Creating DJ Turntable effects in Blender Game Engine using physics of platter rotation

[Michael Z Freeman]

(LINKS TO YOUTUBE VIDEO)

BlenderArtists thread with blend download: DJ turntable platter physics simulation: Link sound pitch to platter rotation speed ?

Thought I'd tell you folks about this . This was a bit of Eureka moment for me. After becoming very frustrated with a lot of so called "Digital DJ'ing" software I had to rethink. For some reason they throw out a lot of turntablism techniques that took around 50 years to invent ! In every piece of DJ software I have checked there is not way to add speed up's and slow downs as well as other effects that most turntables can produce. Mixxx has a Javascript "break" function. But it's pre scripted, its not dynamic. Ableton is vastly better when it comes to mixing and loops. But it was designed from the bottom up as a live instrument, not a DJ'ing tool. It's fine for that and very good at matching rhythms and so on, but NO dynamic turntable effect. Of course you can use timecoded vinyl but, even if its useful, that always seemed like a "kludge" to me.

So I went back to the drawing board so to speak. I thought what exactly IS IT that produces that sexy, slinky Technics 1200/1210 sound. I've always found it so SMOOTH. You can switch the deck off and a record will come smoothly to a standstill, and it never seems to sound the same. Even switch off, then reverse the platter and get a reverse slow down. Then of course there's all the Hip Hop scratching, not to forget the fine tweaking of mixed/beat matched tracks using pitch control and nudging the platter.

So what is it ?

PHYSICS.

It's the physics of that heavy rotating platter as well as the powerful direct drive motor. So, only recently having obtained a single vinyl DJ deck and having lost Technics years ago in ignominious circumstances (long story) I wanted to do this on the computer. I fire up Blender and start making a prototype in the game engine using the physics (see video linked top of post) and LO ! It works and SOUNDS GOOD.

Think I'm onto something here folks want to help out ?

I'm surprised that no other software has ever done this apart from some obscure reference I found in a physics form to a VB application.

So the current problem is how to allow the sound to reverse when the platter spins back the other way. It involves using audaspace in Python, unless there's a way of using logic bricks which I don't think there is. I also hope audaspace can access the sound actuator as I'm trying to keep it all to python modules and logic bricks. I think that is easier to understand and find one huge python script off putting.

[gimmeapill]

Interesting approach.
I'm not particularly interested or able to help, but I remember a few years ago, one of the long time Mixxx devs, DJ Pegasus (https://github.com/Pegasus-RPG) spent a lot of hours trying to understand the physics behind scratching, with relative success.
Instead of reinventing the wheel (sorry for the pun ), If you think you've made a big breakthrough, why don't you contact the Mixxx Devs see what they think about it? That could maybe be integrated as an external scratching library or sth like that...

[Michael Z Freeman]

Interesting approach.
I'm not particularly interested or able to help, but I remember a few years ago, one of the long time Mixxx devs, DJ Pegasus (https://github.com/Pegasus-RPG) spent a lot of hours trying to understand the physics behind scratching, with relative success.
Instead of reinventing the wheel (sorry for the pun ), If you think you've made a big breakthrough, why don't you contact the Mixxx Devs see what they think about it? That could maybe be integrated as an external scratching library or sth like that...

Cheers. Yes I remember DJ Pegasus. I'll contact him as he may be interested. I'm not reinventing anything. Well, I actually discovered this approach independently. It's rare but not unheard of. For example I found a project in a Physics forum: DJ Turntable Simulation and Scratching Wavs DJ Turntable Simulation. All the approaches I've seen try and replicate "turntable effects" as a sort of one off reproduction of it in code. But IMO they never worked out the core of WHY those effects sound like they do which is the physics of the rotating platter. This is like the difference between using drum samples in a drum machine verses actually mathematically calculating the vibrations in a drum skin to create a DYNAMIC (different every time) drum sound. Ableton Live has some of this now in its instruments.

[CrocoDuck]

Pretty cool stuff! I will look into if I find the time!

[SyncroScales]

Hello.

I just want to read this right, the dj programs are not scratching properly? Is this the Linux or Production based programs? They are not acting like Serato and Traktor or Virtual Dj do?

Note: You should make sure you copyright your work(s) in this thread, all of you. Get the paperwork done even if this is open-sourced. Should Michael Z Freeman care?

I was looking forward to setting out Mixxx.

Thanks.