Additive synthesis? Korg Poly-800 & EX-800

Discussions about anything analog, digital, MIDI, synth technology, techniques, theories and more.

Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Sat Mar 18, 2017 12:34 am

Watch on youtube.com


The Korg Poly-800 and EX-800 have very interesting oscillators (DCOs) - they create these cool waveforms called step waves. This allows you to turn on/off harmonics at different feet intervals. The video explains how.

Is this additive synthesis?
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby Baus » Sat Mar 18, 2017 12:47 am

I think Additive Synthesis is based on adding Sine waves to create harmonics.

I have a Suzuki SX-500, which is basically a Siel EX-80, which is almost a copy of the Korg EX-800.
It has the same feature of adding four square waves together to create a harmonically richer sound.
I see it more as the drawbars on an organ that you pull out/push in to create a harmonically different sound.

Robin.
Baus
Junior Member
Junior Member
 
Posts: 195
Joined: Fri Apr 24, 2015 1:56 pm

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Sat Mar 18, 2017 2:12 am

Yeah - that really explains it nicely. I bet the old organs are where they got the idea from too!
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby meatballfulton » Sat Mar 18, 2017 1:10 pm

Technically it's additive but so is detuning oscillators by octaves and fifths on any synth.

The Poly 800 has no sawtooth wave and stacking up multiple squares starts to sound something like a saw but there's not really enough footages available. Even Hammond organs have nine footages (partials). Additive synths like the Kawai K5 and K5000 and the many software additive synths can stack up hundreds of partials and then apply different amplitude envelopes to them which is when additive really gets interesting.
I listened to Hatfield and the North at Rainbow. They were very wonderful and they made my heart a prisoner.
User avatar
meatballfulton
Moderator
Moderator
 
Posts: 5258
Joined: Wed Apr 13, 2005 9:29 pm
Gear: Motif XF6, Evolver, Zero Coast, Cubase 8, Live 9

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby Baus » Mon Mar 20, 2017 11:51 pm

Actually I am working on the Mirage with this.

With Soundprocess it's possible to Harmonically define waveforms by adjusting the levels of the first 10 Harmonics.
The Mirage will then calculate the waveform.

Does the Poly-800 really have no saw wave? The manual states it does...or...at least says that Wave 2 is 'a close approximation of a saw wave'.
Baus
Junior Member
Junior Member
 
Posts: 195
Joined: Fri Apr 24, 2015 1:56 pm

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby mis psiquicios y yo » Tue Mar 21, 2017 2:55 am

meatballfulton wrote:Technically it's additive but so is detuning oscillators by octaves and fifths on any synth.

The Poly 800 has no sawtooth wave and stacking up multiple squares starts to sound something like a saw but there's not really enough footages available. Even Hammond organs have nine footages (partials). Additive synths like the Kawai K5 and K5000 and the many software additive synths can stack up hundreds of partials and then apply different amplitude envelopes to them which is when additive really gets interesting.


The Poly 800 has sawtooth wave. It only has sawtooth and square
Mis Psiquicos y Yo
Toys: Moog Source, E-mu Emax rack, Yamaha DX 7-9-11-100, ensoniq VFX-SD, Korg Microkorg XL, volcas & DotCom modular
User avatar
mis psiquicios y yo
Junior Member
Junior Member
 
Posts: 237
Joined: Fri Jun 10, 2005 6:33 pm
Location: Mexico

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Tue Mar 21, 2017 3:44 am

Baus wrote:Actually I am working on the Mirage with this.

With Soundprocess it's possible to Harmonically define waveforms by adjusting the levels of the first 10 Harmonics.
The Mirage will then calculate the waveform.

Does the Poly-800 really have no saw wave? The manual states it does...or...at least says that Wave 2 is 'a close approximation of a saw wave'.


It isn't a true sawtooth waveform. It uses what they call a "Step Wave" - which is a bunch of harmonically stepped (in level) square waves. My video actually covers this :)
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Tue Mar 21, 2017 3:45 am

mis psiquicios y yo wrote:
meatballfulton wrote:Technically it's additive but so is detuning oscillators by octaves and fifths on any synth.

