Okay, I hear this question a lot.
A VST pretty much makes simple sounds and changes them with effects and modulation.We all know that. All VSTs do this in one way, shape, or form. However some have different interfaces and workflows to others.
However most VSTs can do the same things. At the same time, and due to their different interfaces, all these different VSTs can also make slightly different sounds that others can't.
For an example of the former, let's use two popular VSTs - Native Instruments'sMassive and FL Studio's built in tool3xOsc. Both are triple-oscillator synths with changeable waveforms.
Making, say, a very simple jungle reese bassline is accomplishable in both synths.Take two/three saws, detune two/one of them. Done.
We could go one step further and add a lowpass filter and EQ up the low end to help it sit in the bass register better. Massive can do this with built-in filters and a simple EQ. With 3xOsc, however, we may need to end up using external filters. There's no problem with that; personally I like using external effects in comparo to internal ones! But that's just me, and that's why I'd prefer to make a reese in 3xOsc than Massive.
Now for an example of the latter; both Massive and 3xOsc can all make simple sounds with three oscillators and simple on-board envelope control. But with the help of it's unique brand of inbuilt automation, one person could create and sequence a simple synthesised drum beat in the one VST, whereas the same thing would not be as possible in 3xOsc by default.
And how about the classic and infamous Modern Talking bass? 3xOsc could never really accomplish this, as it can't play the Modern Talking waveform (one could sample it, though, into 3xOsc's custom waveform feature. But why do it when you could just use Massive?).
However, both use wavetable synthesis, so are both comparable and can be used for similar things. In fact, I use a lot of 3xOsc and Operator in lieu of Massive and FM8 for my music!
But FM8 does FM synthesis, which makes comparing it to 3xOsc or Massive equal to comparing apples and plums.
So, all VSTs have their features that make them stand out from others, ergo making them better for some forms of music.
Now that we know this, let's define what a "dubstep bass" actually is:
- Usually sitting in the low-mid-range,
- Often has some form of constant and synchronised modulation on one of the parameters - a filter, pwm, the volume, etc.,
- Gritty and distorted,
- Can be repetitive,
- Sometimes has a "vocal"/"vowel" sound in the instrument.
With these criteria we can start to see which synthesisers and what synth methods are suiting dubstep.
FM Synthesisis always good for getting a vocal sound (the classic "bitcrusher"/"yoi-yoi" sound, usually). It uses a lot of modulation-based work for making sounds - tweaking a certain knob can uncover a whole new sound, often. However it usually has a clinically clean sound associated with it, and usually the internal distortion is too clean and soft (this can often be fixed with external distortion effects, like Ohmicide or Fast Dist, however).
Plugins like Native Instruments's FM8 and Ableton's Operator use FM synthesis to create sounds.
Wavetable synthesis relies on using pre-defined waveforms, and therefore some people can tell what synth was used to make a sound (a la Modern Talking and Polysaw synths in Massive - easy to pick out). However most WT synths make up for this by encompassing a lot of on-board effects and filters.
Plugins like Massive, 3xOsc, chipsounds and Dirty Harry use wavetable synthesis to make sounds.
There are other synthesis methods like subtractive, additive, and AM synthesis, which all have their perks and caveats. Look them up for more info.
That said, a lot of the synth work actually lies outside of the synth itself, and in the external effects. So make sure you invest a lot of time into external automation, filters and effects as well as the initial design of the synth!
Personally, I use Operator (FM, built into Ableton),3xOsc (WT, built into FL Studio), Thor (a lot of synth methods, built into Reason) and Vanguard (unsure, VST plugin), with a lot of external effects - usually the ones built into Reason, FL and Ableton. I will say this: a few of my favourite third party plugins areOhmicide for distortion, the CMT Bitcrusher for a lot of effects, and this random zip-file full of various guitar distortion pedal emulations (which really affect the sound a lot).
Really, there's no one "best" dubstep synth. But I hope this info here helps you pick out a good synth to use!