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I'm building an SP-1200 clone with a few extra features Drum Machines & Samplers
Old 16th January 2019
  #1
Gear Head
I'm building an SP-1200 clone with a few extra features



I'm an SP-1200 user and a software engineer with a small bit of knowledge in electronics. I have started working on a replica of the SP based on an Arduino & Raspberry Pi.

Basically the same appearance, same layout, same user interface, same features but all with some nice modern touches and extra bells and whistles.
As as far as the sound goes, I have already reverse engineered the SP's pitch shifting algorithm which is by far the main contributing factor to the crunchy sound everyone recognizes as the SP. I've actually posted a blindtest between my emulation and the real thing in the facebook SP12/1200 user group and most people got it wrong.
Here are some famous samples and breaks I ran through my emulation: Uploadfiles.io - SP-algorithm-test.zip

I am currently working with an established eurorack modules manufacturer for the PCB design and analog circuitry, which will include the updated SSI2144 filter (made by Dave Rossum as a better version of the SSM2044), the same TL084 channel output op-amps, and analog input filtering modeled after the real thing.

However a gold part of the motivation behind this project is the workflow and ease of use which is one of my favourite things about the SP (if you're comparing the volca sample workflow to the SP's, you've obviously never used one).

Some of the updates to the original design I have planned are:
  • A more compact layout
  • Portable, with the option to either run on battery or plugged into the wall
  • Some effects (reverb, delay, compression, etc...) assignable to individual sounds
  • Access to external usb storage in addition to the internal storage which is an SD card
  • Sounds stored in wav, so you can just copy/paste to and from a computer
  • Variable bit-depth from 12 to 1bit, on a per-pad basis
  • Wireless transfer of sounds to/from a phone or pc
  • The ability to both tune AND decay a sound (one of my pet peeves with the SP haha)
  • Access to a lot more sample time if you want to, but also the option to keep the same 10s & 2.5s limitations
  • And a lot more...

I have made some good progress so far just about a week into the project, here's a video of the prototype in action.
You can see more and follow the development on my instagram @Low_Hiss



Currently working features (will try to keep this up to date):
  • The 4 banks of 8 pads wired and working, playing sounds and able to be cycled through
  • 8 pots wired and able to control volume or pitch of the individual sounds from all 4 banks
  • Overall volume knob
  • Multi-pitch mode
  • Multi level mode
  • Channel assign
  • Truncating samples
  • Basic 24ppq sequencer & quantizing
  • Overall user interface for all the menus, using a 16x2 LCD screen (may switch to a 20x4 to be able to display more info)
  • Reverse engineered pitch-shifting algorithm

Let me know what you guys think, does it make sense as a project in today's market? What would you like to see on an SP clone? Any feedback is welcome.



Old 17th January 2019
  #2
Lives for gear
 

This is really cool!

The SP is great due to three key properties:

Sound:
It adds a certain punch/kick to drum and bass samples. The aliasing produced by the transpose function has a certain classic sparkle that works very well on many sounds. Personally I don't use the dynamic lowpass filters much, but many people seem to like those.

Sequencer:
The sequencer (especially with double time) has a certain groove that's very musical for a variety of styles.

Interface:
Unlike many other simliar products, the SP is easy and fun to use, thanks to its transparent and intuitive layout.


So these are the main features I would look for in any clone/emulation. The sequencer is probably the hardest. The schematics are straight forward and there isn't anything unobtainable used on sampling/reproduction side of things.
Old 18th January 2019
  #3
Lives for gear
 
parkay909's Avatar
Wow, that impressive. You should consider at least emulating the A/D and filter with DSP. A huge portion of the sound was the low resolution ADDA aliasing and granulation noise...
Old 18th January 2019
  #4
Lives for gear
 
xanax's Avatar
Very cool indeed! Long-time SP user here..

A lot of people have been waiting for an SP clone. People on the EDM section have sort of been petitioning for Behringer to make one

As a kickstarter or something I think if done correctly it could really blow up.

To me The workflow, UI & sequencer are the most important.

The sound probably won't be that easy to emulate, this guy seemed to have nailed thanks to the orginal service manual as a starting point:
Emu SP12 and SP1200 Software Model

Sadly his project was never released.

I'd be fine with 12-bit 26khz & 16-bit 44khz options. Again the sound is a little bit secondary to me but of course if the OG sound can be nailed than all the better!

As for the UI, the faders are IMO a big part of the workflow I find, much better/fun than knobs for mixing, tuning, truncating etc.

That said I understand for the sake of compactness & streamlining that knobs may be an easier solution. Perhaps the various levels could still be represented vertically on the LCD when knobs are turned?

