Author Topic: New MXR Distortion+ VST  (Read 6758 times)

CynicalMan

New MXR Distortion+ VST
« on: April 17, 2011, 07:51:21 PM »


I've been looking into VSTs recently as a way to emulate analog stompboxes. I'm actually a bit disappointed by how few effect emulations there are,
especially with free VSTs. So, I pulled out an old copy of SynthEdit (from back when the free version allowed your VSTs to have backgrounds), and
I've made an emulation of the MXR Distortion+. It took a bit of research, especially for emulating the diode clippers. Most diode models are
iterative, which would be too time-consuming for a realtime effect. After some experimenting with functions, I ended up using Vout=arctan(6*Vin)/7 to
simulate the whole clipping setup.

Here's the structure of the whole effect:
Input attenuator -> Input HPF -> Pickup simulation LPF -> Op amp gain -> Op amp HPF -> Op amp bandwidth LPF -> Op amp clipper -> Output HPF -> Output LPF -> Output attenuator -> Diode clipping emulation -> Volume

And here's the file:
http://sites.google.com/site/distorque/home/vsts/distortion/Distorque-Dist%2B.zip

The controls:
These two are the original Distortion+ controls:
Output - Controls the output level.
Distortion - Controls the distortion and some of the filtering.
These are controls I've added to emulate other factors in the sound of a physical pedal:
Input Type - 'Pickup' adds a low-pass filter on the input to emulate the interaction between the 1nF cap on the input and a guitar pickup. 'Buffered' removes this filter.
Input level - This is a linear volume control on the input of the effect. At maximum, the pedal acts as if 0dB = 2VP. This goes all the way down to no input.


I don't own a Distortion+ but I've compared the VST to a LTSpice sim of a D+. Here are the results:
http://sites.google.com/site/distorque/home/vsts/distortion/Distortion%2Bcomparison.mp3
And this is the file put through an amp sim (Voxengo Boogex)
https://sites.google.com/site/distorque/home/vsts/distortion/Distortion%2Bcomparisonamped.mp3
The VST is first, the sim is second. Personally, I can't tell the difference, but maybe someone with better ears can tell me what differences they hear.


This VST isn't finished, but I'm looking for people to test this out and give feedback on it. I'm planning to improve, if necessary, the op amp clipping emulation, the diode clipping emulation, the 'Pickup' setting, the CPU usage, and the GUI, but I'd like other suggestions. Also, I'd like someone to compare this to a real MXR D+ and tell me how it sounds in comparison.

So, what do you guys think?

CynicalMan

Re: New MXR Distortion+ VST
« Reply #1 on: April 20, 2011, 03:04:08 PM »
Anyone?
I'm planning to post this on KVR but I figured I have a better chance of finding someone here who can compare this plugin to a real Distortion+.

Ice-9

Re: New MXR Distortion+ VST
« Reply #2 on: April 20, 2011, 03:34:37 PM »
Excellent work on the VST plugin, I can't really hear much difference between the two sound samples. I wish I hadn't sold my old distortion+ now , then I could of made a direct comparison.
www.stanleyfx.co.uk

It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

slacker

Re: New MXR Distortion+ VST
« Reply #3 on: April 20, 2011, 03:38:50 PM »
That's pretty cool, I'd say the clips sound like they're in the right ball park. What setting is the virtual gain pot at? It sounds like quite a low gain setting, I'd say cranked a Distortion + is a lot dirtier than that as there's a lot of opamp clipping happening before the signal even gets to the diodes.  

CynicalMan

Re: New MXR Distortion+ VST
« Reply #4 on: April 20, 2011, 04:41:34 PM »
Thanks guys!
The gain pot is at halfway (75k), but the input level control is also set halfway. That means that 0dB equals 1V. So, the clean guitar input was at around 0.6-0.8V at peaks and 0.1-0.3V after. Also, I've made a couple of adjustments to the plugin and to the simulation that increase the distortion slightly.
« Last Edit: April 20, 2011, 04:43:35 PM by CynicalMan »

thedefog

Re: New MXR Distortion+ VST
« Reply #5 on: May 03, 2011, 12:39:40 PM »
Hey there,

I just went to check it out, but the link is dead. I'd love to make some A/B comparisons for you.

CynicalMan

Re: New MXR Distortion+ VST
« Reply #6 on: May 03, 2011, 03:27:19 PM »
The main page for the plugin is here:
http://sites.google.com/site/distorque/home/vsts/distortion

The download link is here:
goo.gl/D30Rw


I'd like to hear any comments you have in general, but one of the issues I'm specifically looking at is where the default Input Level control should be set. At what setting do you think it mimics the real D+ the best?

thedefog

Re: New MXR Distortion+ VST
« Reply #7 on: May 04, 2011, 01:14:04 PM »
The main page for the plugin is here:
http://sites.google.com/site/distorque/home/vsts/distortion

The download link is here:
goo.gl/D30Rw


I'd like to hear any comments you have in general, but one of the issues I'm specifically looking at is where the default Input Level control should be set. At what setting do you think it mimics the real D+ the best?

Cool, I'll check it out and compare tonight.