melody, there are a few notes that are REALLY low, c1, c0 range. It also has a decent amount of mid-range tones in this synth.

When the synth is played in this low range, it causes them to get slightly detuned and makes them sound slow. By slow I mean the regular notes have a sort of bite and feeling as if someone were strumming them ridiculously fast (best way I can describe it). When they are played in this low note range the reverberation or super fast strumming effect slows down more and more the lower it gets. Its almost analogous to someone applying and LFO to the bass at a extremely high rate, but this rate gets lower and lower evenly as the pitch goes down.

This is extremely frustrating because when I raise those notes up an octave they sound great but it totally throws off the melody. I wrote a melody that works well with the sound because of this but if possible I would like to use the original.

EDIT: Here is a clip from the song that shows what is happening. The first part has the really low notes and the second part is the revised edition but if you listen carefully you can hear the slight detuning of the notes in that part. The melody matches the theory of my chord structure... so it shouldn't be this off.

EDIT: One last thing in case anybody knows much about Massive. The three oscillators I chose were a sawtooth (I believe sin/saw 1 with the wavetable position all the way on saw), deep throat, and modern talking (not the overused dubstep method). The last two are talking/vocal/formant type oscillators.

Why does it do this and can it be avoided?

Answer 1

By slow I mean the regular notes have a sort of bite and feeling as if someone were strumming them ridiculously fast (best way I can describe it). When they are played in this low note range the reverberation or super fast strumming effect slows down more and more the lower it gets. Its almost analogous to someone applying and LFO to the bass at a extremely high rate, but this rate gets lower and lower evenly as the pitch goes down.

Are you using a sub oscillator, or detuning any of your main oscillators?

It is easy to generate the effect you are talking about by adding a low-frequency saw wave to your oscillators. The saw is low enough that your ears don't perceive its fundamental frequency as sound but you do hear it modulating the upper frequencies.

Try slowly sweeping a high-pass filter from about 50 Hz to 200 Hz to get rid of those very low frequencies.

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I created a patch in massive that replicates the same low-frequency beating that your soundcloud sample demonstrates. I'm using Ableton, so I dropped an EQ Three right after massive, turned GainLow down to -inf. I found that frequencies values between 50 Hz and 100 Hz preserve most of the character of my patch, though the "beating" is reduced near 100 Hz.

You don't need to do this in Ableton or with EQ Three - any DAW and any EQ plugin should do the job.

Answer 2

As ObscureRobot is getting to, your problem is coming from interferences, particularly from frequencies you can't hear. As you play lower, the frequency difference (in Hz) between the octaves (or whatever harmonic you have playing) decreases, and therefore the apparent LFO rate decreases.

For example, An A octave has one note at 220 and another at 440. That's a difference of 220 Hz, which will not be noticed as a "strumming". If you drop to sub-levels, then the differences can much more noticeably be heard as "strumming".

A high-pass filter might work, but the harmonics of the low frequencies might remain. I would try adjusting the gain on the lowest oscillator. See what works, and keeps your bass sounding how you want it too. If the bass starts sounding to weak, without enough bottom, you could try changing to a sine wave for the lowest oscillator. They tend to sound fuller.