The sequencer, with the infamous SP swing/slop is another crucial thing to get right. A lot has been debated about this and i seem to remember the bottom line was 24PPQ resolution with some steady fixed-jitter (the exact numbers were discussed in an old thread here). Or maybe the SP1200 Ableton Groove Template could be reversed engineered as a starting point. It sounds fairly close to my ears.
Old 18th January 2019
  #5
Lives for gear
 

Nobody has nailed the sound so far. Maybe the transpose algorithm and its artifacts, but not the converter/analog part. For me that part was a major reason to get another SP and consider it really important. The lossy power supply might have something to do with it as well. Luckily, identical components or adaquaete substitutes for everything should be availible.
Old 18th January 2019
  #6
Gear Head
Don't get me wrong I'll try to model the sound as best I can, and I'm actually looking into using the original AD/DA, the reissued SSM2044 (SSI2144) filter and the original channel output stages. But I know for a fact I won't be able to completely capture the sound and character of the SP, so I'm not trying to get people's hopes up on that.

It's basically something I'll only really get around to once my prototype is complete (ie most/all the menus and functions of the SP are emulated).
Old 18th January 2019
  #7
Gear Head
@xanax about the Sequencer, I do agree and it's something I'll try to carefully model. Dave Rossum said in the interview about the SP on youtube that jitter is about 2ms. The swing is an important part too, I will record my own templates and make sure my sequencer matches.

I have laid down the foundations of the code for the 24ppq sequencer and quantizing, posted a vid on instagram
Old 18th January 2019
  #8
Deleted ac1715a
Guest


Sound and work flow, in that order, are what make the classic units so great. Nail those aspects and youre golden!
Old 19th January 2019
  #9
Gear Maniac
FINALLY YES !!!!
I had an SP1200 for years and what I loved most about it was the sequencer nothing else like it in my opinion. While I also loved the sound,sequencer was the most important thing to me.
I will be following closely
Old 19th January 2019
  #10
Lives for gear
 
Patrick_'s Avatar
Nice. I’m willing to invest to see this materialize.
Old 19th January 2019
  #11
mp3
Lives for gear
 

There’s a modern version of the SSM2044 chip found in the original SP series available. It’s called the SSI2144 and if you put eight of them in this box I’ll buy two.

And if you put them in the box then the guy who actually gave us the original SP will get his cut. That would be poetic justice!
Old 19th January 2019
  #12
Lives for gear
 

Do it as a DIY kit, keep the cost as low as possible, doing all this effort on something very niche has to be done with care for your own sanity, you have the possibility of Behringer doing the exact same thing, plus the problem that while the SP market seems huge because of idiots asking silly money, it really isn't as big as SP fans think.
As a fairly cheap easy kit build this has huge potential, as an expensive boutique pre built, this will struggle at best.
Old 4 weeks ago
  #13
Gear Head
Low Hiss on Instagram: “Which bank is the SP and which bank is my copy of its tuning algorithm? Go! I've been busy copying the exact way the SP pitches samples up…”

Which bank is the SP and which bank is my copy of its tuning algorithm? Go! (see the link above)

I've been busy copying the exact way the SP pitches samples up and down, as laid out very precisely and technically in the service manual.
I took a famous sample, pitched it down 8 steps in the SP and recorded each step. I took the same sample, and put it on multipitch mode on my SP-clone.

Can you tell which is the SP and which is my copy? Is the SP the green bank or the yellow bank?

Tomorrow I will post the end of the video where I reveal which is which (it's written on these 2 pieces of cardboard that are face down).
Old 4 weeks ago
  #14
Lives for gear
 

Quote:
Originally Posted by Low Hiss View Post
Low Hiss on Instagram: “Which bank is the SP and which bank is my copy of its tuning algorithm? Go! I've been busy copying the exact way the SP pitches samples up…”

Which bank is the SP and which bank is my copy of its tuning algorithm? Go! (see the link above)

I've been busy copying the exact way the SP pitches samples up and down, as laid out very precisely and technically in the service manual.
I took a famous sample, pitched it down 8 steps in the SP and recorded each step. I took the same sample, and put it on multipitch mode on my SP-clone.

Can you tell which is the SP and which is my copy? Is the SP the green bank or the yellow bank?