The Poly 800 has no sawtooth wave and stacking up multiple squares starts to sound something like a saw but there's not really enough footages available. Even Hammond organs have nine footages (partials). Additive synths like the Kawai K5 and K5000 and the many software additive synths can stack up hundreds of partials and then apply different amplitude envelopes to them which is when additive really gets interesting.


The Poly 800 has sawtooth wave. It only has sawtooth and square


No it isn't a true sawtooth waveform - it is a harmonically stepped bundle of square waveforms - using the inverse Walsh theory. Please watch the vid ... it does cover it ;)
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby cornutt » Tue Mar 21, 2017 6:52 pm

It's a very crude version of something called Walsh functions, which are often used in radio signal processing but haven't gotten much use in electronic music. Walsh functions are somewhat analogous to Fourier analysis, but rely on pulse waves (of varying amplitude and duty cycle) to construct waveforms, instead of sine waves. (Walsh functions were discovered by a mathematician named Joe Walsh, not related to Joe Walsh the musician.)

The Poly-800 and EX-800 are very unusual in terms of circuit architecture. They are based on a video game tune chip that was made by Oki Semiconductor. All of the oddities of those synths (such as the lack of a proper triangle wave, and the paraphonic VCF) are due to the properties and limitations of the tune chip.
Switches, knobs, buttons, LEDs, LCD screens, monitors, keys, mice, jacks, sockets. Now two joysticks!
User avatar
cornutt
Moderator
Moderator
 
Posts: 2100
Joined: Sun Dec 02, 2007 6:03 am
Location: Rocket City USA
Gear: 6th

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby cornutt » Tue Mar 21, 2017 6:56 pm

Here's a writeup I did a few years ago:

http://sequence15.blogspot.com/2013/08/ ... works.html
Switches, knobs, buttons, LEDs, LCD screens, monitors, keys, mice, jacks, sockets. Now two joysticks!
User avatar
cornutt
Moderator
Moderator
 
Posts: 2100
Joined: Sun Dec 02, 2007 6:03 am
Location: Rocket City USA
Gear: 6th

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Tue Mar 21, 2017 11:09 pm

cornutt wrote:It's a very crude version of something called Walsh functions, which are often used in radio signal processing but haven't gotten much use in electronic music. Walsh functions are somewhat analogous to Fourier analysis, but rely on pulse waves (of varying amplitude and duty cycle) to construct waveforms, instead of sine waves. (Walsh functions were discovered by a mathematician named Joe Walsh, not related to Joe Walsh the musician.)

The Poly-800 and EX-800 are very unusual in terms of circuit architecture. They are based on a video game tune chip that was made by Oki Semiconductor. All of the oddities of those synths (such as the lack of a proper triangle wave, and the paraphonic VCF) are due to the properties and limitations of the tune chip.


I love that article! Nice to see you are lurking around the boards still. Great work btw!
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby cornutt » Wed Mar 22, 2017 5:56 pm

Thanks! I've actually been around here more again lately. And I need to get Sequence 15 started back up... I've got about 10 articles queued up that I need to finish. :shock:
Switches, knobs, buttons, LEDs, LCD screens, monitors, keys, mice, jacks, sockets. Now two joysticks!
User avatar
cornutt
Moderator
Moderator
 
Posts: 2100
Joined: Sun Dec 02, 2007 6:03 am
Location: Rocket City USA
Gear: 6th

Re: Additive synthesis? Korg Poly-800 & EX-800

Postby ranzee » Thu Mar 23, 2017 12:27 am

cornutt wrote:Thanks! I've actually been around here more again lately. And I need to get Sequence 15 started back up... I've got about 10 articles queued up that I need to finish. :shock:


Nice! If you ever need a hand :)
User avatar
ranzee
Junior Member
Junior Member
 
Posts: 208
Joined: Mon Mar 03, 2014 12:07 pm
Real name: Ranz
Gear: http://www.ranzs.com/gear-list/
Band: ranzee ranz


Return to General Synthesizers

Who is online

Users browsing this forum: Baidu [Spider], Bing [Bot], Google Adsense [Bot] and 4 guests