Alias Free Oscillators

Many synthesizers are advertised as alias free.

If you place a spectrum analyzer on the plugin track it reveals a frequency profile which gradually tapers off into the upper frequencies. This is proof that your synth is using aliased waveforms and internally filtering the oscillator.

For an oscillator to be called alias free it must be created from component partials or sin waves so that the frequency content is controlled before it is filtered.

Filtering should be your choice, not built into your oscillators.

Shown above is an unedited screen capture of the Fathom Saw Tooth at 32 partials in the frequency domain. Our saw tooth has a high frequency noise floor of less than -144 dB. or less than a factor of 0.0000001 in relation to the amplitude.

We achieve this by constructing our waveforms from partials and additionally using massive buffers of 16384 samples for each oscillator single cycle, along with run-time table extrapolation between points. This is also true for the waveforms you create yourself.

In addition, you can control the number of partials as well as modulate it.

No Clicking

Clicking results from starting a waveform in mid-cycle which creates an abrupt change in amplitude from one sample to the next. Many software synth’s have the clicking problem because they do not take steps to avoid it. Clicking also happens when any modulation which effects the waveform passes through the vertical edge of an envelope while the oscillator is in mid-cycle.

Fathom contains real time logic which virtually eliminates clicking and enforces perfectly smooth oscillator note transitions and modulations.

Even with oscillator voices detuned, the processor keeps track of the relative phase of each oscillator, and at the start of each note plays each oscillator virtually with no volume for a few microseconds until the beginning of its waveform. In this way all voices maintain their relative phase but never start in the middle of a waveform.

Smooth Note Transitions


Shown above is a screen capture of a Fathom note transition with a single oscillator sin wave and detune set to one voice in free running mode. If a sequencer note stops and a new one starts at the same point in the host sequence, Fathom will make the frequency transition in mid-cycle, emulating a single oscillator hardware synth, even when running in polyphonic mode. 


Above is a Fathom note transition, single oscillator sin wave, with detune set to eight voices in retrigger mode. All voices finish their cycle in the terminating note and start at the beginning of their cycle in the new note.


Single oscillator sin wave, detune 8 voices, free running mode, polyphonic.


Single oscillator sin wave, detune 8 voices, free running mode, monophonic with gilde.