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FM-800By Atom Smasher Filter Mod for Korg EX-800 and Poly-800
Samples, Reviews, Technical Comments
atom@smasher.org
| gzipped WAV | MP3 | Notes | |
| Madness #1 <David Mochen> |
mp3 2M |
Original sound played first, no mods involved. Sequencer running fast, arpeggiator-like. Nice unwanted side-effect of having an external pot for white noise, the synth picks up some radio waves which then get processed by the filter (I'm gonna take care of that with a shielded cable but will try to keep the "antenna" as an option). Then I kick Moogslayer in with reso to the max and begin fiddling with cutoff (BTW I used a 100k pot, sound gets more filtered anti-clock wise, also installed the switch for toggling between factory and MS). Instant R2-D2. Then judicious amounts of FM-800 are applied, some joystick... Sequencer off and real-time playing and fiddling. Later I set parameter 84 (VCF mod) to 01 and param 81 (LFO speed) to 00 for a slow, stepped quantized modulation of the filter. Ah, can't stop those knobs from turning!! | |
| Madness #2 <David Mochen> |
mp3 2.0M |
Original first, then moogslayer with 12dB filter slope. Then FM-800... then various keypressings and fiddling with the knobs. | |
| Madness #3 <David Mochen> |
mp3 3.0M |
Original first, then a combination of all effects... | |
| Sweeping Bass <Justin Pope> |
mp3 809K |
Sweeping bass sound tweaked with Moog Slayer and FM-800 modifications. | |
| dtron fm-mod <Randy Dever> |
mp3 1.2M |
Recorded running bare naked into Audacity. First 10 seconds are just to establish a baseline, then I open up the cutoff, then bring up the resonance to make it sing, then I let the FM kick in, open it up pretty much all the way, then get scared and bring it down and play with the joystick a bit, then out. | |
| Poly Loves Hell <Manuel Montoto> |
mp3 659K |
It's the standard sound 27, last two keys pressed (B and C). It starts with resonance pot set to 0%, about 10% of the cutoff knob, and 0% of FM knob. Then, I added about 10% of the FM knob, and then added more on the cutoff knob... | |
| Fm800-Test03 <Manuel Montoto> |
mp3 525K |
Normalized with Sound Forge | |
| Fm800-Test04 <Manuel Montoto> |
mp3 1.1M |
Normalized with Sound Forge | |
| Fm800-Test06 <Manuel Montoto> |
mp3 503K |
Normalized with Sound Forge | |
| Fm800-Test08 <Manuel Montoto> |
mp3 696K |
Normalized with Sound Forge | |
| Noisy SFX Tim Bieniosek |
mp3 596K |
Arcade game sounds (Alesis Micro Limiter) | |
| Hi-Q Filter Tim Bieniosek |
mp3 114K |
(Alesis Micro Limiter) | |
| It Might Be Music Tim Bieniosek |
mp3 521K |
(Alesis Micro Limiter) | |
| Scale Tim Bieniosek |
mp3 134K |
Showing irregularities in the "FM" effect across frequencies (Alesis Micro Limiter) [It may not be good enough for some kinds of music, but it sure sounds good for techno! -atom] |
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From: David Mochen
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From: Justin Pope
Great addition to the Moog Slayer Mod. Makes this synth more versatile. Both mods together make this synth great for deep throaty bass sounds and blippy effects. I've even got a few decent drones out of it too. Needless to say the mods deffiently help bring this synth out of its digital sound. Then once you add some external effects you can make some great fun for industrial/electro. Thanks atom! (oh also thanks for always responding to my stupid questions!) BTW keep bringing on the mods! I should have a pic of my synth with all three knobs soon! |
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From: Randy Dever - devetron
HOLY CRAP!!! Thank you! Just when I thought the poly 800 couldn't get any more lovable, wow. I can't say enough good about it. The Poly 800 can get really dirty now! Lunch is on me next time you are in Minneapolis. I have a sample of some noodling attached to this email. It should be noted that my poly mk1 has the non-slayer cutoff and resonance mod (i'm a puss, I know). I don't have a limiter or anything like that as of yet. [If you don't have a limiter just set the resonance (parameter #42) low enough that it won't self oscillate. That should keep you from causing too much damage. -atom]
R22 with lead attached:
R74 with lead attached: |
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From: Manuel Montoto
Yeeeeeeeeeah!!!
R22 with lead attached:
R74 with lead attached:
Pot with 1K resistor attached:
Map of main PCB and locations of where we need to solder: |
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From: jure zitnik
well i've tried it - it's a really easy mod - and it works very nicely! you basically get an extra knob that determines the level of filter modulation from one of the DCOs. that gives us nice additional timbres and can make the poly800 even more dirty/raspy sounding. taking this further, it can be combined nicely with the moogslayer! if the resonance is set high enough for self-oscillation and filter tracking set to full, you can play with the new setting to get all kinds of wacky sounds! ...not to mention that pressing a few keys at once with both the resonance and the new FM depth setting maxed unleashes a true sonic mayhem! |
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From: Tim Bieniosek
Wow, what nasty sounds! Thank you atom smasher! With the filter in self-oscillation you get real "FM" sounds. Without being able to precisely scale the filter keyboard tracking it's not really playable, but it is great for sfx. With resonance down there is the potential for more musical, playable tones I would describe as grungy, especially with filter cutoff down as well. With cutoff halfway up I could get some tones reminiscent of a cello or a human voice. |
DCO1 feeds the FM, even if the LEVEL setting (parameter 17) is set to 0. This may be useful for detuning DCO2 (parameter 32) to get different sounds.
When MODE (parameter 18) is set to WHOLE (1) the synth operates in 8-voice mode. As the voices rotate through the DCOs four notes will drive the FM effect, then four notes won't. If this is undesirable set MODE (parameter 18) to DOUBLE (2).
When playing notes polyphonically with the FM knob turned up, strange atonal noise may result from different notes modulating the filter at the same time. This may be desirable for some effects, but can be avoided if you use the right scale. Octave intervals seem to avoid this.
Detail of pots and switches (one for Factory/Moogslayer, another one for 12db/24dB). Jack for VCF
audio-in yet to be connected.
FM-800 pot, installation unfinished. Notice how I had to carve the keyboard chassis in order to
make it sit onto the synth's body without coming in contact with the pot. Sacrilege!!!