Tomorrow I will post the end of the video where I reveal which is which (it's written on these 2 pieces of cardboard that are face down).
Both sound good, but one has less high end. The SP has an analog low pass filter on every channel, so my guess would be the one with less high end is the SP.
Old 4 weeks ago
  #15
Gear Addict
I like the one with the more aliasing more But since its recorded over speaker -> microphone and compressed into mp4 I cannot tell which is the SP.
However, this project looks very impressive and I like the idea from above to release it as a DIY kit. Just like those old Dr.Böhm organs :o)
Nuff respect

peace
Old 4 weeks ago
  #16
mp3
Lives for gear
 

Quote:
Originally Posted by living sounds View Post
Both sound good, but one has less high end. The SP has an analog low pass filter on every channel, so my guess would be the one with less high end is the SP.
There are only six LPFs in the SP. And there are 8 outputs. Outs 7/8 are unfiltered.

On that note, I hope you don’t stick to the original design there. Eight filters with full control over cutoff/resonance please!
Old 4 weeks ago
  #17
Gear Head
 

Oh yeah an SD option would be dope it can be floppy emulator I'd be cool with it.
Old 4 weeks ago
  #18
Gear Nut
 

awesome!

isn't behringer working on this as well?
a while back they anounced a bunch of clones.
Old 4 weeks ago
  #19
Lives for gear
 
the fxs's Avatar
 

cool project!

EDIT: just listened to your quick test video...
you're definitely on to something here, keep up the good work!

Last edited by the fxs; 4 weeks ago at 12:55 PM..
Old 4 weeks ago
  #20
Lives for gear
 

Quote:
Originally Posted by mp3 View Post
There are only six LPFs in the SP. And there are 8 outputs. Outs 7/8 are unfiltered.

On that note, I hope you don’t stick to the original design there. Eight filters with full control over cutoff/resonance please!
There's a passive lowpass filter (cap to ground) on every channel. Probably above audio band though.
Old 4 weeks ago
  #21
Lives for gear
 
akai612's Avatar
 

If its about an "easy straight forward" workflow one could get a Volca Sample for 100.-- Euros which also has kind of a good vintage sound and a great "knock" to.

The Elektron Model Sampler is likely going to be a killer....first demos sound awesome. Also they did take care about the workflow thing...as far as I read...

Thus, the really interesting thing at this point would be the re-creation of the sound of the SP.

Someone else managed to reverse ingeneer the Tr-909 and called it Nava...he nailed it pretty fantastic...
Old 4 weeks ago
  #22
Lives for gear
 

He didn't reverse engineer the 909, he just remade it using the original circuit designs, this is a lot more work.
Old 4 weeks ago
  #23
Gear Head
I took a few famous breaks and samples and ran them through my SP emulation, here are the results in wav: Uploadfiles.io - SP-algorithm-test.zip

In each folder you'll find:
- The original unprocessed sample
- The original sample sped-up to 45rpm +16%
- A folder containg 8 steps of the unprocessed sample pitched down using my algorithm
- A folder containing 8 steps of the sped-up sample pitched down using my algorithm (so that the 8th one is the same pitch as the original sample, but with the SP aliasing)

Let me know what y'all think. Keep in mind this is only emulating the tuning algorithm and 12bit depth of the SP, there's still quite a few things I can do to make it sound even closer.
Old 4 weeks ago
  #24
Lives for gear
 
xanax's Avatar
impressive work! aliasing sounds pretty damn close!

+1 on full filter controls (especially if SSMs get put in there!) so you could do this type of stuff:

Old 4 weeks ago
  #25
Gear Nut
 

samples sound close yes!
Old 4 weeks ago
  #26
mp3
Lives for gear
 

Indeed they do sound close. Wow. Get your kickstarter going already...

Old 4 weeks ago
  #27
mp3
Lives for gear
 

And another suggestion for those filters. Since the SSI2144 also has a VCA, a programmable amp envelope would be just awesome!

Hell, while you’re at it, a filter envelope would be great too! And a couple of LFOs for filter, amp, and pitch perhaps? I know that would make it a bit more than an emulation, but those are the reasons I’m not drawn back to the OG SP even after cutting my teeth on it back in the early 90’s.
Old 3 weeks ago
  #28
Lives for gear
 
Cornish1999's Avatar
This is amazing work OP. Cash waiting lol, keep the updates flowing
Old 3 weeks ago
  #29
Lives for gear
 

Hi Low Hiss

Congratulation for your SP1200 project. As it is, it already starts to sound promising. The files sound nice. Please also implement the original analog and AD/DA circuits. Parts are still available.

Any chance you will have PCBs for sale for us (or make your project open source) ?
I would really love to build a modern version of the SP1200

Good luck with your project and keep us informed how things are evolving.
Keep up the good work

chris
Old 3 weeks ago
  #30
Gear Addict
 

Cash in hand for a DIY kit, where do I send payment.
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